IONIZING RADIATION
CASRN: NO CAS RN Ionizing radiation may result from unstable atomic nuclei or from high
energy electron transitions. It includes electromagnetic radiation (e.g., gamma
rays and X-rays) as well as particles (e.g., alpha particles, beta particles,
high-speed neutrons, high-speed electrons, high-speed protons, etc.) having
energies greater than 34 ev. Such electromagnetic radiation and particles are
capable of producing charged particles (e.g., ions) that can impact matter,
including tissue, where DNA strand breaks may be produced. This record contains
general toxicological, safety and handling, measurement, and environmental
information on ionizing radiation emitted from chemical sources, whether these
sources are compounds or metals. For information on specific radionuclides,
refer to the appropriate individual records.
Human Health Effects:
Toxicity Summary:
Epidemiological studies of radiation exposure provide a consistent body of
evidence for the carcinogenicity of X-radiation and gamma radiation in humans.
Exposure to X-radiation and gamma radiation is most strongly associated with
leukemia and cancer of the thyroid, breast, and lung; associations have been
reported at absorbed doses of less than 0.2 Gy. The risk of developing these
cancers, however, depends to some extent on age at exposure. Childhood exposure
is mainly responsible for increased leukemia and thyroid-cancer risks, and
reproductive-age exposure for increased breast-cancer risk. In addition, some
evidence suggests that lung-cancer risk may be most strongly related to exposure
later in life. Associations between radiation exposure and cancer of the
salivary glands, stomach, colon, bladder, ovary, central nervous system, and
skin also have been reported, usually at higher doses of radiation (>1Gy).
The first large study of sarcomas (using the U.S. Surveillance, Epidemiology,
and End Results cancer registry) added angiosarcomas to the list of
radiation-induced cancers occurring within the field of radiation at high
therapeutic doses. Two studies, one of workers at a Russian nuclear
bomb and fuel reprocessing plant and another of Japanese atomic-bomb survivors,
suggested that radiation exposure could cause liver cancer at doses above 100
mSv (in the worker population especially with concurrent exposure to
radionuclides). Among the atomic-bomb survivors, the liver-cancer risk increased
linearly with increasing radiation dose. A study of children medically exposed
to radiation (other than for cancer treatment) provided some evidence that
radiation exposure during childhood may increase the incidence of lymphomas and
melanomas. In addition, chronic lymphatic leukemia, Hodgkin's disease (malignant
lymphoma), and cancer of the cervix, prostate, testis, and pancreas are
generally considered not to be associated with radiation exposure. X-radiation
and gamma radiation are clearly carcinogenic in all species of experimental
animals tested (mouse, rat, and monkey for X-radiation and mouse, rat, rabbit,
and dog for gamma radiation). Among these species, radiation-induced tumors have
been observed in about 17 tissues or organs, including those observed in humans
(i.e., leukemia, thyroid gland, breast, and lung). X-radiation and gamma
radiation have been shown to induce a broad spectrum of genetic effects,
including gene mutations, minisatellite mutations (changes in numbers of tandem
repeats of DNA sequences), micronucleus formation (a sign of chromosome damage
or loss), chromosomal aberrations (changes in chromosome structure or number),
ploidy changes (changes in the number of sets of chromosomes), DNA strand
breaks, and chromosomal instability. Neutrons induce similar genetic effects as
X-radiation and gamma radiation. They induce a broad spectrum of genetic damage,
including gene mutations, micronucleus formation, sister chromatid exchange,
chromosomal aberrations, DNA strand breaks, and chromosomal instability.
Although the genetic damage caused by neutron radiation is qualitatively similar
to that caused by X-radiation and gamma radiation, it differs quantitatively. In
general, neutron radiation induces chromosomal aberrations, mutations, and DNA
damage more efficiently than does low-LET radiation; DNA lesions caused by
neutron radiation are more severe and are repaired less efficiently; and neutron
radiation induces higher proportions of complex chromosomal aberrations.
Neutrons are clearly carcinogenic in all species of experimental animals tested,
including mouse, rat, rabbit, dog, and monkey. Among these species,
radiation-induced tumors have been observed in at least 20 tissues or organs,
including those observed in humans (i.e., leukemia, thyroid gland, breast, and
lung).
Evidence for Carcinogenicity:
Evaluation. There is sufficient evidence in humans for the carcinogenicity of
X-radiation and gamma-radiation. There is sufficient evidence in experimental
animals for the carcinogenicity of X-radiation and gamma-radiation. Overall
evaluation. X-radiation and gamma-radiation are carcinogenic to humans (Group
1).
Evaluation. There is inadequate evidence in humans for the carcinogenicity of
neutrons. There is sufficient evidence in experimental animals for the
carcinogenicity of neutrons. Overall evaluation. Neutrons are carcinogenic to
humans (Group 1). In making the overall evaluation, the Working Group took into
consideration the following: When interacting with biological material, fission
neutrons generate protons, and the higher-energy neutrons used in therapy
generate protons and alpha particles. Alpha Particle-emitting radionuclides
(e.g. radon) are known to be human carcinogens. The linear energy transfer of
protons overlaps with that of the lower-energy electrons produced by
gamma-radiation. Neutron interactions also generate gamma-radiation, which is a
human carcinogen. Gross chromosomal aberrations (including rings, dicentrics and
acentric fragments) and numerical chromosomal aberrations are induced in the
lymphocytes of people exposed to neutrons. The spectrum of DNA damage induced by
neutrons is similar to that induced by X-radiation but contains relatively more
of the serious (i.e. less readily repairable) types. Every relevant biological
effect of gamma- or X-radiation that has been examined has been found to be
induced by neutrons. Neutrons are several times more effective than X- and
gamma-radiation in inducing neoplastic cell transformation, mutation in vitro,
germ-cell mutation in vivo, chromosomal aberrations in vivo and in vitro and
cancer in experimental animals.
Internalized radionuclides that emit alpha-particles are carcinogenic to humans
(Group 1). In making this overall evaluation, the Working Group took into
consideration the following: (1) Alpha-Particles emitted by radionuclides,
irrespective of their source, produce the same pattern of secondary ionizations
and the same pattern of localized damage to biological molecules, including DNA.
These effects, observed in vitro, include DNA double-strand breaks, chromosomal
aberrations, gene mutations and cell transformation. (2) All radionuclides that
emit alpha-particles and that have been adequately studied, including radon-222
and its decay products, have been shown to cause cancer in humans and in
experimental animals. (3) Alpha-Particles emitted by radionuclides, irrespective
of their source, have been shown to cause chromosomal aberrations in circulating
lymphocytes and gene mutations in humans in vivo. (4) The evidence from studies
in humans and experimental animals suggests that similar doses to the same
tissues, for example lung cells or bone surfaces, from alpha particles emitted
during the decay of different radionuclides produce the same types of non-neoplastic
effects and cancers.
Internalized radionuclides that emit beta-particles are carcinogenic to humans
(Group 1). In making this overall evaluation, the Working Group took into
consideration the following: (1) Beta-Particles emitted by radionuclides,
irrespective of their source, produce the same pattern of secondary ionizations
and the same pattern of localized damage to biological molecules, including DNA.
These effects, observed in vitro, include DNA double-strand breaks, chromosomal
aberrations, gene mutations and cell transformation. (2) All radionuclides that
emit beta-particles and that have been adequately studied, have been shown to
cause cancer in humans and in experimental animals. This includes hydrogen-3
/tritium/, which produces beta-particles of very low energy, but for which there
is nonetheless sufficient evidence of carcinogenicity in experimental animals.
beta-Particles emitted by radionuclides, irrespective of their source, have been
shown to cause chromosomal aberrations in circulating lymphocytes and gene
mutations in humans in vivo. (3) The evidence from studies in humans and
experimental animals suggests that similar doses to the same tissues, for
example lung cells or bone surfaces, from beta particles emitted during the
decay of different radionuclides produce the same types of non-neoplastic
effects and cancers.
Human Toxicity Excerpts:
/SIGNS AND SYMPTOMS/ /LOCALIZED RADIATION INJURIES/ Deterministic thresholds
/for localized radiation injuries/ exist as follows for certain clinical signs:
(1) 3-Gy (300 rad) threshold for epilation, beginning 14 to 21 days post
accident. (2) 6-Gy (600 rad) threshold for erythema, soon postaccident and
possibly again 14 to 21 days thereafter. (3) 10-15-Gy (1,000 to 1,500 rad)
threshold for dry desquamation of the skin secondary to radiation to the
germinal layer. (4) 20-50-Gy (2,000 to 5,000 rad) threshold for wet desquamation
(partial-thickness injury) at least 2 to 3 weeks postexposure, depending on
dose. (5) For doses significantly greater than 50 Gy (5,000 rad), overt
radionecrosis and ulceration, resulting from endothelial cell damage and
fibrinoid necrosis of the arterioles and venules in the affected area (a
cutaneous syndrome, arising from high-level whole-body along with local injury,
has also been described).
/SIGNS AND SYMPTOMS/ /ACUTE RADIATION SYNDROME/ At doses between 500 and 800
centiGy, the victims will present moderate to severe vomiting, fatigue and
weakness in almost all those exposed. These symptoms will appear quickly, within
the first hour of exposure. Bed rest, electrolyte replacement, antibiotics, and
general supportive care are called for. Deaths will occur in some 50% at the low
end of the range within six weeks. The clinical results will show almost no
lymphocytes after two days. There will be a subsequent severe drop in platelet
and granulocyte counts a few days later.
/SIGNS AND SYMPTOMS/ /ACUTE RADIATION SYNDROME, GI Syndrome/ The
gastrointestinal syndrome occurs from acute whole-body doses of approximately 6
to 20 Gy (600 to 2,000 rad), primarily because of death of intestinal mucosal
stem cells. In this syndrome, there is prompt onset of nausea, vomiting, and
diarrhea. There is a latent period of approximately 1 week and then recurrence
of gastrointestinal symptoms, sepsis, electrolyte imbalance, and ultimately
death.
/SIGNS AND SYMPTOMS/ /ACUTE RADIATION SYNDROME: SKIN/ Radiation accidents that
involve localized irradiation to small parts of the body are much more frequent
than those that result in whole-body radiation. ... Most cases of localized
overexposure are usually compatible with life because of the small volume of
tissue irradiated; however, highly penetrating localized irradiation injury (LRI)
to /vital/ organs ... can lead to death. ...The clinical course of LRI in a
specific case depends upon ... the kind for radiation ... and its penetrating
ability; type of source ...; dose including dose rate characteristics; duration
of exposure ..., distribution within the tissue exposed; part of body and size
of area exposed. ...The visible clinical changes in LRI relate to the skin.
...Massive death of the stem cells of the skin is the basic process underlying
the main clinical manifestations that are seen, particularly dry and moist
desquamation. The threshold doses for these effects are 8 to 12 Gy and 15 to 20
Gy, respectively. Death of skin cells is not the only process responsible ... .
Early and secondary erythema depend on the functional changes in the blood
vessels and the appearance of ulcers may be due to necrosis /or/ injury to blood
vessels and underlying connective tissue elements.
/SIGNS AND SYMPTOMS/ /ACUTE RADIATION SYNDROME/ Cardiovascular & CNS System
Syndrome/ At dose levels greater than 30 Gy (3,000 rad) of whole-body
penetrating radiation, the cardiovascular/central nervous system syndrome occurs
primarily as a result of hypotension and cerebral edema. There is almost
immediate nausea, vomiting, prostration, hypotension, ataxia, and convulsion.
These casualties should receive palliative treatment only because death
invariably occurs within several days. Events that have produced this dose level
are extremely rare, having occurred in only a handful of accident victims
worldwide.
/SIGNS AND SYMPTOMS/ /ACUTE RADIATION SYNDROME: SKIN/ Local radiation injury (LRI)
progresses in a sequence... . The first phase of LRI is initial erythema. Skin
reddening may occur in the first minutes or hours after exposure and is usually
observed for at least 1 to 2 days. ... The latent phase occurs after the initial
erythema. The duration ... is longer as the dose is decreased although this
dependence is ... shorter for skin of the face, neck, and chest, and longer for
palmar surfaces of the hands and feet. ... The latent period ends when the
second (or main) erythema appears. The time of its appearance corresponds to the
renewal of the epidermal cells at about 2 to 3 weeks. ... In many cases the
color of the skin becomes somewhat brown. After 1 to 2 weeks dry desquamation
then develops. This is grade I LRI. If edema occurs, not only of the skin, but
also of subcutaneous tissues, and blisters develop with resultant moist
desquamation, this is characterized as grade II LRI. If secondary erythema ...
is followed by erosions and ulceration, as well as severe pain, this is grade
III in severity. The healing of ulcers formed with this type of injury is very
difficult and takes a long time. ... When the dose of ... highly penetrating
radiation is 800 Gy and higher, there is an early erythema accompanied by
swelling, no latent phase occurs, and a secondary erythema and blisters appear
within day 3 or 5. ...There is substantial pain, and tissues become necrotic
within the first week. In most severe cases, there is early ischemia of tissue;
the tissue turns white and then dark blue or black with substantial pain. This
is a grade IV injury.
/SIGNS AND SYMPTOMS/ /ACUTE RADIATION SYNDROME/ Acute Radiation Syndrome (ARS)
(sometimes known as radiation toxicity or radiation sickness) is an acute
illness caused by irradiation of the entire body (or most of the body) by a high
dose of penetrating radiation in a very short period of time (usually a matter
of minutes). The major cause of this syndrome is depletion of immature
parenchymal stem cells in specific tissues. ...The required conditions for Acute
Radiation Syndrome (ARS) are: (1) The radiation dose must be large (i.e.,
greater than 0.7 Gray (Gy) (70 rads). ... (2) The dose usually must be external
(i.e., the source of radiation is outside of the patient's body). ... (3) The
radiation must be penetrating (i.e., able to reach the internal organs). ... (4)
The entire body (or a significant portion of it) must have received the dose.
... (5) The dose must have been delivered in a short time (usually a matter of
minutes). ... The three classic ARS Syndromes are: (1)Bone marrow syndrome
(sometimes referred to as hematopoietic syndrome): the full syndrome will
usually occur with a dose greater than approximately 0.7 Gy (70 rads) although
mild symptoms may occur as low as 0.3 Gy or 30 rads. The survival rate of
patients with this syndrome decreases with increasing dose. The primary cause of
death is the destruction of the bone marrow, resulting in infection and
hemorrhage. (2) Gastrointestinal (GI) syndrome: the full syndrome will usually
occur with a dose greater than approximately 10 Gy (1,000 rads) although some
symptoms may occur as low as 6 Gy or 600 rads. Children and infants are
especially sensitive. Survival is extremely unlikely with this syndrome.
Destructive and irreparable changes in the GI tract and bone marrow usually
cause infection, dehydration, and electrolyte imbalance. Death usually occurs
within 2 weeks. (3) Cardiovascular (CV)/ Central Nervous System (CNS) syndrome:
the full syndrome will usually occur with a dose greater than approximately 50
Gy (5,000 rads) although some symptoms may occur as low as 20 Gy or 2,000 rads.
Death occurs within 3 days. Death likely is due to collapse of the circulatory
system as well as increased pressure in the confining cranial vault as the
result of increased fluid content caused by edema, vasculitis, and meningitis.
/SIGNS AND SYMPTOMS/ /ACUTE RADIATION SYNDROME/ For doses greater than 800
centiGy (cGy), severe nausea, vomiting, fatigue, weakness, dizziness, and
disorientation will be present. There will be moderate to severe fluid and
electrolyte imbalance with high fever and collapse within the first few minutes
of exposure and lasting until death. At about 1,000 cGy, there will be 100%
fatalities at two to three weeks, even with supportive care. Clinically, the
bone marrow will be totally depleted in two days.
/SIGNS AND SYMPTOMS/ /ACUTE RADIATION SYNDROME/ For doses between 300 and 500
centiGy, there will be transient moderate nausea and vomiting in up to 80% of
the victims. Moderate fatigue and weakness will be common in up to 90% of those
exposed. These symptoms will usually appear rapidly, within two hours. Later
symptoms include bleeding, ulcers, loss of appetite, and diarrhea. After about
two weeks, there may be hair loss. Opportunistic infection will be likely, even
up to five weeks following exposure. Death will range from less than 10% at the
lower end of the range to as many as 50% at the upper end. Clinically, there
will be moderate to severe depression of the lymphocyte count with moderate drop
in platelet an granulocyte counts.
/SIGNS AND SYMPTOMS/ /ACUTE RADIATION SYNDROME/ For doses between 150 and 300
centiGy, there will present transient mild to moderate nausea with vomiting in
up to 70% of the victims. 25% to 60% of those exposed will show mild to moderate
fatigue and weakness. A few deaths may occur, especially at the upper range of
exposure, ranging from 5% to 10% of the victims. Opportunistic infections, with
attendant fever and bleeding, are very possible for the survivors, even as
delayed as much as a month. Symptoms may appear as soon as two hours and last as
long as two days. Bed rest and supportive care should be provided. Antibiotics
should be administered unless otherwise contraindicated. Clinically, if there
are more than 1.7x10+9 lymphocytes per liter at two days after the exposure, it
is unlikely that the individual has received a lethal dose.
/SIGNS AND SYMPTOMS/ /ACUTE RADIATION SYNDROME/ For doses between 0 and 70
centigray (cGy), initial symptoms will be none to slight incidence of transient
headache and nausea with up to 5% of the victims vomiting, especially at the
high end of the range. ... These symptoms, when present, will appear in about
six hours and begin subsiding in about twelve hours. The only clinical
manifestation is a mild depression of lymphocyte counts at the upper range of
the dosage. Patients should receive rest and, possibly, electrolytes.
/SIGNS AND SYMPTOMS/ /ACUTE RADIATION SYNDROME//ARS is a sequence of phased
symptoms.... Prodromal Phase: The prodrome is characterized by the relatively
rapid onset of nausea, vomiting, and malaise. This is a nonspecific clinical
response to acute radiation exposure. An early onset of symptoms in the absence
of associated trauma suggests a large radiation exposure. ... Latent Period:
Following recovery from the prodromal phase, the exposed individual will be
relatively symptom free. The length of this phase varies with the dose. The
latent phase is longest preceding the bone-marrow depression of the
hematopoietic syndrome and may vary between 2 and 6 weeks. The latent period is
somewhat shorter prior to the gastrointestinal syndrome, lasting from a few days
to a week. It is shortest of all preceding the neurovascular syndrome, lasting
only a matter of hours. These times are exceedingly variable and may be modified
by the presence of other disease or injury. ... Manifest Illness: This phase
presents with the clinical symptoms associated with the major organ system
injured (marrow, intestinal, neurovascular). ... Acute Radiation Syndrome
patients who have received doses of radiation between 0.7 and 4 Gy will have
depression of bone-marrow function leading to pancytopenia. Changes within the
peripheral blood profile will occur as early as 24 hours postirradiation.
Lymphocytes will be depressed most rapidly; other leukocytes and thrombocytes
will be depressed somewhat less rapidly. Decreased resistance to infection and
anemia will vary considerably from as early as 10 days to as much as 6 to 8
weeks after exposure. Erythrocytes are least affected due to their useful
lifespan in circulation. The average time of onset of clinical problems of
bleeding and anemia and decreased resistance to infection is 2 to 3 weeks. Even
potentially lethal cases of bone-marrow depression may not occur until 6 weeks
after exposure. The presence of other injuries will increase the severity and
accelerate the time of maximum bone-marrow depression.
/SIGNS AND SYMPTOMS/ /ACUTE RADIATION SYNDROME/ Radiation-Induced Early
Transient Incapacitation: Early transient incapacitation (ETI) is associated
with very high acute doses of radiation. In humans, it has occurred only during
fuel reprocessing accidents. The lower limit is probably 20 to 40 Gy. The latent
period, a return of partial functionality, is very short, varying from several
hours to 1 to 3 days. Subsequently, a deteriorating state of consciousness with
vascular instability and death is typical.
/SIGNS AND SYMPTOMS/ /ACUTE RADIATION SYNDROME/ The four stages of ARS are: (1)
Prodromal stage (N-V-D stage): The classic symptoms for this stage are nausea,
vomiting, as well as anorexia and possibly diarrhea (depending on dose), which
occur from minutes to days following exposure. The symptoms may last
(episodically) for minutes up to several days. (2) Latent stage: In this stage,
the patient looks and feels generally healthy for a few hours or even up to a
few weeks. (3) Manifest illness stage: In this stage, the symptoms depend on the
specific syndrome and last from hours up to several months. (4) Recovery or
death: Most patients who do not recover will die within several months of
exposure. The recovery process lasts from several weeks up to two years.
/SIGNS AND SYMPTOMS/ /SKIN/ The signs and symptoms of /cutaneous radiation
injury/ CRI are as follows: Intensely painful burn-like skin injuries (including
itching, tingling, erythema, or edema) without a history of exposure to heat or
caustic chemicals (Note: Erythema will not be seen for hours to days following
exposure, and its appearance is cyclic); epilation; a tendency to bleed,
possible signs and symptoms of acute radiation syndrome. ? local injuries to the
skin from acute radiation exposure evolve slowly over time, and symptoms may not
manifest for days to weeks after exposure.
/SIGNS AND SYMPTOMS/ /ACUTE RADIATION SYNDROME, Transient Psychological
Incapacitation/ At doses beginning at about 100 centaGy (cGy), depending upon
the rate at which the dose is received, a condition known as transient
psychological incapacitation may appear. In this condition, higher levels of
brain activity (e.g., reasoning, detailed study) may be diminished. Lower-level
functions, like breathing or rote activities, are not as affected. This is
important in a combat situation in which nuclear
weapons are used. Soldiers, but more especially pilots, might find themselves
unable to make critical decisions involving intense thought. They might still be
able to fly the aircraft, but be unable to calculate the exact time to release a
bomb or missile. Studies are continuing into these radiation effects, and much
of the data are classified.
/SIGNS AND SYMPTOMS/ /SKIN/Cutaneous Radiation Syndrome (CRS):The concept of CRS
was introduced in recent years to describe the complex pathological syndrome
that results from acute radiation exposure to the skin. Acute Radiation Syndrome
(ARS) usually will be accompanied by some skin damage. It is also possible to
receive a damaging dose to the skin without symptoms of ARS, especially with
acute exposures to beta radiation or X-rays. Sometimes this occurs when
radioactive materials contaminate a patient's skin or clothes. When the basal
cell layer of the skin is damaged by radiation, inflammation, erythema, and dry
or moist desquamation can occur. Also, hair follicles may be damaged, causing
epilation. Within a few hours after irradiation, a transient and inconsistent
erythema (associated with itching) can occur. Then, a latent phase may occur and
last from a few days up to several weeks, when intense reddening, blistering,
and ulceration of the irradiated site are visible. In most cases, healing occurs
by regenerative means; however, very large skin doses can cause permanent hair
loss, damaged sebaceous and sweat glands, atrophy, fibrosis, decreased or
increased skin pigmentation, and ulceration or necrosis of the exposed tissue.
/SIGNS AND SYMPTOMS/ /ACUTE RADIATION SYNDROME, Hematopoietic Syndrome/ The
hematopoietic syndrome occurs from acute whole-body doses of approximately 2 to
10 Gy (200 to 1,000 rad) as a result of bone marrow depression. After prodromal
symptoms, there is a latent period of 2 to 3 weeks during which the patient may
feel well. During this time, arrangements for medical care at an appropriate
center should be coordinated. Lymphocyte depression can occur within 48 hours
and is a useful indicator of dose. Maximal bone marrow depression with
leukopenia and thrombocytopenia occurs several weeks after exposure; hemorrhage
and infection can be major clinical problems.
/SIGNS AND SYMPTOMS/ /ACUTE RADIATION SYNDROME/ Early Effects of Ionizing
Radiation in Humans. Nonlife-threatening effects include temporary or permanent
sterility, depression of rapidly proliferating cell types (e.g., bone marrow
stem cells), vomiting, skin reddening, hair loss, and cataracts. ...
/CASE REPORTS/ /EYES/ At least 17 of the /Chernobyl/ survivors who developed
acute radiation sickness have developed radiation cataracts. All of these
patients (excluding one) had gamma radiation doses over 2 Gy. The cataracts
formed 3 to 8 years postexposure.
/CASE REPORTS/ /CENTRAL NERVOUS SYSTEM, OTHER LOCAL EFFECTS/ An accident
occurred with the Alycon II radiotherapy unit at San Juan de Dios Hospital in
San Jose, Costa Rica /from August 24 to September 27, 1996. ... As a result the
dose rate was underestimated by a factor of 1.66. ... In the course of this
accident, 114 patients were treated. In July 1997, the medical team examined 70
of the 73 surviving patients, and in October 1998, the same team examined 51 of
the surviving patients. There were five general categories of effects as
follows: 1. Nervous system: Brain: Atrophy, necrosis, decreased cognitive
function, headaches, mood alteration, seizures, decreased intellectual function.
Spinal cord: Paralysis, quadriplegia, paraplegia. 2. Skin: Fibrosis, atrophy,
contraction, induration, edema, pigmentation, puritis, hypersensitivity, pain.
3. Lower gastrointestinal: Chronic or bloody diarrhea, bowel stenosis,
stricture, fibrosis, obstruction, fistula perforation. 4. Bladder: Dysuria,
hematuria, contracture, incontinence. 5. Vascular and lymphatic: Stenosis and
premature atherosclerosis. The team also reviewed the available autopsy and
histological data on patients who had died. ... Autopsy data were available on
41 of 61 patients (67%) who had died. ... The 17 patients for whom there were
sufficient data to think that they died from radiation-related injuries can be
divided into three general categories, as follows: 1. Central nervous system:
Brain necrosis and complications of quadriplegia. 2. Neck and upper mediastinal:
Pharynx, tracheal, and bronchial necrosis, tracheoesophageal fistula. 3. Lower
gastrointestinal: Colitis, hemorrhage, obstruction, fistula, perforation,
peritonitis. During the course of the accident, there were 125 different
anatomical sites treated /head, neck, spine, chest or shoulder, abdomen, pelvis,
and extremity/.
/EPIDEMIOLOGY STUDIES/ /HEMATOPOIETIC or LYMPHATIC SYSTEM/ The European
Childhood Leukemia-Lymphoma Incidence Study was designed to address concerns
about a possible increase in the risk for cancer in Europe after the Chernobyl
accident... . During the period 1980-91, 23,756 cases of leukemia were diagnosed
in children aged 0 to 14 ... . Although there was a slight increase in the
incidence of childhood leukemia in Europe during the period studied, the overall
geographical pattern of change bears no relation to estimated exposure to
radiation from the Chernobyl fall-out.
/EPIDEMIOLOGY STUDIES/ /ENDOCRINE ORGANS/ A highly significant, dose-related
excess risk of thyroid cancer was observed among 10,834 Israeli patients treated
as children by X-ray depilation for ringworm of the scalp (tinea capitis), with
estimated (fractionated) dose to the thyroid gland averaging 90 mGy (range
40-500 mGy) ... No significant excess was observed among 2,224 patients given
similar treatment (average thyroid dose 60 mGy) in the United States.
/EPIDEMIOLOGY STUDIES/ /BRAIN, DIGESTIVE SYSTEM, HEMATOPOIETIC or LYMPHATIC
SYSTEM/ A cohort study of mortality among 15,727 employees at the Los Alamos
National Laboratory ... between 1947 and 1990, who had been hired in 1943-77
showed an association between the dose of radiation and cancers of the esophagus
and brain and Hodgkin disease, but not for leukemia or all cancers combined).
/EPIDEMIOLOGY STUDIES/ /GASTROINTESTINAL SYSTEM/ Colon cancer risks have been
examined in various epidemiological studies of radiation-exposed groups. ...
Data on the Japanese atomic bomb survivors are consistent with a linear dose
response. The effect of gender, age at exposure, and time since exposure on the
excess relative risk per Sv is not clear, although the excess relative risk per
Sv does increase with increasing time since exposure in the Life Span Study.
Changes over time in baseline rates in Japan make it difficult to decide how to
transfer risk across populations.
/EPIDEMIOLOGY STUDIES/ /LIVER/ ... the mortality data from the Life Span Study
of survivors of the atomic bombings indicate a significant dose response /for
liver cancer/. This relationship is strengthened by the analysis of incidence
data based on histologically and clinically verified primary liver cancer cases.
Studies of thorotrast-exposed patients consistently show increased risks of
liver cancer from alpha-radiation exposure. While the types of liver cancer
associated with thorotrast exposure are typically cholangiocarcinoma, followed
by angiosarcoma and hepatocellular carcinoma, the excess risk associated with
low-LET exposure in Japanese atomic bomb survivors is primarily hepatocellular
carcinoma.
/EPIDEMIOLOGY STUDIES/ /SOLID CANCERS; HEMATOPOIETIC SYSTEM/ The 15-Country
Study included almost 600,000 individually monitored workers from 15 countries.
...The main analysis included 407,391 nuclear
industry workers who were employed for at least one year in a participating
facility and who were monitored individually for external radiation. The total
duration of follow-up was 5,192,710 person-years, and the total collective
recorded dose was 7,892 Sv, almost exclusively from external photon exposure.
Most workers in the study were men (90%), who received 98% of the collective
dose. The overall average cumulative recorded dose was 19.4 mSv. ... The excess
relative risk estimate for all cancers excluding leukemia was reported as 0.97
per Gy (95% CI 0.14-1.97), and that for all solid cancers was 0.87 per Gy (95%
CI 0.03-1.88).
/EPIDEMIOLOGY STUDIES/ /HEMATOPOIETIC or LYMPHATIC SYSTEM; ENDOCRINE SYSTEM/ In
a follow-up /to the Chernobyl accident/ in the Ukraine, the incidences of
leukemia and lymphoma in the three most heavily contaminated regions (oblasts)
... increased during the period 1980-93; however, the incidences of leukemia ...
and other cancers in countries of the former USSR had shown an increasing trend
before the accident, in 1981... . In a study of the population of Kaluga oblast,
the part of the Russian Federation nearest Chernobyl ...no statistically
significant increase in trends of cancer incidence or mortality was seen after
the accident, although a statistically significant increase in the incidence of
thyroid cancer was observed in women.
/EPIDEMIOLOGY STUDIES/ /LUNG/ Results from the Japanese atomic bomb survivors
and from several groups of patients with acute high-dose exposures show elevated
risks of lung cancer associated with external low-LET radiation. ... Studies of
tuberculosis patients who received multiple chest fluoroscopies have not
demonstrated increased risks of lung cancer, in spite of the large number of
patients with moderate or high lung doses. ... In contrast to internal low-LET
irradiation, there is a substantial amount of information on lung cancer in
relation to internal high-LET exposure. Most of this information comes from
studies of radon-exposed miners. In particular, the risk appears to increase
linearly with cumulative radon exposure, measured in WLM (working-level months),
but the excess relative risk per WLM decreases with increasing attained age and
time since exposure. ... Findings from case-control studies of domestic radon
exposure have been variable but are consistent with predictions from the miner
studies. Among studies of other types of high-LET exposure, the most informative
are those of workers at the Mayak plant in the Russian Federation, which show an
elevated risk for high lung doses from plutonium ... .
/EPIDEMIOLOGY STUDIES/ /HEMATOPOIETIC or LYMPHATIC SYSTEM/ All 888 cases of
acute leukemia diagnosed in Sweden in 1980-92, after the Chernobyl accident, in
children aged 0-15 years, were examined in a population based study in which
place of birth and residence at the time of diagnosis were included. A
dose-response analysis showed no association between the degree of contamination
and the incidence of childhood leukemia. ...The incidence of leukemia in Finland
among children aged 0-14 in 1976-92 in relation to fall-out from the Chernobyl
accident, measured as external exposure in 455 municipalities throughout the
country. ... did not increase over the period studied, and the excess relative
risk in 1989-92 was not significantly different from zero. The incidence of
leukemia among infants in Greece after exposure in utero as a consequence of the
Chernobyl accident was ... higher in children born to mothers who lived in areas
with relatively greater contamination. On the basis of 12 cases diagnosed in
infants under the age of one year, a statistically significant increase in the
incidence of infant leukemia was observed (rate ratio, 2.6; 95% CI 1.4-5.1). No
significant difference in the incidence of leukemia among 43 children aged 12-47
months born to presumably exposed mothers was found. ...In a study of childhood
leukemia in relation to exposure in utero due to the Chernobyl accident based on
the population-based cancer registry in Germany, cohorts were defined as exposed
or unexposed on the basis of date of birth and using the same selection criteria
as /the Greek study/. Overall, a significantly elevated risk was seen (RR, 1.5;
95% CI 1.0-2.15; n=35) for the exposed group ... compared with the unexposed
cohort /but/ the incidence was higher among infants born in April-December 1987
(RR, 1.7; 95% CI 1.05-2.7) than among those born between July 1986 and March
1987 (RR,1.3; 95% CI 0.76-2.2), although the exposure of the latter group in
utero would have been greater than that of the former group.
/EPIDEMIOLOGY STUDIES/ /BREAST CANCER/ Extensive information from the Japanese
atomic bomb survivors and several medically exposed groups demonstrates elevated
risks of female breast cancer following external low-LET irradiation. The trend
in risk with dose is consistent with linearity, and the excess relative risk per
Sv is particularly high for exposure at young ages. In contrast, there is little
evidence of increased risks for exposure at ages of more than 40 years... .
Examination of data for the atomic bomb survivors and some of the medical
studies tend to suggest that dose fractionation has little influence on the risk
per unit dose.
/EPIDEMIOLOGY STUDIES/ /GASTROINTESTINAL SYSTEM/ Much of the information on
stomach cancer risks following radiation exposure comes from the Life Span Study
of survivors of the atomic bombings. ...The Life Span Study indicates that the
dose response is consistent with linearity and that the excess relative risk per
Sv decreases with increasing age at exposure, does not appear to vary with time
since exposure, and may be higher for females than for males. ... Some but not
all, studies of external low-LET medical irradiation also show an association
between radiation exposure and stomach cancer risk.
/EPIDEMIOLOGY STUDIES/ /URINARY BLADDER/ Statistically significant excess risks
of cancer of the urinary bladder are seen in several population exposed to
low-LET radiation. The Life Span Study risk estimates are somewhat greater than
those seen for cancer patients; however, since the cancer patient studies
involve extremely high doses, the differences may reflect cell killing.
/EPIDEMIOLOGY STUDIES/ /LUNG/ A cohort study of mortality among 106,020 persons
employed in 1943-85 at the four nuclear
plants in Oak Ridge, Tennessee, showed a slight excess of deaths from lung
cancer among white male employees. In a dose response analysis restricted to
28,347 white men at two plants who had received a mean dose of 10 mSv,
significant positive relationships were found with deaths from all causes
(Excess relative risk per Sv, 0.31; 95% CI 0.1 -1.01), deaths from all cancers
(Excess relative risk per Sv, 1.45; 95% CI 0.15-3.5; n=4673) and lung cancer
(Excess relative risk per Sv, 1.7; 95% CI 0.03-4.9; n=1848) after adjustment for
age, year of birth, socioeconomic status, facility and length of employment;
however, no information on smoking was available. For leukemia, the excess
relative risk per sievert was negative (upper 95% confidence limit 6.5; n =
180).
/EPIDEMIOLOGY STUDIES/ /HEMATOPOIETIC or LYMPHATIC SYSTEM/ A cohort study of
people who had worked at the Mayak nuclear
complex in the early years of its operation showed an increased mortality rate
from all cancers and from leukemia (44 cases; 38 men).
/EPIDEMIOLOGY STUDIES/ /HEMATOPOIETIC or LYMPHATIC SYSTEM; ENDOCRINE SYSTEM;
SKIN/ The Life Span Study is /investigating/.. the long-term health effects of
exposure to radiation during the atomic bombings of Hiroshima and Nagasaki,
Japan, in 1945. ... The subjects were all Japanese exposed during wartime, and
host and environmental factors may have modified their risk for cancer. In
addition, the study sample includes only those still alive five years after the
bombings. ...The Life Span Study cohort consists of approximately 120,000 people
who were identified at the time of the 1950 census, and individual doses have
been reconstructed. ... The latest published data on mortality from cancer cover
the period 1950-90. An additional source of information on leukemia and related
hematological disease is the Leukemia Registry. It /is/ ... possible to analyze
cancer incidence by linkage to the Hiroshima and Nagasaki tumor registries... .
/although/... these data ... do not include diagnoses of cancers before 1958 or
for persons who migrated from the two cities. ...(a) Leukemia: Leukemia was the
first cancer to be linked with exposure to radiation after the atomic bombings,
and the Excess relative risk for this malignancy is by far the highest, /with/
... a clear increase in risk with increasing dose over the range 0-2.5 Sv.
...Although the temporal patterns of leukemia risk are more complex than those
of solid tumors, the largest excess risks were generally seen in the early years
of follow-up. For people exposed as children, essentially all of the excess
deaths appear to have occurred early in the follow-up. For people exposed as
adults, the excess risk was lower than that of people exposed as children and
appears to have persisted throughout the follow-up. ...The other major type of
leukemia, chronic lymphocytic leukemia, is infrequent in Japan, and no excess
was seen in the Life Span Study cohort. ... (b) All solid tumors: ... As for
leukemia, an increase in risk with increasing dose over the range 0-2.5 Sv is
seen. ... The attributable risk for solid tumors is estimated to be 8%, much
smaller than the estimate of 44% for leukemia. The temporal pattern of solid
tumors differs from that of leukemia as it includes a longer minimal latent
period. .... For people who were exposed when they were under the age of 30,
nearly half of the excess deaths during the entire 40 years of follow-up have
occurred in the last five years. Of the 86,572 subjects for whom ... dose
estimates are available, 56% were still alive at the end of 1990, the end of the
period for which mortality has been reported. Of the 46,263 subjects who were
under the age of 30 at the time of the bombings, 87% were still alive at the end
of 1990. ...(c) Site-specific cancer risks: ... The following discussion of
site-specific cancer risks is ... based primarily on incidence. (i) Female
breast cancer: The risk for breast cancer among women in the Life Span Study
shows a strong linear dose-response relationship and a remarkable age
dependence. The Excess Relative Risk (ERR) for this cancer is one of the largest
of those for solid tumors, but it decreases smoothly and significantly with
increasing age at the time of exposure. Figures on incidence from the tumor
registries showed, for example, that the ERR of women who were under 10 years of
age at the time of exposure was five times that of women who were over 40 years
of age at that time. ... (ii) Thyroid cancer: ... a dose-related increase in the
incidence of thyroid cancer was demonstrated in the early 1960s from the results
of periodic clinical examinations of a subcohort of approximately 20,000 persons
(the 'Adult Health Study'). More detailed analyses based on incidence in the
Life Span Study cohort showed a strong dependence of risk with age at exposure,
the risk being higher among people who had been less than 19 years old at the
time of the bombings. ...Among children who were under 15 at the time of the
bombings, a steep decrease in risk with age at exposure was found, and children
who were exposed between the ages of 10 and 14 had one-fifth the risk of those
exposed when they were under 5. (iii) Other sites: Cancers at other sites that
are clearly linked with exposure to radiation in the Life Span Study include
those of the salivary glands, stomach, colon, lung, liver, ovary, and urinary
bladder, and nonmelanoma skin cancer. For most of these sites, statistically
significant associations were found for both mortality and incidence. ... The
evidence for an association with exposure to radiation is equivocal for cancers
of the esophagus, gall-bladder, kidney and nervous system and for non-Hodgkin
lymphoma and multiple myeloma, as the results are either of borderline
statistical significance or those for incidence and mortality conflict. Cancers
for which there is little evidence of an association with exposure to radiation
include those of the oral cavity (except salivary glands), rectum, pancreas,
uterus, and prostate, and Hodgkin disease.
/EPIDEMIOLOGY STUDIES/ /HEMATOPOIETIC or LYMPHATIC SYSTEM/ A combined cohort
study of mortality from cancer among 95,673 nuclear
industry workers in Canada, the United Kingdom and the USA has been published.
The persons had been employed for at least six months and had been monitored for
external exposure. The activities of the nuclear
facilities included power production, research, weapons production, reprocessing
and waste management. The mean
cumulative dose was 40 mSv. Data on socioeconomic status were available for all
except the Canadian workers, and adjustment was made for this variable in the
analysis. The combined analysis covered 2,124,526 person-years and 36,976 deaths
from cancer. The risk for leukemia other than chronic lymphocytic leukemia was
statistically significantly associated with the cumulative external dose of
radiation (one-sided p value, 0.046). The excess relative risk estimate for
leukemia other than the chronic lymphocytic type was 2.2 per Sv (90% CI 0.1-5.7;
n=119). ... Of the 31 specific cancer types other than leukemia, only multiple
myeloma was statistically significantly associated with the exposure (p=0.04;
Excess relative risk per Sv, 4.2; 90% CI 0.3-14; n=44).
/EPIDEMIOLOGY STUDIES/ /THYROID/ For purposes of characterization /of Chernobyl
patients/, these subjects are often divided into patients with acute radiation
sickness and others who were exposed during the so-called "iodine
period" (April to June of 1986, Group 1). Group 2 usually refers to those
recovery workers engaged in work at or near the plant during 1986 and 1987. ...
In both Groups 1 and 2, there may be an increased risk of cancer, although with,
with the exception of childhood thyroid cancer, this is unlikely to occur within
10 years post-exposure. ... The Chernobyl accident released a large amount of
iodine-131, as well as other short-lived radioiodines. Over the last decade,
there has been a marked increase in the number of thyroid cancers among children
and adolescents. Among those less than 18 years of age at the time of the
accident, over 1400 cases of thyroid cancer were diagnosed between 1990 and
1997. ... The risk of leukemia has been shown in other epidemiological studies
to be increased by radiation exposure. However, as of 1999, no increased risk of
leukemia linked to ionizing radiation has been described in children, recovery
workers, or in the general population as a result of exposure from the Chernobyl
accident.
/EPIDEMIOLOGY STUDIES/ /HEMATOPOIETIC or LYMPHATIC SYSTEM/ Follow-up of more
than 20,000 participants in the 21 atmospheric nuclear
tests conducted by the United Kingdom in 1952 to 58 in Australia and islands in
the Pacific Ocean and of an equally large control group of military personnel
through 1991 showed that the rate of death from leukemia among participants was
similar to that of the general population (Standardized Mortality Ratio (SMR),1.0
(95% Confidence Interval (CI) 0.7-1.4)) but was higher than that of the control
group (Relative Risk (RR), 1.8; 95% CI 1.0-3.1). A small study, with follow-up
for the period 1957 to 87, of approximately 500 personnel of the Royal New
Zealand Navy involved in the test program ... in the Pacific Ocean in 1957 to
58, showed that mortality from all cancers was similar (RR, 1.2; 95% CI 0.8-1.7)
to that of 1,504 Navy personnel who were not involved in the tests; however,
mortality from leukemia was greater among participants than controls (RR, 5.6;
95% CI 1.0-42; four cases). In a cohort study of participants in five US nuclear
bomb test series between 1953 and 1957, more than 46,000 subjects were
followed-up by linkage to Veterans' Administration records, which showed 5,113
deaths. No increase in mortality from leukemia was observed (SMR, 0.9; 95% CI
0.6-1.2) ... . Approximately 8,500 Navy veterans who had participated in the US
'Hard tack I' operation in 1958, which included 35 tests in the Pacific Ocean,
were found to have had a median dose of 4 mSv. The mortality rates from all
cancers (RR, 1.1; 95% CI 1.0-1.3) and leukemia (RR, 0.7; 95% CI 0.3-1.8) were
comparable to those for an unexposed group of veterans. In a study of 40,000
military veterans who had participated in a test in the Bikini atoll, Marshall
Islands, in 1946, the mortality rates from all cancers (RR, 1.0; 95% CI
0.96-1.1) and from leukemia (RR, 1.0; 95% CI 0.75-1.4) were similar to those for
nonparticipants.
/EPIDEMIOLOGY STUDIES/ /HEMATOPOIETIC or LYMPHATIC SYSTEM/ In 1949, the
Semipalatinsk test site was created in northeastern Kazakhstan, then part of the
USSR, and 118 atmospheric nuclear and
thermonuclear devices were exploded before 1962, 26 of which were near the
ground ... . The estimated effective doses from external and internal exposure
attributable to the 1949 and 1953 tests (the two largest atmospheric tests) in
villages near the test site range from 70 to 4,470 mSv, most local residents
being exposed to an effective dose of 100 mSv. ... Among children under the age
of 15 during 1981-90 in four administrative zones of Khazakhstan ...: the risk
for acute leukemia rose significantly with increasing proximity of residence to
the testing areas, although the absolute value of the risk gradient was
relatively small.
/BIOMONITORING/ A group of children exposed to the ionizing radiation released
during the Chernobyl accident had an appreciable number of chromosomal breaks
and rearrangements several years later, reflecting the persistence of the
radiation-induced damage. ... In a follow-up study, 31 exposed children were
compared with a control group of 11 children. ... The frequency of chromosomal
aberrations in the exposed children was significantly greater than that in the
control group, confirming the earlier report that a persistently abnormal
cytogenetic pattern was still present many years after the accident.
/BIOMONITORING/ A group of 125 workers involved in the initial /Chernobyl/
clean-up operation (called 'liquidators', exposed mainly in 1986) and 42 people
recovering from acute radiation sickness of second- and third-degree severity
were examined in 1992-93 for cytogenetic effects. Increased frequencies of
unstable and stable markers of exposure to radiation were found in all groups,
showing a positive correlation with the initial exposure even as long as six to
seven years after the accident. ... Cytogenetic monitoring was also conducted
among children, tractor drivers and foresters living in areas of the Ukraine
contaminated by radionuclides released after the Chernobyl accident. All groups
showed significantly increased frequencies of aberrant metaphases, chromosomal
aberrations (both unstable and stable) and chromatid aberrations, and the number
of aberrations in the children's cells correlated to the duration of exposure.
/BIOMONITORING/ After the Chernobyl accident, germ-line mutations at human
minisatellite loci were studied among children born in heavily polluted areas of
the Mogilev district of Belarus. ... Blood samples were collected from 79
families (father, mother, child) of children born between February and September
1994 whose parents had both lived in the Mogilev district since the time of the
Chernobyl accident. The control sample consisted of 105 unirradiated white
families in the United Kingdom ... . The mutation frequency was found to be
twice as high in the exposed families as in the control group. When the exposed
families were divided into those that lived in an area with less than the median
level of cesium-137 surface contamination and those that lived in more
contaminated areas, the mutation rate in people in more contaminated areas was
1.5 times higher than that in those in the less contaminated areas.
/BIOMONITORING/ Chromosomal aberrations were examined in lymphocytes from eight
men aged 24 to 56 who were exposed during a criticality accident ... . The blood
samples were drawn about 2.5 years after the irradiation; blood from five
unirradiated subjects was used as a control. Only chromatid-type aberrations
were found in the controls. In the subjects exposed to the higher doses, the
frequency of aneuploid cells was 7 to 23%, and gross aberrations, such as rings,
dicentrics and minutes, were found in 2 to 20% of the cells. The men who
received doses of 0.23 to 0.69 Gy /mixed gamma radiation and fission neutrons/
also had abnormalities but at a much lower frequency. ...The men were further
examined 7 and 16 and 17 year after the accident. At 16 to 17 years, six of the
men still had residual chromosomal aberrations.
/BIOMONITORING/ The scoring of chromosome aberrations in human peripheral blood
lymphocytes provides a sensitive method for biological dosimetry. ... By scoring
dicentric aberrations in the full genome of about 1,000 cells, average
whole-body doses of about 100 mGy from X-rays or gamma rays may be detected and
higher doses estimated.
/BIOMONITORING/ The induction of chromosomal aberrations, particularly
dicentrics, in human lymphocytes has been well established in vitro and has been
used as a biological dosimeter in a variety of situations of exposure in which
induction of aberrations has occurred. The persons exposed include inhabitants
of areas with a high background level of natural radiation, survivors of the
atomic bombings, workers involved in cleaning-up after the accident at the
Chernobyl nuclear reactor in
Chernobyl, Ukraine, and people accidentally exposed to a discarded source of
cesium-137 in Goiania, Brazil.
/BIOMONITORING/ Between 1986 and 1992, peripheral blood samples were obtained
from 102 workers who were on the site during the Chernobyl emergency or arrived
there shortly thereafter to assist in the clean-up ... . Blood was also taken
from 13 unexposed individuals. ... The frequency of N/O variant red cells
increased in proportion to the estimated exposure to radiation of each
individual. The dose-response function derived for this population closely
resembled that determined previously for atomic bomb survivors whose blood
samples were obtained and analyzed 40 years after exposure ... . Measurements on
multiple blood samples from each of 10 donors taken over seven years showed no
significant change in N/O variant cell frequency, confirming the persistence of
radiation-induced somatic mutations in long-lived bone-marrow stem cells.
/OTHER TOXICITY INFORMATION/ /BONE MARROW/ The erythropoietic system ... has a
marked propensity for regeneration following irradiation. ... Although anemia
may be evident in the later stages of the bone-marrow syndrome, it should not be
considered a survival-limiting factor. The function of the myelopoietic cell
renewal system is mainly to produce mature granulocytes ... . Neutrophils are
the most important cell type in this cell line because of their role in
combating infection. ... Because of the rapid turnover in the granulocyte cell
renewal system (approximately 8-day cellular life cycle), evidence of radiation
damage to marrow myelopoiesis occurs in the peripheral blood within 2 to 4 days
after whole-body irradiation. Recovery of myelopoiesis lags slightly behind
erythropoiesis ... Platelets are produced by megakaryocytes in the bone marrow.
Both platelets and mature megakaryocytes are relatively radioresistant; however,
the stem cells and immature stages are very radiosensitive. ... Thrombocytopenia
is reached by 3 to 4 weeks after midlethal-range doses and occurs from the
killing of stem cells and immature megakaryocyte stages, with subsequent
maturational depletion of functional megakaryocytes. Regeneration of
thrombocytopoiesis after sublethal irradiation normally lags behind both
erythropoiesis and myelopoiesis. ... Blood coagulation defects with concomitant
hemorrhage constitute important clinical sequelae during the thrombocytopenic
phase of bone-marrow and gastrointestinal syndromes.
/OTHER TOXICITY INFORMATION/ /GASTROINTESTINAL SYSTEM/ Gastrointestinal
Kinetics: The vulnerability of the small intestine to radiation is primarily in
the cell renewal system of the intestinal villi... . Because of the high
turnover rate occurring within the stem cell and proliferating cell compartment
of the crypt, marked damage occurs in this region from whole-body radiation
doses above the midlethal range. Destruction as well as mitotic inhibition
occurs within the highly radiosensitive crypt cells within hours after high
doses. Maturing and functional epithelial cells continue to migrate up the
villus wall and are extruded, albeit the process is slowed. Shrinkage of villi
and morphological changes in mucosal cells occur as new cell production is
diminished within the crypts. Continued loss of epithelial cells in the absence
of cell production results in denudation of the intestinal mucosa. Concomitant
injury to the microvasculature of the mucosa results in hemorrhage and marked
fluid and electrolyte loss contributing to shock. These events normally occur
within 1 to 2 weeks after irradiation.
/OTHER TOXICITY INFORMATION/ /FETUS/The sensitivity of the embryo-fetus for both
mental retardation and cancer should be considered in all situations involving
irradiation of the embryo-fetus.
/OTHER TOXICITY INFORMATION/ /SKIN/The most common type of radiation injury in
the United States has been a local injury to some part of the body. Of all
documented local injuries, 77% involved the fingers and hands. Another 6% were
extremity injuries involving the arms, legs, or feet. A further 9% of local
injuries involved the head or neck, and the remainder was injuries to the thorax
and other areas. The radiation sources in these cases of local injury were
predominantly sealed sources of iridium-192 and cobalt-60.
/OTHER TOXICITY INFORMATION/ /IMMUNE SYSTEM/ /Chernobyl/ Patients with grade III
to IV acute radiation sickness (ARS) were initially severely immunocompromised.
While hematopoietic recovery in the survivors occurred within a matter of weeks,
or at most months, future reconstitution of functional immunity may take at
least half a year and may not be normal for several years. Studies of the immune
status have revealed abnormalities in T-cell immunity for patients who received
high doses of radiation. These abnormalities, however, have not been clearly
associated with clinically manifest immunodeficiency.
/OTHER TOXICITY INFORMATION/ /REPRODUCTIVE FUNCTION/ Sexual behavior and
fertility among acute radiation sickness /Chernobyl/ survivors was investigated
up until 1996. In the majority of cases, functional sexual disturbances
predominated, but fertility has recovered in persons who planned to have
children; 14 normal children were born to ARS survivor families within the first
5 years of the accident.
/OTHER TOXICITY INFORMATION/ /FETUS/Potential Health Effects of Prenatal
Radiation Exposure (Other than Cancer). Acute Radiation Dose to Embryo or Fetus:
< 0.05 Gy (5 rads): noncancer health effects not detectable. 0.05-0.50 Gy
(5-50 rads), blastogenesis (up to 2 weeks) incidence of failure to implant may
increase slightly; organogenesis (2-7 weeks) incidence of major malformations
may increase slightly and growth retardation possible; Fetogenesis (8-15 wks)
growth retardation possible, ... incidence of severe mental retardation up to
20%; Fetogenesis (16-38 wks) noncancer health effects unlikely. >0.50 Gy (50
rads), blastogenesis incidence of failure to implant likely to be large,
organogenesis indicine of miscarriage may increase, substantial risk of major
malformations such as neurological and motor deficiencies, growth retardation.
Fetogenesis (8-15 wks) incidence of miscarriage probably will increase, growth
retardation likely, ... incidence of severe mental retardation >20%,
incidence of major malformations will probably increase. Fetogenesis (16-25 wks)
incidence of miscarriage may increase, growth retardation possible, reduction in
IQ possible, severe mental retardation possible, incidence of major malformation
may increase. Fetogenesis (26-38 wks) Incidence of miscarriage and neonatal
death will probably increase. /From table/
/OTHER TOXICITY INFORMATION/ /SKIN/ Ionizing radiation can induce non-melanoma
skin cancer, but the relationship is almost entirely due to a strong association
with basal-cell carcinoma. ... When radiation exposure occurs during childhood,
the excess relative risk for basal-cell carcinoma is considerably larger than
when the exposure occurs during adulthood.
/OTHER TOXICITY INFORMATION/ /CENTRAL NERVOUS SYSTEM/ Ionizing radiation can
induce tumors of the CNS, although the relationship is not as strong as for many
other tumors, and most of the observed radiation-associated tumors are benign.
Indeed, neurilemmomas, which are highly curable, are the only tumors that
consistently exhibit risks. Overall, exposure during childhood appears to be
more effective in tumor induction than adult exposure, but the data on adult
exposure are fairly sparse, and the most recent study of atomic bomb survivors
demonstrate an excess relative risk for neurilemmomas following exposure at all
ages. ... The association between benign tumors, particularly meningiomas and
neurilemmomas, and radiation appears to be substantially stronger than with
malignant tumors. Malignant brain tumors are seen only after radiotherapy.
/OTHER TOXICITY INFORMATION/ /THYROID/ The thyroid gland is highly susceptible
to the carcinogenic effects of external radiation during childhood. Age at
exposure is an important modifier of risk, and a very strong tendency for risk
to decrease with increasing age at exposure is observed in most studies.
Although thyroid cancer occurs naturally more frequently among women, the excess
relative risk does not appear to differ significantly for men and women. Among
people exposed during childhood, the excess relative risk of thyroid cancer is
highest 15-29 years after exposure, but elevated risks persist even 40 years
after exposure. The carcinogenic effects of iodine-131 are less well understood.
Most epidemiological studies have shown little risk following a wide range of
exposure levels, but almost all of them looked at adult exposures. Recent
results from Chernobyl indicate that radioactive iodine exposure during
childhood is linked to thyroid cancer development, but the level of risk is not
yet well quantified.
/OTHER TOXICITY INFORMATION/ /HEMATOPOIETIC or LYMPHATIC SYSTEM/There is a
substantial amount of information on the risks of leukemia from radiation
exposure. This reflects the high relative increase in risk compared with other
cancer types and the temporal pattern in risk, with many of the excess leukemias
occurring within about the first two decades following exposure, particularly
among those irradiated at young ages. ... Case-control studies of prenatal
X-rays indicate an increased risk of leukemia in childhood due to in utero
irradiation, although the absence of a dose-related increase in the sparse
corresponding data for atomic bomb survivors adds uncertainty to the magnitude
of the risk. Epidemiological evidence does not suggest that irradiation prior to
conception give rise to a material risk of childhood leukemia. ... There is no
convincing evidence of an increased risk of leukemia due to environmental
exposures associated with the Chernobyl accident, although investigations are
continuing. Excesses of childhood leukemia have been reported around some nuclear
installations in the United Kingdom, but generally not in other countries. ...
Dose-related increases in leukemia risk have been seen among patients with large
exposures to high-LET radiation arising from injections of thorotrast, a
diagnostic X-ray contrast medium. There is less evidence for elevated risks
among patients injected with radium-224 and little or no evidence for increased
risks among radium dial workers or from studies with individual assessments of
radon exposure, either in mines or in homes.
/OTHER TOXICITY INFORMATION/ Many hormones are potent growth stimulators. ...
Thyroid stimulating hormone is increased during puberty and pregnancy as a
result of increased levels of female sex hormones. There is epidemiological
evidence suggesting that the development of thyroid cancer after high-dose
radiation exposure in females can be potentiated by subsequent child bearing.
Marshall Islanders who were exposed to radioactive fallout from a nuclear
weapons test in 1954 received high thyroid doses from radioiodines. Women who
later became pregnant were at higher risk of thyroid cancer than exposed women
who remained nulliparous. The numbers, however, were small.
/OTHER TOXICITY INFORMATION/ Ionizing radiation represents a possible teratogen
for the fetus, but this risk has been found to be dependent on the dosage and
the effects correlatable to the gestational age at exposure. Recently, of
particular note is the fact that maternal thyroid exposure to diagnostic
radiation has been associated with a slight reduction in the birth weight.
Inadvertent exposure from diagnostic procedures in pregnancy does not usually
increase the natural risk of congenital anomalies but creates a considerable
state of maternal anxiety. Diagnostic radiological procedures should be avoided
in pregnant women unless the information cannot be obtained by other techniques.
/OTHER TOXICITY INFORMATION/ Second cancer incidence /was studied/ in a
multinational cohort study of 28,843 men who had been diagnosed with testicular
cancer between 1935 and 1993 ... .Cases of second cancer occurring between 1965
and 1994 were significantly increased ... in general, as well as of leukemia (64
cases) and of stomach cancer (93 cases). /In a/ case-control study of leukemia
nested within a multinational cohort of 18,567 patients diagnosed with
testicular cancer ... men who did not receive chemotherapy (mean radiation dose
to 12.6 Gy) had a 3.1-fold elevation of leukemia risk.
/OTHER TOXICITY INFORMATION/ Studies of second cancer following radiotherapy
have generally focused on patients treated for cervical cancer, breast cancer,
Hodgkins disease, and childhood cancers ... . Survivors of these cancers may
live long enough to develop a second, treatment-related malignancy. ... Most of
the information on second cancers following radiotherapy for cervical cancer
comes from ... a multinational cohort study of nearly 200,000 women patients
treated for cancer of the cervix after 1960. ... A total of 7,543 cases were
included. This study confirmed ... /an/ increased risk of malignancies following
radiotherapy and that the increased risk persists over time. ... A cohort study
of second cancer risk following radiation therapy for cancer of the uterine
cervix was also carried out in Japan among 11,855 patients. Significant excesses
of leukemia and of cancers of the rectum, bladder and lung were observed.
/OTHER TOXICITY INFORMATION/ For average tissue absorbed doses of 0.2 mGy from
Low-LET cobalt-60 gamma rays, for example, spherical nuclei of say 8 um diameter
would each receive, on average, about 0.2 tracks. In this case, just 18 percent
of cells would receive any radiation tract at all and less than 2 percent of
cell would receive more than one track. ...The situation is quite different for
exposures to high-LET radiation. When a tissue receives an average dose of 1 mGy
from alpha particles, only about 0.3% of the nuclei are struck by a track at
all; the remaining 99.7% are totally unirradiated. When a single track does
strike, it delivers to the nucleus a very large dose, of about 379 nGy on
average. In individual nuclei the dose may be any value up to about 1,000 mGy.
Human Toxicity Values:
When appropriate medical care is not provided, the median lethal dose of
radiation ...that ... will kill 50% of the exposed persons within a period of 60
days is estimated to be 3.5 Gy. High-dose partial-body radiation exposures
represent a common clinical radiation scenario in accidents. Differences of 10%
in absorbed dose can produce clearly observable variations in biological
response.
Drug Warnings:
No one specific type of secondary cancer is seen after therapeutic irradiation.
Secondary cancers can occur after any initial cancer, when survival surpasses
the latent period. Radiation-induced leukemias begin to appear after 3-5 years.
Solid cancers typically emerge more than 10 years after treatment but may occur
earlier in particularly susceptible individuals. When the risk of secondary
solid cancer is elevated, it rises with increasing radiation dose to the site
and with increasing time since treatment and persists as long as 20 years
There is little indication that heritable sensitivity to treatment is a
significant component of secondary cancer, but intensive multiple agent therapy
used in childhood cancer treatment acts as an independent etiological factor for
a second tumor. The risk for a second malignant neoplasm after cancer in
childhood is considerable. Absolute risks up to 7 % over 15 years following
diagnosis of the primary cancer were found for Hodgkins's disease. This amounts
to an excess relative risk (ERR) of about 17, with breast cancer contributing
the most.
Following childhood cancer therapy ... the risk for bone sarcoma rose
dramatically with increasing doses of radiation. ... Patients with heritable
retinoblastoma had a much higher risk for secondary bone sarcoma ... radiation
and alkylating agents acted additively.
Thyroid cancer risk after treatment of childhood cancer is increased 53-fold
compared with general population rates. The risk for thyroid cancer rose with
increasing radiation dose. There was no increased risk of thyroid cancer
associated with alkylating-agent chemotherapy. There was a seven fold increased
risk of secondary cancers after treatment of acute lymphoblastic leukemia. Most
of this risk was due to a 22-fold increase in brain cancers.
The interaction of alkylating agents with radiation in producing leukemia in
women treated for breast cancer was investigated in a cohort of 82,700 patients
in the United States. Based on 74 cases, the risk of acute nonlymphocytic
leukemia (ANL) was significantly increased after radiotherapy alone (relative
risk - 2.4, 7.5 Gy mean dose to the active marrow and alkylating agents (melphalan
and cyclophosphamide) alone (relative risk = 10). Combined therapy resulted in a
more-than-additive relative risk of 17.4.
Following therapeutic nuclear medicine
interventions, some radiopharmaceuticals cause the patient's urine, sweat,
saliva, and blood to contain a high level of radioactivity. In many instances,
patients must be hospitalized for several days to prevent contamination of the
public.
Studies of second cancer following radiotherapy have generally focused on
patients treated for cervical cancer, breast cancer, Hodgkin disease, and
childhood cancers ... . Survivors of these cancers may live long enough to
develop a second, treatment-related malignancy. ... Most of the information on
second cancers following radiotherapy for cervical cancer comes from ... a
multinational cohort study of nearly 200,000 women patients treated for cancer
of the cervix after 1960. ... A total of 7,543 cases were included. This study
confirmed ... /an/ increased risk of malignancies following radiotherapy and
that the increased risk persists over time. ... A cohort study of second cancer
risk following radiation therapy for cancer of the uterine cervix was also
carried out in Japan among 11,855 patients. Significant excesses of leukemia and
of cancers of the rectum, bladder and lung were observed.
Following a first report ... in 1972, a number of authors have studied the risk
of second cancer following treatment for Hodgkin disease. The initial reports
focused mainly on the risk of leukemia following this treatment but, as longer
follow-up periods were considered, an excess risk of a number of solid cancers
(in particular breast and lung) became apparent.
A case-control study of leukemia (excluding chronic lymphatic leukemia) was
carried out nested within a cohort of 82,700 women with breast cancer /treated
by radiation/ in the US. A total of 90 cases and 264 controls were included .
... A significant /radiation/ dose-response was seen for acute non-lymphocytic
leukemia.
Cardiovascular mortality /was studied/ in a cohort of 89,407 Swedish women
identified from the Swedish cancer registry as having had unilateral breast
cancer /treated by radiation/ between the ages of 18 and 79 years between 1970
and 1996. Mortality from cardiovascular disease was higher in women who had left
sided tumors (odds ratio (OR) 1.10, 95% CI 1.03-1.18) ten years or more after
the diagnosis of breast cancer.
Second cancer incidence /was studied/ in a multinational cohort study of 28,843
men who had been diagnosed with testicular cancer between 1935 and 1993 ...
.Cases of second cancer occurring between 1965 and 1994 were significantly
increased ... in general, as well as of leukemia (64 cases) and of stomach
cancer (93 cases). /In a/ case-control study of leukemia nested within a
multinational cohort of 18,567 patients diagnosed with testicular cancer ... men
who did not receive chemotherapy (mean radiation dose to 12.6 Gy) had a 3.1-fold
elevation of leukemia risk.
Since childhood cancer is rare, national and international groups such as the
Late Effects Study Group ... combined their data to evaluate risks. Results from
these cohort studies have indicated that the risk for developing a second cancer
in the 25 years after the diagnosis of the first cancer was as high as 12%.
Among patients treated for hereditary retinoblastoma, the risk of developing a
second cancer in the 50 years after the initial diagnosis was as high as 51%.
Many drugs inhibit the repair of radiation damage. Antitumor antibiotics (e.g.
dactinomycin and doxorubicin), antimetabolites (e.g. hydroxyurea, cytarabine,
and arabinofuranosyl-adenine), and alkylating agents and platinum analogues
(e.g. cisplatin) have been shown to inhibit radiation-induced DNA damage repair.
Smoking is an important cofactor, and studies of patients with Hodgkin disease
and small-cell lung cancer suggest that continued use of tobacco after
radiotherapy potentiates the risk for a second cancer in the lung.
Medical Surveillance:
/ACCIDENTAL EXPOSURE/ In a radiation event/ asymptomatic patients with dose
estimates less than 100 rem (1 Sv) can be followed on an outpatient basis. The
patient and his/her family will be very anxious about the exposure. Therefore,
early and continuous counseling regarding radiation effects will be required.
/ACCIDENTAL EXPOSURE/ If pulmonary or gastrointestinal tract contamination is
suspected, perform partial or whole body counting, if appropriate, for the
isotope involved. ... Counts to estimate the presence of contamination, or to
verify there is no contamination, may be performed a short time after the
exposure. However, counts used to quantify the amount of internal contamination
in the lungs should be performed 24 hours or more after the exposure to minimize
interference from very low levels (less than amounts detectable by frisking) of
external contamination remaining on the skin. For individuals who have internal
contamination, an appropriate program of follow-up counts should be established
to monitor deposition and to determine the resultant dose assignment.
/ACCIDENTAL EXPOSURE/ Localized radiation injury occurs from direct handling of
intense radioactive sources. The patient often survives, even if local absorbed
doses are very high. Because dose rate drops very quickly with distance from the
radioactive item, systemic manifestations are less severe than the local injury.
In contrast to thermal burns, radiation injury presents with delayed erythema
and desquamation or blistering (12 to 20 days postevent). Months to several
years after radiation skin burns, vascular insufficiency can cause ulceration or
necrosis of tissues that had previously healed. Treatment of localized radiation
injuries includes pain control, prevention of infection, vasodilators, and
sometimes plastic surgery, grafting or amputation.
/ACCIDENTAL EXPOSURE/ Laboratory Issues. In the management of mass casualties,
basic precepts of medicine should take hold with regard to testing; Minimize the
amount of testing and only perform those thest that can affect the immedite care
of the patient. In a mass casualty incident, hundreds to thougands of patients
may flood hospitals, a situation in which they cannot practically take a blood
count on every patient. Anyone who has or might exhibit prodromal effects would
need to be considered for a CBC with differential to test for acute radiation
syndrome. If possible, this should be repeated every six hours for about 72
hours. Other laboratory tests to consider, if warreanted, include cytogenetic
analysis.
/ACCIDENTAL EXPOSURE/ In the recovery phase from a major /radiation/ event,
there is a public health requirement for counseling individuals on the
longer-term implications of their exposure, principally cancer risk. An estimate
of the dose received by an individual will greatly facilitate the advice that
can be given. There are three principal methods for assessing doses by
biological measures: changes of the hematological parameters (blood cell counts,
especially lymphocytes); cytogenetic changes; and radicals induced by radiation
in bone and teeth, measured by electron spin resonance (ESR)....
/ACCIDENTAL EXPOSURE/ Delayed effects may appear months to years after
irradiation and include a wide variety of effects involving almost all tissues
or organs. Some of the possible delayed consequences of radiation injury are
life shortening, carcinogenesis, cataract formation, chronic radiodermatitis,
decreased fertility, and genetic mutations.
/ACCIDENTAL EXPOSURE/ Follow-up to a Radiation Event/ It is possible that a
radiological incident could impact patterns of reproductive behavior. For
example, there could be an increase in legally induced abortions, even in
locations that are removed from areas most affected by the release. It will be
important, therefore, to have accurate information and counseling services
available to assist people who are making reproductive decisions in the
aftermath of an incident.
/ROUTINE MONITORING/ The information required to assess the internal dose
following an intake of radioactive materials is: 1. The route of entry of the
radionuclide...2. the chemical form of the radioactive compound 3. The
metabolism of the radioactive compound 4. The rate of elimination of the
radioactive compound and its metabolites 5. The physical properties of the
radiations emitted and 6. An estimate of the body content, organ content, or the
magnitude of the intake of the radionuclide. Published calculations of the
internal committed dose equivalent to tissues of the body are correctly
normalized to a unit intake of activity, i.e., Sv/Bq. These calculations use
averaged metabolic data and are adequate for assessing routine exposures that
are well below the effective dose limit...The assessment of nonroutine exposures
to internally deposited radionuclides that approach or exceed the limit on
effective dose should be based on the actual metabolism of the material in the
exposed individual.
/ROUTINE MONITORING/ Criteria for selecting /workers/ for participation in a/
routine/ bioassay program should be based on the probability and the severity of
the potential exposure... General types of bioassay that should be considered
...are: baseline or preparatory, termination, diagnostic, and routine or
periodic...There are two general types of bioassay measurements, direct and
indirect. The method that is selected depends on the route of entry into the
body, the solubility of the material, the metabolism of the material, knowledge
of the route of excretion, the sensitivity of the measurement technique, and
many other factors. ...Direct bioassay (often called in vivo bioassay) involves
the "direct" measurement of the radioactivity in organs or tissues, or
the entire body. This measurement is accomplished by positioning very sensitive
radiation detectors near the body and detecting the radiation that escapes the
body. This method is used primarily to detect photon-emitting radionuclides.
/ROUTINE MONITORING/ Indirect bioassay (often called in vitro bioassay) includes
a number of techniques that are designed to measure the concentration of
radioactive material in biological samples, including urine, feces, exhaled
breath, perspiration, saliva, blood, and even hair, fingernail and biopsy
samples. A fundamental knowledge of the metabolism of the radionuclide in the
body and the relationship of the concentration in the bioassay sample to the
quantity in the organs and tissues of interest is required to select the
appropriate bioassay technique... /See ICRP Publication 100 (in press as of July
2006), ICRP Supporting Guidance 3: Guide for the Practical Application of the
ICRP Human Respiratory Tract Model, ICRP Publication 68: Dose Coefficients for
Intakes of Radionuclides by Workers, 68, and ICRP Publication 66: Human
Respiratory Tract Model for Radiological Protection, 66, and ICRP Publication 30
and its supporting supplements which are, in part, superseded by ICRP 68/.
...Radiations that are not easily measured by external means (e.g., alpha and
beta particles) can be detected /and/ external contamination can be excluded.
Populations at Special Risk:
Ataxia-telangiectasia is the best described of radiosensitive disorders. ...The
radiosensitive phenotype of ataxia-telangiectasia is also readily demonstrated
in cells cultured from patients, using cell survival and chromosome damage
assays.
Nijmegen breakage syndrome is a clinically separate radiosensitive disorder.
Animals and humans (Li-Fraumeni syndrome) deficient in p53 show elevated levels
of cancer; irradiation of p53-deficient mice has a marked effect on the latency
period for tumor formation and gives a high incidence of thymic lymphomas.
Recent evidence suggests that the genes involved in familial susceptibility to
breast and ovarian cancers (the BRCA genes) are involved in DNA repair processes
and lead to radiation sensitivity when defective in mice.
Individuals vary considerably in their ability to respond to radiation ... .
Chromosomal radiosensitivity has been observed in a number of syndromes
characterized by a predisposition to cancer. Severe clinical radiosensitivity
... is observed in ... approximately 5% of breast cancer patients. Some of these
patients may harbor a mutation in the ATM (ataxia telangiectasia mutated) gene.
Retinoblastoma ... has served as the prototypic example of genetic
predisposition to cancer. ... A significant proportion of children with the
heritable bilateral form of retinoblastoma develop second cancers ... .
Radiotherapy for retinoblastoma further increased the risk of dying from a
second neoplasm.
Children with /nevoid basal-cell carcinoma/ syndrome who were treated /with
radiation/ for medulloblastoma developed multiple basal-cell carcinomas on
irradiated skin.
Second malignant neoplasms occur at a higher frequency than expected after prior
treatment with radiotherapy, particularly of childhood cancer.
Antidote and Emergency Treatment:
A hospital should initiate its emergency radiological response upon notification
of an incident. Designated personnel should immediately report to the individual
in charge of the facility's radiation protection program. Ambulance personnel
should be notified which entrance has been designated for receipt of
radiological casualties for transport to the emergency room.
ER Emergency Supplies: In the event of a radiation emergency involving
contamination, bring the following supplies to the /emergency room area/:
Surgical caps, surgical scrub suits, surgical masks, plastic gloves, film badges
and/or pocket dosimeters, respirators (if necessary), adhesive tape, plastic
sheets and bags, surgical gowns, shoe covers, Geiger counters, filter paper for
smears, signs and labels stating "radioactive material" and/or
"radiation area", cotton-tipped applicators, large barrels marked with
radiation signs...
The Radiation Emergency Assistance Center/Training Site provides ... a 24-hour
emergency response program at the Oak Ridge Institute for Science and Education
(ORISE). REAC/TS trains, consults, or assists in the response to all types of
radiation accidents or incidents ... on either the local, national, or
international level.
Immediate First Aid/ Ensure that adequate decontamination has been carried out
as needed. If patient is not breathing, start artificial respiration, preferably
with a demand valve resuscitator, bag-valve-mask device, or pocket mask, as
trained. Perform CPR if necessary. Immediately flush contaminated eyes with
gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient
forward or place on left side (Head-down position, if possible) to maintain an
open airway and prevent aspiration. Keep patient quiet and maintain normal body
temperature. Obtain medical attention. /Radiological Threats: Radiological
Dispersal Devices or Weapons/
All patients should have their traumatic injuries medically stabilized before
radiation injuries are considered. Patients should then be evaluated for both
external radiation exposure and radioactive contamination.
Radiation (Ionizing) Emergency and Supportive Measures. Treatment of serious
medical problems takes precedence over radiologic concerns. Maintain an open
airway and assist ventilation if necessary. Treat coma and seizures if they
occur. Replace fluid losses from gastroenteritis with intravenous crystalloid
solutions. Treat leukopenia and resulting infections as needed. Immunosuppressed
patients require reverse isolation and appropriate broad-spectrum antibiotic
therapy. Bone marrow stimulants may help selected patients. Specific drugs and
antidotes. Chelating agents or pharmacologic blocking drugs may be useful in
some cases of ingestion or inhalation of certain biologically active radioactive
materials, if they are given before or shortly after exposure. /Radiation
(Ionizing)/
Basic Treatment. Establish a patent airway (oropharyngeal or nasopharyngeal
airway, if needed). Suction if necessary. Watch for signs of respiratory
insufficiency and assist ventilations if necessary. Administer oxygen by
nonrebreather mask at 10 to 15 mL/min. Monitor for shock and treat if necessary.
Anticipate seizures and treat if necessary. Perform routine emergency care for
associated injuries. ... Perform routine basic life support care as necessary. /Radioactives
I, II, and III/
Basic Treatment. Establish a patent airway (oropharyngeal or nasopharyngeal
airway, if needed). Watch for signs of respiratory insufficiency and assist
ventilations if necessary. Administer oxygen by nonrebreather mask at 10 to 15
L/min. Monitor for shock and treat if necessary. Anticipate seizures and treat
if necessary. Perform routine emergency care for associated injuries. For eye
contamination, flush eyes immediately with water. Irrigate each eye continuously
during transport. Do not use emetics. For ingestion, rinse mouth and administer
5 mL/kg up to 200 mL of water for dilution if the patient can swallow, has a
good gag reflex, and does not drool. Perform routine BLS care as necessary.
/Radiological Threats: Radiological Dispersal Devices or Weapons/
Advanced Treatment. Consider orotracheal or nasotracheal intubation for airway
control in the patient who is unconscious or is in severe respiratory distress.
Monitor cardiac rhythm and treat arrhythmias as necessary. Start IV
administration of 0.9% saline (NS) or lactated Ringer's (LF) TKO. For
hypotension with signs of hypovolemia, administer fluid cautiously. Watch for
signs of fluid overload. Treat seizures with diazepam or lorazepam. Perform
routine advanced life support care as needed. Use proparacaine hydrochloride to
assist eye irrigation. /Radioactives I, II, and III/
Advanced Treatment. Consider orotracheal or nasotracheal intubation for airway
control in the patient who is unconscious or is in severe respiratory distress.
Monitor cardiac rhythm and treat arrhythmias as necessary. Start IV
administration of 0.9% saline (NS) or lactated Ringer's (LR). For hypotension
with signs of hypovolemia, administered fluid cautiously. Watch for signs of
fluid overload. Treat seizures with diazepam (Valium) or lorazepam (Ativan).
Perform routine advanced life support care as needed. Use proparacaine
hydrochloride to assist eye irrigation. /Radiological Threats: Radiological
Dispersal Devices or Weapons/
The patient who is both contaminated and injured must be treated in the
emergency department's Radiation Emergency Treatment Area where the patient can
receive adequate medical care while the contamination is controlled.
...Following any "quick decontamination" for the unusual high level of
contamination, a more orderly management of the patient should begin. After
stabilization, a careful survey of the naked body should begin. The amount of
activity and its location are carefully recorded on anatomical burn type charts.
Then, and only then, should an orderly decontamination begin. Decontamination
should be performed with the following priorities: (1) Wounds, (2) Orifices, (3)
High-level skin areas, (4) Low-level skin areas. Following decontamination, the
patient should be evaluated for total body and skin exposure. Depending on the
clinical setting, a radiation specialist may need to be notified.
From a medical treatment perspective, radioactive contamination in wounds or
burns should be handled as if it were simple dirt. If an unknown metallic object
is encountered, it should only be handled with instruments such as forceps and
should be placed in a protected or shielded area. There is a possibility that
the metallic object could be a fragment from a radioactive source, so radiation
protection experts should be notified and consulted.
As a general rule of thumb, removal of outer clothing and shoes should reduce
the level of external contamination by approximately 90%. Residual contamination
can be assessed by passing a radiation detector held a constant distance from
the skin over the entire body. Subsequent decontamination of the skin and hair
with soap and warm water and gentle brushing to dislodge radioactive particles
bound to skin proteins will significantly reduce the remaining contamination.
The goal of decontamination should be to remove as much radioactive material as
possible without damaging the skin. Open wounds should be covered so as to
minimize the risk of internal contamination. The level of contamination should
then be reassessed using the same technique and distance from the skin as in the
primary survey. The goal of decontamination is to reduce the level of
contamination to less than 2 times background radiation or until subsequent
attempts reduce the level of contamination by less than 10%.
Decontamination. 1. Exposure to particle-emitting solids or liquids. The victim
is potentially highly contaminating to rescuers, transport vehicles, and
attending health personnel. 1. Remove victims from exposure, and if their
conditions permit, remove all contaminated clothing and wash the victims with
soap and water. b. All clothing and cleansing water must be saved, evaluated for
radioactivity, and properly disposed of. c. Rescuers should wear protective
clothing and respiratory gear to avoid contamination. At the hospital, measures
must be taken to prevent contamination of facilities and personnel. d. Induce
vomiting or perform gastric lavage if radioactive material has been ingested.
Administer activated charcoal, although its effectiveness is unknown. Certain
other adsorbent materials may also be effective. e. Contact Radiation Emergency
Assistance Center & Training Site (REAC/TS/: telephone (865) 576-3131 or
(865) 481-1000)/ and the state radiologic health department for further advice.
In some exposures, unusually aggressive steps may be needed (eg, lung lavage for
significant inhalation of plutonium). 2. Electromagnetic radiation exposure. The
patient is not radioactive and does not pose a contamination threat. There is no
need for decontamination once the patient has been removed from the source of
exposure, unless electromagnetic radiation emitter fragments are embedded in
body tissues. /Radiation (Ionizing)/
Contamination on the skin can be effectively removed with soap, warm water, and
a washcloth. Care should be taken not to damage the skin by scrubbing. Initial
decontamination efforts can usually be stopped once the contamination level is
reduced to two times the background count rate or if repeated decontamination
efforts are ineffective. ...Contaminated clothing should be placed in
double-sealed bags/containers and labeled. Wash water from large numbers of
people will usually have to be disposed of in the sewer system, but this needs
to be considered at the planning stage.
The cleaning of contaminated wounds will depend on the nature of the injury.
Abrasions can be cleaned using standard decontamination techniques, whereas
lacerations may require excision of the contaminated tissue if irrigation alone
is not effective. Contaminated puncture wounds have sometimes been cleaned
successfully using oral irrigators or water jets but typically are difficult to
decontaminate because of poor access to the contaminants. Wounds containing
radioactive shrapnel must be handled with special care (it has occasionally been
necessary to amputate heavily contaminated extremities when radioactive shrapnel
could not be removed). All contaminated wounds can increase the level of
internal contamination through absorption of radioactive materials directly into
the circulatory and lymphatic systems.
Special Considerations: Most symptoms from radioactive product exposure are
delayed; treat other medical or trauma problems according to normal protocols.
An accurate history of the exposure is essential to determine risk and proper
treatment modalities. The dose of radiation determines the type and clinical
course of exposure: 100 rads: GI symptoms (nausea, vomiting, abdominal cramps,
diarrhea). Symptom onset within a few hours. 600 rads: Severe GI symptoms
(necrotic gastroenteritis) may result in dehydration and death within a few
days. Several thousand rads: neurological/cardiovascular symptoms (confusion,
lethargy, ataxia, seizures, coma, cardiovascular collapse) within minutes to
hours. Bone marrow depression, leucopenia, and infections usually follow severe
exposures. /Radioactives I, II, and III/
Special Considerations. Radiation monitors should be available to evaluate the
radiation dose rates and compute/verify safe times to remain in contaminated
areas. Experts are needed to review the data and provide specific
recommendations to the Incident Commander as to the hazards present in the
affected areas. Medical radiation experts should be available to guide patient
treatment. Most symptoms from radioactive product exposure are delayed; treat
other medical or trauma problems according to normal protocols. An accurate
history of the exposure is essential to determine risk and proper treatment
modalities. The dose of radiation determines the type and clinical course of
exposure: 100 rads: GI symptoms (nausea, vomiting, abdominal cramps, diarrhea).
Symptom onset within a few hours. 600 rads: Severe GI symptoms (Necrotic
gastroenteritis) may result in dehydration and death within a few days. Several
thousand rads: neurological/cardiovascular symptoms (confusion, lethargy,
ataxia, seizures, coma, cardiovascular collapse) within minutes to hours. Bone
marrow depression, leukopenia, and infections usually follow severe exposures.
Assistance and advice on patient care concerns may be obtained from the Oak
Ridge Radiation Emergency Assistance Center and Training Site 24 hours a day by
calling (615) 576-3131 or (615) 481-1000, ext. 1502 or beeper 241. /Radiological
Threats: Radiological Dispersal Devices or Weapons/
Care of Special Populations. Special populations-immunocompromised patients,
equipment-dependent patients (especially those requiring ventilators), disabled
people requiring wheelchairs or other mechanisms of assistance, nursing home
residents, mentally ill people, elderly people, and so on - do not generally
require special treatment, although pregnant women may need extra reassurance
and communication.
A rapid radiological triage for high external exposure can be most easily
accomplished by observing the symptoms of nausea, vomiting, and diarrhea. ...
Exposed people who experience radiation-induced vomiting within approximately 1
hr of the event will require extensive and prolonged medical intervention, and
an ultimately fatal outcome is expected in many cases. If the approximate time
to vomiting is 1-4 hr, these people are likely to require hospitalization and
should be referred for immediate medical evaluation (particularly serial
complete blood counts). If the approximate time to vomiting is greater than 4
hr, the person should be referred for delayed evaluation (approximately 24-72
hr) if no concurrent injury exists. These people may have received doses up to
1000 mSv and may have some minimal bone marrow depression and increased risk of
cancer. However, they do not require specialized hospitalization. For those
without vomiting, no medical follow-up is needed in the immediate or urgent
phases, but medical evaluation on a less urgent basis may be indicated. It
should be noted that stress reactions can induce nausea and vomiting. However,
any person exhibiting these symptoms in the time frames listed above should be
assumed to have been exposed until this is excluded by further medical
evaluation. Studies of peripheral blood cell counts, especially lymphocytes,
during the following days can confirm the decisions...
Nausea, vomiting, diarrhea, and skin erythema within 4 hr may indicate very high
(but treatable) external radiation exposures. Such patients will show obvious
lymphopenia within 8-24 hr, and evaluation for symptomatic patients includes a
complete blood count every 6-12 hours for 2-3 days. Primary systems involved
will be skin, intestinal tract, and bone marrow. Treatment should be supported
with fluids, antibiotics, and transfusion stimulating factors. If there are
early central nervous system findings or unexplained hypotension, survival is
unlikely.
Initial Emergency Department Considerations. Chelating agents or pharmacologic
blocking drugs (potassium iodide, DTPA, BAL, bicarbonate, Prussian blue, calcium
gluconate, ammonium chloride, barium sulfate, sodium alginate, D-penicillamine)
may be useful if given before or immediately after exposure. /Radioactives I,
II, and III/
Initial Emergency Department Considerations. Chelating agents or pharmacologic
blocking drugs (potassium iodine, diethylenetriamine pentaacetic acid (DTPA),
dimercaprol (British antilewisite, BAL), sodium bicarbonate, Prussian blue,
calcium gluconate, ammonium chloride, barium sulfate, sodium alginate, D-penicillamine)
may be useful if given before or immediately after exposure. The Oak Ridge
number listed /in Special Considerations/ can be contacted for specific
treatment advice. /Radiological Threats: Radiological Dispersal Devices or
Weapons/
Medical Management of Acute Radiation Syndrome. In the emergency department,
after airway and breathing have been managed appropriately, iv access should be
established. As with thermal burns, peripheral IV are more prone to infection,
and central venous access is recommended. Fluid replacement may begin with
crystalloid solution where the rate will be modified by recorded inputs and
outputs and assessment of surface area burns if any. Emergency management of
emesis and pain may be difficult in those patients who received a high dose of
radiation. Many types of antiemetics are used to control an irradiated patient's
vomiting. The 5-HT antagonists ondansetron and genisetron are particularly
effective. ... Mild pain may be managed with acetaminophen, but NSAID
medications are not recommended ... Morphine is recommended for the management
of more severe pain. ... As with burn patients, prophylactic use of antibiotics
is not recommended.
If the patient is aware, radioactive source exposure, description, time of onset
of symptoms, and symptom severity should be documented. An early baseline CBC
with differential should be obtained and repeated every 4 to 6 hours to monitor
for declines in the lymphocyte and neutrophil count. In addition, blood may be
obtained after 24 hours for chromosomal aberration biodosimetry.
In the emergency department it is important to obtain blood samples for baseline
lymphocyte count and for blood typing. ... The degrees of lymphopenia and
granulocytopenia within the first 24 to 48 hr postexposure are important for
estimating the dose and directing therapy. Blood typing early is important
because the patient may require transfusions of red blood cells and platelets.
Use of irradiated cells is recommended to avoid graft-versus-host disease.
After medical stabilization, patients should be assessed for radiation injury on
the basis of dose, isotope, and presence of internal contamination. Rapid sort,
automated chromosome biodosimetry and assessment of clinical characteristics
such as the time to emesis post event and lymphocyte depletion kinetics estimate
radiation dose to a patient involved in a mass casualty incident. Time to
emesis, measured from the time of irradiation, decreases monotonically with
increasing dose. For time to emesis less than 4 hours, the effective whole-body
dose is likely to be at least 3.5 Gy. If time to emesis is less than 1 hour, the
whole-body dose probably exceeds 6.5 Gy, and a very complicated and likely fatal
medical course may be expected.
Medical treatment can be more effective if there is readily available data on
the type of radiation that people were exposed to. Data may be basic - such as
whether the radiation was alpha, beta, gamma, neutron, or X-rays, or more
sophisticated, and may include knowledge of specific radionuclides. Hand-held
spectrometers with the capability to identify up to 300 radionuclides are
commercially available. If these instruments were made available to specially
trained personnel ..., they could be used not only to improve the effectiveness
of treating exposed people, but also to provide authorities with rapid data
relative to the nature and scope of the event.
For patients who survive the acute period, sepsis is the leading cause of death.
To maximize survival, patients with a severe radiation exposure should be
treated as other severely burned or immuno-compromised patients regarding their
risk of infection. Rigorous attention must be paid to the proper use of H2
antagonists, antibiotics, antifungals, antivirals, and cultures of body fluids.
If ingestion (as opposed to inhalation) of radioactive material is suspected,
administration of aluminum hydroxide or magnesium carbonate antacids is
indicated to reduce gastrointestinal absorption. Aluminum-containing antacids
should be administered if there is reason to believe that strontium isotopes
have been ingested. If ingestion has occurred no more than 1 to 2 hours before
evaluation, gastric lavage may be performed to reduce internal contamination.
For large ingestions, cathartics (including enemas) may be administered to
decrease gastrointestinal transit time. Pulmonary lavage may be considered after
significant inhalations of insoluble radionuclides but in general is rarely
indicated.
Lymphocyte depletion follows first-order kinetics after high-level gamma and
criticality incidents. An estimation of patient radiation dose may be obtained
from the medical history, serial lymphocyte counts, and time to emesis using
algorithms from the Armed Forces Radiobiology Research Institute's free
Biological Assessment Tool, which may be requested on the Internet.
Depending on the isotope and chemical form, estimates of internal contamination
may be made by collecting a 24-hour stool sample if GI contamination is
suspected and a 24-hour urine sample if other internal contamination is
suspected. Estimates of potential contamination intake may be made by comparing
the known airborne levels and duration of exposure with the derived air
concentration (DAC) limits in the Title 10, Code of Federal Regulations. (A
listing of the DACs can be found in 10 CFR Part 20, Appendix B.)
Treatment with mobilizing or chelating agents should be initiated as soon as
practical when the probable exposure is judged to be significant.
Potassium iodide is the drug of choice to prevent thyroid uptake of radioiodines,
but it provides no protection from external irradiation. It must be administered
within a few hours of exposure to confer its thyroid-protective benefits. ...
Potassium iodide therapy in the setting of acute radioiodine exposure is rarely
indicated in adults older than 40 years and generally only if there is a
projected thyroid dose of 5 Gy or greater. In neonates, infants, and children,
therapy should be initiated to avert as little as 10 mGy of radiation. Potassium
iodide has been associated with rashes, allergic reactions, and gastrointestinal
symptoms. Persons with underlying thyroid disease are at risk for iodine-induced
thyroid dysfunction.
FDA Guidance document recommends that persons with known iodine sensitivity
should avoid potassium iodide, as should individuals with dermatitis
herpetiformis and hypocomplementemic vasculitis, extremely rare conditions
associated with an increased risk of iodine hypersensitivity. Individuals with
multinodular goiter, Graves' disease, and autoimmune thyroiditis should be
treated with caution - especially if dosing extends beyond a few days. Unless
other protective measures are not available, repeat dosing for pregnant females
and neonates in not recommended because of the potential for potassium iodide to
suppress thyroid function in the fetus and neonate. Hospital staff should not
leave patients and the community with the impression that potassium iodide
prevents adverse health effects from radiation exposure in general ...
Iodine prophylaxis. ... The administration of potassium (stable) iodide (KI) to
the public is an effective early measure for protection of the thyroid ... It
must be clearly stated that KI is only useful for protecting the thyroid against
intake of radioactive iodine and it is not a generic "anti-radiation
medicine" as is often implied by the media. In relation to a radiological
attack, the administration of KI as a protective action would only be beneficial
if the attack involved the release of radioiodine. Conversely, the sabotage of a
nuclear installation could lead to the
release of substantive amounts of radioiodine, and the use of KI could well be
justified. ... A limitation of KI is that its efficacy is dependent on its
ingestion either before or immediately after exposure. Due to the short time
available, the distribution of stable iodine may present a practical problem
....Administration of KI will rarely be used as a stand-alone protective action;
it will normally be recommended in conjunction with sheltering or evacuation...
Ferric hexacyanoferrate, or Prussian blue, is an insoluble dye that, when
administered orally, enhances fecal excretion of cesium and thallium from the
body by means of ion exchange. ... Treatment of internal contamination with
cesium-137 is not usually indicated in persons for whom the internal
contamination is less than 1 annual limit of intake (ALI). An ALI for cesium-137
is 200 uCi (7.4 MBq) from inhalation and 100 uCi (3.7 Mbq) from ingestion.
Treating physicians should consult with a qualified health physicist to
determine whether the ALI has been exceeded. At 1 to 10 times the ALI, treatment
is usually indicated. Prussian blue generally should be discontinued once less
than 1 ALI remains in the patient. If, after prolonged therapy, greater than 1
ALI of contamination persists, Prussian blue can also be discontinued at the
discretion of the treating physician.
The FDA recommends that adults and adolescents receive 3 g of Prussian blue 3
times a day and children 2 to 12 years of age receive 1 g 3 times a day for a
minimum of 30 days. Treatment may be individualized, depending on the level of
internal contamination. The most significant adverse effect associated with
Prussian blue is constipation. Prussian blue should be used with caution in
patients with decreased gastrointestinal motility.
Chelation agents may be used to remove many metals from the body. Calcium
edetate (EDTA) is used primarily to treat lead poisoning but must be used with
extreme caution in patients with preexisting renal disease.
Diethylenetriaminepentaacetic acid (DTPA) is more effective in removing many of
the heavy-metal, multivalent radionuclides ... /but/ repeated use of the calcium
salt can deplete zinc and cause trace metal deficiencies. Dimercaprol forms
stable chelates with mercury, lead, arsenic, gold, bismuth, chromium, and nickel
and therefore may be considered for the treatment of internal contamination with
the radioisotopes of these elements. Penicillamine chelates copper, iron,
mercury, lead, gold, and possibly other heavy metals.
Ca- and Zn-DTPA are chelating agents used to treat internal contamination with
the transuranic elements plutonium, americium, and curium. Ca- and Zn-DTPA react
with these elements to form stable ionic complexes, which are then excreted in
the urine. The FDA recommends that therapy be initiated with a single 1.0-g
loading dose of Ca-DTPA in adults (14 mg/kg in children younger than 12 years)
administered intravenously as soon as possible after exposure. Ca-DTPA is
believed to be teratogenic and should not be administered to pregnant women if
Zn-DTPA is available.
The recommended maintenance dose is 1.0 g (14 mg/kg in children) of Zn-DTPA
administered intravenously once a day, administered over days, months, or years,
depending on the level of internal contamination. Ca-DTPA is also effective when
administered by nebulizer. Serum levels of trace minerals, including zinc,
magnesium, and manganese, should be monitored during therapy.
The efficacy of Ca-DTPA and/or Zn-DTPA treatment is good for internal
contamination with the soluble plutonium salts, such as the nitrate or chloride,
but is essentially nil for highly insoluble compounds, such as the high-fired
oxide. The same efficacy is noted experimentally when a soluble (monomeric) form
of plutonium is administered that gradually converts to less soluble (polymeric)
forms as it is distributed and deposited in various tissues in the body. Thus,
chelation is highly dependent not only on the actual metal, but also on the
chemical and physical characteristics of the compound at the time of DTPA
administration. Because the efficiency of chelation decreases with time, DTPA
should be given within 6 hours of exposure, if possible. CONTRAINDICATIONS Ca-DTPA
is contraindicated for minors, pregnant women, patients with the nephrotic
syndrome, and in patients with bone marrow depression. (Such patients may be
treated with Zn-DTPA.) Ca-DTPA should not to be used as a chelator for uranium
or neptunium. Internal contamination with uranium is currently treated by
alkalizing the urine with bicarbonate in order to promote excretion. DTPA has
also been postulated to form an unstable complex with neptunium, which may
increase bone deposition of this actinide.
SYNOPSIS OF TREATMENT REGIMENS FOR INTERNAL EMITTERS (As Described in this
Section; Consult Individual Records for Details)
RADIONUCLIDE
TREATMENT REGIMEN
Strontium
Aluminum-containing antacids
Iodine
Potassium iodide prophylaxis
Cesium
Prussian blue
Thallium
Prussian blue
Lead
Calcium EDTA, penicillamine or dimercaprol
Americium
Calcium or zinc DTPA
Mercury
Dimercaprol or penicillamine
Plutonium
Calcium or zinc DTPA
Arsenic
Dimercaprol
Uranium
Bicarbonates to alkalinize urine
Curium
Calcium or zinc DTPA
Gold
Dimercaprol or penicillamine
Tritium
Water (dilution)
Bismuth
Dimercaprol
Chromium
Dimercaprol
Nickel
Dimercaprol
Copper
Penicillamine
Iron
Penicillamine
INGESTION: General
Aluminum hydroxide or magnesium carbonate antacids
CONTRAINDICATIONS
CaDTPA or ZnDTPA for treatment of neptunium; CaDTPA for pregnant women
Lymphocytes in peripheral blood will decrease significantly within days after
exposure to radiation doses of 1000 mSv and higher ... The extent of this effect
and the time course is dose dependent. After higher whole body doses (>3000
mSv), the number of granulocytes and (later) thrombocytes and erythrocytes will
also decrease. From these changes ... rough dose estimates can be obtained.
More accurate estimates of dose ... can be obtained by cytogenetic measurements.
After significant radiation exposures, chromosomal aberrations become visible,
with the formation of dicentric chromosomes being particularly important for
dose estimation. In recent years, chromosomal translocations have also been
measured by the fluorescence in-situ hybridization technique. In specialized
laboratories, it is possible to estimate doses in the range of approximately 100
mSv and higher from chromosomal aberration studies in peripheral blood
lymphocytes. The technique needs good expertise and is laborious. ... An easier
technique is ... measuring micronuclei in lymphocytes; this method is less
sensitive and laborious, quicker, and a higher number of individuals can be
studied. There are few laboratories in the world experienced in these
techniques, therefore international co-operation is necessary.
Should there be an attack involving radiological or nuclear
materials and affecting a large population, cytogenetic biodosimetry can be used
as a proven technique for calculating the radiation doses to the victims.
Knowing this information ultimately results in better treatment decisions and
better management of valuable response resources. Currently only one laboratory
in the United States has this capacity - the Armed Forces Radiobiology Research
Institute in Bethesda, MD. /As of July 2006/ a new lab operated as part of
ORISE's Radiation Emergency Assistance Center/Training Site (REAC/TS) /is being
established./ ... REAC/TS is /also/ establishing a network of satellite
cytogenetic laboratories nationwide. A number of College of American
Pathologists-accredited laboratories perform non-radiation cytogenetic analysis.
REAC/TS plans to train researchers at these other labs in the specific
techniques required for performing dose estimates during an emergency response.
... In the event of an emergency, blood samples would be sent to /the ORISE/
laboratory partners for initial exams. Then images could be transmitted to ORISE
for expert diagnosis and dose estimation.
After radiation exposure, radicals are formed in the exposed material. They
disappear quickly in soft tissues, but remain in bone and teeth for a longer
period of time. With the ESR method, these radicals can be measured and doses
can be estimated in ranges of several hundred mSv and higher... . Again, there
are only a few specialized laboratories with this capability, which means that
the cytogenetic and ESR methods are not practicable if dose estimates are needed
for more than a few hundred people.
Given the importance of psychosocial factors in such an incident, appropriate
training modules on the unique social-behavioral challenges of radiological
terrorist incidents need to be developed for hospital-based behavioral health
staff. In addition, the availability of such modules needs to be publicized
through professional societies and professional publications. Finally,
behavioral health and social services staff should be included when WMD /weapons
of mass destruction/ training is conducted at a medical facility.
The need for psychological aid ... should be anticipated and provided in the
first hours, days, and weeks after exposure to a traumatic event. The most
important elements of psychological first aid are to provide good medical care,
to offer re-evaluation if symptoms persist, and to educate about the expected
process that occurs for most people over time.
Animal Toxicity Studies:
Toxicity Summary:
Epidemiological studies of radiation exposure provide a consistent body of
evidence for the carcinogenicity of X-radiation and gamma radiation in humans.
Exposure to X-radiation and gamma radiation is most strongly associated with
leukemia and cancer of the thyroid, breast, and lung; associations have been
reported at absorbed doses of less than 0.2 Gy. The risk of developing these
cancers, however, depends to some extent on age at exposure. Childhood exposure
is mainly responsible for increased leukemia and thyroid-cancer risks, and
reproductive-age exposure for increased breast-cancer risk. In addition, some
evidence suggests that lung-cancer risk may be most strongly related to exposure
later in life. Associations between radiation exposure and cancer of the
salivary glands, stomach, colon, bladder, ovary, central nervous system, and
skin also have been reported, usually at higher doses of radiation (>1Gy).
The first large study of sarcomas (using the U.S. Surveillance, Epidemiology,
and End Results cancer registry) added angiosarcomas to the list of
radiation-induced cancers occurring within the field of radiation at high
therapeutic doses. Two studies, one of workers at a Russian nuclear
bomb and fuel reprocessing plant and another of Japanese atomic-bomb survivors,
suggested that radiation exposure could cause liver cancer at doses above 100
mSv (in the worker population especially with concurrent exposure to
radionuclides). Among the atomic-bomb survivors, the liver-cancer risk increased
linearly with increasing radiation dose. A study of children medically exposed
to radiation (other than for cancer treatment) provided some evidence that
radiation exposure during childhood may increase the incidence of lymphomas and
melanomas. In addition, chronic lymphatic leukemia, Hodgkin's disease (malignant
lymphoma), and cancer of the cervix, prostate, testis, and pancreas are
generally considered not to be associated with radiation exposure. X-radiation
and gamma radiation are clearly carcinogenic in all species of experimental
animals tested (mouse, rat, and monkey for X-radiation and mouse, rat, rabbit,
and dog for gamma radiation). Among these species, radiation-induced tumors have
been observed in about 17 tissues or organs, including those observed in humans
(i.e., leukemia, thyroid gland, breast, and lung). X-radiation and gamma
radiation have been shown to induce a broad spectrum of genetic effects,
including gene mutations, minisatellite mutations (changes in numbers of tandem
repeats of DNA sequences), micronucleus formation (a sign of chromosome damage
or loss), chromosomal aberrations (changes in chromosome structure or number),
ploidy changes (changes in the number of sets of chromosomes), DNA strand
breaks, and chromosomal instability. Neutrons induce similar genetic effects as
X-radiation and gamma radiation. They induce a broad spectrum of genetic damage,
including gene mutations, micronucleus formation, sister chromatid exchange,
chromosomal aberrations, DNA strand breaks, and chromosomal instability.
Although the genetic damage caused by neutron radiation is qualitatively similar
to that caused by X-radiation and gamma radiation, it differs quantitatively. In
general, neutron radiation induces chromosomal aberrations, mutations, and DNA
damage more efficiently than does low-LET radiation; DNA lesions caused by
neutron radiation are more severe and are repaired less efficiently; and neutron
radiation induces higher proportions of complex chromosomal aberrations.
Neutrons are clearly carcinogenic in all species of experimental animals tested,
including mouse, rat, rabbit, dog, and monkey. Among these species,
radiation-induced tumors have been observed in at least 20 tissues or organs,
including those observed in humans (i.e., leukemia, thyroid gland, breast, and
lung).
Evidence for Carcinogenicity:
Evaluation. There is sufficient evidence in humans for the carcinogenicity of
X-radiation and gamma-radiation. There is sufficient evidence in experimental
animals for the carcinogenicity of X-radiation and gamma-radiation. Overall
evaluation. X-radiation and gamma-radiation are carcinogenic to humans (Group
1).
Evaluation. There is inadequate evidence in humans for the carcinogenicity of
neutrons. There is sufficient evidence in experimental animals for the
carcinogenicity of neutrons. Overall evaluation. Neutrons are carcinogenic to
humans (Group 1). In making the overall evaluation, the Working Group took into
consideration the following: When interacting with biological material, fission
neutrons generate protons, and the higher-energy neutrons used in therapy
generate protons and alpha particles. Alpha Particle-emitting radionuclides
(e.g. radon) are known to be human carcinogens. The linear energy transfer of
protons overlaps with that of the lower-energy electrons produced by
gamma-radiation. Neutron interactions also generate gamma-radiation, which is a
human carcinogen. Gross chromosomal aberrations (including rings, dicentrics and
acentric fragments) and numerical chromosomal aberrations are induced in the
lymphocytes of people exposed to neutrons. The spectrum of DNA damage induced by
neutrons is similar to that induced by X-radiation but contains relatively more
of the serious (i.e. less readily repairable) types. Every relevant biological
effect of gamma- or X-radiation that has been examined has been found to be
induced by neutrons. Neutrons are several times more effective than X- and
gamma-radiation in inducing neoplastic cell transformation, mutation in vitro,
germ-cell mutation in vivo, chromosomal aberrations in vivo and in vitro and
cancer in experimental animals.
Internalized radionuclides that emit alpha-particles are carcinogenic to humans
(Group 1). In making this overall evaluation, the Working Group took into
consideration the following: (1) Alpha-Particles emitted by radionuclides,
irrespective of their source, produce the same pattern of secondary ionizations
and the same pattern of localized damage to biological molecules, including DNA.
These effects, observed in vitro, include DNA double-strand breaks, chromosomal
aberrations, gene mutations and cell transformation. (2) All radionuclides that
emit alpha-particles and that have been adequately studied, including radon-222
and its decay products, have been shown to cause cancer in humans and in
experimental animals. (3) Alpha-Particles emitted by radionuclides, irrespective
of their source, have been shown to cause chromosomal aberrations in circulating
lymphocytes and gene mutations in humans in vivo. (4) The evidence from studies
in humans and experimental animals suggests that similar doses to the same
tissues, for example lung cells or bone surfaces, from alpha particles emitted
during the decay of different radionuclides produce the same types of non-neoplastic
effects and cancers.
Internalized radionuclides that emit beta-particles are carcinogenic to humans
(Group 1). In making this overall evaluation, the Working Group took into
consideration the following: (1) Beta-Particles emitted by radionuclides,
irrespective of their source, produce the same pattern of secondary ionizations
and the same pattern of localized damage to biological molecules, including DNA.
These effects, observed in vitro, include DNA double-strand breaks, chromosomal
aberrations, gene mutations and cell transformation. (2) All radionuclides that
emit beta-particles and that have been adequately studied, have been shown to
cause cancer in humans and in experimental animals. This includes hydrogen-3
/tritium/, which produces beta-particles of very low energy, but for which there
is nonetheless sufficient evidence of carcinogenicity in experimental animals.
beta-Particles emitted by radionuclides, irrespective of their source, have been
shown to cause chromosomal aberrations in circulating lymphocytes and gene
mutations in humans in vivo. (3) The evidence from studies in humans and
experimental animals suggests that similar doses to the same tissues, for
example lung cells or bone surfaces, from beta particles emitted during the
decay of different radionuclides produce the same types of non-neoplastic
effects and cancers.
Non-Human Toxicity Excerpts:
/LABORATORY ANIMALS: Chronic Exposure or Carcinogenicity/ Groups of 140 to 182
female BALB/c/AnNBd mice, 12 weeks of age, received a single whole-body exposure
to 0.025, 0.05, 0.10, 0.20, 0.50 or 2.0 Gy of fission neutrons at a dose rate of
50-250 mGy per min. The animals were studied for life, and tumors were examined
histologically. A group of 263 controls was available. The ovary was very
sensitive to the induction of tumors (granulosa-cell tumors, luteomas and
tubular adenomas), the incidence increasing from 2% in controls to 76% after
exposure to 0.50 Gy; at 2.0 Gy, the incidence was 56%. For mammary
adenocarcinomas, a linear dose-response relationship was reported up to a dose
of 0.50 Gy, from 8% in controls to 25%. For lung adenocarcinomas, a convex
upward curve was seen over the dose range 0-0.50 Gy. In the dose range 0.1 -0.2
Gy, the dose-response curve for the induction of lung and mammary tumors
appeared to 'bend over'. ... In the same model, the effects of dose rate and of
dose fractionation on the carcinogenic effects of fission spectrum neutrons were
examined for doses of 0, 0.025, 0.05, 0.10, 0.20 or 0.50 Gy in 263 controls and
140 to 191 animals in the various irradiated groups. Whole-body irradiation was
given as a single dose or split at 24-hr or 30-day intervals at dose rates of
10-250 mGy per min, depending on the total dose. The incidence of ovarian tumors
was not altered by fractionation, but lowering the dose rate reduced the
incidence of ovarian tumors and enhanced the frequency of mammary tumors at
doses as low as 0.025 Gy.
/LABORATORY ANIMALS: Chronic Exposure or Carcinogenicity/ In a study of the
influences of strain and sex on the development of tumors, 190 male and 151
female B6C3F1 hybrid ... 65 male and 60 female C3B6F1, 117 male and 112 female
C57BL/6N and 156 male and 139 female C3H/HeN mice, six weeks of age, were
exposed by whole-body irradiation to 0 (control), 0.125, 0.5 or 2 Gy of 252Cf
neutrons at a rate of 6-8 mGy per minute (mean energy, 2.13 MeV; gamma ray
component, 35%) and were observed up to 13 months of age. Tumors were identified
histopathologically. The total tumor incidence was high in C3H/HeN, moderate in
B6C3F1 and C3B6F1 and low in C57BL/6N mice because of high frequencies of liver
tumors in males and ovarian tumors in females. A dose-dependent increase in
liver tumors was reported in both males and females of all strains but the
increase was greater in males than in females. Ovarian tumors were more frequent
in C3H/HeN mice, followed by B6C3F1, C3B6F1 and C57BL/6N. Of the strains and
hybrids, B6C3F1, C57BL/6N and C3H/HeN were the most sensitive to low doses
around 0.50 Gy.
/LABORATORY ANIMALS: Chronic Exposure or Carcinogenicity/ In a series of
experiments during the period 1971-86, thousands of male and female B6C3F1 mice
were exposed by whole-body irradiation to single or fractionated doses of
fission neutrons. ...Several thousand male and female B6C ...mice...were exposed
to 0 to 2.4 Gy of fission neutrons, as single doses, 24 equal doses once weekly
or 60 equal doses once weekly. The mean energy was 0.85 MeV; 2.5% of the dose
was due to gamma radiation and 0.1% was thermal neutrons. A total of 901
age-matched males and 1,199 age-matched females were used as controls.
....Dose-dependent increases in the /lifetime/ incidence of lymphoreticular,
lung, liver, Harderian gland and ovarian tumors were observed. ... A total of
742 male BC3F1 mice, three months of age, were exposed to five equal daily
fractions of fission neutrons with a mean neutron energy of 4 MeV and a 12%
gamma ray component, to yield cumulative doses of 0.025, 0.05, 0.1, 0.17, 0.25,
0.36, 0.535 and 0.71 Gy, given at a rate of 4 mGy per minute. ...The animals
were kept for life, and... the incidence of myeloid leukemia showed a
significant positive trend (Peto's test) at doses of 0-0.17 Gy and up to 0.36 Gy.
The incidence of epithelial tumors was increased significantly (p < 0.001) at
doses from 0.17 Gy, those of liver and lung tumors at doses from 0.025 Gy, that
of skin tumors from 0.36 Gy and that of soft-tissue tumors only at the highest
dose, 0.71 Gy. The total numbers of solid tumors in the lung, liver,
gastrointestinal tract, adrenal gland, kidney, soft tissues, mammary gland,
urinary bladder, vascular system, bone, Harderian gland, skin and salivary gland
were 33, 41, 25, 28, 24, 24, 26, 20 and 27 at the respective doses. There were
no differences in survival or tumor incidence between this study at 4 mGy per
minute and a previous report in which dose rates of 50 and 250 mGy per minute
were used. In a subsequent study, it was shown that male CBA/Cne mice were more
susceptible to tumor induction than females.
/LABORATORY ANIMALS: Chronic Exposure or Carcinogenicity/ A total of 312 adult
female Sprague-Dawley/ANL rats, two to three months of age, were exposed by
whole-body irradiation to single doses of 0 (control), 0.05, 0.10-0.12,
0.18-0.22, 0.35, 0.5, 1.5 or 2.5 Gy of fission neutrons (10-15% gamma ray
contamination) ... . The animals were observed for life, and ... the percentages
of rats with mammary tumor were 48, 78, 85, 73, 80, 84, 87 and 76% at the
different doses, respectively. Of the 126 mammary tumors in 223 rats irradiated
with 0.05-2.5 Gy, 66% were benign ... and 34% were malignant ...
/LABORATORY ANIMALS: Chronic Exposure or Carcinogenicity/ Groups of 15 and 34
female Long-Evans/Simonsen, 14 and 36 female Sprague-Dawley/Harlan, 15 and 34
female Buffalo/Simonsen, 14 and 36 female Fischer 344/Simonsen and 14 and 36
female Wistar-Lewis/Simonsen rats, two months of age, received whole-body
irradiation with a single dose of 0 (control) or 0.5 Gy of fission neutrons. One
year after irradiation, mammary tumors were identified histopathologically. The
Long-Evans and Sprague-Dawley strains were the most sensitive, Buffalo and
Fischer rats were moderately sensitive, and Wistar-Lewis rats were quite
resistant ..., the incidences being 56, 56, 29, 26 and 5.5% in exposed rats of
the five strains, respectively.
/LABORATORY ANIMALS: Chronic Exposure or Carcinogenicity/ A total of 767 male
and female Sprague-Dawley rats, three months of age, were exposed by whole-body
irradiation to fission neutrons at doses of 0.012, 0.02, 0.06, 0.1, 0.3, 0.5
(irradiation period, one day), 1.5, 2.3 (irradiation period, 14 days), 3.9
(irradiation period, 23 days), 5.3 or 8 Gy (irradiation period, 42 days) from a
neutron reactor (1.6 MeV; neutron: gamma ray ratio, 3:1) and were observed for
the induction of pulmonary neoplasms for life. ... The lung tumors /observed/
included bronchogenic carcinomas, bronchoalveolar carcinomas, lung carcinomas,
adenomas and sarcomas. The numbers of animals with lung carcinomas were
dose-dependent up to doses of 2.3 Gy, with a reduced mean survival. The numbers
of animals with lung carcinoma or adenomas also increased at doses up to 2.3 Gy,
but decreased at higher doses. An apparent life-shortening was observed at
higher doses.
/LABORATORY ANIMALS: Chronic Exposure or Carcinogenicity/ A total of 46 male
Beagle dogs, one year of age, were exposed to fast neutrons with a mean energy
of 15 MeV in one of three dose-limiting normal tissues, spinal cord, lung and
brain. The radiation was given in four fractions per week for five weeks to the
spinal cord, for six weeks to the lung or for seven weeks to the brain. ... The
animals were observed for life, and...no tumors were reported in the /11/
unirradiated controls. Nine neoplasms developed within the irradiated fields in
seven dogs receiving fast neutrons...
/LABORATORY ANIMALS: Chronic Exposure or Carcinogenicity/ A large series of
studies ... examined the induction of neoplasms in male and female RF/Un mice
after irradiation with 250-kVp X-rays or cobalt-60 gamma rays over a range of
doses and dose rates. Whole-body irradiation was initiated when the animals were
10 weeks of age, and the animals were allowed to live out their lifespan or were
killed when moribund. All animals were fully necropsied, but only selected
lesions were examined histopathologically, as needed to confirm diagnoses. A
total of 4,100 female and 2,901 male mice were used, with 554 female and 623
male controls. The doses ranged from 0.25 to 4.5 Gy for acute X-irradiation and
from about 1 Gy to 98.75 Gy for chronic cobalt-60 gamma irradiation. An
increased frequency of all neoplasms was observed even at the lowest acute dose.
The specific tumor types found included myeloid leukemia and thymic lymphoma in
both males and females, and an increased incidence of ovarian tumors ... in
females. ... Male mice exposed to X-rays were more sensitive to the induction of
myeloid leukemia than to thymic lymphoma, whereas females exposed to gamma rays
were more sensitive to the induction of thymic lymphoma. Under conditions of a
continuous low dose rate of cobalt-60 gamma irradiation for 23 hours daily, the
incidences of all neoplasms, myeloid leukemia, thymic lymphoma and ovarian
cancer were reduced when compared with acute X-irradiation.
/LABORATORY ANIMALS: Chronic Exposure or Carcinogenicity/ A group of 21 male and
female Dutch rabbits was irradiated with 4.4 to 14.1 Gy of 2.5-MeV gamma rays at
a dose rate of 17.6 Gy per hour; a control group of 17 unirradiated rabbits was
available. The animals were allowed to die naturally, and selected tissues were
examined histologically. Tumors were found in 24% of controls, 75% at 4.4 Gy,
88% at 8.8 to 10.6 Gy and 56% at 11.5 to 14.1 Gy. The tumors included four
osteosarcomas of the jaw, five fibrosarcomas of the dermis and six basal-cell
tumors of the skin.
/LABORATORY ANIMALS: Chronic Exposure or Carcinogenicity/ One of the most
comprehensive ... studies on the induction of cancer by gamma rays was reported
... in male and female RFM/Un mice and in female BALB/c mice exposed to a range
of doses of cesium-137 gamma rays at acute (0.4 Gy/min) and low dose rates (0.08
Gy per 20 hour day). A total of 17,610 female and 1,602 male RFM mice and 5,659
female BALB/c mice were used; ... 4,762 female and 430 male RFM mice and 865
female BALB/c mice served as controls. The doses ranged from 0.1 to 3 Gy for the
RFM mice and 0.5 to 2 Gy for BALB/c mice. ... Male and female RFM/Un mice showed
dose-dependent increases in the frequencies of myeloid leukemia and thymic
lymphoma; females were more sensitive to the induction of thymic lymphoma.
Significantly increased frequencies of thymic lymphomas were observed at doses
as low as 0.25 Gy in both male and female RFM mice. Dose dependent increased
frequencies of ovarian, pituitary and Harderian gland tumors were observed in
female RFM mice ..., with an almost threefold increase in the frequency of
ovarian cancer at 0.25 Gy. Higher doses were required to increase the
frequencies of tumors at other sites. In male RFM mice, only the frequency of
Harderian gland tumors was clearly increased in a dose-dependent manner, and
males and females were equally sensitive to the induction of these tumors.
Lowering the dose rate reduced the carcinogenic effectiveness of the radiation.
In the same study, female BALB/c mice were not sensitive to the induction of
leukemia or lymphoma over the dose range used (0.5-2.0 Gy), but dose dependent
increased frequencies of ovarian tumors and significant increases in the
frequencies of lung and mammary adenocarcinomas were observed even at the lowest
dose. Again, lowering the dose rate markedly reduced the carcinogenic effect.
Subsequent studies ... provided extensive data on the dose response and
time-dose relationships of cesium-137 gamma rays in the induction of both lung
and mammary adenocarcinomas in female BALB/c mice at doses as low as 0.1 Gy. ...
Chronic exposure at a low dose rate (0.08 Gy per day) reduced the risk, while
the effects of fractionated doses depended on the fraction size. ... When
multiple small acute daily fractions of 0.01 Gy were given, the results were
similar to those with the low dose rate, whereas the cancer incidence after the
same total doses were delivered as 0.05-Gy daily fractions was similar to that
after single acute doses.
/LABORATORY ANIMALS: Chronic Exposure or Carcinogenicity/ ... /In/ a large
series of experiments with more than 8,000 male and female B6CF1... mice, which
were irradiated with cobalt-60 gamma rays at 0.225-7.88 Gy at high dose rates,
at 0.225-24.6 Gy at low dose rates, or in fractionation regimens, increased
frequencies of lymphoreticular tumors, tumors of the lung and Harderian gland
and all epithelial tumors were observed in male mice, which appeared to increase
as a linear function of dose. In addition, increased frequencies of ovarian
tumors were observed in female mice... . Protraction or fractionation of the
dose reduced the carcinogenic effects of the radiation.
/LABORATORY ANIMALS: Chronic Exposure or Carcinogenicity/ A total of 398 female
adult Sprague-Dawley rats were divided into seven groups and exposed to gamma
rays ...: to single doses of 5 Gy at 40 days of age or 160 days of age or to
four fractionated doses of 1.25 Gy; to eight fractions of 0.62 Gy; to 16
fractions of 0.3 Gy or to 32 fractions of 0.15 Gy at 40 days of age. One group
was sham-irradiated. All of the fractionated doses of cobalt-60 gamma rays were
delivered twice weekly at a dose rate of 0.40 Gy/min. The incidence of mammary
tumors (adenocarcinomas, adenofibromas and fibroadenomas) was determined
histologically up to the age of 1,000 days. An increased frequency of mammary
fibroadenomas and, to a lesser extent, adenocarcinomas, was observed, with 64 in
controls and 92, 90, 96, 89, 85 and 87% with the different regimes,
respectively. No significant difference between single and fractionated
exposures was reported.
/LABORATORY ANIMALS: Chronic Exposure or Carcinogenicity/ A total of 191 female
adult Sprague-Dawley rats, 61-63 days of age, were given single whole-body doses
of 0.28, 0.56 or 0.85 Gy of 250-kVp X-rays at a dose rate of 0.30 Gy per minute.
...The animals were observed over their lifespan (1,033-1,053 days) for the
induction of mammary tumors, and the neoplasms were identified
histopathologically as adenocarcinomas or fibroadenomas. The incidences of
mammary tumors were 67% in /167/ controls and 72, 77 and 79% in the irradiated
groups, showing a dose-dependent increase in all mammary tumors and in
particular in fibroadenomas. The principal effect of the irradiation was to
cause an earlier time of onset of fibroadenomas, which was dose-dependent.
/LABORATORY ANIMALS: Chronic Exposure or Carcinogenicity/ Groups of...female
WAG/Rij, BN/Bi and Sprague-Dawley rats, eight weeks of age, were exposed by
whole-body irradiation to a single dose of 300-kVp X-rays (Sprague-Dawley rats,
0.1, 0.3, 1 or 2 Gy; WAG/Rij and BN/bi rats, 0.5, 1 and 4 Gy [dose rate not
given]). ...The animals were observed for life, and the mammary tumor incidences
were determined by gross and histopathological observations. A dose-dependent
increase in the incidence of all mammary tumors was observed: Sprague-Dawley
rats, 30 (control), 70, 72, 75 and 86%; WAG/Rij rats, 27 (control), 26, 35 and
76%; and BN/Bi rats, 8 (control), 15, 86 and 88%.
/LABORATORY ANIMALS: Chronic Exposure or Carcinogenicity/ Groups of 120 male and
female Beagle dogs, aged 2 or 70 days, were exposed by whole-body irradiation to
0.88 or 0.83 Gy of cobalt-60 gamma rays, and a further group of 240 dogs
received 0.81 Gy at 365 days of age; 360 controls were available. ... In 1,343
dogs allowed to live out their life span, heritable lymphocytic thyroiditis with
hypothyroidism was a major contributor to mortality. Of 86 dogs irradiated at 70
days of age, 25/86 had thyroid follicular adenomas and 10/86 had carcinomas,
which represented a significant increase (p < 0.01) over the 40/231 controls
with adenomas and 16/231 with carcinomas. No significant increase in the
incidence of thyroid tumors was found in dogs irradiated at 2 or 365 days of
age. The irradiated dogs showed a consistent trend for a lower incidence of
hypothyroidism when compared with controls. Hypothyroidal dogs had a
significantly increased risk for thyroid neoplasia, including a greater risk for
carcinomas, but no evidence was found in this group of a greater sensitivity to
radiation-induced tumors.
/LABORATORY ANIMALS: Chronic Exposure or Carcinogenicity/ Twenty rhesus monkeys
(Macaca mulatta), three years of age, were exposed by whole-body irradiation to
doses of 4 to 8.6 Gy of X-rays (300 kVp; half-value layer, 3 mm Cu) at a dose
rate of 0.3 Gy per minute. A few hours after irradiation, most of the animals
received intravenous grafts of 2-4 x10+8 autologous bone-marrow cells. Between
7.5 and 15.5 years later, eight animals developed malignant tumors, comprising
five adenocarcinomas of the kidney, two follicular carcinomas of the thyroid,
two osteocarcinomas and one glomus tumor of the subcutaneous tissues. No
malignant tumors occurred in 21 controls within 18 years.
/LABORATORY ANIMALS: Chronic Exposure or Carcinogenicity/ A total of 3,265
female RFM/Un mice, 12 weeks of age, received whole-body irradiation with
neutrons at doses of 0.048, 0.096, 0.192, 0.24, 0.47, 0.94 or 1.88 Gy at rates
of 50 or 250 mGy per minute or 10 mGy per day. A reactor was used to deliver the
high dose rate, and the low dose rate was produced from a 1.1-mg californium-252
source surrounded by a depleted uranium-238 sphere. The ratios of neutrons to
gamma rays were 7:1 for the reactor and 3:1 for the californium-252 source. A
control group of 648 mice was available. The animals were followed for life, and
tumors were diagnosed histologically. A positive dose-response relationship for
thymic lymphoma was observed at all doses up to 1.0 Gy at both dose rates; at
the highest dose, the low dose rate was more effective. At low doses, a weak
dependence on rate was observed. Increased incidences of thymic lymphoma, lung
adenoma and endocrine tumors were seen at doses as low as 0.24 Gy. The highest
dose of radiation at the low rate (10 mGy per day) appeared to induce thymic
lymphomas more efficiently than irradiation at the high dose rate (250 mGy per
minute). The incidence of ovarian tumors was lower at all doses given at the low
rate than at the high rate. After exposure to doses of 0.24 to 0.47 Gy, the RBE
/relative biological effectiveness/ for thymic lymphoma was 3 to 4 in relation
to acute exposure to cesium-137 gamma rays, and the induction of mammary tumors
also appeared to be more sensitive to neutrons; however, no apparent effect of
dose or dose rate was reported over the dose range used. Because of the
relatively large carcinogenic effect, the authors concluded that the gamma
radiation component had little or no effect on the dose-response relationship
observed.
/LABORATORY ANIMALS: Developmental or Reproductive Toxicity/ Groups of pregnant
female BC3F1... mice were exposed to 0, 0.09, 0.27, 0.45 or 0.62 Gy of fission
neutrons (mean energy, about 0.4 MeV; gamma ray contamination, about 12% of the
total dose; minimum and maximum fast neutron dose rates, about 0.049 and 0.248
Gy per minute on day 17 of gestation and were allowed to deliver their
offspring, which were observed for life. ... A total of 379 offspring were
necropsied. The incidences of liver adenomas and carcinomas were increased to
11, 31, 29 and 52% with the respective neutron doses but decreased to 18% after
exposure to the highest dose of 0.62 Gy.
/LABORATORY ANIMALS: Developmental or Reproductive Toxicity/ Groups of male C3H
mice, seven weeks of age, were exposed by whole body irradiation to neutrons
(californium-252; mean energy, 2.13 MeV) at total doses of 0, 0.5, 1 or 2 Gy and
were mated two weeks or three months later with unexposed C57BL females. On day
18 of gestation, some pregnant mice were killed to detect dominant lethal
mutations. The incidence of dominant lethal mutations increased in a dose
dependent manner only after postmeiotic exposure, at two weeks. The other
pregnant mice were allowed to deliver, and a total of 387 offspring were killed
at the age of 14.5 months. ... The numbers of liver tumors per male offspring of
male mice exposed to 0.50 or 1 Gy californium-252 at either the postmeiotic or
the spermatogonial stage were significantly higher than those in unirradiated
controls. No increase in the incidence of liver tumors was observed in female
offspring. The offspring of male parents irradiated with 2 Gy two weeks before
mating did not survive more than two days after birth.
/LABORATORY ANIMALS: Developmental or Reproductive Toxicity/ C57BL/6 female
mice, 10-14 weeks of age, were mated with WHT/Ht males... . Subsequently, 19
pregnant females were irradiated with approximately 2 Gy of X-rays ... at a dose
rate of 0.86 Gy per min on days 12 or 16-18 post coitum. A total of 573 male and
female offspring were delivered and observed for life, and all suspected lesions
or tumors were examined histopathologically. The control group consisted of 141
unirradiated C57BL/6 x WHT/Ht offspring of 19 mice. Significant increases were
found in the incidences of tumors of the lung (both sexes), the pituitary gland
(females) and the ovary of the offspring that had been irradiated on days 16-18
post coitum ... whereas X-irradiation at day 12 post coitum did not increase the
incidence of tumors in the offspring. In a study of 167 B6WF1 (C57BL/6 x WHT/Ht)
female mice irradiated 17 days post coitum with approximately 1.5 or 3 Gy of
X-rays ... at a dose rate of 0.5-0.6 Gy per minute the offspring were allowed to
die naturally. Significant increases were observed in the incidences of
hepatocellular tumors in both male and female offspring in a dose-dependent
manner.
/LABORATORY ANIMALS: Developmental or Reproductive Toxicity/ A total of 410
C57BL/6 female x DBA/2 male fetuses were exposed to 0.2, 0.5, 1.0 or 2.0 Gy of
cobalt-60 gamma rays on day 18 of gestation and were killed and autopsied when
moribund or at two years of age. Tissues showing macroscopic alterations were
submitted to histopathological examination. ... Tumors were found mainly in the
lung, uterus and lymphoid tissues, and the total tumor incidence was
significantly increased at 0.5, 1.0 and 2.0 Gy.
/LABORATORY ANIMALS: Developmental or Reproductive Toxicity/ Groups of 60 male
and 60 female Beagles received mean doses of 0.16 or 0.83 Gy of cobalt-60 gamma
radiation on day 8 (preimplantation), 28 (embryonic) or 55 (late fetal) post
coitum ... . As controls, 360 dogs were sham-irradiated. The tumors found
predominantly in the offspring of irradiated and unirradiated bitches up to 16
years of age were malignant lymphoma, hemangiosarcoma and mammary carcinoma.
Analysis of trends with increasing dose indicated that the incidences of both
fatal malignancies and all neoplasms were significantly increased in the
offspring of bitches irradiated on day 55 post coitum, while no significant
increase was observed after exposure in utero at day 28 post coitum; however,
the incidence of fatal hemangiosarcomas was significantly increased in the
offspring of bitches exposed on day 8 post coitum.
/LABORATORY ANIMALS: Developmental or Reproductive Toxicity/ Male and female ICR
mice were treated with X-rays ... at 0.36, 1.08, 2.16, 3.6 or 5.04 Gy at a dose
rate of 0.72 Gy per minute and mated with untreated mice at various intervals
... to examine the sensitivity of germ cells at different stages. About half of
the pregnant mice were killed just before delivery (day 18 of gestation), and
the others were allowed to deliver live offspring. Significant increases in the
frequencies of dominant lethal mutations and congenital malformations were
observed in a dose-dependent manner after exposure of the spermatozoa and
spermatid stages to X-rays. Groups of 1,529 and 1,155 live offspring of male and
female exposed parental mice were killed at eight months of age, and suspected
tumors were diagnosed histopathologically. ... Significant increases in the
incidences of total tumors were reported after paternal (153 of 1,529, 10.0%)
and maternal exposure (101 of 1,155, 8.7%), when compared with controls (29 of
548, 5.3%; p < 0.01-0.005 ...). About 87% of the induced tumors were in the
lung. At both germ-cell stages, the tumor incidence in the offspring increased
in a nearly linear, dose-dependent mode after paternal exposure, and the
increase was statistically significant at the high doses ... . The sensitivity
at the spermatogonial stage was about half that at the spermatid stage. No
increase in the incidence of tumors was observed in offspring after maternal
exposure to up to 1.08 Gy, but the incidence increased significantly at higher
doses. When male and female parental mice were treated with doses of 0.36 Gy of
X-rays at 2 hour intervals, fractionation significantly reduced the carcinogenic
effects of irradiation in offspring exposed at the spermatogonial and mature
oocyte stages; however, no such reduction was observed when postmeiotic stages
were treated. In another study, F1 offspring of X-irradiated male mice were
mated and their progeny were examined. Significantly higher incidences of tumors
were observed in the F2 generation of F1 progeny that had tumors. The author
suggested that germ-line alterations that caused tumors were transmitted to the
next generation.
/LABORATORY ANIMALS: Developmental or Reproductive Toxicity/ ... male mice of
the N5 and LT strains were ... treated with 5.04 Gy of X-rays at the
spermatogonial or postmeiotic stage, respectively, and 229 irradiated and 244
unirradiated N5 offspring and 75 irradiated and 411 unirradiated LT offspring
were killed at 12 months of age. A significant increase in the incidence of
lymphocytic leukemias was observed: N5 strain, 3.9% versus 0.4% in controls and
LT strain, 5.3% versus 1.0% in controls (p < 0.05 ...).
/LABORATORY ANIMALS: Developmental or Reproductive Toxicity/ Groups of 27-28
male N5 mice were irradiated... with 0 (control) or 5 Gy of X-rays... [dose rate
not given] and mated 3, 7, 10 or 17 days after irradiation; 312 irradiated and
305 unirradiated offspring were observed until they were killed at one year of
age. ...The probability of dying from leukemia ... and overall survival...were
statistically significantly different (p < 0.05) in the offspring of
X-ray-treated males and unirradiated controls. The incidences of leukemia at one
year of age were 11/165 (6.7%) in those exposed to X-rays and 10/305 (3.3%) in
controls... .
/LABORATORY ANIMALS: Developmental or Reproductive Toxicity/ The present
investigation was carried out to study the effects of in utero exposure to
low-level gamma radiation (0.25, 0.35, or 0.50 Gy) on the postnatal
neurophysiology and neurochemistry of the mouse. Pregnant Swiss albino mice were
irradiated on days 11.5, 12.5, 14.5, or 17.5 post coitus (PC) and allowed to
deliver. Locomotor and exploratory activities, learning and memory functions,
and emotional activities were tested at 3 months of age using behavior tests. A
representative group of animals was killed and hippocampal biogenic amines,
noradrenaline, dopamine, serotonin (5-HT), and 5-HT's metabolite 5-hydroxy
indoleactetic acid (5-HIAA), were measured. Exposure to 0.25 Gy at any of the
gestation days did not produce any significant impairment in brain functions.
However, an increase in gamma irradiation to 0.50 Gy on all the gestation days
produced significant impairment in locomotor (open-field test) and anxiolytic
(light and dark area test) activities, learning (hole board test), memory
functions (active avoidance test), and emotional activity (rearings). The late
fetal period is relatively resistant to radiation-induced impairment of brain
functions. Both of the organogenesis gestation days showed a higher sensitivity
than the fetal gestation days studied. Even a lower dose of 0.35 Gy when exposed
on the late organogenesis days 11.5 and 12.5 PC, produced significant reduction
in locomotor and exploratory activities. Day 11.5 PC showed a higher sensitivity
than the other PC days studied. Biogenic amines did not show significant change
after any of the exposures on any of the gestation days. The results suggest a
threshold between 0.25 to 0.35 Gy for postnatal neurobehavior changes.
/LABORATORY ANIMALS: Developmental or Reproductive Toxicity/ The aim of the
study was to investigate the effects of subchronic irradiation of male mice on
reproduction ability and induction of male-mediated teratogenesis. Male mice
were irradiated to 0.05 Gy, 0.10 Gy and 0.20 Gy daily for 8 weeks, 5 days per
week. The total doses were 2.00 Gy, 4.00 Gy and 8.00 Gy, respectively. After the
end of exposure each male was caged with two untreated females. The females were
sacrificed on day 17 based on the finding of a vaginal plug. Females were
examined for the number of live and dead implantations and the incidence of
congenital malformations of survival fetuses. The fertilization ability of males
was not diminished. The exposure to 0.20 Gy daily significantly decreased the
percent of pregnant females and the number of total implantations. Exposure to
0.10 Gy and 0.20 Gy daily caused decreases in the number of live fetuses and
induced dominant lethal mutations (over 50% at the highest dose). Exposure to
each dose significantly enhanced the number of deaths (especially early)
implants. The incidence of gross and skeletal malformations was not
statistically significant, except for skeletal malformations at the highest
dose. /The authors concluded that the /Results confirmed that irradiation of
male germ cells cause genetic effects which could be transmitted to the
offspring. After subchronic exposure to low doses the majority of mutations
caused premature death. Subchronic exposure to low doses of X-rays did not
induce external and skeletal malformations of surviving fetuses.
/GENOTOXICITY/ The effects of 2.3-MeV (mean energy) neutrons and 250-kVp X-rays
on cell survival and DNA double-strand break induction and repair (measured by
neutral elution) were investigated in Chinese hamster V79 cells. The lethal
effects of neutrons were ... significantly greater than those of a similar dose
of X-rays (RBE, 3.55 at 10% survival), but the RBE (relative biological
effectiveness) for double-strand break induction, in a dose range of 10-50 Gy,
was 1. ...
/GENOTOXICITY/ Six European laboratories collaborated in a study that was
specifically designed to address the issue of the dose response at low doses of
low-LET radiation with the C3H10T1/2 transformation... Dose-response data were
obtained for exposure to 250 kVp x-rays at dose intervals from 0.25 to 5 Gy, and
a total of 51,000 petri dishes were scored. In total, 759 transformed loci were
obtained, far in excess of the numbers reported in any other study involving
low-LET radiation and the C3H1-T1/2 cell transformation system.
/GENOTOXICITY/ In experiments with synchronized mouse C3H10T1/2 cells, /it was/
found that the G1 phase of the cell cycle (4-6 hr after mitotic 'shake-off') was
the most sensitive to neutron-induced oncogenic transformation, in contrast to
what has been observed with X-radiation where the peak was 14-16 hr after
'shake-off', reflecting mostly G2 cells.
/GENOTOXICITY/ Sister chromatid exchanges were scored in bone-marrow cells from
... rats as a function of time after exposure to 2 Gy of whole-body radiation
with 1-MeV fission neutrons. ... In controls, the mean number of sister
chromatid exchanges per cell remained constant from 3 to 24 months of age (2.38
per cell; SD, 0.21), but irradiation induced two distinct increases in the
frequency: the first occurred during the days following exposure and the second
between days 150 and 240. ... Between the two increases (i.e. days 15-150), the
number of sister chromatid exchanges dropped to control values. Analysis of the
distribution per cell showed that the changes were not confined to a particular
cell population. These results suggest that, in irradiated rats, the second
increase in sister chromatid exchange coincides with tumor growth, whereas the
first increase may be due to DNA damage that is rapidly repaired.
/GENOTOXICITY/ DNA lesions induced by fast neutrons in L5178Y mouse lymphoma
cells were classified into three types on the basis of their repair profiles:
rapidly repaired breaks (half-time, 3 to 5 min), slowly repaired breaks (70 min)
and unrepairable breaks. ...Neutrons induced less rapidly repaired damage, a
nearly equal amount of slowly repaired damage and more unrepairable damage when
compared with equal doses of gamma-radiation or X-radiation.
/GENOTOXICITY/ Gene mutations and chromosomal aberrations are induced in
mammalian cells many times more efficiently by neutrons than by the same
absorbed dose of X- or gamma-radiation. Fission neutrons have been shown to
induce germ-line mutations in mice, including visible dominant mutations,
dominant lethal mutations, visible recessive mutations and specific locus
mutations. When compared with sparsely ionizing radiation on the basis of
absorbed dose, fission neutrons are many-fold more effective.
/GENOTOXICITY/ Radiation-induced genomic instability /is/ the manifestation of
genetic damage in a certain fraction of irradiated cells over many cell cycles
after they were irradiated. This persistent instability is expressed as
chromosomal rearrangements, chromosomal bridge formation, chromatid breaks and
gaps, and micronuclei in progeny of cells that survive irradiation. Reduction in
cell cloning efficiency several generations after irradiation is called delayed
lethality; it is supposedly a manifestation of genomic instability associated
with an increase in lethal mutations. Also, gene mutations, such as HPRT
mutations, that arise de novo several generations after irradiation are thought
to be another manifestation of genomic instability. ...The similarity in the
frequencies of genomic instability induced in X-irradiated cells... and the
frequencies of chromosomal aberrations induced directly by irradiation may
suggest that induction of chromosomal aberrations is a primary event that plays
a major role in radiation-induced genomic instability. ... Because chromosomal
instability has been associated with breakage-fusion-bridge cycles, the roles of
telomers may be particularly relevant.
/GENOTOXICITY/ /An/ apparent adaptive response has been well documented for
induction of chromatid-type breaks and mutations in human lymphocytes stimulated
to divide. ... For several mammalian cell lines in culture, an adaptive response
for cell lethality after doses of 200-600 mGy and for enhanced removal of
thymine glycols after a dose of 2 Gy have been observed 4-6 hr after a priming
dose of 200 mGy. In Chinese hamster V79 cells, the rate of repair of DNA double
strand breaks induced by 1.5 or 5.0 Gy was increased 4 hr after a priming dose
of 50 mGy. The adaptive responses of mammalian cells described above, at least
for cell survival and repair of DNA strand breaks, may be associated in part
with the down-regulation of a gene, DIR 1?
/GENOTOXICITY/ A bystander effect has been demonstrated conclusively for cells
in culture exposed to high-LET radiation, usually alpha particles. ... A single
alpha particle traversing a cell can induce Hypoxanthine
PhosphoRibosylTransferase (HPRT) mutations, sister chromatid exchanges,
upregulation of p21 and p53, down-regulation of cyclin B1, cdc2, and rad51 in
unirradiated cells. At least for the bystander effect on signal-transduction
pathways and induction of mutations, the irradiated and nonirradiated cells had
to be in contact with each other through gap junctions. ... Regardless of the
molecular mechanisms involved, the bystander effects observed with high-LET
particles may have important implications for low doses of high-LET radiation.
/GENOTOXICIY/ In brief, aberration complexity reflects the number of DNA double
strand breaks involved in a given chromosomal exchange event... . The precise
mechanism of formation of these complexes remains uncertain, but multiple
pairwise exchanges involving the same chromosomes does play some part. However,
cyclic exchanges involving three and four breaks are not uncommon, implying that
the interaction of multiple DNA double strand breaks can occur. Recent studies
using multicolor FISH analyses further emphasize the complexity of many
radiation-induced chromosomal exchanges produced after high acute doses of
radiation. These multicolor FISH analyses also show that even after exposure at
very low dose rates, the formation of complex chromosomal exchanges is not
completely eliminated.
/ALTERNATIVE IN VITRO STUDIES/ The problem of determining RBE (relative
biological effectiveness) values for Auger emitters incorporated into
proliferating mammalian cells is examined. In general, the reference radiation
plays a key role in obtaining experimental RBE values. Using survival of
cultured Chinese hamster V79 cells as the experimental model, new data are
provided regarding selection of a reference radiation for internal Auger
emitters. These data show that gamma rays delivered acutely (cesium-137) are
more than twice as lethal as gamma rays delivered chronically with an
exponentially decreasing dose rate (technicium-99m). The results confirm that
the reference radiation should be delivered chronically in a manner consistent
with the extended exposure received by the cells in the case of incorporated
radionuclides. Through a direct comparison of the radiotoxicity of Auger
emitters and alpha emitters, the high RBE values reported for DNA-bound Auger
emitters are confirmed. These studies reveal that the DNA binding compound
(iodine-125)iododeoxyuridine (125-IdU) is about 1.6 times more effective in
killing V79 cells than 5.3 MeV alpha particles from intracellularly localized
polonium-210 citrate. In addition, toxicity studies with the radiochemicals
125-IdU and (125)-iododeoxycytidine (125-IdC) establish the equivalence of the
radiosensitivity of thymine and cytosine base sites in the DNA. In view of these
results, and information already available, the question of establishing quality
factors for Auger emitters is considered. Finally, a method for calculation of
the dose equivalent for internal Auger emitters is advanced.
/OTHER TOXICITY INFORMATION/ Dose rate, i.e., the time over which a radiation
dose is delivered, may influence risk in a variety of ways. In experimental
animals, the risk per unit dose is usually greater at higher dose rates, for the
same cumulative dose of low-LET radiation.
/OTHER TOXICITY INFORMATION//LUNG/ Damage to the lung induced by neutron
radiation occurs both early, described as pneumonitis, and late after exposure,
in the form of fibrosis. In contrast to most other tissues, the lung does not
show significant differences in the RBE (relative biological effectiveness)
values for early and late effects.
Ecotoxicity Excerpts:
/BIRDS and MAMMALS/ MORBIDITY AND MORTALITY. For organisms other than man,
morbidity (and mortality) are usually only considered as a consequence of acute
(short term) high dose radiation exposure. Laboratory or controlled field
studies of radiation-induced mortality usually determine the total dose required
to kill 50 per cent of the organisms, the LD50, within a specified period of
time immediately post-exposure. Part of the wide variation in apparent
radiosensitivity is due to the use of a 30 day time period for assessing the
expression of the radiation-induced mortality (giving the LD50/30) although this
is strictly applicable only to small mammals where essentially all the deaths
occur within this interval. For fish and other aquatic organisms it has been
shown that a 50 to 60 day period is necessary to encompass the acute response as
a consequence of their poikilothermic metabolism giving an increase in apparent
radiosensitivity. Adjustment of the data for this factor reduces, but does not
eliminate, the general tendency for radiosensitivity to increase with the
increasing biological complexity of the organism. Another factor which
influences the relative radiosensitivity between groups, e.g. insects and
mammals, arises from the developmental progression through the life cycle. In
the former, most of the cellular proliferation and differentiation occurs in the
developing embryo, whereas for the latter, it continues in certain tissues
throughout life. In general, developing embryos are more radiosensitive than
fully formed adults and across groups of organisms this again tends to reduce
the overall range of radiosensitivity; the developing vertebrate embryo does,
however, retain its position of greatest radiosensitivity.
/BIRDS and MAMMALS/ The FASSET project has established that there are major gaps
in the scientific knowledge base of effects of radiation on plants and animals,
particularly for chronic exposures at dose rates typical of those in the
environment. Much of the data is old and relates to relatively high dose rates
and acute exposures. From the available data, and in general, for most studies,
the threshold for statistically significant effects on individual organisms is
about 100 uGy per hr; the responses then increase progressively with increasing
dose rate and usually become very clear at dose rates >1000 uGy per hr.
/BIRDS and MAMMALS/ Black-headed gulls: Type of exposure - acute and chronic.
Acute exposure of 0.48 Gy/min given on day 10 of incubation, known to be the
most sensitive stage. Chronic exposure continuous at rates between 0.004 and
0.08 Gy/hr for 20 day during incubation. Hatching was deemed successful if the
chick freed itself from at least half of the eggshell. The mortality peaks
suggest that day 10 of incubation is the most radiosensitive stage of
development. Acute and chronic doses >9.6 Gy produced an increase in the
incidence of foot and leg deformities (up to 50% of the chicks at 9.6 Gy
exhibited such effects). Dead embryos were examined for gross congenital
abnormalities.
/AQUATIC SPECIES/ Fish: radiobiological studies have indicated that these are
probably the aquatic organisms most sensitive to radiation. Assessments for
bathypelagic and benthic types allow the contribution from gamma-emitters in the
sediment to be highlighted. Large crustaceans: these organisms generally have
higher concentration factors than fish, thus increasing the importance of
internal exposure relative to external sources. Again, assessments for
bathypelagic and benthic types show the importance of both beta- and
gamma-emitters in the sediment. Molluscs: these organisms generally have higher
concentration factors than the previous two groups and, with smaller size, show
the effect of these factors on dose rate; Small crustaceans: assuming that the
data available for surface-living zooplankton are applicable, these organisms
would have the highest concentration factors for most elements. Also, being the
smallest organisms, they show most clearly the effects of size on the relative
contributions of internal and external sources.
/AQUATIC SPECIES/ This report summarizes the scientific literature on the
effects of radiation on aquatic animals such as fish and concludes that these
scientific studies have shown that reproductive and early developmental effects
are the most important responses to chronic exposure. In field studies,
detrimental effects have not been observed at radiation levels that are within
public health guidelines for human exposures.
/AQUATIC SPECIES/ The paper presents the extraction of data from the EPIC
database, outlining the effects of chronic radiation exposure in fish. The EPIC
database ?Radiation effects on aquatic biota? is compiled as part of the current
European Community Project EPIC (Environmental Protection from Ionizing
Contaminants in the Arctic). The EPIC database is based on information from
publications in Russian (Russian/former Soviet Union data). The data are focused
on the effects in fish at relatively low doses of chronic radiation exposure.
The effects are grouped by three key endpoints: morbidity, reproduction, and
mortality/life shortening. A preliminary scale of dose - effects relationships
for fish has been constructed.
/AQUATIC SPECIES/ Uncertainties associated with the effects from chronic
low-level exposures to radiation prompted /the authors/ to construct a Low Dose
Rate Irradiation Facility (LoDIF). The facility was designed specifically to
test the appropriateness of the 10 mGy per day guideline often espoused as
acceptable for protection of aquatic biota from ionizing radiation. Scientists
at the 0.4 ha facility use 40 outdoor mesocosms and cesium-137 irradiators of
three different source strengths to research the effects of chronic low-level
irradiation at different levels of biological organization. ... Results from a
pilot study in which Japanese medaka (a small fish native to Asia) were
chronically irradiated at the highest dose rate possible within the facility
(350+/-150 mGy per day). Irradiated fish produced fewer eggs per day (p=0.03);
had a lower percentage of viable eggs (p=0.04), and produced a lower percentage
of hatchlings (p=0.05). Although these data are not surprising based on the
relatively high dose rates, they are important to future work at the LoDIF...
/AQUATIC SPECIES/ Pleuronectes platessa (Plaice): acute external exposure to
x-rays; a dose of 30 rads has little effect on % survival at time of hatch
whereas doses above 150 rads kill the majority of the larvae before
metamorphosis.
/AQUATIC SPECIES/ Salmo gairdnerii (Rainbow trout) acute external exposure to
X-rays at 0.1, 1, and 10 Gy. Endpoint number of embryos with visible
malformations at 0.5 to 1.5 days. Various malformations were apparently
identical to those previously observed as a consequence of irradiations of sperm
and egg. Thus, vulnerable processes must be upset in similar ways in the embryo.
Irradiated groups are not significantly different to controls.
/OTHER TERRESTRIAL SPECIES/ Aphidae Aphids (insects): Transitory exposure in a
field study of mixed radiation type in the Chernobyl 5-km zone in 1986; The
estimated dose was 50 Gy and the specific endpoint was numbers of aphid species.
Only two species of aphids were found on birch trees which usually contain 12 to
14 species. In the investigated zone, such common species as Aphis pomi, A.
craccivora, A. sambuci, Myrus ceraci and others were absent or very rare.
/OTHER TERRESTRIAL SPECIES/ Rana arvalis (Brown frog); in field studies between
1987 and 1989 in the Chernobyl 30-km zone; chronic exposure to mixed radiation.
The chromosome aberration frequency in cells was higher than the control by 4 to
7 times in 1987, by 2 to 5 times in 1988 and by 2 to 3 times in 1989.
/PLANTS/ GAMETOGENESIS: Available reviews do not provide any detailed discussion
of the effects of radiation on gametogenesis in plants and there appear to be
few data in the literature. A single reference notes that flowering and seed set
occurred in the herbaceous plant, Carex pensylvanica, in the dose rate range
0.1716 Gy per day. This plant species was, however, fairly resistant to the
damaging effects of radiation in somatic tissue, so this rather low
radiosensitivity is probably not typical of the plant kingdom.
/FIELD STUDIES/ There are few data in the scientific literature on effects of
irradiation on populations of organisms. From recent population modelling work,
it seems that small impacts on individual organisms could aggregate in a greater
than linear manner, to produce larger effects on populations.
/FIELD STUDIES/ An alternative approach which has been adopted /by the IAEA and
NCRP/ is to estimate the radionuclide concentrations in the environment which
would, through reasonable human use of that environment for food production,
leisure etc., result in the limiting dose equivalent of 1 mSv (annual dose)
being received by a critical group. These environmental concentrations may then
be used as the basis for dose estimates to populations of wild organisms also
inhabiting the area. The quality of the results thus obtained depends, among
other things, upon the validity of both the assumptions made concerning the
behavior of the radionuclides in the environment and the models used to describe
this behavior and generate predictions of radionuclide distributions. ...the
major limiting factor in the determination of dose rates to wild organisms in
contaminated environments is the availability of the necessary data on
radionuclide distributions in the organisms and their environment. Where data
are available, dosimetry models of sufficient sophistication have been developed
to make complete use of the information provided on radionuclide distributions
/FIELD STUDIES/ The effects of ionizing radiation have been studied in a wide
range of plant and animal species at all scales of biological organization from
biomolecules through cellular organelles, whole cells, tissues, organs, whole
organisms, populations and, finally, at the community level. ... A general
conclusion which can be drawn from these data, ... is that, because ionizing
radiation acts by depositing energy and inducing change at the molecular level,
there can be no effect at any higher level of organization without detectable
change at successively lower levels. In particular, radiation damage will not
become apparent at the population level unless there is a clear response, in the
individuals making up the population, in those characteristics which influence
the maintenance of the population including individual morbidity, fertility (gametogenesis),
fecundity (the production of viable offspring) and the gene pool. It follows
that if the radiation dose (rate) either from a waste
disposal practice, or arising from an accident, is sufficiently low that there
can be no significant effects on these individual characteristics, then there
can be no impact on the population, which, as already indicated, is generally
accepted to be the object of protection. This apparently conclusive statement
does raise two questions: 1. What is the relevant population; and 2. For this
population, what is the relevant dose (rate)? In principle, the population could
be defined as all the members of a particular species, but in practice this is
rarely helpful. ... A useful definition suggests that the population would be an
essentially self-sustaining unit of a particular species, i.e. immigration into,
emigration from, and interbreeding with, other populations of the species would
be very minor factors in the overall maintenance of this population. Thus it is
clear, for example, that all the perch, brown trout or mussels in a freshwater
lake could be considered as single populations, whereas ducks overwintering on
the lake might be only a small proportion of a much larger interbreeding
population. The more mobile the organism (including, for example, aerial
dispersion of pollen and seeds, and water transport of gametes, eggs and larvae
in the sea), the larger the space scale which needs to be considered in
attempting to define the appropriate population.
/FIELD STUDIES/ Reviews of the available data /by IAEA and NCRP/ ... have
concluded that there would be no significant effects in wild populations of: 1.
terrestrial animals if the dose rate to the most exposed individuals were to be
less than 1 mGy per day (0.04 mGy per hr); and 2. terrestrial plants, and
aquatic plants and animals if the dose rates to the most exposed individuals
were to be less than 10 mGy per day) (0.4 mGy per hr). Assessments of the dose
rates actually (or potentially) arising from controlled waste
disposal operations indicate that, with very few exceptions, these values have
not been (or would not be) exceeded; often there is a large margin of safety.
The one major exception relates to dumping of packaged low-level radioactive waste
into the deep ocean where, because of the remoteness of the release point from
man and his food chains, and the time taken for radionuclide dispersion to take
place, it is possible to envisage dumping rates, controlled on the basis of
ultimate human exposure, at which very high dose rates could be delivered to
benthic organisms at the dumpsite. The situation for a major nuclear
accident is, as Chernobyl has shown, quite different. Effects were readily
apparent in the pine trees close to the plant, and less dramatic responses have
been detected in animals. Even here, however, it is debatable whether the
long-term survival of the populations has been put at serious risk.
/FIELD STUDIES/ The ICRP considers that its system of radiological protection
has provided a fairly good indirect protection of the human habitat. However, no
internationally agreed criteria or policies explicitly address protection of the
environment from ionizing radiation, and it is difficult to determine or
demonstrate whether or not the environment is adequately protected from
potential impacts of radiation under different circumstances. The present report
suggests a framework, based on scientific and ethical-philosophical principles,
by which a policy for the protection of non-human species could be achieved. The
primary purpose of developing such a framework is to fill a conceptual gap in
radiological protection; it does not reflect any particular concern over
environmental radiation hazards. ...An agreed set of quantities and units, a set
of reference dose models, reference dose-per-unit-intake (or unit exposure), and
reference fauna and flora are required to serve as a basis for the more
fundamental understanding and interpretation of the relationships between
exposure and dose and between dose and certain categories of effect, for a few,
clearly defined types of animals and plants. As a first step, a small set of
reference fauna and flora with supporting databases will be developed by the
ICRP. Others can then develop more area- and situation-specific approaches to
assess and manage risks to non-human species.
/FIELD STUDIES/ This paper provides a bridge between the fields of ecological
risk assessment (ERA) and radioecology by presenting key biota dose assessment
issues identified in the US Department of Energy's Graded Approach for
Evaluating Radiation Doses to Aquatic and Terrestrial Biota in a manner
consistent with the US Environmental Protection Agency's framework for ERA.
Current radiological ERA methods and data are intended for use in protecting
natural populations of biota, rather than individual members of a population.
Potentially susceptible receptors include vertebrates and terrestrial plants.
One must ensure that all media, radionuclides (including short-lived radioactive
decay products), types of radiations (i.e., alpha particles, electrons, and
photons), and pathways (i.e., internal and external contamination) are combined
in each exposure scenario. The relative biological effectiveness of alpha
particles with respect to deterministic effects must also be considered.
Expected safe levels of exposure are available for the protection of natural
populations of aquatic biota (10 mGy d(-1)) and terrestrial plants (10 mGy/d)
and animals (1 mGy/d) and are appropriate for use in all radiological ERA tiers,
provided that appropriate exposure assumptions are used. Caution must be
exercised (and a thorough justification provided) if more restrictive limits are
selected, to ensure that the supporting data are of high quality, reproducible,
and clearly relevant to the protection of natural populations.
/FIELD STUDIES/ A methodological approach for a comparative assessment of
ionizing radiation effects on man and non-human species, based on the use of
Radiation Impact Factor (RIF) (ratios of actual exposure doses to biota species
and man to critical dose) is described. As such doses, radiation safety
standards limiting radiation exposure of man and doses at which radiobiological
effects in non-human species were not observed after the Chernobyl accident,
were employed. For the study area within the 30 km ChNPP zone dose burdens to 10
reference biota groups and the population (with and without evacuation) and the
corresponding RIFs were calculated. It has been found that in 1986 (early period
after the accident) the emergency radiation standards for man do not guarantee
adequate protection of the environment, some species of which could be affected
more than man. In 1991 RIFs for man were considerably (by factor of 20.0 to 1.1
x 10+5) higher compared with those for selected non-human species. Thus, for the
long term after the accident radiation safety standards for man are shown to
ensure radiation safety for biota as well.
/FIELD STUDIES/ Free-ranging, wild meadow voles (Microtus pennsylvanicus) were
exposed to gamma radiation from a cesium-137 irradiator in a series of
experiments conducted on six 1-ha meadows within a mixed deciduous forest in
Manitoba, Canada. Over a period of 1 to 1.5 years in each of three experiments,
vole populations were monitored with capture-mark-release techniques at nominal
exposure rates of 200 times, 9000 times and 40,000 times background. No effects
on population or individual characteristics were detected up to the highest
exposure rate (81 mGy/d). At this level, third generation voles were monitored
up to a lifetime dose of about 5.7 Gy, at a measured dose rate of 44 mGy/d.
Smaller numbers of overwintered animals survived and reproduced normally at
doses up to 10 Gy. These results are discussed in terms of low-LET, external
chronic radiation effects on rodents in the laboratory and the field, relative
to current views on appropriate benchmarks for the protection of biota.
LD50, Gy, Higher plants (trees, shrubs and herbs): 7-800
LD50, Gy, Primitive plants (mosses, lichens and algae) 30 to >13,000
Metabolism/Pharmacokinetics:
Absorption, Distribution & Excretion:
The routes of intake are inhalation, ingestion, wound contamination, and skin
absorption. Within the respiratory tract, ... soluble particles will be either
absorbed into the blood stream directly or pass through the lymphatic system.
Insoluble particles, until cleared from the respiratory tract, will continue to
irradiate surrounding tissues. In the alveoli, fibrosis and scarring are more
likely to occur due to the localized inflammatory response. All swallowed
radioactive material will be handled like any other element in the digestive
tract. Absorption depends on the chemical makeup of the contaminant and its
solubility. ... The lower GI tract is considered the target organ for ingested
insoluble radionuclides that pass unchanged in the feces. The skin is
impermeable to most radionuclides. Wounds and burns create a portal for any
particulate contamination to bypass the epithelial barrier. ... Once a
radionuclide is absorbed, it crosses capillary membranes through passive and
active diffusion mechanisms and then is distributed throughout the body. The
rate of distribution to each organ is related to ... metabolism, the ease of
chemical transport, and the affinity of the radionuclide for chemicals within
the organ. The liver, kidney, adipose tissue, and bone have higher capacities
for binding radionuclides due to their high protein and lipid makeup.
If a radionuclide that enters the blood is an isotope of an element that is
required by the body then it will follow the normal metabolic pathways for that
element (e.g., sodium-24, phosphorus-32/ as orthophosphate/, potassium-42,
calcium-45, iron-59). If it has similar chemical properties to an element that
is normally present then it will tend to follow the biokinetic pathways of that
element although its rates of transfer...may be different (e.g., strontium-90,
radium-226. rubidium-86). For other radionuclides their behavior in the body
will depend upon their affinity for biological ligands and other transport
systems in the body .. the extent of uptake and retention...must be assessed
from the available human or animal data (e.g., plutonium-239, americium-241,
cerium-144).
The Human Respiratory Tract Model (HRTM) described in ICRP Publication 66 was
applied to calculate inhalation dose coefficients for workers and members of the
public in publications 68, 71 and 72 and bioassay functions in Publication 78.
...In the HRTM, the respiratory tract is represented by five regions. The
extrathoracic (ET) airways are divided into the anterior nasal passage and the
posterial nasal passage, the pharynx and the larynx. The thoracic regions are
bronchial, bronchiolar, and alveolar-interstitial. Lymphatic tissue is
associated with the extrathoracic and thoracic airways. ... Absorption /is
considered to be a two-stage process that/ depends on the physical and chemical
form of the deposited material. ... Uptake to body fluids of dissolved material
can usually be treated as instantaneous .../except when activity is retained in
a bound state/. ...For absorption Types F (100% absorbed with a half-time of 10
min), M (10% absorbed with a half-time of 10 min and 90% with a half-time of 140
d) and S (0.1% absorbed with a half-time of 10 min and 99.9% with a half time of
7000 d), all the material deposited in the anterior nasal passage is removed by
extrinsic means. Most of the deposited material that is not absorbed is cleared
to the alimentary tract by particle transport. The small amounts transferred to
lymph nodes continue to be absorbed into body fluids at the same rate as in the
respiratory tract. ... For radionuclides inhaled as particles the HRTM assumes
that total and regional deposition in the respiratory tract is determined only
by the size distribution of the aerosol particles. ... For gases and vapors ...
deposition in the respiratory tract depends entirely on the chemical form. ...
The general defaults for gases and vapors are 100% total deposition in the
respiratory tract. These are known as `default' or `reference' values, and were
chosen to be typical, representative values. In any particular situation the
actual values of many parameters can be considerably different from the
reference values. Usually, doses from intakes of radionuclides are low compared
with the relevant limit or constraint, and the resulting difference is
unimportant. There are, however, circumstances where more reliable assessments
of intake and dose are desirable. This Guidance Document therefore gives advice
on applying specific information within the framework of the HRTM for assessing
occupational and environmental exposures and for interpreting bioassay data.
The Human Alimentary Tract (HATM) model of the gastrointestinal tract was issued
as ICRP Publication 100. ... In this report, ICRP provides a new biokinetic and
dosimetric model of the human alimentary tract to replace the Publication 30 (ICRP,
1979) model. The new Human Alimentary Tract Model (HATM) will be used together
with the Human Respiratory Tract Model (HRTM: ICRP, 1994) in future ICRP
publications on doses from ingested and inhaled radionuclides. The HATM is
applicable to all situations of radionuclide intake by children and adults. It
provides age-dependent parameter values for the dimensions of the alimentary
tract regions and associated transit times for the movement of materials through
these regions. For adults, gender-dependent parameter values are given for
dimensions and transit times. The default assumption is that radionuclide
absorption takes place in the small intestine but the model allows for
absorption in other regions and for retention in or on tissues within the
alimentary tract when information is available. Doses are calculated to target
cells for cancer induction in the oral cavity, esophagus, stomach, small
intestine and colon. The report provides reviews of information on the transit
of materials through the alimentary tract and on radionuclide retention and
absorption. It considers data on health effects, principally in order to specify
the target cells for cancer induction within the mucosal lining of the tract and
to justify approaches taken to dose averaging within regions. Comparisons are
made between doses calculated using the HATM and Publication 30 model for
examples of radionuclide ingestion for which absorption is assumed to occur only
in the small intestine. Examples are also given of the effect on doses of
considering absorption from other regions and the effect of possible retention
in the alimentary tract. The report also considers uncertainties in model
assumptions and their effect on doses, including alimentary tract dimensions,
transit times, radionuclide absorption values and the location of targets for
cancer induction. First order kinetics is assumed for all transfers in the HATM.
... For ingested food and liquids, the HATM specifies two components of
esophageal transient representing relatively fast transfer of 90% (mean transit
time of 7 sec) of the swallowed material and relatively slow transit of the
residual 10% (40 sec). ... The oral cavity and esophagus receive very low doses
from radionuclides because of their short transit times... In general, the
alimentary tract regions of greatest importance ... are the stomach and
particularly the colon. While the small intestine may receive greater doses than
the stomach, it is not sensitive to radiation-induced cancer.
For skin contamination, both the radiation dose to the area of skin contaminated
and the dose to the whole body as a result of absorption need to be considered.
ICRP 60 has recommended that for skin contamination doses should be calculated
to sensitive cells, assumed to be at a depth of 70 um. For deposited activity
doses are to be calculated as an average to each square cm of skin tissue.
Mechanism of Action:
Damage to DNA, which carries the genetic information in chromosomes in the cell
nucleus, is considered to be the main initiating event by which radiation damage
to cells results in the development of cancer and hereditary disease. Either one
or both strands of the DNA helix in cells may be damaged or broken, resulting in
cell death, damage to chromosomes, or mutational events. Radiation is thought to
have an effect on DNA either through the direct interaction of ionizing
particles with DNA molecules or through the action of free radicals or other
chemical intermediates produced by the interaction of radiation with neighboring
molecules. ...
The quantitative cytogenetic systems developed over the years, particularly in
G(0) human lymphocytes, have been utilized in studies on the effects of dose,
dose rate, and radiation quality. From a mechanistic viewpoint there is
compelling evidence that the induction and interaction of DNA double strand
break ... is the principal mechanism for the production of chromosome
aberrations.
A current explanation of the ... dose-response characteristics /produced by
radiation/ is that DNA double strand breaks (dsb) are the principal causal
events for aberration induction, and that these are induced with linear kinetics
at around 30 DNA dsb per Gy. Correct repair and misrepair processes operate in
competition for these DNA dsb with the majority of breaks restituting correctly
and a small fraction taking part in misrepair-mediated chromosomal exchanges.
The vast majority of initial unrepaired and misrepaired lesions are expressed as
chromosomal damage at the first division. Cells carrying unbalanced chromosomal
exchanges (dicentrics) or substantial chromosomal losses are not expected to
contribute to the viable post-irradiation population. By contrast, cells
carrying small deletions or balanced exchanges such as reciprocal translocations
are likely to remain viable, and some may have the potential to contribute to
tumor development.
Evidence has been presented that radiation-induced apoptosis can occur via
p53-dependent and p53-independent mechanisms initiated in the nucleus or
cytoplasm/membrane. ... The signal-transduction pathways resulting in
radiation-induced apoptosis involve the nucleus and cytoplasm with alterations
in mitochondrial electron transport and release of cytochrome c from the
mitochondria, which initiates caspase cleavage and terminates in activation of a
nuclease responsible for internucleosomal digestion of DNA.
There is strong molecular evidence that, in most circumstances, a DNA deletion
mechanism dominates mutagenic response after ionizing radiation, and it is for
this reason that the genetic context of the mutation is of great importance. ...
Gene loss mutations are characteristic of radiation, but their recovery in
viable cells can be a major limiting factor. Also, gene amplification can result
from the process of double strand break repair. ... These features are important
for consideration of carcinogenic mechanisms. ... DNA sequence data for
radiation-induced intra-genic deletions in adenine-phospho-ribosyltrans-ferase (APRT)
and larger deletions encompassing hypoxanthine-guanine phosphoribosyltransferase
(HPRT) indicate the frequent involvement of short direct or inverted DNA repeats
at deletion breakpoints. The presence of these short repeats is highly
suggestive of an important role for illegitimate recombination processes in
mutagenesis and, as for chromosome aberration induction, the involvement of DNA
double strand breaks and error-prone Non-homologous End Joining (NHEJ) repair.
If, as molecular data suggest, error-prone NHEJ repair of DNA double strand
breaks is the principal source of radiation-induced gene mutations, then a
linear dose response would be anticipated at low doses. ... There is consistent
evidence for potentially increased efficiency of repair of pre-mutagenic lesions
at low-dose rates, but none of these studies specifically suggest the presence
of a low dose threshold.
Since neutrons are uncharged, they do not interact directly with orbital
electrons in tissues to produce the ions that initiate the chemical events
leading to cell injury. Rather, they induce ionizing events in tissues mainly by
elastic collision with the hydrogen nuclei of the tissue molecules; the
recoiling nucleus (charged proton) is the source of ionizing events. As about
half of the neutron's energy is given to the proton on each collision, the
low-energy neutrons provide an internal source of low-energy protons deep within
body tissues. The low-energy protons form densely ionizing tracks (high linear
energy transfer (LET)) which are efficient in producing biological injury.
Interactions:
In a terrorist attack, using a "dirty bomb" together with biological
or chemical agents, the fatality rates can be increased considerably over those
from any one of the agents alone.
It is important to remember that concurrent injuries can reduce the time to
infection as well as increase the fatality rate. A radiation dose of a few
hundred centigray can halve the survival rate for persons with serious burns.
The interaction of alkylating agents with radiation in producing leukemia in
women treated for breast cancer was investigated in a cohort of 82,700 patients
in the United States. Based on 74 cases, the risk of acute nonlymphocytic
leukemia (ANL) was significantly increased after radiotherapy alone (relative
risk - 2.4, 7.5 Gy mean dose to the active marrow and alkylating agents (melphalan
and cyclophosphamide) alone (relative risk = 10). Combined therapy resulted in a
more-than-additive relative risk of 17.4.
Mineral dust and fibers, including asbestos, tend to show supra-additive
interaction with radiation at high exposure levels. These levels were reached in
workplaces in the 1950s and earlier. Today the occupational exposures are lower,
but these agents still deserve attention for their potential to enhance risks
after combined exposure.
At high exposures, a wealth of supra-additive effects between genotoxic
chemicals (e.g. alkylating agents) and radiation were recorded. For low-level
exposures, there is no mechanistic evidence of combined effects at the cellular
level greater than those predicted from isoadditivity. Nor are these agents
expected to show a more-than-additive effect at the organ level. However, non-genotoxic
agents with mitogenic, cytotoxic, or hormonal activity may interact with
radiation in an additive to highly supra-additive manner.
Normal tissue can be protected from radiation effects by radioprotective agents.
... By far the most widely studied class of radioprotective agents is the thiols,
and the most important non-protein thiol present in cells is glutathione. Other
classes of agents conferring radioresistance to normal tissue are the
eicosanoids, which are biologically active compounds derived from arachidonic
acid, the lipoic acids, and calcium antagonists
Mustard agents and radiation ... used in combination will have a geometric
effect on morbidity.
Radiation will lower the threshold for seizure activity and may potentiate the
effects /of nerve agents/ on the central nervous system.
The primary cause of death from radiation injury is infection by normal
pathogens during the phase of manifest illness. Even minimally symptomatic doses
of radiation depress the immune response and will dramatically increase the
infectivity and apparent virulence of biological agents. Biological weapons may
be significantly more devastating against an irradiated population. Early
research with radiation injury and an anthrax simulant demonstrates that
significantly fewer spores are required to induce infection.
Immunization efficacy will be diminished if instituted prior to complete immune
system recovery. Use of live agent vaccines after irradiation injury could
conceivably result in disseminated infection with the inoculation strain. ...
Research suggests a shortened fatal course of disease when virulent-strain virus
is injected into sublethally irradiated test models.
The interaction of alkylating agents with radiation in producing leukemia in
women treated for breast cancer was investigated in a cohort of 82,700 patients
in the United States. Based on 74 cases, the risk of acute nonlymphocytic
leukemia (ANL) was significantly increased after radiotherapy alone (relative
risk - 2.4, 7.5 Gy mean dose to the active marrow and alkylating agents (melphalan
and cyclophosphamide) alone (relative risk = 10). Combined therapy resulted in a
more-than-additive relative risk of 17.4.
Pharmacology:
Therapeutic Uses:
Approximately 400 million medical diagnostic examinations and 150 million dental
X-ray examinations are performed annually in the United States. In contrast,
therapeutic exposures are less frequent, and the levels of dose are higher in
view of the different purpose.
/As of 1996/ X-ray imaging continue/d/ to comprise 80 to 90 percent of all
imaging procedures. It is performed using three different imaging techniques:
radiographic imaging, fluoroscopic imaging, and computed tomography (CT). ...
The vast majority of x-ray procedures are performed by radiographic imaging. ?
Radiographic imaging procedures are ... divided into what are considered
"conventional" examinations ... and "contrast studies." ...
Most notable among the conventional examinations is chest radiography, the most
common of all radiographic imaging procedures.
In nuclear imaging, clinicians either
inject small amounts of radiopharmaceuticals into patients intravenously or have
patients inhale or ingest the material. Depending on the metabolic pathways of
the pharmaceutical in question and disease status of the patient to be studied,
the radiopharmaceutical is distributed nonuniformly throughout the body. Gamma
rays emitted from these locations escape the body and are imaged by means of a
position-sensitive scintillation detector, commonly called a gamma camera.
Teletherapy is radiation therapy delivered using an external beam of ionizing
radiation. Options include gamma rays (from a radioactive cobalt-60 source) and
photons or electrons (from an x-ray generator or accelerator). ... Electrons,
which have less power to penetrate tissue, are used to treat skin lesions,
superficial lymph nodes, and other tumors situated near the surface of the
patient. In addition to "conventional" radiation therapy, experts in
radiation oncology have developed several other methods of external beam
therapy. Intraoperative radiation therapy (IORT) uses electrons to treat tumors
that have been surgically exposed. ? Stereotactic radiosurgery (SRS) delivers
radiation beams to a small target within the skull. The resulting dose
distribution yields a small region of high dose precisely conforming to the
target. ...
Malignant neoplasms also may be treated by /intracavitary brachytherapy or
interstitial brachytherapy/. ... The original method of brachytherapy is now
sometimes called "low dose rate" (LDR) brachytherapy. ... To give a
tumor-killing dose, sources had to be left in place for days. Because of the low
activity, these sources could be handled manually. ... With "high dose
rate" (HDR) brachytherapy, a treatment can be completed in a matter of
minutes. The high activity of these sources precludes their manual handling.
Therapy in nuclear medicine involves
oral, intravenous, or intracavitary delivery of radionuclides in liquid form
(sometimes called "unsealed" radionuclides). ... Radionuclides
commonly used for therapeutic nuclear
medicine include: colloidal gold-198; iodine-131 as sodium iodide, meta-iodobenzylguanidine,
monoclonal antibodies; colloidal phosphorous-32; and strontium-89 chloride /from
table/.
Cell-cycle synchronization exploits the fact that many cytotoxic drugs and
radiation show some degree of selectivity in cell killing at certain phases of
the cell cycle. Antimetabolites show a maximum effect on cells undergoing the S
phase. Radiation sensitivity is highest in the G2/M phase. There is, therefore,
an attractive possibility of complementary action between drugs and radiation.
The most attractive possibility seems to be the interaction between microtubule
and topoisomerase poisons and primary DNA-damaging agents such as radiation.
Activation of apoptosis by differential pathways increases cell killing during
tumor therapy and is therefore another possibility for combined action of
radiation and chemotherapeutic drugs. Ionizing radiation may activate the
apoptotic process by a DNA damage-p53 dependent pathway, whereas taxoids like
paclitaxel may activate a pathway downstream of p53 by phosphorylation of Bcl-2.
There is, therefore, a possibility that radiation-induced cell killing can
increase, even in p53-deficient tumors.
Reduction of the hypoxic fraction by bioreductive drugs targeted at hypoxic
tumor cells increases tumor radiosensitivity. Most promising here is the
development of dual-function drugs specific to hypoxic cells and with intrinsic
cytotoxic activity (e.g. alkylating activity).
Drug Warnings:
No one specific type of secondary cancer is seen after therapeutic irradiation.
Secondary cancers can occur after any initial cancer, when survival surpasses
the latent period. Radiation-induced leukemias begin to appear after 3-5 years.
Solid cancers typically emerge more than 10 years after treatment but may occur
earlier in particularly susceptible individuals. When the risk of secondary
solid cancer is elevated, it rises with increasing radiation dose to the site
and with increasing time since treatment and persists as long as 20 years
There is little indication that heritable sensitivity to treatment is a
significant component of secondary cancer, but intensive multiple agent therapy
used in childhood cancer treatment acts as an independent etiological factor for
a second tumor. The risk for a second malignant neoplasm after cancer in
childhood is considerable. Absolute risks up to 7 % over 15 years following
diagnosis of the primary cancer were found for Hodgkins's disease. This amounts
to an excess relative risk (ERR) of about 17, with breast cancer contributing
the most.
Following childhood cancer therapy ... the risk for bone sarcoma rose
dramatically with increasing doses of radiation. ... Patients with heritable
retinoblastoma had a much higher risk for secondary bone sarcoma ... radiation
and alkylating agents acted additively.
Thyroid cancer risk after treatment of childhood cancer is increased 53-fold
compared with general population rates. The risk for thyroid cancer rose with
increasing radiation dose. There was no increased risk of thyroid cancer
associated with alkylating-agent chemotherapy. There was a seven fold increased
risk of secondary cancers after treatment of acute lymphoblastic leukemia. Most
of this risk was due to a 22-fold increase in brain cancers.
The interaction of alkylating agents with radiation in producing leukemia in
women treated for breast cancer was investigated in a cohort of 82,700 patients
in the United States. Based on 74 cases, the risk of acute nonlymphocytic
leukemia (ANL) was significantly increased after radiotherapy alone (relative
risk - 2.4, 7.5 Gy mean dose to the active marrow and alkylating agents (melphalan
and cyclophosphamide) alone (relative risk = 10). Combined therapy resulted in a
more-than-additive relative risk of 17.4.
Following therapeutic nuclear medicine
interventions, some radiopharmaceuticals cause the patient's urine, sweat,
saliva, and blood to contain a high level of radioactivity. In many instances,
patients must be hospitalized for several days to prevent contamination of the
public.
Studies of second cancer following radiotherapy have generally focused on
patients treated for cervical cancer, breast cancer, Hodgkin disease, and
childhood cancers ... . Survivors of these cancers may live long enough to
develop a second, treatment-related malignancy. ... Most of the information on
second cancers following radiotherapy for cervical cancer comes from ... a
multinational cohort study of nearly 200,000 women patients treated for cancer
of the cervix after 1960. ... A total of 7,543 cases were included. This study
confirmed ... /an/ increased risk of malignancies following radiotherapy and
that the increased risk persists over time. ... A cohort study of second cancer
risk following radiation therapy for cancer of the uterine cervix was also
carried out in Japan among 11,855 patients. Significant excesses of leukemia and
of cancers of the rectum, bladder and lung were observed.
Following a first report ... in 1972, a number of authors have studied the risk
of second cancer following treatment for Hodgkin disease. The initial reports
focused mainly on the risk of leukemia following this treatment but, as longer
follow-up periods were considered, an excess risk of a number of solid cancers
(in particular breast and lung) became apparent.
A case-control study of leukemia (excluding chronic lymphatic leukemia) was
carried out nested within a cohort of 82,700 women with breast cancer /treated
by radiation/ in the US. A total of 90 cases and 264 controls were included .
... A significant /radiation/ dose-response was seen for acute non-lymphocytic
leukemia.
Cardiovascular mortality /was studied/ in a cohort of 89,407 Swedish women
identified from the Swedish cancer registry as having had unilateral breast
cancer /treated by radiation/ between the ages of 18 and 79 years between 1970
and 1996. Mortality from cardiovascular disease was higher in women who had left
sided tumors (odds ratio (OR) 1.10, 95% CI 1.03-1.18) ten years or more after
the diagnosis of breast cancer.
Second cancer incidence /was studied/ in a multinational cohort study of 28,843
men who had been diagnosed with testicular cancer between 1935 and 1993 ...
.Cases of second cancer occurring between 1965 and 1994 were significantly
increased ... in general, as well as of leukemia (64 cases) and of stomach
cancer (93 cases). /In a/ case-control study of leukemia nested within a
multinational cohort of 18,567 patients diagnosed with testicular cancer ... men
who did not receive chemotherapy (mean radiation dose to 12.6 Gy) had a 3.1-fold
elevation of leukemia risk.
Since childhood cancer is rare, national and international groups such as the
Late Effects Study Group ... combined their data to evaluate risks. Results from
these cohort studies have indicated that the risk for developing a second cancer
in the 25 years after the diagnosis of the first cancer was as high as 12%.
Among patients treated for hereditary retinoblastoma, the risk of developing a
second cancer in the 50 years after the initial diagnosis was as high as 51%.
Many drugs inhibit the repair of radiation damage. Antitumor antibiotics (e.g.
dactinomycin and doxorubicin), antimetabolites (e.g. hydroxyurea, cytarabine,
and arabinofuranosyl-adenine), and alkylating agents and platinum analogues
(e.g. cisplatin) have been shown to inhibit radiation-induced DNA damage repair.
Smoking is an important cofactor, and studies of patients with Hodgkin disease
and small-cell lung cancer suggest that continued use of tobacco after
radiotherapy potentiates the risk for a second cancer in the lung.
Interactions:
In a terrorist attack, using a "dirty bomb" together with biological
or chemical agents, the fatality rates can be increased considerably over those
from any one of the agents alone.
It is important to remember that concurrent injuries can reduce the time to
infection as well as increase the fatality rate. A radiation dose of a few
hundred centigray can halve the survival rate for persons with serious burns.
The interaction of alkylating agents with radiation in producing leukemia in
women treated for breast cancer was investigated in a cohort of 82,700 patients
in the United States. Based on 74 cases, the risk of acute nonlymphocytic
leukemia (ANL) was significantly increased after radiotherapy alone (relative
risk - 2.4, 7.5 Gy mean dose to the active marrow and alkylating agents (melphalan
and cyclophosphamide) alone (relative risk = 10). Combined therapy resulted in a
more-than-additive relative risk of 17.4.
Mineral dust and fibers, including asbestos, tend to show supra-additive
interaction with radiation at high exposure levels. These levels were reached in
workplaces in the 1950s and earlier. Today the occupational exposures are lower,
but these agents still deserve attention for their potential to enhance risks
after combined exposure.
At high exposures, a wealth of supra-additive effects between genotoxic
chemicals (e.g. alkylating agents) and radiation were recorded. For low-level
exposures, there is no mechanistic evidence of combined effects at the cellular
level greater than those predicted from isoadditivity. Nor are these agents
expected to show a more-than-additive effect at the organ level. However, non-genotoxic
agents with mitogenic, cytotoxic, or hormonal activity may interact with
radiation in an additive to highly supra-additive manner.
Normal tissue can be protected from radiation effects by radioprotective agents.
... By far the most widely studied class of radioprotective agents is the thiols,
and the most important non-protein thiol present in cells is glutathione. Other
classes of agents conferring radioresistance to normal tissue are the
eicosanoids, which are biologically active compounds derived from arachidonic
acid, the lipoic acids, and calcium antagonists
Mustard agents and radiation ... used in combination will have a geometric
effect on morbidity.
Radiation will lower the threshold for seizure activity and may potentiate the
effects /of nerve agents/ on the central nervous system.
The primary cause of death from radiation injury is infection by normal
pathogens during the phase of manifest illness. Even minimally symptomatic doses
of radiation depress the immune response and will dramatically increase the
infectivity and apparent virulence of biological agents. Biological weapons may
be significantly more devastating against an irradiated population. Early
research with radiation injury and an anthrax simulant demonstrates that
significantly fewer spores are required to induce infection.
Immunization efficacy will be diminished if instituted prior to complete immune
system recovery. Use of live agent vaccines after irradiation injury could
conceivably result in disseminated infection with the inoculation strain. ...
Research suggests a shortened fatal course of disease when virulent-strain virus
is injected into sublethally irradiated test models.
The interaction of alkylating agents with radiation in producing leukemia in
women treated for breast cancer was investigated in a cohort of 82,700 patients
in the United States. Based on 74 cases, the risk of acute nonlymphocytic
leukemia (ANL) was significantly increased after radiotherapy alone (relative
risk - 2.4, 7.5 Gy mean dose to the active marrow and alkylating agents (melphalan
and cyclophosphamide) alone (relative risk = 10). Combined therapy resulted in a
more-than-additive relative risk of 17.4.
Environmental Fate & Exposure:
Natural Pollution Sources:
Natural radioactivity is derived from extraterrestrial sources and from
radioactive elements in the earth's crust. Seventy of the 340 nuclides found in
nature are radioactive. All elements with atomic number (number of protons)
>80 have some radioactive isotopes; all isotopes of elements with atomic
number >83 are radioactive. Natural radioactively can be divided into 3
categories, each derived from either primordial, secondary, or and cosmogenic
radionuclides. Primordial radionuclides are radionuclides that have sufficiently
long half-lives to survive since their creation. Radioisotopes with half-lives
<100 million years are undetectable after 30 half-lives; whereas,
radioisotopes with half-lives >10 billion years have decayed very little
since their creation. Secondary radionuclides are those derived from the decay
of the primordial radionuclides. Cosmogenic radionuclides are continuously
produced by the bombardment of stable isotopes, primarily in the atmosphere, by
cosmic rays. Naturally occurring isotopes either occur singly, or as components
for three chains of radioactive elements: the uranium series, originating with
uranium-238 (half-life = 4.47X10+9 years); the thorium series, originating with
thorium-232 (half-life = 1.4X10+10 years); and the actinium series originating
with uranium-235 (half-life = 7.038X10+8 years). The neptunium series, which
originated with plutonium-241, is no relevant to human exposure, since the
half-life of plutonium-241 is about 14 years. The uranium, thorium, and actinium
series, and the primordial radioisotope, potassium-40 (half-life = 1.26X10+9
years) account for much of the external background radiation dose of the general
population. Of the 22 cosmogenic nuclides, only carbon-14 (half-life = 5,730
years), hydrogen-3 (half-life = 12.33 years), sodium-22 (half-life = 2.60
years), and beryllium-7 (half-life = 53.3 days) are important to human exposure.
Potassium-40 and rubidium-87 (half-life = 4.8X10+10 years) are the only two of
the 17 non-series, primordial radioisotopes that are important for human
exposure. In general, natural radioactivity varies within narrow limits;
however, wide deviations from normal levels can occur in areas with abnormally
high soil concentrations of radioactive mineral(1).
Environmental Standards & Regulations:
RCRA Requirements:
Low-Activity Mixed Waste (LAMW) is
produced commercially at industrial, medical, and nuclear
power facilities...This waste is being
stored, indefinitely in many cases, by small commercial generators because the
current regulatory framework severely limits disposal options. The U.S. EPA is
working with NRC to develop a mixed waste
rule for the management, storage, and disposal of commercially generated LLW
mixed with RCRA hazardous waste. RCRA
gives EPA the authority to regulate hazardous waste
from "cradle-to-grave." The definition of hazardous waste
under the Resource Conservation and Recovery Act, Public Law 94-580, as amended,
et seq., 1984, specifically excludes source, special nuclear,
or byproduct material as defined by the Atomic Energy Act.
Atmospheric Standards:
Radionuclides have been designated as a hazardous air pollutants under section
112 of the Clean Air Act. /Radionuclides/
Federal Drinking Water Standards:
MCL for gross alpha particle activity (excluding radon and uranium): The maximum
contaminant level for gross alpha particle activity (including radium-226 but
excluding radon and uranium) is 15 pCi/L. ...MCL for beta particle and photon
radioactivity: ... The average annual concentration of beta particle and photon
radioactivity from man-made radionuclides in drinking water must not produce an
annual dose equivalent to the total body or any internal organ greater than 4
millirem/year (mrem/year). ... If two or more radionuclides are present, the sum
of their annual dose equivalent to the body or to any organ shall not exceed 4
mrem/year.
FDA Requirements:
21 CFR 1002.20. Accidental Radiation Occurrences documents any actual or
possible unexpected exposure during manufacturing, testing or use of ANY
electronic product. Reports are due immediately after the event is known.
Diagnostic X-Ray Systems and their Major Components applies to tube housings,
generators and controls, film changers; fluoroscopic assemblies; spot film and
image intensifiers; cephalometric devices; image receptor support devices for
mammographic systems; diagnostic systems; CT systems (in part) and limits
leakage at 1 meter from the source to 100 mR in 1 hr and at 5 cm from any other
components to 2 mR in 1 hr.
Radiographic Equipment requires control and indication of technique factors;
timer termination conditions; accuracy and reproducibility specifications;
indication and limits on field size and alignment, etc., and limits transmission
through mammographic image support systems at 5 cm to 0.1 mR for each tube
activation.
Cabinet X-Ray Systems applies to systems with X-ray tube installed in an
enclosure, including carry-on baggage inspection systems. It limits radiation at
5 cm to 0.5 mR/hr under maximized operating conditions and door positions;
restricts human access to the primary beam and requires 2 interlocks on each
door with 1 resulting in physical disconnection of energy to the generator; key
control; 2 independent x-ray on indicators; warning indicators and labels; user
instructions, etc.
Because linear accelerators and radiation therapy treatment planning systems are
Class III medical devices (see 21 CFR 860.3), their safety and manufacture is
controlled by the U.S. FDA. Problems with the operation of such equipment,
particularly those resulting in an adverse patient outcome, must be reported
subject to the Safe Medical Device Act, as amended in 1991 (USC Section 360i(b)
and 21 CFR part 803).
Chemical/Physical Properties:
Chemical Safety & Handling:
Hazards Summary:
In the U.S., the routine use, shipment, and disposal of radioactive materials is
highly regulated to limit hazards to workers and the public. In the workplace,
U.S. Nuclear Regulatory Commission
(NRC) rules apply to the use of source material, special nuclear
material, and byproduct material. Individual states usually regulate the sources
of ionizing radiation that NRC does not, e.g., naturally occurring radioactive
materials and radioactive materials produced in particle accelerators. Medical
devices producing radiation are regulated by the U.S. Food and Drug
Administration (FDA). The public is protected by U.S. Environmental Protection
Agency (EPA) standards applicable environmental ionizing radiation standards and
requirements for waste disposal. All
radioactive materials, including wastes,
are shipped in accordance with stringent NRC and U.S. Department of
Transportation (DOT) standards. Almost all radioactive waste
for disposal in the U.S. consists of low-level waste
shipped in Type A containers. Wastes
containing higher levels of radioactivity must be shipped in Type B or C
containers intended to resist release of radioactive materials from impact, or
in a fire or submersion in water. Shipments of radioactive materials may also
bear warning labels - White-I for shipments releasing a maximum of 0.5 mrem/hr
at the surface; Yellow-II with a maximum of 50 mrem/hr at the package surface,
and Yellow-III with a maximum of 200 mrem/hr at the surface (also required for
all fissile class III or large quantity shipments). These regulations guide the
protective measures employed to limit the risks to transport workers, emergency
response personnel, and the public in the event of a transportation accident
involving radioactive materials. Within the workplace, NRC, FDA and state
regulations dictate radiation safety programs of licensees. To obtain and retain
a license for on-site use of radioactive materials, licensees generally must
establish a Radiation Safety Committee (RSC) that provides oversight of the
Radiation Safety Office (RSO). The RSC develops a formal radiation safety manual
that dictates how the facility will assure compliance with its licensing
agreements; individuals using isotopes under the license receive training to
ensure an understanding of the manual contents. NRC and state regulations
establish requirements for the safe shipping and storage of radioactive
materials, the use of protective equipment, and evaluation of worker exposure.
The RSC through the RSO ensures compliance by establishing respirator programs,
conducting sealed source leak tests, testing for surface contamination and
ventilation effectiveness, conducting a personal and area sampling program to
record airborne exposures, and other measures as determined by the license
agreement. In some cases, in vitro and in vivo monitoring of individual workers
is conducted. Since radiation dose is cumulative over a lifetime, records for
individual exposure and intake are generally retained in perpetuity and may be
passed from employer to employer. In contrast to the controlled situations
within the workplace, a nuclear or
radiological emergency may be large scale, affecting hundreds of thousands of
persons, or more likely, small scale, causing acute radiation-induced toxicity
to only a few persons. Regardless of a radiation event, the practical goals are
to regain control of the situation; to mitigate consequences at the scene; to
prevent the occurrence of deterministic (acute) health effects in workers and
the public; to manage the treatment of radiation injuries; to limit the
occurrence of stochastic (chronic) health effects in the population; to protect,
to the extent practicable, property and the environment; and to prepare for the
resumption of normal social and economic activity. The response to a radiation
event will involve organizations that respond to conventional emergencies as
well as highly specialized agencies and technical experts. Therefore, in order
to be effective, the response to a nuclear
or radiological emergency must be well coordinated and preplanning, equipment
purchase and training on the basis of established principles of radiation
protection and safety is essential. In a radiation event, certain principles of
radiation protection apply to first responders and medical personnel. If the
radiological emergency arises from a source that poses a hazard from external
radiation, first responders need to limit time spent near contamination; keep as
much distance from the contaminated area as practicable; and shield with any
available material. However, victims will pose no radiation risk to the persons
treating them. If victims are physically contaminated with radioactive
materials, there is a medical concern about the long term consequences of
internal exposure to the victim. There is also a need to limit contamination of
health care workers and the facility. Thus, in a radiation event an assessment
center removed from the emergency or intake department needs to be established
to screen victims for injury and contamination and to provide for
decontamination. Radiation control zones within the hospital should also be
established and enforced to limit contamination. However, treatment of
life-threatening injuries always takes precedence over measures to address
radioactive contamination or exposure.
DOT Emergency Guidelines:
/GUIDE 161: RADIOACTIVE MATERIALS (LOW LEVEL RADIATION)/ Health: Radiation
presents minimal risk to transport workers, emergency response personnel, and
the public during transportation accidents. Packaging durability increases as
potential hazard of radioactive content increases. Very low levels of contained
radioactive materials and low radiation levels outside packages result in low
risks to people. Damaged packages may release measurable amounts of radioactive
material, but the resulting risks are expected to be low. Some radioactive
materials cannot be detected by commonly available instruments. Packages do not
have RADIOACTIVE I, II, or III labels. Some may have EMPTY labels or may have
the word "Radioactive" in the package marking. /UN 2908, UN 2909, UN
2910, UN 2911/
/GUIDE 161: RADIOACTIVE MATERIALS (LOW LEVEL RADIATION)/ Fire or explosion: Some
of these materials may burn, but most do not ignite readily. Many have cardboard
outer packaging; content (physically large or small) can be of many different
physical forms. Radioactivity does not change flammability or other properties
of materials. /UN 2908, UN 2909, UN 2910, UN 2911/
/GUIDE 161: RADIOACTIVE MATERIALS (LOW LEVEL RADIATION)/ Public safety: CALL
Emergency Response Telephone Number. ... Priorities for rescue, life-saving,
first aid, fire control and other hazards are higher than the priority for
measuring radiation levels. Radiation Authority must be notified of accident
conditions. Radiation Authority is usually responsible for decisions about
radiological consequences and closure of emergencies. As an immediate
precautionary measure, isolate spill or leak area immediately for at least 25
meters (75 feet) in all directions. Stay upwind. Keep unauthorized personnel
away. Detain or isolate uninjured persons or equipment suspected to be
contaminated; delay decontamination and cleanup until instructions are received
from Radiation Authority. /UN 2908, UN 2909, UN 2910, UN 2911/
/GUIDE 161: RADIOACTIVE MATERIALS (LOW LEVEL RADIATION)/ Protective clothing:
Positive pressure self-contained breathing apparatus (SCBA) and structural
firefighters' protective clothing will provide adequate protection. /UN 2908, UN
2909, UN 2910, UN 2911/
/GUIDE 161: RADIOACTIVE MATERIALS (LOW LEVEL RADIATION)/ Evacuation: Large
Spill: Consider initial downwind evacuation for at least 100 meters (330 feet).
Fire: When a large quantity of this material is involved in a major fire,
consider an initial evacuation distance of 300 meters (1000 feet) in all
directions. /UN 2908, UN 2909, UN 2910, UN 2911/
/GUIDE 161: RADIOACTIVE MATERIALS (LOW LEVEL RADIATION)/ Fire: Presence of
radioactive material will not influence the fire control processes and should
not influence selection of techniques. Move containers from fire area if you can
do it without risk. Do not move damaged packages; move undamaged packages out of
fire zone. Small fires: Dry chemical, CO2, water spray or regular foam. Large
fires: Water spray, fog (flooding amounts). /UN 2908, UN 2909, UN 2910, UN 2911/
/GUIDE 161: RADIOACTIVE MATERIALS (LOW LEVEL RADIATION)/ Spill or leak: Do not
touch damaged packages or spilled material. Cover liquid spill with sand, earth
or other non-combustible absorbent material. Cover powder spill with plastic
sheet or tarp to minimize spreading. /UN 2908, UN 2909, UN 2910, UN 2911/
/GUIDE 161: RADIOACTIVE MATERIALS (LOW LEVEL RADIATION)/ First aid: Medical
problems take priority over radiological concerns. Use first aid treatment
according to the nature of the injury. Do not delay care and transport of a
seriously injured person. Give artificial respiration if victim is not
breathing. Administer oxygen if breathing is difficult. In case of contact with
substance, immediately flush skin or eyes with running water for at least 20
minutes. Injured persons contaminated by contact with released material are not
a serious hazard to health care personnel, equipment and facilities. Ensure that
medical personnel are aware of the material(s) involved, and take precautions to
protect themselves and prevent spread of contamination. /UN 2908, UN 2909, UN
2910, UN 2911/
/GUIDE 162: RADIOACTIVE MATERIALS (LOW TO MODERATE LEVEL RADIATION)/ Health:
Radiation presents minimal risk to transport workers, emergency response
personnel, and the public during transportation accidents. Packaging durability
increases as potential hazard of radioactive content increases. Undamaged
packages are safe. Contents of damaged packages may cause external radiation
exposure, or both external and internal radiation exposure if contents are
released. Low radiation hazard when material is inside container. If material is
released from package or bulk container, hazard will vary from low to moderate.
Level of hazard will depend on the type and amount of radioactivity, the kind of
material it is in, and/or the surfaces it is on. Some material may be released
from packages during accidents of moderate severity but risks to people are not
great. Released radioactive materials or contaminated objects usually will be
visible if packaging fails. Some exclusive use shipments of bulk and packaged
materials will not have "RADIOACTIVE" labels. Placards, markings, and
shipping papers provide identification. Some packages may have a
"RADIOACTIVE" label and a second hazard label. The second hazard is
usually greater than the radiation hazard; so follow this Guide as well as the
response Guide for the second hazard class label. Some radioactive materials
cannot be detected by commonly available instruments. Runoff from control of
cargo fire may cause low-level pollution. /UN 2912, UN 2913, UN 3321, UN 3322/
/GUIDE 162: RADIOACTIVE MATERIALS (LOW TO MODERATE LEVEL RADIATION)/ Fire or
explosion: Some of these materials may burn, but most do not ignite readily.
Uranium and thorium metal cuttings or granules may ignite spontaneously if
exposed to air (see Guide 136). Nitrates are oxidizers and may ignite other
combustibles (see Guide 141). /UN 2912, UN 2913, UN 3321, UN 3322/
/GUIDE 162: RADIOACTIVE MATERIALS (LOW TO MODERATE LEVEL RADIATION)/ Public
safety: CALL Emergency Response Telephone Number ... . Priorities for rescue,
life-saving, first aid, fire control and other hazards are higher than the
priority for measuring radiation levels. Radiation Authority must be notified of
accident conditions. Radiation Authority is usually responsible for decisions
about radiological consequences and closure of emergencies. As an immediate
precautionary measure, isolate spill or leak area immediately for at least 25
meters (75 feet) in all directions. Stay upwind. Keep unauthorized personnel
away. Detain or isolate uninjured persons or equipment suspected to be
contaminated; delay decontamination and cleanup until instructions are received
from Radiation Authority. /UN 2912, UN 2913, UN 3321, UN 3322/
/GUIDE 162: RADIOACTIVE MATERIALS (LOW TO MODERATE LEVEL RADIATION)/ Protective
clothing: Positive pressure self-contained breathing apparatus (SCBA) and
structural firefighters' protective clothing will provide adequate protection.
/UN 2912, UN 2913, UN 3321, UN 3322/
/GUIDE 162: RADIOACTIVE MATERIALS (LOW TO MODERATE LEVEL RADIATION)/ Evacuation:
Large Spill: Consider initial downwind evacuation for at least 100 meters (330
feet). Fire: When a large quantity of this material is involved in a major fire,
consider an initial evacuation distance of 300 meters (1000 feet) in all
directions. /UN 2912, UN 2913, UN 3321, UN 3322/
/GUIDE 162: RADIOACTIVE MATERIALS (LOW TO MODERATE LEVEL RADIATION)/ Fire:
Presence of radioactive material will not influence the fire control processes
and should not influence selection of techniques. Move containers from fire area
if you can do it without risk. Do not move damaged packages; move undamaged
packages out of fire zone. Small fires: Dry chemical, CO2, water spray or
regular foam. Large fires: Water spray, fog (flooding amounts). Dike
fire-control water for later disposal. /UN 2912, UN 2913, UN 3321, UN 3322/
/GUIDE 162: RADIOACTIVE MATERIALS (LOW TO MODERATE LEVEL RADIATION)/ Spill or
leak: Do not touch damaged packages or spilled material. Cover liquid spill with
sand, earth or other non-combustible absorbent material. Dike to collect large
liquid spills. Cover powder spill with plastic sheet or tarp to minimize
spreading. /UN 2912, UN 2913, UN 3321, UN 3322/
/GUIDE 162: RADIOACTIVE MATERIALS (LOW TO MODERATE LEVEL RADIATION)/ First aid:
Medical problems take priority over radiological concerns. Use first aid
treatment according to the nature of the injury. Do not delay care and transport
of a seriously injured person. Give artificial respiration if victim is not
breathing. Administer oxygen if breathing is difficult. In case of contact with
substance, wipe from skin immediately; flush skin or eyes with running water for
at least 20 minutes. Injured persons contaminated by contact with released
material are not a serious hazard to health care personnel, equipment or
facilities. Ensure that medical personnel are aware of the material(s) involved,
and take precautions to protect themselves and prevent spread of contamination.
/UN 2912, UN 2913, UN 3321, UN 3322/
/GUIDE 163: RADIOACTIVE MATERIALS (LOW TO HIGH LEVEL RADIATION)/ Health:
Radiation presents minimal risk to transport workers, emergency response
personnel, and the public during transportation accidents. Packaging durability
increases as potential hazard of radioactive content increases. Undamaged
packages are safe. Contents of damaged packages may cause higher external
radiation exposure, or both external and internal radiation exposure if contents
are released. Type A packages (cartons, boxes, drums, articles, etc.) identified
as "Type A" by marking on packages or by shipping papers contain
non-life endangering amounts. Partial releases might be expected if "Type
A" packages are damaged in moderately severe accidents. Type B packages and
the rarely occurring Type C packages, (large and small, usually metal) contain
the most hazardous amounts. They can be identified by package markings or by
shipping papers. Life threatening conditions may exist only if contents are
released or package shielding fails. Because of design, evaluation, and testing
of packages, these conditions would be expected only for accidents of utmost
severity. The rarely occurring "Special Arrangement" shipments may be
of Type A, Type B, or Type C packages. Package type will be marked on packages,
and shipment details will be on shipping papers. Radioactive White-l labels
indicate radiation levels outside single, isolated, undamaged packages are very
low (less than 0.005 mSv/hr (0.5 mrem/hr)). Radioactive Yellow-II and Yellow-III
labeled packages have higher radiation levels. The transport index (TI) on the
label identifies the maximum radiation level in mrem/h one meter from a single,
isolated, undamaged package. Some radioactive materials cannot be detected by
commonly available instruments. Water from cargo fire control may cause
pollution. /UN 2915, UN 2916, UN 2917, UN 2919, UN 2982, UN 3323/
/GUIDE 163: RADIOACTIVE MATERIALS (LOW TO HIGH LEVEL RADIATION)/ Fire or
explosion: Some of these materials may burn, but most do not ignite readily.
Radioactivity does not change flammability or other properties of materials.
Type B packages are designed and evaluated to withstand total engulfment in
flames at temperatures of 800 deg C (1475 deg F) for a period of 30 minutes. /UN
2915, UN 2916, UN 2917, UN 2919, UN 2982, UN 3323/
/GUIDE 163: RADIOACTIVE MATERIALS (LOW TO HIGH LEVEL RADIATION)/ Public safety:
Call Emergency Response Telephone Number. ... Priorities for rescue,
life-saving, first aid, fire control and other hazards are higher than the
priority for measuring radiation levels. Radiation Authority must be notified of
accident conditions. Radiation Authority is usually responsible for decisions
about radiological consequences and closure of emergencies. As an immediate
precautionary measure, isolate spill or leak area immediately for at least 25
meters (75 feet) in all directions. Stay upwind. Keep unauthorized personnel
away. Detain or isolate uninjured persons or equipment suspected to be
contaminated; delay decontamination and cleanup until instructions are received
from Radiation Authority. /UN 2915, UN 2916, UN 2917, UN 2919, UN 2982, UN 3323/
/GUIDE 163: RADIOACTIVE MATERIALS (LOW TO HIGH LEVEL RADIATION)/ Protective
clothing: Positive pressure self-contained breathing apparatus (SCBA) and
structural firefighters' protective clothing will provide adequate protection
against internal radiation exposure, but not external radiation exposure. /UN
2915, UN 2916, UN 2917, UN 2919, UN 2982, UN 3323/
/GUIDE 163: RADIOACTIVE MATERIALS (LOW TO HIGH LEVEL RADIATION)/ Evacuation:
Large Spill: Consider initial downwind evacuation for at least 100 meters (330
feet). Fire: When a large quantity of this material is involved in a major fire,
consider an initial evacuation distances of 300 meters (1000 feet) in all
directions. /UN 2915, UN 2916, UN 2917, UN 2919, UN 2982, UN 3323/
/GUIDE 163: RADIOACTIVE MATERIALS (LOW TO HIGH LEVEL RADIATION)/ Fire: Presence
of radioactive material will not influence the control processes and should not
influence selection of techniques. Move containers from fire area if you can do
it without risk. Do not move damaged packages; move undamaged packages out of
fire zone. Small fires: Dry chemical, CO2, water spray or regular foam. Large
fires: Water spray, fog (flooding amounts). Dike fire-control water for later
disposal. /UN 2915, UN 2916, UN 2917, UN 2919, UN 2982, UN 3323/
/GUIDE 163: RADIOACTIVE MATERIALS (LOW TO HIGH LEVEL RADIATION)/ Spill or leak:
Do not touch damaged packages or spilled material. Damp surfaces on undamaged or
slightly damaged packages are seldom an indication of packaging failure. Most
packaging for liquid content have inner containers and/or inner absorbent
materials. Cover liquid spill with sand, earth or other noncombustible absorbent
material. /UN 2915, UN 2916, UN 2917, UN 2919, UN 2982, UN 3323/
/GUIDE 163: RADIOACTIVE MATERIALS (LOW TO HIGH LEVEL RADIATION)/ First aid:
Medical problems take priority over radiological concerns. Use first aid
treatment according to the nature of the injury. Do not delay care and transport
of a seriously injured person. Give artificial respiration if victim is not
breathing. Administer oxygen if breathing is difficult. In case of contact with
the substance, immediately flush skin or eyes with running water for at least 20
minutes. Injured persons contaminated by contact with released material are not
a serious hazard to health care personnel, equipment or facilities. Ensure that
medical personnel are aware of the material(s) involved, take precautions to
protect themselves and prevent spread of contamination. /UN 2915, UN 2916, UN
2917, UN 2919, UN 2982, UN 3323/
/GUIDE 164: RADIOACTIVE MATERIALS (SPECIAL FORM/LOW TO HIGH LEVEL EXTERNAL
RADIATION)/ Health: Radiation presents minimal risk to transport workers,
emergency response personnel, and the public during transportation accidents.
Packaging durability increases as potential hazard of radioactive content
increases. Undamaged packages are safe; contents of damaged packages may cause
external radiation exposure, and much higher external exposure if contents
(source capsules) are released. Contamination and internal radiation hazards are
not expected, but not impossible. Type A packages (cartons, boxes, drums,
articles, etc.) identified as "Type A" by marking on packages or by
shipping papers contain non-life endangering amounts. Radioactive sources may be
released if "Type A" packages are damaged in moderately severe
accidents. Type B packages, and rarely occurring Type C packages, (large and
small, usually metal) contain the most hazardous amounts. They can be identified
by package markings or shipping papers. Life threatening conditions may exist
only if contents are released or packages shielding fails. Because of design,
evaluation, and testing of packages, these conditions would be expected only for
accidents of utmost severity. Radioactive White-I labels indicate radiation
levels outside single, isolated, undamaged packages are very low (less than
0.005 mSv/hr (0.5 mrem/hr)). Radioactive Yellow-II and Yellow-III labeled
packages have higher radiation levels. The transport index (TI) on the label
identifies the maximum radiation level in mrem/h one meter from a single
isolated, undamaged package. Radiation from the package contents, usually in
durable metal capsules, can be detected by most radiation instruments. Water
from cargo fire control is not expected to cause pollution. /UN 2974, UN 3332/
/GUIDE 164: RADIOACTIVE MATERIALS (SPECIAL FORM/LOW TO HIGH LEVEL EXTERNAL
RADIATION)/ Fire or explosion: Packagings can burn completely without risk of
content loss from sealed source capsule. Radioactivity does not change
flammability or other properties of materials. Radioactive source capsules and
Type B packages are designed and evaluated to withstand total engulfment in
flames at temperatures of 800 deg C (1475 deg F). /UN 2974, UN 3332/
/GUIDE 164: RADIOACTIVE MATERIALS (SPECIAL FORM/LOW TO HIGH LEVEL EXTERNAL
RADIATION)/ Public safety: CALL Emergency Response Telephone Number. ...
Priorities for rescue, life-saving, first aid, and control of fire and other
hazards are higher than the priority for measuring radiation levels. Radiation
Authority must be notified of accident conditions, and is usually responsible
for radiological consequences and closure of emergencies. As an immediate
precautionary measure, isolate spill or leak area immediately for at least 25
meters (75 feet) in all directions. Stay upwind. Keep unauthorized personnel
away. Delay final cleanup until instructions or advice is received from
Radiation Authority. /UN 2974, UN 3332/
/GUIDE 164: RADIOACTIVE MATERIALS (SPECIAL FORM/LOW TO HIGH LEVEL EXTERNAL
RADIATION)/ Protective clothing: Positive pressure self-contained breathing
apparatus (SCBA) and structural firefighters' protective clothing will provide
adequate protection against internal radiation exposure, but not external
radiation exposure. /UN 2974, UN 3332/
/GUIDE 164: RADIOACTIVE MATERIALS (SPECIAL FORM/LOW TO HIGH LEVEL EXTERNAL
RADIATION)/ Evacuation: Large Spill: Consider initial downwind evacuation for at
least 100 meters (330 feet). Fire: When a large quantity of this material is
involved in a major fire, consider an initial evacuation distance of 300 meters
(1000 feet) in all directions. /UN 2974, UN 3332/
/GUIDE 164: RADIOACTIVE MATERIALS (SPECIAL FORM/LOW TO HIGH LEVEL EXTERNAL
RADIATION)/ Fire: Presence of radioactive material will not influence the fire
control processes and should not influence selection of techniques. Move
containers from fire area if you can do it without risk. Do not move damaged
packages; move undamaged packages out of fire zone. Small fires: Dry chemical,
CO2, water spray or regular foam. Large fires: Water spray, fog (flooding
amounts). /UN 2974, UN 3332/
/GUIDE 164: RADIOACTIVE MATERIALS (SPECIAL FORM/LOW TO HIGH LEVEL EXTERNAL
RADIATION)/ Spill or leak: Do not touch damaged packages or spilled material.
Damp surfaces on undamaged or slightly damaged packages are seldom an indication
of packaging failure. Contents are seldom liquid. Content is usually a metal
capsule, easily seen if released from package. If source capsule is identified
as being out of package, DO NOT TOUCH. Stay away and await advice from Radiation
Authority. /UN 2974, UN 3332/
/GUIDE 164: RADIOACTIVE MATERIALS (SPECIAL FORM/LOW TO HIGH LEVEL EXTERNAL
RADIATION)/ First aid: Medical problems take priority over radiological
concerns. Use first aid treatment according to the nature of the injury. Do not
delay care and transport of a seriously injured person. Persons exposed to
special form sources are not likely to be contaminated with radioactive
material. Give artificial respiration if victim is not breathing. Administer
oxygen if breathing is difficult. Injured persons contaminated by contact with
released material are not a serious hazard to health care personnel, equipment
or facilities. Ensure that medical personnel are aware of the material(s)
involved, take precautions to protect themselves and prevent spread of
contamination. /UN 2974, UN 3332/
/GUIDE 165: RADIOACTIVE MATERIALS (FISSILE/LOW TO HIGH LEVEL RADIATION)/ Health:
Radiation presents minimal risk to transport workers, emergency response
personnel, and the public during transportation accidents. Packaging durability
increases as potential radiation and critically hazards of the content increase.
Undamaged packages are safe. Contents of damaged packages may cause higher
external radiation exposure, or both external and internal radiation exposure if
contents are released. Type AF or IF packages, identified by package markings,
do not contain life-threatening amounts of material. External radiation levels
are low and packages are designed, evaluated, and tested to control releases and
to prevent a fission chain reaction under severe transport accident conditions.
Type B(U)F, or B(M)F and CF packages (identified by markings on packages or
shipping papers) contain potentially life endangering amounts. Because of
design, evaluation, and testing of packages, fission chain reactions are
prevented and releases are not expected to be life endangering for all accidents
except those of utmost severity. The rarely occurring "Special
Arrangement" shipments may be of Type AF, BF, or CF packages. Package type
will be marked on packages, and shipment details will be on shipping papers. The
transport index (TI) shown on labels or a shipping paper might not indicate the
radiation level at one meter from a single isolated, undamaged package; instead,
it may relate to controls needed during transport because of the fissile
properties of the materials. Alternatively, the fissile nature of the contents
may be indicated by a criticality safety index (CSI) on a special FISSILE label
or on the shipping paper. Some radioactive materials cannot be detected by
commonly available instruments. Water from cargo fire control is not expected to
cause pollution. /UN 2918, UN 3324, UN 3325, UN 3326, UN 3327, UN 3328, UN 3329,
UN 3330, UN 3331, UN 3333/
/GUIDE 165: RADIOACTIVE MATERIALS (FISSILE/LOW TO HIGH LEVEL RADIATION)/ Fire or
explosion: These materials are seldom flammable. Packages are designed to
withstand fires without damage to contents. Radioactivity does not change
flammability or other properties of materials. Type AF, IF, B(U)F, B(M)F and CF
packages are designed and evaluated to withstand total engulfment in flames at
temperatures of 800 deg C (1475 deg F) for a period of 30 minutes. /UN 2918, UN
3324, UN 3325, UN 3326, UN 3327, UN 3328, UN 3329, UN 3330, UN 3331, UN 3333/
/GUIDE 165: RADIOACTIVE MATERIALS (FISSILE/LOW TO HIGH LEVEL RADIATION)/ Public
safety: CALL Emergency Response Telephone Number. ... Priorities for rescue,
life-saving, first aid, control of fire and other hazards are higher than the
priority for measuring radiation levels. Radiation Authority must be notified of
accident conditions. Radiation Authority is usually responsible for decisions
about radiological consequences and closure of emergencies. As an immediate
precautionary measure, isolate spill or leak area immediately for at least 25
meters (75 feet) in all directions. Stay upwind. Keep unauthorized personnel
away. Detain or isolate uninjured persons or equipment suspected to be
contaminated; delay decontamination and cleanup until instructions are received
from Radiation Authority. /UN 2918, UN 3324, UN 3325, UN 3326, UN 3327, UN 3328,
UN 3329, UN 3330, UN 3331, UN 3333/
/GUIDE 165: RADIOACTIVE MATERIALS (FISSILE/LOW TO HIGH LEVEL RADIATION)/
Protective clothing: Positive pressure self-contained breathing apparatus (SCBA)
and structural firefighters' protective clothing will provide adequate
protection against internal radiation exposure, but not external radiation
exposure. /UN 2918, UN 3324, UN 3325, UN 3326, UN 3327, UN 3328, UN 3329, UN
3330, UN 3331, UN 3333/
/GUIDE 165: RADIOACTIVE MATERIALS (FISSILE/LOW TO HIGH LEVEL RADIATION)/
Evacuation: Large Spill: Consider initial downwind evacuation for at least 100
meters (330 feet. Fire: When a large quantity of this material is involved in a
major fire, consider an initial evacuation distance of 300 meters (1000 feet) in
all directions. /UN 2918, UN 3324, UN 3325, UN 3326, UN 3327, UN 3328, UN 3329,
UN 3330, UN 3331, UN 3333/
/GUIDE 165: RADIOACTIVE MATERIALS (FISSILE/LOW TO HIGH LEVEL RADIATION)/ Fire:
Presence of radioactive material will not influence the fire control processes
and should not influence selection of techniques. Move containers from fire area
if you can do it without risk. Do not move damaged packages; move undamaged
packages out of fire zone. Small fires: Dry chemical, CO2, water spray or
regular foam. Large fires: Water spray, fog (flooding amounts). /UN 2918, UN
3324, UN 3325, UN 3326, UN 3327, UN 3328, UN 3329, UN 3330, UN 3331, UN 3333/
/GUIDE 165: RADIOACTIVE MATERIALS (FISSILE/LOW TO HIGH LEVEL RADIATION)/ Spill
or leak: Do not touch damaged packages or spilled material. Damp surfaces on
undamaged or slightly damaged packages are seldom an indication of packaging
failure. Most packaging for liquid content have inner containers and/or inner
absorbent materials. Liquid spills: Package contents are seldom liquid. If any
radioactive contamination resulting from a liquid release is present, it
probably will be low-level. /UN 2918, UN 3324, UN 3325, UN 3326, UN 3327, UN
3328, UN 3329, UN 3330, UN 3331, UN 3333/
/GUIDE 165: RADIOACTIVE MATERIALS (FISSILE/LOW TO HIGH LEVEL RADIATION)/ First
aid: Medical problems take priority over radiological concerns. Use first aid
treatment according to the nature of the injury. Do not delay care and transport
of a seriously injured person. Give artificial respiration if victim is not
breathing. Administer oxygen if breathing is difficult. In case of contact with
substance, immediately flush skin or eyes with running water for at least 20
minutes. Injured persons contaminated by contact with released material are not
a serious hazard to health care personnel, equipment or facilities. Ensure that
medical personnel are aware of the material(s) involved, take precautions to
protect themselves and prevent spread of contamination. /UN 2918, UN 3324, UN
3325, UN 3326, UN 3327, UN 3328, UN 3329, UN 3330, UN 3331, UN 3333/
Fire Fighting Procedures:
General Guidelines for Responding to a Fire: Consult the DOT Emergency Response
Guidebook. Some materials may react with water or water vapor in air to form a
hazardous vapor. Small Fires: Dry chemical, CO2, Halon, water spray, or regular
foam. Large Fires: Water spray, fog, or regular foam. Move undamaged containers
from fire area if you can do it without risk. Do not touch damaged containers.
Cool containers that are exposed to flames with water from the side until well
after fire is out. Fight fire as if toxic chemicals are involved. To the extent
possible, keep upwind and avoid smoke, fumes, gases, and dusts. For massive fire
in cargo area, use unmanned hose holder or monitor nozzles; if this is
impossible, withdraw from area and let fire burn. Stay away from ends of tanks.
Withdraw immediately in case of rising sound from a venting safety device or if
there is discoloration of tanks due to fire. Fight fires from maximum distance.
Delay cleanup until radiation authority provides guidance. As much as possible,
form barrier to contain fire, water that may be contaminated with radioactive,
and/or other chemicals. Use established fire-fighting procedures and protocols.
Radioactivity does not change flammability or other properties of materials.
Radioactive material that presents a radiological risk: if material on fire or
involved in fire, contact the local, state, or Department of Energy Radiological
Response Team. Extinguish fire using agent suitable for type of surrounding
fire. Cool all affected containers with flooding quantities of water. Apply
water from as far a distance as possible.
Radioactive material, Type A package are materials that pose a minimal risk to
transport workers, emergency response personnel and the public during
transportation. If material on fire or involved in fire, contact the local,
state, or Department of Energy Radiological Response Team. Do not use water. Use
graphite, soda ash, powdered sodium chloride, or suitable dry powder.
Radioactive material, Type B(U) package is radioactive material in a package
designed in such a way that it is unlikely to release its radioactive contents
or lose its shielding integrity in accidents. In case of trouble with these
shipments all unauthorized persons should be kept as far away as possible. If
material on fire or involved in fire, contact the local. State, or Department of
Energy Radiological Response Team. Extinguish fire using agent suitable or type
of surrounding fire, Cool all affected containers with flooding quantities of
water, Apply water from as far a distance as possible.
Radioactive material, Type C: if material on fire do not use water. Use
graphite, soda ash, powdered sodium chloride, or suitable dry powder. If
material not involved in fire, keep sparks, flames, and other sources of
ignition away. Keep material out of water sources and sewers. Keep material dry.
Do not attempt to sweep up dry material.
The spread of radioactive contamination may be an important issue associated
with a number of possible radiological attack scenarios. This spread of
contamination may occur through water runoff from fire-fighting activities,
smoke from burning debris, or transit of vehicles or personnel through a
contaminated area prior to control being established. In certain situations,
extinguishing a fire may be more hazardous than leaving it to burn...
Firefighting Hazards:
/In a radiation event fires may/ produce dangerous chemical fumes from burning
metals and plastics and deplete closed-space oxygen; a self-contained breathing
apparatus may be necessary in such cases.
Other Hazardous Reaction:
Neutrons are primarily released from nuclear
fission ... . The natural decay of radionuclides does not include emission of
neutrons. This is mainly a health hazard for workers in a nuclear
power facility or victims of a nuclear
explosion. Unique among the particles of radioactivity, when neutrons are
stopped or captured they can cause a previously stable atom to become
radioactive. This is the principle behind radioactive fallout.
Prior History of Accidents:
Radiation as a toxin became a concern for scientists only a year following the
discovery of X-rays by Wilhelm Roentgen in 1895. Thomas Edison conducted
thousands of experiments using an x-ray generator of his own design. He reported
corneal injuries in several of his workers in 1896. Eight years later, Clarence
Dally, one of Edison's most dependable assistants, became the first
radiation-related death in the United States. Physicians quickly recognized this
new tool and began to manufacture x-ray machines to help diagnose various
illnesses... . However, over the next 10 to 15 years, radioactive substance also
found their way into society as objects of fascination and as a means of
alternative medical therapies. ... The opening of the Radium Luminous Materials
Corporation in Orange, NJ in 1917 represented the first of several companies to
profit from the novelty and popularity of radium's bluish glow. In an industry
that eventually employed over 4000 workers, nearly all of whom were female, the
radium was handpainted onto watch and instrument dials. These young women were
instructed to obtain a fine tip on their paintbrushes using a technique called
"lip pointing" ... Unaware of the danger, some of these women also
painted their nails, lips, and eyelids with the radioactive paint. By 1927,
about 100 of these women died from osteosarcoma, brain tumors, and developed
other non cancerous lesions of the mouth, all related to radium exposure.
The Life Span Study is /investigating/... the long-term health effects of
exposure to radiation during the atomic bombings of Hiroshima and Nagasaki,
Japan, in 1945. ... The subjects were all Japanese exposed during wartime, and
host and environmental factors may have modified their risk for cancer. In
addition, the study sample includes only those still alive five years after the
bombings. ...The Life Span Study cohort consists of approximately 120,000 people
who were identified at the time of the 1950 census, and individual doses have
been reconstructed. ... The latest published data on mortality from cancer cover
the period 1950-90. An additional source of information on leukemia and related
hematological disease is the Leukemia Registry. It /is/ ... possible to analyze
cancer incidence by linkage to the Hiroshima and Nagasaki tumor registries... .
/although/... these data ... do not include diagnoses of cancers before 1958 or
for persons who migrated from the two cities. ...(a) Leukemia: Leukemia was the
first cancer to be linked with exposure to radiation after the atomic bombings,
and the Excess relative risk for this malignancy is by far the highest, /with/
... a clear increase in risk with increasing dose over the range 0-2.5 Sv.
...Although the temporal patterns of leukemia risk are more complex than those
of solid tumors, the largest excess risks were generally seen in the early years
of follow-up. For people exposed as children, essentially all of the excess
deaths appear to have occurred early in the follow-up. For people exposed as
adults, the excess risk was lower than that of people exposed as children and
appears to have persisted throughout the follow-up. ...The other major type of
leukemia, chronic lymphocytic leukemia, is infrequent in Japan, and no excess
was seen in the Life Span Study cohort. ... (b) All solid tumors: ... As for
leukemia, an increase in risk with increasing dose over the range 0-2.5 Sv is
seen. ... The attributable risk for solid tumors is estimated to be 8%, much
smaller than the estimate of 44% for leukemia. The temporal pattern of solid
tumors differs from that of leukemia as it includes a longer minimal latent
period. .... For people who were exposed when they were under the age of 30,
nearly half of the excess deaths during the entire 40 years of follow-up have
occurred in the last five years. Of the 86,572 subjects for whom ... dose
estimates are available, 56% were still alive at the end of 1990, the end of the
period for which mortality has been reported. Of the 46,263 subjects who were
under the age of 30 at the time of the bombings, 87% were still alive at the end
of 1990. ...(c) Site-specific cancer risks: ... The following discussion of
site-specific cancer risks is ... based primarily on incidence. (i) Female
breast cancer: The risk for breast cancer among women in the Life Span Study
shows a strong linear dose-response relationship and a remarkable age
dependence. The excess relative risk for this cancer is one of the largest of
those for solid tumors, but it decreases smoothly and significantly with
increasing age at the time of exposure. Figures on incidence from the tumor
registries showed, for example, that the Excess relative risk of women who were
under 10 years of age at the time of exposure was five times that of women who
were over 40 years of age at that time. ... (ii) Thyroid cancer: ... a
dose-related increase in the incidence of thyroid cancer was demonstrated in the
early 1960s from the results of periodic clinical examinations of a subcohort of
approximately 20,000 persons (the 'Adult Health Study'). More detailed analyses
based on incidence in the Life Span Study cohort showed a strong dependence of
risk with age at exposure, the risk being higher among people who had been less
than 19 years old at the time of the bombings. ...Among children who were under
15 at the time of the bombings, a steep decrease in risk with age at exposure
was found, and children who were exposed between the ages of 10 and 14 had
one-fifth the risk of those exposed when they were under 5. (iii) Other sites:
Cancers at other sites that are clearly linked with exposure to radiation in the
Life Span Study include those of the salivary glands, stomach, colon, lung,
liver, ovary and urinary bladder, and nonmelanoma skin cancer. For most of these
sites, statistically significant associations were found for both mortality and
incidence. ... The evidence for an association with exposure to radiation is
equivocal for cancers of the esophagus, gall-bladder, kidney and nervous system
and for non-Hodgkin lymphoma and multiple myeloma, as the results are either of
borderline statistical significance or those for incidence and mortality
conflict. Cancers for which there is little evidence of an association with
exposure to radiation include those of the oral cavity (except salivary glands),
rectum, pancreas, uterus and prostate and Hodgkin disease.
During an engineering test of one of the four reactors at the Chernobyl nuclear
power plant in the Ukraine on 26 April 1986, the safety systems had been
switched off, and unstable operation of the reactor allowed an uncontrollable
power surge to occur, leading to successive steam explosions and resulting in
destruction of the reactor. Within days or weeks of this accident, 28
power-plant employees and firemen had died due to exposure to radiation. During
1986, about 220,000 people were evacuated from areas surrounding the reactor,
and about 250,000 people were relocated subsequently. About 600,000 persons
worked, and some still do, in cleaning-up the accident; they are known as
'recovery operation workers' or 'liquidators'. The radionuclides were released
mainly over a period of 10 days after the accident, contaminating vast areas of
the Ukraine, Belarus, and the Russian Federation, and trace deposition of
released radionuclides was measurable in all countries of the northern
hemisphere. The contamination beyond the 30-km exclusion zone was determined
primarily by wind direction. ... The total releases of iodine-131 and cesium-137
in 1996 are estimated to have been 1760 and 85 PBq (1760 and 85x10+15 Bq; 50%
and 30% of the core inventory), respectively. ... In the European part of the
former USSR, 3% of the land was contaminated after the Chernobyl accident, with
cesium-137 deposition densities > 37 kBq/m2. Many people areas in which the
cesium-137 deposition density was > 555 kBq/m2 were considered to be areas of
strict control. Initially, 786 settlements inhabited by 273,000 people were
considered to be strict control zones. Within these areas, radiation monitoring
and preventive measures were taken with the aim of maintaining the annual
effective dose within 5 mSv; in 1995, about 150,000 people were living in the
areas of strict control. The average effective individual dose received by the
inhabitants of these zones was 37 mSv during the first year after the accident.
The percentage of the population />5 million/ living in areas with the
highest contamination was about 5% in Belarus and the Russian Federation and
< 1% in the Ukraine. The doses due to internal exposure came essentially from
the intake of iodine-131 and other short-lived radioiodines during the first
days or weeks after the accident and, subsequently, from intake of cesium-134
and cesium-137. Other long-lived radionuclides, notably strontium-90,
plutonium-239 and plutonium-240, have so far contributed relatively little to
the internal doses, but they will play a more important role in the future. ...
Between 600,000 and 800,000 workers ('liquidators') are thought to have
participated in cleaning-up after the accident in the restricted 30-km zone
around the Chernobyl power plants and in contaminated areas of Belarus and the
Ukraine between 1986 and 1989 (200,000 in 1986-87). ... In most of the papers
published to date, the mortality rates and sometimes the morbidity due to cancer
of the liquidators have been compared only with those of the general population.
An increased incidence of leukemia was reported among Belarussian, Russian and
Ukrainian liquidators who worked in the 30-km zone, but no excess was found in a
small Estonian study with complete follow-up. ... The results of a cohort study
of 169,372 emergency workers, including 119,000 (71%) for whom individual doses
of external exposure were available /were described/. The mean age of the
workers during their period of duty in the 30-km zone was 33.4 years. Of the
46,575 persons with the highest exposure, who were exposed in 1986, 4.5% have
been assigned doses in excess of 250 mGy. In a nested case-control study of
leukemia within the subcohort of emergency workers with officially documented
doses, no significant difference was seen in dose between 34 cases occurring
more than two years after first exposure and 136 controls matched on date of
birth ... and region of residence.
The Chelyabinsk region of the southern Ural Mountains was one of the main
military production centers of the former USSR and included the Mayak nuclear
materials production complex in the closed city of Ozersk. Accidents, nuclearwaste disposal and day-to-day
operation of the Mayak reactor and radiochemical plant contaminated the nearby
Techa River. The period of most releases of radioactive material was 1949-56,
with a peak in 1950-51. During the first years of the releases, 39 settlements
were located along the banks of the Techa River, and the total population was
about 28,000. Technical flaws and lack of expertise in radioactive waste
management led to contamination of vast areas, and the population was not
informed about the releases. The protective measures that were implemented
(evacuations, restrictions on the use of flood lands and river water in
agricultural production and for domestic purposes) proved to be ineffective,
since they were implemented too late. Approximately 7,500 people were evacuated
from villages near the River between 1953 and 1960. ... During 1949-56, 7.6 x
10(+7) cubic meters of liquid wastes
with a total radioactivity of 100 Pbq were released into the Techa-Isset-Tobol
river system. ... Large populations were exposed over long periods to external
gamma radiation, due largely to cesium-137 but also to other gamma-emitting
radionuclides such as zirconium-95, niobium-95 and ruthenium-106 present in the
water and on the banks of the Techa River. The internal radiation dose was from
ingestion of strontium-90 and cesium-137 over long periods... .Systematic follow
up of a cohort of almost 30,000 individuals who received significant exposure
from the releases was begun in 1967. ... The preliminary results of follow-up
from 1950 through 1989, which were analyzed in linear dose-response models for
excess relative risk, indicate an increased rate of mortality from leukemia and
solid tumors related to internal and external doses of ionizing radiation.
In 1957, a nuclearwaste
storage facility in the Chelyabinsk region, near the town of Kyshtym, exploded
(the Kyshtym accident) due to a chemical reaction, producing contamination
referred to as the East Urals Radiation Trace (EURT). About 273, 000 people
lived in the contaminated area. Ten years later, in 1967, after an exceptionally
dry summer, the water of the Karachay Lake, an open depot of liquid radioactive waste,
evaporated, and a storm transported radionuclides from the dry shores. Eleven
thousand individuals were resettled as a result of the Kyshtym accident, of whom
1,500 had previously been resettled from the Techa River.
In October 1957 in Windscale, England, the fuel elements in a graphite-moderated
nuclear reactor used to produce
plutonium for military purposes caught fire. The fire was detected three days
later and, when efforts to extinguish it with carbon dioxide failed, the core
was flooded with water. A total of 1.5x10+15 Bq of radioactive material were
released into the environment, including the radionuclides xenon-133 (14x10+15
Bq), iodine-131(1.4x10+15 Bq), cesium-137 (0.04x10+15 Bq) and polonium-210
(0.009x10+15 Bq). The total collective effective dose was 2000 person-Sv,
including 900 person-Sv from inhalation and 800 person-Sv from ingestion of milk
and other foods. Children in the vicinity of the nuclear
plant received doses to the thyroid of up to 100 mGy.
The releases of radiation from the accident at the Three Mile Island reactor in
Pennsylvania, USA, in March 1979 were caused by failure to close a pressure
relief valve, which led to melting of the uncooled fuel. The large release of
radioactive material was dispersed to only a minor extent outside the
containment building; however, xenon-133 (370x10+15 Bq) and iodine-131(550x10+9
Bq) were released into the environment, leading to a total collective dose of 40
person-Sv and an average individual dose from external gamma-radiation of 15 uSv.
No individual was considered to have received doses to the thyroid of > 850
uSv ...The nuclear reactor accident at
Three-Mile Island, Pennsylvania (USA), released little radioactivity into the
environment and resulted in doses to the population that were much lower than
those received from the natural background.
Equipment & Clothing:
/ALL USES/ /SRP/ Protective equipment and respirators do not provide protection
against penetrating beta and gamma radiation. However, respirators prevent the
inhalation of radioactive materials. Respirators should be tested and certified
for the given use by NIOSH and persons using the respirator should have been fit
tested before donning the equipment.
/RADIATION EVENTS/ /FIRST RESPONDERS/ In most situations, respiratory protection
that is designed to protect responders against chemical or biological agents is
likely to offer some degree of respiratory protection in a radiological attack.
Concerns about the presence of chemical or biological contaminants will
influence the selection of respiratory protection. If used properly, simple face
masks provide reasonably good protection against inhaling particulates, and
allow sufficient air transfer for working at high breathing rates. If available,
high-efficiency particulate air filter masks provide even better protection.
/RADIATION EVENTS/ /FIRST RESPONDERS/ The ICRP recommends that integrating
alarming dose meters should be provided to /first/ responders, with appropriate
alarms /that/ warn first responders when their doses approach levels of 100,
500, and 1000 mSv. ... Following the detonation of a radioactive dispersion
device, the radiation fields in the immediate vicinity may be extremely
inhomogeneous due to the presence of highly radioactive fragments - resulting in
radiation "hot-spots." People managing field exposures need to be
aware of the possibility, especially if the variable "time" is used to
manage the doses to first responders.
/RADIATION EVENTS/ /FIRST RESPONDERS/ The skin should be protected to reduce
potential burns from high levels of relatively non-penetrating radiation, and to
prevent possible transfer of radioactive material into the body through the skin
and inadvertently through the mouth or nose. The choice of clothing will often
be influenced by more immediate hazards such as fire, heat, or chemicals.
Protection against these other hazards will generally provide protection from
radioactive material.
/RADIATION EVENTS/ /FIRST RESPONDERS/ Because they are directional and can give
erroneous readings in extremely high radiation fields, GM counters/with or
without pancake probes/ are not recommended for general area readings by the
teams entering intense radiation areas to save lives or to map the areas.
Organizations using Geiger counters should have access to a qualified technician
who can train the team members in use of the device.
/RADIATION EVENTS/ /FIRST RESPONDERS/ Since alpha emitters are internal hazards,
not external hazards, if there is any concern about alpha emitters, first
responders can enter with respiratory protection and not worry about the
presence of the alpha emitting material. The decontamination station personnel
can determine whether radioactive material is present using a pancake probe.
Alpha detectors are only useful in the reentry and cleanup phase of the
incident.
/RADIATION EVENTS/ /HOSPITAL WORKERS/ Ordinary surgical facemasks provide good
protection against inhaling particulates, and allow excellent air transfer for
working at high breathing rates. If available, high efficiency particulate air (HEPA)
filter masks such as the NIOSH "N-95" mask provide even better
protection. These are standard issue for health care workers who work with
patients with tuberculosis and other highly contagious diseases. These masks
must be fit-tested to each individual by personnel trained in the OSHA-accepted
methods. Under stressful conditions, however, they may cause breathing
difficulties, due to their inherently reduced air transfer.
/RADIATION EVENTS/ /HOSPITAL WORKERS/ For medical personnel, normal barrier
clothing and gloves may provide personal protection against intake of
contamination. Disposable medical scrub suits, high-density polyethylene or
other close-weave coveralls, and hoods should be used if available. Secondary
contamination of the medical staff from handling patients should not be a cause
of great concern; however, to prevent the unnecessary spread of contamination
and thereby reducing the need for clean up, it is prudent to utilize
conventional protective clothing.
/RADIATION EVENTS/ /HOSPITAL WORKERS/ Suggested personnel protection equipment
that also facilitates the ease of clean-up includes: (1) Universal precautions
clothing (facemask, goggles, gowns, double-gloves with inner one taped and outer
glove removed after each contact). (2) Plastic wrap (e.g., disposable trash
bags, Saran Wrap., ZipLoc bags, etc.) ... (3) Disposable shoe coverings. (4)
Butcher paper or equivalent on floor. (4) If possible, personal dosimeters for
staff members who might have frequent contact with contaminated patients.
/RADIATION EVENTS/ /HOSPITAL WORKERS/ Since the presence or absence of
radiation, and its magnitude, is all that emergency responders entering an area
to save lives need to be aware of, knowing the specific radioisotope involved
would not be immediately helpful. Therefore, portable spectrometers are not
recommended for first responders. However, personnel making protective action
recommendations need to know what radioisotopes are present, specifically to
guide the treatment of internal contamination, so they need the capability of
performing isotopic identification.
/RADIATION EVENTS/ /HOSPITAL WORKERS/ A portal monitor, ... a doorway-type
device that allows people to walk through to detect the presence of radiation,
... can be used to check large numbers of people more rapidly than a technician
with a hand-held meter so they are useful at decontamination stations
established for screening mobile but possibly contaminated people. Many types of
portal monitors are not wide enough to accommodate wheel chairs or gurneys and
all require periodic calibration and testing. Some portal monitors can be
expanded to allow vehicles to pass through, but most are for the monitoring of
people.
/OPERATIONAL RADIATION SAFETY/ In most /routine/ cases, protective clothing is
used to avoid getting radioactive contamination on the worker, to prevent the
spread of contamination, and in some instances, to provide protection against
external radiation. It is always preferable to shield the radiation at its
source rather than to place a shield on the worker. ... Protective clothing for
external radiation is effective primarily against beta particles and X-and gamma
rays with energies less than 200 keV. The most common types of protective
clothing for external radiation are lead impregnated gloves, aprons and vests.
... Plastic glasses or face shields can be useful for reducing the dose from
beta particles... A lab coat, or a single or double layer of coveralls that is
useful for eliminating the direct contamination of the skin can also provide
some protection against beta radiation.
/OPERATIONAL RADIATION SAFETY/ Operations that routinely produce airborne
contamination should use engineered containment and ventilation systems to
prevent exposures to individuals from airborne releases to the environment. ...
Appropriate personal respiratory protective devices may be used ... but only in
abnormal situations or when effective engineering controls are not
feasible...For radiation safety, the primary functions of a ventilation system
are to move airborne contamination away from occupied work areas (and the
potentially exposed workers) and to provide a mechanism for the "recontainment"
of the airborne radioactive material that was released. To meet these
objectives, the ventilation system must have acceptable pressure differentials
between work areas and the outside environment. High-efficiency particulate air
(HEPA) filtration or other appropriate filtration may be needed, but the
radiation exposure of individuals from the radioactive materials retained on the
filter should be evaluated. A pressure differential system should be used to
control the flow of airborne contamination. In the system design, a pressure
gradient should be established, with the lowest pressure and collection points
in areas with the highest potential for release of dispersible material. The
flow should always be from clean areas to contaminated areas.
/OPERATIONAL RADIATION SAFETY/ /U.S. NRC licensees must/ use only respiratory
protection equipment that is tested and certified by the National Institute for
Occupational Safety and Health (NIOSH) ... . The licensee /must/ implement and
maintain a respiratory protection program that includes: (1) Air sampling
sufficient to identify the potential hazard, permit proper equipment selection,
and estimate doses; (2) Surveys and bioassays, as necessary, to evaluate actual
intakes; (3) Testing of respirators for operability (user seal check for face
sealing devices and functional check for others) immediately prior to each use;
(4) Written procedures regarding: (i) Monitoring, including air sampling and
bioassays; (ii) Supervision and training of respirator users; (iii) Fit testing;
(iv) Respirator selection; (v) Breathing air quality; (vi) Inventory and
control; (vii) Storage, issuance, maintenance, repair, testing, and quality
assurance of respiratory protection equipment; (viii) Recordkeeping; and (ix)
Limitations on periods of respirator use and relief from respirator use; (5)
Determination by a physician that the individual user is medically fit to use
respiratory protection equipment: (i) Before the initial fitting of a face
sealing respirator; (ii) Before the first field use of non-face sealing
respirators, and (iii) Either every 12 months thereafter, or periodically at a
frequency determined by a physician. (6) Fit testing, with fit factor > 10
times the approved protection factor (APF) for negative pressure devices, and a
fit factor > 500 for any positive pressure, continuous flow, and
pressure-demand devices, before the first field use of tight fitting,
face-sealing respirators and periodically thereafter at a frequency not to
exceed 1 year. ... Standby rescue persons are required whenever one-piece
atmosphere-supplying suits, or any combination of supplied air respiratory
protection device and personnel protective equipment are used from which an
unaided individual would have difficulty extricating himself or herself. The
standby persons must be equipped with respiratory protection devices or other
apparatus appropriate for the potential hazards.
/OPERATIONAL RADIATION SAFETY/ For external doses, a protective plastic suit can
be worn as shielding against weakly penetrating radiation from airborne
radioactive materials. This shielding will stop alphas and most betas and
radioactive material, such as tritium, that can be also absorbed through the
skin. For internal doses, one can wear a respirator, or wear a nonporous suit in
atmospheres containing absorbable radionuclides.
Preventive Measures:
/RADIATION EVENTS/ /OVERVIEW/ Guidelines for Incident Command. 1. Approach site
with caution. Position personnel, vehicles, and command post at a safe distance
upwind and uphill of the site, if possible. 2. Ensure safety of responders.
Identify all hazards (danger of fire, explosion, toxic fumes, electrical
hazards, structural collapse, etc.). 3. Identify cargo. Obtain information
concerning the cargo from placards, labels, shipping documents, and other
immediately available sources. Consult DOT Emergency Response Guidebook. Keep
upwind of smoke, fumes, etc. Follow usual protocols for respiratory protection,
use of protective clothing, and turnout gear. Monitor changing conditions that
could create hazardous situations. ... 4. Establish a control zone. Reroute
traffic. Mark controlled area by use of ropes or tapes. Limit entry to rescue
personnel only. Order evacuation or sheltering as needed. 5. Prevent/fight fires
as if toxic chemicals are involved. 6. Ensure radiation protection and
contamination control. Do not allow eating, drinking, smoking, or other
activities within contaminated areas that might lead to intake of radioactive
material. Avoid direct contact with radioactive materials where possible.
Utilize protective clothing and anything available for remote handling (shovels,
branches, ropes, etc.) Limit time near radioactive materials to the minimum
necessary. Rotate staff as necessary. Determine radiation levels within
controlled area and monitor rescue personnel with individual dosimeters, if
available. Evacuate personnel from the immediate downwind area. Detain personnel
who were in the accident area until they can be checked by radiological
monitors. Follow instruction of radiation authority. Remove protective
gear/clothing at the control line. Wrap, label, and isolate all clothing, tools,
etc. used in the controlled area, and retain them until they can be cleared by
radiation authority. Determine if measures are needed to contain all accident
debris in the control zone until cleanup is achieved. Prevent unnecessary
handling of incident debris. 7. Documentation. Record the names and addresses of
all persons involved, including those who insist on leaving the area; rescuers;
those removed for medical attention; and ambulance personnel. Make detailed
records of the incident.
/RADIATION EVENTS/ /PLANNING/ In developing an emergency preparedness program,
the following infrastructure elements are ... required to be considered at local
and national level: authority; organization; co-ordination; plans and
procedures; logistic support and facilities; training drills and exercises; and
quality assurance. Among many other elements, this will include the designation
of a continuously available contact point for receiving and acting on
information, an emergency management organization, arrangements for technical
information management, and public communication arrangements. More specifically
planning for attacks involving radioactive material needs to ensure that: first
responders are trained and have the proper instruments to identify the presence
of radiation; radiological specialists are readily available to respond promptly
to suspected hazards to advise first responders; local authorities and others;
and robust operational criteria have been established in advance for taking
protective measures under various scenarios. Given credible indication that an
attack has occurred, it may be prudent to assume that such an attack does
involve radiological, chemical, and/or biological hazards until proven
otherwise. This dictates the adoption of an all-hazard approach to emergency
response. ... Current international guidance emphasizes the need for all-hazard
planning where radiological emergency plans are well integrated with
arrangements and resources in place for conventional emergencies.
/RADIATION EVENTS/ /PLANNING/ Another important difference between a
conventional radiological accident and a radiological attack is that after the
latter, ... police will always be involved and may need to declare the area a
crime scene... . the objectives of forensic investigations and evidence
preservation often conflict with those of radiological protection ... Therefore,
one of the most critical preplanning issues is how the various law enforcement
and investigation groups will work collaboratively with the radiological
protection groups.
/RADIATION EVENTS/ /PLANNING/ Every hospital should have a well defined Medical
Radiation Plan that will guide the emergency participants in preparation of the
medical radiation emergency room, assembly of supplies and instrumentation that
might be needed in handling the patient, procedures for gowning, monitoring and
protecting staff, and procedures for dealing with contamination, including its
evaluation and effective removal. The medical radiation emergency plan should
identify the members of the radiation safety staff who will respond immediately
and assist in activating the plan. If the hospital does not have a health
physics staff, then the plan should include names and phone numbers of
consultants who can be called in if needed.
/RADIATION EVENTS/ /TRAINING/ Preparedness ... to respond to a terrorist event
involving radiological materials requires a well-trained response team. Training
provides the knowledge by which responders can minimize their own and others'
radiation exposure and enable them to make sound decisions to protect health in
relation to other, nonradiological hazards. Training must be audience-specific,
and focused on developing the skills and expertise to respond effectively to the
consequences. It will encompass a range of activities including classroom
instruction, hands-on training, drills and participation in well-crafted
exercises.
/RADIATION EVENTS/ /TRAINING/ Hospitals should purchase and maintain radiation
survey meters for detection procedures ... and identify during their emergency
planning what agencies or laboratories the /blood, urine, nasal swab, etc./
samples should go to for analysis. ... Every employee at the hospital needs
simple, competency-based training that is preferably conducted on-site and
includes: (1) The basic principles of radiation protection and the realties of
treating contaminated patients. (2) A clear definition of the roles and
responsibilities of all staff members involved in a response to a mass casualty
incident. Hospitals should incorporate this training into employee orientation
and differentiate radiation training from other HazMat trainings.
/RADIATION EVENTS/ /RESPONSE/ The likely reality is that the only information
/that would be/ known is that there was an explosion, that radiation detectors
are alarming, and that the wind is blowing in a given direction, and yet
government officials and news reporters will demand immediate answers to
questions, such as should people evacuate and how far away should they move. The
lack of early information will, in fact have a significant impact on the extent
of what might be recommended for protective actions. In order to maintain
confidence and reduce confusion, it is considered appropriate to establish a
"standard" response strategy that is triggered by key observable
parameters and criteria, to train all personnel, including political decision
makers, to implement the plan efficiently and effectively, and then adjust the
details of the strategy as better assessments of the circumstances become
available.
/RADIATION EVENTS/ /RESPONSE/ Many of the postulated scenarios are for some type
of explosive initiating event, which in fact are the easier events to respond to
because the initiation is obvious. Many countries equip first responders, such
as fire fighters, with some type of radiation detection capability onboard their
vehicles. These first responders will usually react in the same way as they
would for any other type of explosion and situations potentially involving
hazardous material, namely establishing a perimeter for access control, taking
life-saving measures, and aiming to control the situation. For most types of
situations, the standoff distance that fire brigades typically establish when
responding to an explosion is also adequate when radioactive material is
involved. When the results from radiological surveys are available, the
perimeter can be adjusted as needed.
/RADIATION EVENTS/ /RESPONSE/ Establishing a Control Zone. Guidelines for
Emergency Medical Management: 1. Approach site with caution--look for evidence
of hazardous materials. 2. If radiation hazard is suspected, position personnel,
vehicles, and command post at a safe distance (approx. 150 feet) upwind and
uphill of the site. 3. Notify proper authorities and hospital. 4. Put on
protective gear and use dosimeters and survey meters if immediately available.
5. Determine whether injured victims are present. 6. Assess and treat
life-threatening injuries immediately. Do not delay advanced life support if
victims cannot be moved or to assess contamination status. Perform routine
emergency care during extrication procedures. 7. Move victims away from the
radiation hazard area, using proper patient transfer techniques to prevent
further injury. Stay within the controlled zone if contamination is suspected.
8. Expose wounds and cover with sterile dressings. 9. Victims should be
monitored at the control line for possible contamination only after they are
medically stable. Radiation levels above background indicate the presence of
contamination. Remove the contaminated accident victims' clothing, provided
removal can be accomplished without causing further injury. 10. Move the
ambulance cot to the clean side of the control line and unfold a clean sheet or
blanket over it. Place the victim on the covered cot and package for transport.
Do not remove the victim from the backboard if one was used. 11. Package the
victim by folding the stretcher sheet or blanket over and securing them in the
appropriate manner. 12. Before leaving the controlled area, rescuers should
remove protective gear at the control line. If possible, the victim should be
transported by personnel who have not entered the controlled area. Ambulance
personnel attending victims should wear gloves. 13. Transport the victims to the
hospital emergency department. The hospital should be given additional
appropriate information, and the ambulance crew should ask for any special
instructions the hospital may have. 14. Follow the hospital's radiological
protocol upon arrival. 15. The ambulance and crew should not return to regular
service until the crew, vehicle, and equipment have undergone monitoring and
necessary decontamination by the radiation safety officer.16. Personnel should
not eat drink, smoke, etc., at the accident site, in the ambulance, or at the
hospital until they have been released by the radiation safety officer.
/RADIATION EVENTS/ /RESPONSE/ Protecting the Public...Rescue Phase. Control of
access to an area affected by a radiological attack should automatically follow
its occurrence... . The arrangements for control of access should include
establishing an inner-cordoned zone (safety area) ... An outer-cordoned zone
(security area) will often be established to immediately encompass the inner
zone. This ... ensures that members of the public cannot inadvertently enter
zones where protective actions are needed.
/DECONTAMINATION IN A RADIATION EVENT/ A controlled triage site staffed with
medical staff, radiation monitors and security personnel should be established
away from the Emergency Department.
/DECONTAMINATION IN A RADIATION EVENT/ Treatment of life-threatening injuries
always takes precedence over measures to address radioactive contamination or
exposure. Individuals with such injuries should be stabilized, if possible, and
immediately transported to a medical facility. ... The possibility of
contamination on or in the patient may be determined in the field, in route to a
treatment facility, or at a hospital depending on the condition of the patient.
/DECONTAMINATION IN A RADIATION EVENT/ Other injured personnel should be sorted
and treated according to standard medical triage guidelines with the exception
that those who are contaminated should be separated so that they can receive a
preliminary decontamination before or during transport to a hospital for final
treatment. Individuals who are only externally contaminated and not otherwise
injured should ... be decontaminated at some place other than a hospital.
/DECONTAMINATION IN A RADIATION EVENT/ If there are open wounds and they are
free of contamination, they should be covered with a water-proof dressing to
prevent cross-contamination.
/DECONTAMINATION IN A RADIATION EVENT/ External decontamination procedures /on
contaminated individuals with no other significant injuries/ ... begins with the
single most effective action: the removal of the outer clothing of the
contaminated individual. ...The clothing should be placed in a sealed container
... labeled with the patient's name, location, time and date, and marked clearly
with: "RADIOACTIVE-DO NOT DISCARD."
/DECONTAMINATION IN A RADIATION EVENT/ After removing the contaminated clothing,
if inhalation is suspected, a nasal sample, from both nostrils, using two clean
swabs can be taken for later analysis.
/DECONTAMINATION IN A RADIATION EVENT/ For a more localized area of
contamination, a simple irrigation may be all that is needed. Tepid water, with
or without a mild detergent is generally very effective. ... The decontamination
of intact skin should begin with areas of highest contamination levels and
progress to areas of lower contamination levels. Every effort should be made to
avoid contamination of otherwise clean areas ... . Procedures such as shaving or
harsh scrubbing are not appropriate. Although it is usually not required, if
hair needs to be removed, clipping is effective. Decontamination should begin
with the least aggressive method and progress to more aggressive ones, always
taking care not to break or irritate the skin. Radioactive material removed from
the patient should be preserved for later analysis to identify the specific
radionuclide.
/DECONTAMINATION IN A RADIATION EVENT/ Under the circumstances in which very
large numbers of individuals need to be decontaminated, ... individuals that are
expected to be contaminated should be transported to suitable locations (e.g.,
sport centers, military installations) where large shower facilities are
available and/or, in good weather conditions, to temporary outdoor facilities
organized to accommodate this procedure.
/DECONTAMINATION IN A RADIATION EVENT/ Runoff at decontamination sites:
Responders should closely monitor the direction of runoff /at decontamination
centers/ to prevent cross contamination between lanes and between zones. If
possible, the decontamination area should contain a storm water drain or be on a
slope that allows control of water runoff.
/RADIOLOGICAL ASSESSMENT IN A RADIATION EVENT/ The radiological assessment of an
injured individual should be performed by an individual with radiological health
training and only under the supervision of on-scene medical personnel. This
assessment includes radiation measurements and collection of information that is
relevant to the decontamination and treatment of the patient. The instrument
used to perform the survey should be sensitive to both penetrating and
non-penetrating radiation (e.g., a Geiger-Mueller tube with a thin wall or
entrance widow). Care should be taken not to contaminate the probe by contact
with the patient or any other potentially contaminated surface.
/RADIOLOGICAL ASSESSMENT IN A RADIATION EVENT/ When surveying shows that
preliminary decontamination of individuals has not been complete, they should be
sent to a second stage decontamination facility (e.g., specialized
decontamination tent). Supplies of clean clothing (sheets, blankets, scrub
suits, etc.) should be available for individuals exiting decontamination
stations. Provide baggies for personal items, wallets, jewelry. Patients exiting
second stage decontamination facilities need to be provided with clean clothes
(hospital gowns, coveralls, sheets or blankets). Individuals exiting the second
stage decontamination facility should be surveyed again to determine the
effectiveness of decontamination. Individuals found to be still contaminated can
be rerouted through the second stage decontamination effort.
/RADIOLOGICAL ASSESSMENT IN A RADIATION EVENT/ Experience with accidents in
which there was dispersion of radioactive materials indicates that many people
who are not actually injured, exposed, or contaminated will still be concerned
and are likely to go to hospitals for evaluation. These people can easily number
in the thousands and may arrive at hospitals by private car and taxi, even
before ambulances are able to bring the casualties who need urgent attention. It
has long been realized that hospitals will need to set up and staff a
"secondary assessment center" to attend to these "worried
well." Such a secondary assessment center will need to have, at the
minimum, detection equipment, an ability to record patients' names and
identifying information, and will need to be able to perform a cursory medical
evaluation.
/PROTECTION OF HOSPITAL STAFF/ Medical staff can protect themselves against
radioactive contamination by observing standard precautions, including the use
of protective clothing, gloves, and a mask. The principle of
time/distance/shielding is key for protection against external radiation.
/PROTECTION OF THE HOSPITAL STAFF/ /The health physicist is responsible for
/monitoring and surveying of the patient for contamination, monitoring of staff
exposures and surveying to verify they do not become contaminated or are
appropriately decontaminated, surveying of any samples or items (such as
clothing) taken from the patient, and surveying anything brought from the
medical radiation emergency room. A survey of the emergency department entryway
may be necessary to return the corridor to routine traffic use. Sampling /also/
involves anything taken from the patient that might be useful in determining the
contaminating radionuclides, level of contamination, resulting doses and
effective medical care. Samples might include blood, urine, feces, nasal
secretions, nasal swabs, swipes, shrapnel, excised tissue, irrigation fluids or
the patient's clothing.
/PROTECTION OF THE HOSPITAL STAFF/ Emergency Room Treatment of the Externally
Exposed Patient: In the absence of contamination, this patient can be admitted
to any part of the emergency department without special precautions.
/PROTECTION OF HOSPITAL STAFF/ High external exposure can cause severe tissue
damage (e.g., skin burns or bone marrow depression). This type of
"external" exposure does not make persons radioactive unless they were
exposed to neutron radiation /and/ they are not a hazard to medical staff.
/PROTECTION OF THE HOSPITAL STAFF/ Patients who have no evidence of external
contamination, but are likely to have internal contamination ... may be treated
in routine medical or emergency rooms. However, blood, vomitus, urine or feces
may be contaminated and should be handled with care. Patients with large amounts
of radioactive material imbedded in a wound warrant special attention because
... there may be a significant exposure hazard to treatment personnel.
/PROTECTION OF THE HOSPITAL STAFF/ Once the /radiation/ event is over, the
patient and hospital staff will need to be removed from the medical radiation
emergency area so surveying, decontamination and return of the area to routine
use can be accomplished.
/PROTECTING THE PUBLIC IN A RADIATION EVENT/ Sheltering may be a very effective
protective action early in /a radiation/ event ... There is, however, a need to
have a rapid and effective means of communicating with the people who are
advised to shelter...The disadvantages of sheltering are low if individuals are
in their own homes, and if it is recommended for relatively short periods of
time (i.e., hours). ... On a generic basis, the ICRP estimates that sheltering
will almost always be justified provided that an averted effective dose of 50
mSv can be achieved during the time considered feasible for sheltering. ... if
sheltering cannot avert more than 10 mSv in a period of about 2 days, the
benefit is questionable.
/PROTECTING THE PUBLIC IN A RADIATION EVENT/ Evacuation means the urgent,
temporary removal of people from the affected or potentially affected area, and
is intended to avoid serious deterministic effects and a high risk of stochastic
effects ... On a generic basis, the ICRP estimates that evacuation is almost
always justified if the projected average individual dose to the whole body is
likely to exceed 500 mSv within 1 day, or the averted average individual
effective dose for the duration of the evacuation is 500 mSv or the averted
equivalent dose to the skin is 5000 mSv. ...the generic optimized intervention
level for evacuation is 50 mSv of avertable dose in 1 week, i.e., approximately
100 mSv in 2 weeks. The ICRP ... also advised the use of 500 mSv of skin
equivalent dose in radiological attacks.
/PROTECTING THE PUBLIC IN A RADIATION EVENT/ Relocation refers to the long-term
removal of people from an affected area. It may be undertaken as an extension to
evacuation or it may be introduced /later/ to reduce doses from deposited
radionuclides and to allow remedial measures to be carried out. ... From generic
considerations, an average averted effective dose level of about 1000 mSv is
almost always justified for relocation. Depending on the circumstances,
relocation may be justified at lower levels of averted dose ... the ICRP
estimated the dose rate from deposited activity above which relocation is
optimized at about 10 mSv/month for continuing and prolonged exposure.
Restoration phase ... Clean-up planning and discussions should begin as soon as
practicable after an attack to allow for selection of interested parties and
subject matter experts, planning, analyses, contractual processes, and clean-up
activities. ...These activities should proceed in parallel with ongoing recovery
phase activities, and co-ordination between these sets of activities should be
maintained. Preliminary remediation activities ,,, such as decontamination,
resumption of basic infrastructure function, and some return to normality ...
should not be delayed for the final site remediation decision.
/OPERATIONAL RADIATION SAFETY/ The key to an effective program is the formal
delegation of authority to competent staff members. The manager of the radiation
safety program ... the Radiation Safety officer should be directly responsible
to the highest level of management and should have ready access to all levels of
the organization. ... Management should appoint a Radiation Safety Advisory
Group, the Radiation Safety Committee. The responsibility of the RSC is to
formulate institutional radiation safety policies, review and audit the
effectiveness of the radiation safety program, and provide guidance to the RSC
on the operational uses of radiation and radioactive materials. The RSC is
responsible for advising management concerning radiation safety practices and
regulations. This individual should be delegated the authority to supervise the
operational radiation safety organization, develop a budget and commit
expenditures that are allowed by that budget. ... The RSC is responsible for
periodic and special surveillance of activities such as acquiring and disposing
of radioactive materials, training in radiation safety practices for facility
employees and users, developing and maintaining radiation control and dosimetry
records, and authorizing the use of radiation and radioactive materials within
the facility. The RSC is also responsible for developing and maintaining a
radiation safety manual.
/OPERATIONAL RADIATION SAFETY/ The radiation safety manual should include a
comprehensive statement of policy and the principal administrative and program
procedures established by the RSC. ... The radiation safety manual should
include: (1) management's commitment to proper radiation safety practice (2)
description of the RSC, the radiation safety staff, and the radiation safety
program (3) specific policy and regulatory requirements (4) specific procedures
on how to comply with these requirements.
/OPERATIONAL RADIATION SAFETY/ Depending on the complexity of a particular task
and the training and experience of the individuals involved, procedures for work
that involves radiation or radioactive materials should include the following
elements as appropriate: (1) a description of the work that is authorized (2) a
description of the potential hazards that will be encountered in performing the
work, including potential radiation dose rates, identification of the sources of
radioactive material, potential radioactive contamination levels, and the
potential for intake of radioactive material (3) the identification of
individuals responsible for making sure that the work activities are conducted
in accordance with the safety procedure (4) the safety controls and procedural
safeguards that are necessary to prevent or limit exposure including
requirements for protective clothing, respirator protection, internal and
external dosimetry, radiation surveys, worker time and dose limitations,
limiting conditions fore either radiation or contamination levels, health
physics or radiation safety coverage that is required during the task (5)
required worker qualification including any specialized training (6) actions to
be followed in the event of an emergency (7) a description of contamination
control requirements (8) a description of required training and tasks that
should be completed before beginning the task at hand (9) a description of the
method for authorizing deviations from the specified procedure (10) references
to records and reports to be completed (11) a description of acceptable results
and of actions to be taken in response to unsatisfactory results.
/OPERATIONAL RADIATION SAFETY/ Management should ensure that there is a quality
assurance program in place to provide oversight of the radiation safety program.
... Area surveys and personal monitoring are significant aids for determining
the adequacy of facility design, operating procedures, and worker training. A
high-quality surveillance program depends on the availability of functioning and
calibrated instrumentation. The RSC should expect prompt, accurate and
consistent reports of the results of routine area surveys and personal
monitoring. These reports can provide an indication of serious inadequacies in
the facility procedures and training. ... Routine surveys and personal
monitoring are usually done on a regular schedule, but may be relatively
infrequent (weekly, monthly or quarterly). For this reason, it is important that
supervisors understand their essential role in controlling radiation exposure
and in recognizing the implications of changes in operating conditions. This is
especially critical when high-dose rate radiation sources are being used.
/OPERATIONAL RADIATION SAFETY/ The amount and detail of the records that the
Radiation Safety Committee should maintain has become substantial and their
maintenance represents an appreciable portion of the effort of the radiation
safety staff. ... Included in the records that should be maintained are those
that detail administrative actions that affect the program, report internal and
external audits, and record deficiencies and corrective actions. Operating
procedures, personal monitoring and survey records, instrument calibration
records, waste management records, and
records of worker training should be maintained in a readily retrievable form.
/OPERATIONAL RADIATION SAFETY/ Organizations should establish radiation safety
orientation and training programs that include opportunities for all workers to
receive repeat training at appropriate intervals. Radiation safety policies and
procedures should be integrated into the overall safety program of the
organization. The depth and breadth of training needed varies with the job
requirements and responsibilities of each individual. Factors that influence the
depth of training include the potential for radiation exposure, complexity of
tasks to be performed, degree of supervision ... , amount of previous training,
and degree to which the trainees will instruct or supervise others. Workers who
need specialized radiation safety skills require extensive and ongoing in-depth
training. ... Records of training programs presented, course curricula and
attendance records should be maintained by management.
/OPERATIONAL RADIATION SAFETY/ An external radiation exposure control program
must be established when there is a possibility for workers to be occupationally
exposed or for members of the public to receive exposure from facility
operations. ...The formality of the program is clearly a function of the dose
level. ... Administrative dose guidelines should be established to reduce the
potential for individuals to exceed the recommended dose limits. ... An
effective external radiation exposure control program will ensure that doses to
occupationally exposed individuals are maintained within administrative dose
guidelines and that individual doses are maintained ALARA for the work
performed. ...Engineering controls should be the primary means for controlling
external radiation doses. These include distance and shielding, remote handling
equipment and interlocks. Administrative controls such as safety procedures,
radiation work permits, and radiation monitoring and surveys should be a
secondary means for controlling external doses, but are a necessary part of the
program.
/OPERATIONAL RADIATION SAFETY/ /In facilities where radioactive materials are
handled/ Radiation surveys should be conducted in areas where the potential
exists for exposure to external radiation fields in order to: (1) characterize
the radiation field so that it can be properly posted and controlled, (2)
provide the information required for planning work activities to maintain the
external radiation exposures at levels ALARA, and (3) ensure the prompt
discovery of changed radiation fields...
/OPERATIONAL RADIATION SAFETY/ /In facilities where radioactive materials are
handled/ External radiation dose records should be maintained to demonstrate
compliance with dose limits and administrative dose guidelines, and to assist in
the evaluation of the effectiveness of the external dose control program. ....
In addition, records should be maintained of the external radiation surveys that
are performed.
/OPERATIONAL RADIATION SAFETY/ /In facilities where radioactive materials are
handled/ There should be an airborne monitoring program for radioactive
materials in those areas where there is a significant potential for airborne
contamination. It is not appropriate to use personal monitoring devices to
control internal exposures. Thus, continuously operating samplers equipped with
continuous detection devices may be needed.
/OPERATIONAL RADIATION SAFETY/ Although usually not a significant risk to
workers, contamination of facilities, equipment or people occurs in many
operations involving radioactive material. Contamination control of routine
operations is normally accomplished through containment of the radioactive
material in chemical hoods, gloved boxes, hot cells, or the use of area
exclusion, protective clothing, etc. ...
/OPERATIONAL RADIATION SAFETY/ Shielding may be necessary to reduce the
potential for exposures to workers and visitors at the facility and to the
public in the vicinity of the facility. ... Various materials can be used for
shielding, depending on the type of radiation, its energy and intensity, and the
attenuation required. Typically medium and high atomic number materials such as
iron and lead are effective for shielding X- and gamma rays. For moderating fast
neutrons a material with a high hydrogen content, such as water or polyethylene,
must be included in the design. When thermal neutrons are captured in hydrogen,
cadmium or other elements, high-energy gamma rays are emitted and must be
considered in the shield design. Concrete is suitable for shielding both photons
and neutrons and is a cost-effective material of choice when space is available.
Earth is also an effective and inexpensive material that is widely used as
shielding in various types of facilities. In addition to meeting radiation
protection goals, the selection of shielding material is dependent upon
engineering factors such as weight, cost, structural stability and
compatibility.
/OPERATIONAL RADIATION SAFETY/ Shielding Materials. The choice of shielding
material depends on the type(s) of radiation to be shielded. 1. Alpha (can be
stopped by a single sheet of paper): Due to the extremely low penetrating
ability of alpha particles, shielding is not considered necessary. 2. Beta (can
be stopped by 1/2-inch Plexiglas; 1/4-inch aluminum, wood, rubber): Due to the
potential creation of bremsstrahlung when the beta particles are slowed or
stopped, consideration must be given to shielding these X-rays whenever beta
radiation is present. This phenomenon is strongest when beta particles are
stopped by materials with a high atomic number (such as steel or lead), making
these materials inappropriate for shielding beta particles unless they are
sufficiently thick to stop the bremsstrahlung also. 3. Gamma (lead, concrete,
steel): The denser the material, the better it is suited for attenuation of
gamma and X-rays. 4. Neutron (water, polyethylene, concrete, boron):
Neutron-absorbing radionuclides (such as boron-10) and materials that contain
large amounts of hydrogen make efficient neutron shields.
/OPERATIONAL RADIATION SAFETY/ Sequence of Shielding. Shielding should be
correctly layered for structural integrity and attenuation of different types of
radiation. For example, with gammas and strong betas, a layer of plastic might
precede a layer of lead, so that betas would be captured in the plastic and not
produce bremsstrahlung in the lead.
/OPERATIONAL RADIATION SAFETY/ The investigation of incidents and accidents must
be timely. ... Incident and accident investigations should include a thorough
examination of the scene, interviews with the people involved, a review of
pertinent records, and a complete and accurate report of the incident or
accident and subsequent investigation. The location of the event should be
completely surveyed with appropriate instruments as needed to determine and
document the radiation levels and the extent of radioactive contamination.
Personal monitoring devices should be collected and evaluated, and bioassays
should be performed as needed. An inventory of all radioactive material and waste
should be made. Any records or logs that have been maintained should be
examined. Workers and others in the area should be interviewed early in the
investigation. A photographic record of the area may be important to reconstruct
the incident or accident.
/OPERATIONAL RADIATION SAFETY/ /For protection of the public/ Radiation fields
emanating from the facility are controlled by appropriate shielding of
components or equipment that are sources of radiation. The choices of control
measures are highly dependent on the nature of the facility and its processes,
the quantities and types of radionuclides employed or processed, and the levels
and types of radiation produced. The facility management must ensure that
techniques used for control of releases of radioactive materials are adequate
and that they are functioning at a satisfactory level.
/OPERATIONAL RADIATION SAFETY/ A high radiation area is defined as an area,
accessible to individuals, in which radiation levels could result in an
individual receiving a deep dose equivalent in excess of 100 millirems (1
millisievert) in one hour 30 centimeters from the source or from any surface
through which the ionizing radiation penetrates. A very high radiation area
means an area, accessible to individuals, in which radiation levels from
radiation sources external to the body could result in an individual receiving
an absorbed dose in excess of 500 rads (5 grays) in 1 hour at 1 meter from a
radiation source or 1 meter from any surface that the radiation penetrates.
Access for high radiation areas must be strictly controlled ... and barriers
used to control access should provide reasonable assurance that they secure the
area against unauthorized access and cannot be easily circumvented. ... Because
of the potential danger of life-threatening overexposures, extremely tight
control must be maintained over any entry to very high radiation areas. ... To
the extent possible, entry should be forbidden unless there is a sound
operational or safety reason for entering. ... Entrances to very high radiation
areas should be kept locked except during periods when access to the areas is
required.
/OPERATIONAL RADIATION SAFETY/ STANDARD RADIATION SYMBOL ... shall use the
colors magenta, or purple, or black on yellow background. The symbol ... is the
three-bladed design: (1) Cross-hatched area is to be magenta, or purple, or
black, and (2) The background is to be yellow. POSTING OF RADIATION AREAS. The
/NRC/ licensee /must/ post each radiation area with a conspicuous sign or signs
bearing the radiation symbol and the words "CAUTION, RADIATION AREA."
(b) POSTING OF HIGH RADIATION AREAS. The licensee /must/ post each high
radiation area with a conspicuous sign or signs bearing the radiation symbol and
the words "CAUTION, HIGH RADIATION AREA" or "DANGER, HIGH
RADIATION AREA." (c) POSTING OF VERY HIGH RADIATION AREAS. The licensee
/must/ post each very high radiation area with a conspicuous sign or signs
bearing the radiation symbol and words "GRAVE DANGER, VERY HIGH RADIATION
AREA." (d) POSTING OF AIRBORNE RADIOACTIVITY AREAS. The licensee /must/
post each airborne radioactivity area with a conspicuous sign or signs bearing
the radiation symbol and the words "CAUTION, AIRBORNE RADIOACTIVITY
AREA" or "DANGER, AIRBORNE RADIOACTIVITY AREA." (e) POSTING OF
AREAS OR ROOMS IN WHICH LICENSED MATERIAL IS USED OR STORED. The licensee /must/
post each area or room in which there is used or stored an amount of licensed
material exceeding 10 times the quantity of such material specified in appendix
C to part 20 with a conspicuous sign or signs bearing the radiation symbol and
the words "CAUTION, RADIOACTIVE MATERIAL(S)" or "DANGER,
RADIOACTIVE MATERIAL(S)."
/OPERATIONAL RADIATION SAFETY/ /In the U.S. NRC licensees must/ ensure that each
container of licensed material bears a durable, clearly visible label bearing
the radiation symbol and the words CAUTION, RADIOACTIVE MATERIAL or DANGER,
RADIOACTIVE MATERIAL. The label must also provide sufficient information (such
as the radionuclide(s) present, an estimate of the quantity of radioactivity,
the date for which the activity is estimated, radiation levels, kinds of
materials, and mass enrichment) to permit individuals handling or using the
containers, or working in the vicinity of the containers, to take precautions to
avoid or minimize exposures.
/OPERATIONAL RADIATION SAFETY/ QUANTITIES of SELECTED NRC LICENSED MATERIAL
REQUIRING LABELING
RADIONUCLIDE
QUANTITY (uCi)
Tritium
1,000
Carbon-14
100
Phosphorus-32
10
Potassium-40
100
Cobalt-60
1
Strontium-90
0.1
Technetium-99m
1,000
Iodine-125
1
Iodine-131
1
Cesium-137
10
Iridium-192
1
Lead-210
0.01
Radon-220 & -222
1
Thorium-natural
100
Uranium-233 & -235
0.001
Uranium-238 & natural
100
Plutonium-239
0.001
Americium-241
0.001
/OPERATIONAL RADIATION SAFETY/ SRP: Contaminated protective clothing should be
segregated in such a manner so that there is no direct personal contact by
personnel who handle, dispose, or clean the clothing. Quality assurance to
ascertain the completeness of the cleaning procedures should be implemented
before the decontaminated protective clothing is returned for reuse by the
workers. Contaminated clothing should not be taken home at end of shift, but
should remain at employee's place of work for cleaning.
/OPERATIONAL RADIATION SAFETY/ Shielding for phosphorus-32 and other beta
emitters should be made of material with atomic numbers of <13 (aluminum) to
reduce the generation of Bremsstrahlung X-rays (Braking radiation),
electromagnetic radiation produced by the rapid electromagnetic radiation
produced by the rapid change of velocity of a fast moving particle as it
approaches an atomic nucleus and is deflected. /Beta-emitters/
Shipment Methods and Regulations:
/ALL USES/ /In the U.S./ Regulating the safety of ... shipments /of radioactive
materials/ is the joint responsibility of the NRC and the Department of
Transportation (DOT). The NRC establishes requirements for the design and
manufacture of packages for radioactive materials. The DOT regulates the
shipments while they are in transit and sets standards for labeling these
packages and for smaller quantity packages.
/ALL USES/ All shipments of radioactive material /in the U.S./, with the
exception of those containing limited quantities or those of low specific
activity (LSA), must bear two identifying warning labels affixed to opposite
sides of the outer package. Three different labels -- White-I, Yellow-II, or
Yellow-III -- are used on the external surface of packages containing
radioactive material. The U.N. hazard class "7" is on labels of
radioactive material. /UN 7 is any material or combination of materials that
spontaneously emit ionizing radiation and have a specific activity greater than
0.003 uCi/g./ Package labels specify the radioactive content and the quantity in
curies. Yellow-II and Yellow-III also specify the transport index. Radioactive
White-I: almost no radiation--0.5 mrem/hr (5 uSv/hr) maximum on surface.
Radioactive Yellow-II: low radiation levels--50 mrem/hr (0.5 mSv/hr) maximum on
surface; 1 mrem/hr (10 uSv/hr) maximum at 1 meter. Radioactive Yellow-III:
Higher radiation levels--200 mrem/hr (2 mSv/hr) maximum on surface (
"Exclusive use" shipments may be up to 0.01 Sv/hr (1 rem/hr), provided
an enclosed vehicle is used. An unenclosed shipment (e.g., on a flatbed truck)
may not exceed 2 uSv/hr (200 mrem/hr) on the surface); 10 mrem/hr (0.1 mSv/hr)
maximum at 1 meter; also required for fissile class III or large-quantity
shipments, regardless of radiation level. The number "7" at the bottom
of the placard is the U.N. hazard class description for radioactive materials.
The transport index (TI) indicates the maximum radiation level (in mrem/hr) at a
distance of one meter from the external surface of a package or container.
(Readings in mSv/hr are multiplied by 100 to get mrem/hr.) For example, a TI of
3 would indicate that, at one meter from the labeled package, the radiation
intensity that can be measured is no more than 3 mrem/hr (0.03 mSv/hr).
/ALL USES/ /In the U.S./ The NRC requires that radioactive materials be packaged
for shipment to protect the public in case of an accident. The kind of packaging
required depends on the amounts and types of radioactive elements in the waste.
Low-level waste is shipped in
containers designed to meet stringent NRC and DOT standards. Most low-level waste
contains low enough levels of radioactivity to be shipped in strong, tight
containers or DOT Type A containers. (Type A and B shipping containers bear no
relation to NRC Class A, B and C waste
forms.) Type A containers must be able to withstand ordinary transportation
conditions.
/ALL USES/ Type B package means a Type B packaging together with its radioactive
contents. On approval, a Type B package design is designated by NRC as B(U)
unless the package has a maximum normal operating pressure of more than 700 kPa
(100 lbs/sq in) gauge or a pressure relief device that would allow the release
of radioactive material to the environment under the tests specified in section
71.73 (hypothetical accident conditions), in which case it will receive a
designation B(M). B(U) refers to the need for unilateral approval of
international shipments; B(M) refers to the need for multilateral approval of
international shipments. There is no distinction made in how packages with these
designations may be used in domestic transportation. To determine their
distinction for international transportation, see DOT regulations in 49 CFR Part
173. A Type B package approved before September 6, 1983, was designated only as
Type B. Limitations on its use are specified in paragraph 71.19.
/ALL USES/ /In the U.S./ Radioactive material, Type C packages are materials
with an activity not exceeding any limit specified in the appropriate competent
authority certificate of unilateral approval of Type C packages. ... Caution
should be used when handling the packages. In case of trouble with these
shipments all unauthorized persons should be kept as far away as possible until
qualified people with proper equipment can be obtained. ... Contact CHEMTREC,
800-424-9300 for help.
Storage Conditions:
/OPERATIONAL RADIATION SAFETY/ To reduce unnecessary exposure, radioactive
materials should be stored in areas separate from work places. Ventilation
should be provided for storage areas of radioactive material when airborne
releases are possible, and access to these areas should be controlled.
Cleanup Methods:
/OPERATIONAL RADIATION SAFETY/ In most cases, contamination should be
controlled, and removed as soon as possible. The contaminated area or equipment
should be marked and posted immediately. Nonessential persons should be moved
out of the area until decontamination has been completed. Usually simple
cleaning techniques and procedures are adequate for most decontamination tasks.
Spills and contaminated areas should be cleaned from the outer region inward to
reduce the possibility of further spread of the contamination. After cleaning,
the area or equipment should be surveyed to ensure that all the contamination
has been removed.
/OPERATIONAL RADIATION SAFETY/ Tools and equipment such as survey instruments or
laboratory glassware that have been used in areas in which they may have become
radioactive or contaminated should be surveyed for radioactivity after use.
Those with removable contamination should be decontaminated prior to removal
from the restricted area.
/OPERATIONAL RADIATION SAFETY/ To ensure ease of cleanup, the surfaces of
floors, walls, fixtures, equipment and work surfaces in areas where radioactive
materials may be found should be protected against penetration by contamination.
... If porous materials, like concrete, are used in construction, exposed
surfaces should be faced with nonporous materials or painted with several layers
of nonporous coating. Outer layers of strippable paint may be appropriate.
/OPERATIONAL RADIATION SAFETY and RADIATION EVENTS/ In most cases of
contamination of equipment and buildings, a mixture of normal housecleaning
methods will remove the material. Vacuum cleaners that can handle wet material
and have high-efficiency filters are particularly useful. Some surfaces may
require repeated scrubbing and vacuuming before they are free of contamination.
/OPERATIONAL RADIATION SAFETY/ Many radionuclides in low-level waste
decay to safe levels within a relatively short time. When wastes
are safely stored at their generation sites for a few days to a few years
(depending on half-life and available storage space), the radioactivity may be
reduced to safe background levels /reducing requirements for further treatment
before disposal/.
/OPERATIONAL RADIATION SAFETY/ By decontaminating large pieces of equipment,
tools, metal, glassware and clothing /that would otherwise require disposal as
low-level waste/ ... reuse or
recycling /may be possible/.
/OPERATIONAL RADIATION SAFETY/ Chemical decontamination technologies make use of
manipulation of the chemical properties of the contaminants and their host
matrices to bring about the decontamination. Five chemical decontamination
technologies include: chelation and organic acids, strong mineral acids and
related materials, chemical foams and gels, oxidizing and reducing agents, and
TechXtract ... The advantages of chemical decontamination are: (1) ... can be
relatively quick and simple. (2) ... similar to classical cleaning in general
industry ... (3) relatively inexpensive ... (4) with proper selection of
chemicals, almost all radionuclides can be removed from contaminated surfaces.
(5) decontamination factors of over 10,000 may be achieved. (6) it has the
potential to remove contaminants from areas with restrictions to physical access
... (7) it usually involves little or no airborne contamination. (8) when
properly performed, it can have minimal effects on equipment and surfaces thus
allowing easy reuse. Disadvantages can be significant: (1) chemical
decontamination generates liquid waste
streams that require treatment ... (2) safety concerns arise with the use of
hazardous materials such as strong acids and oxidizers and with the production
of hazardous byproducts such as hydrogen. (3) chemical decontamination is not
usually effective on porous surfaces. (4) by mobilizing the contaminant, there
is increased risk of downstream recontamination and cross contamination of
equipment, and increased ri sk of environmental consequences in the event of
accidental releases. (5) Sometimes higher temperatures are needed ... (6) ....
chemical decontamination often requires the availability of in-depth chemical
expertise. This is true both for the decontamination itself and for ancillary
concerns, such as waste stream
management. ... It should also be realized that a poorly performed chemical
decontamination can increase risks. For example, when contaminants are removed
from a surface by chelation, the chelate-contaminant complex is usually of
higher toxicity than the contaminant ...
/OPERATIONAL RADIATION SAFETY/ Physical decontamination technologies make use of
some form of physical or mechanical abrasion of the contaminant or the host
surface material to effect contamination removal. Physical decontamination
technologies include: strippable coatings, centrifugal shot blasting, the
concrete grinder, the concrete shaver, the concrete spaller, dry ice blasting,
dry vacuum cleaning, electro-hydraulic scabbling, grit blasting, high pressure
water, soft media blast cleaning (sponge blasting), and steam vacuum cleaning.
/OPERATIONAL RADIATION SAFETY/ Physical decontamination ... is the removal of
surface radiological contamination by physical processes such as flushing,
wiping, flushing, vacuuming, grinding, blasting, scabbling, shaving, spalling,
peening, scaling, other forms of scarifying, or the application of strippable
coatings. ... Physical decontamination can be either an alternative or a
complement to chemical decontamination. ... Among the advantages are: (1) ...
can work on almost all surfaces... (2) for some surfaces, physical
decontamination is the only choice. The most common example is a porous surface
such as concrete on which no barrier layer was placed ... (3) physical
decontamination can usually achieve higher decontamination factors than chemical
decontamination simply because it is capable of removing the contaminated
surface in its entirety. (4) surface preparation is usually not an issue ... (5)
waste management tends to be
simpler... . Among the disadvantages of physical decontamination are: (1)
physical decontamination technologies, by their very nature, have no
radionuclide or chemical specificity. (2) physical decontamination technologies,
by their very nature, are destructive to the surface being cleaned ... (3) since
physical decontamination technologies often work by the physical abrasion of the
surface, airborne emission of abraded particulates is an operational problem
that must be addressed ... (4) Access to and the complex geometry of surfaces
can be a significant issue ... (5) physical decontamination technologies tend to
be more "hands-on" requiring workers to operate tools in the immediate
vicinity of the contaminated surface and hence requiring greater general
attention to safety and health concerns ... (6) waste
volumes can be larger ... (7) though surface preparation per se is easier with
physical decontamination technologies, the immediate environment in which the
decontamination is taking place must be properly prepared. ... Generalizations
about the applicability of a given technology are very difficult and, possibly,
counterproductive. The performance of a given technology is highly dependent on
a variety of factors concerning the circumstances of the contamination.
/RADIATION EVENTS/ General Guidelines for Responding to a Spill or Leak: Consult
the U.S. DOT Emergency Response Guidebook. Shut off ignition sources; no flares,
smoking, or flames in hazard area. Keep combustibles (wood, paper, oil, etc.)
away from spilled material. Do not touch spilled material. Do not touch damaged
containers or move anything, except to rescue people. Detour pedestrian and
vehicular traffic. Detain anyone who has been in the area of the spill or area
of suspected contamination (except for victims requiring emergency medical
care). Delay cleanup until the authorities arrive. Minimize dispersal of
material (by wind, rain, etc.) by covering with a tarp, plastic sheet, etc. Tie
down or use weights as necessary. If a right-of-way must be cleared before
radiological emergency assistance arrives, move vehicles and debris the shortest
distance required to open a pathway. Then, before permitting traffic to pass on
the cleared path, spillage should be washed or wetted and swept to the edge with
a minimum dispersal of wash water and spilled material. If radiation protection
experts are not able to get to the scene within a reasonable period of time
because of weather or other constraints and prompt action is required, do the
following: Small Spills: Cover with sand or other noncombustible absorbent
material and place into containers for later disposal. Large Spills: Build a
dike far ahead of the spill to contain spilled material for later disposal.
Note: Some radioactive materials may be corrosive.
Disposal Methods:
/ALL USES/ /In the U.S./ Nuclear
Regulatory Commission regulations separate low-level waste
into three classes: A, B and C. The classification of the waste
depends on the concentration, half-life and types of the various radionuclides
it contains. The NRC ... requirements for packaging and disposal /must be
adhered to for/ each class of waste.
Class A low-level waste contains
radionuclides with the lowest concentrations and the shortest half-lives. About
95 percent of all low-level waste is
categorized as Class A.
/ALL USES/ /In the U.S./ Low-level waste
disposal /must occur/ at commercially operated low-level waste
disposal facilities ... licensed by either the Nuclear
Regulatory Commission or Agreement States. ... There are three existing
low-level waste disposal facilities in
the United States /Barnwell, SC, Richland, WA, Envirocare in Utah/ that accept
... low-level waste. All are in
Agreement States.
/RADIATION EVENTS/ The management of radioactive waste
... is an important component in the planning of restoration activities/ after a
radiation event/. Account must be taken of the volume of waste,
the total activity content that will have to be disposed, and the presence of
long-lived and alpha-emitting materials, depending on the source of the event...
. the majority of the expected wastes
will probably be large amounts of materials with low-level contamination. The
IAEA has issued a number of waste
safety standards establishing specific requirements for handling this type of waste
/which may be consulted and/.a number of countries have ... legally binding
commitments through the international Joint Convention on the Safety of Spent
Fuel Management and the Safety of Radioactive Waste
/which must be adhered to/.
/SRP/ Wastes in the Waste
Isolation Pilot Plant (WIPP) are from the nuclear
weapons industry (plutonium) - research and development. For a waste
to be accepted at WIPP it must be a transuranic "TRU" waste
and: (1) </= 100 nanoCi/gram, (2) an alpha emitting transuranium isotope with
atomic number greater than uranium, and (3) have a half life greater than 20
years. The wastes must be handled
remotely if they produce >/= 200 millirems/hr; if less, they can be contact
handled.
/MEDICAL USES/ The same regulatory apparatus that applies to radiation used in
brachytherapy applies to radiation used for therapeutic nuclear
medicine. For the latter, regulations address the fact that with unsealed source
administration, the patient becomes a source of radiation and radioactive
contamination. Regulations allow patient excreta to be exempt from treatment as
radioactive waste. Hence, disposal of
I-131-contaminated urine down the sanitary sewer system is allowed.
Radiation Limits & Potential:
In addition to alpha particles, beta particles, and gamma rays ... energy from
radioactive atomic transformations can be emitted as protons, neutrons,
neutrinos, internal bremsstrahlung, conversion electrons, X-rays, and Auger
electrons. The beta particles can be either negative or positive electrons,
negative electrons from neutron-rich and positrons from neutron-deficient
nuclei. The emission of a positron from the nucleus is always simultaneously
accompanied by the emission of a neutrino, and that of the electron by an
antineutrino. The sharing of the available energy for decay between the beta
particle and the neutrino accounts for the continuous beta-particle spectra; the
sum of the energies of the beta particle and neutrino in a given transition is
always constant, being equivalent to the mass difference between the parent and
daughter atoms, less such energy as may be emitted in the form of gamma rays (or
conversion electrons, X-rays, or Auger electrons) by the daughter atoms in their
transitions from excited levels to the ground level. ... In alpha-particle decay
no simultaneous radiation, comparable to the neutrino, is emitted from the
parent nucleus and hence groups of alpha particles are always homogeneous in
energy. Again, gamma rays may be emitted promptly from the daughter nucleus in
its decay to the ground level. If the daughter nucleus does not decay promptly
to its ground level, it may exist in a metastable state for a considerable time
and exhibit radioactivity ... in its own right. The delayed transition of an
excited daughter nucleus to a lower-energy level of the same nucleus is called
an isomeric transition and such nuclear
isomerism is denoted by the addition of the letter m (for metastable) after the
atomic-mass number for the given nuclear
species.
The energy associated with the electromagnetic decay of an excited state is not
always emitted as gamma radiation; it may be transferred by a competing
radiationless transition directly to a bound electron from a shell of the same
atom. This process is known as internal conversion. ... The emission of
radiation as a conversion electron is a transition involving the whole atom, and
this process emphasizes how important it is to consider the interactions of the
entire atom in radioactive decay. In the decay of (90m)-Nb and (99m)-Tc, there
are highly converted transitions of relatively low energy which are sensitive to
the chemical or physical environment of the atoms. Experiments have shown that
the decay constants of each of these isomers can be modified both by chemical
composition and pressure. Either an electron-capture or conversion-electron
event creates a vacancy in an atomic shell of the daughter atom. The filling of
this vacancy gives rise either to an x-ray, characteristic of the daughter atom,
or to one or more electrons (Auger electrons) from its outer shells. ... The
emission of an Auger electron instead of a x-ray is analogous to the emission of
a conversion electron instead of a gamma ray, in that the excess energy is
transferred directly to the electrons.
Electron capture and positron decay are alternative processes, the latter being
possible only if the atomic mass of the parent is greater than the atomic mass
of the daughter by more than two electron rest masses. /If the mass is less/ the
transition can still occur by the process of electron capture, excess energy
being carried away by the neutrino.
/In the U.S./ monitoring of an individual's external radiation exposure is
required ... if the external occupational dose is likely to exceed 10% of the
dose limit appropriate for the individual (i.e., adult, minor, or declared
pregnant woman). External radiation monitoring is also required by 10 CFR
20.1502(a)(3) for any individual entering a high or very high radiation area.
... There are three dose limits included in 10 CFR 20.1201 that apply to
external exposure: deep dose to the whole body (5 rems or 0.05 Sv), shallow dose
to the skin or extremities (50 rems or 0.5 Sv), and dose to the lens of the eye
(15 rems or 0.15 Sv). ...
There are at least five methods acceptable to the NRC staff for calculating
committed effective dose equivalent from inhaled radioactive materials. The five
methods are described below. (1) Federal Guidance Report No. 11 lists the
committed effective dose equivalent per unit intake by inhalation in sieverts
per becquerel in its Table 2.1. These values may be used directly after
converting the units from sieverts per becquerel to rem per microcurie (Sv/Bq x
3.7x10+6 = rem/uCi). (2) ALI values ... are presented in Table 1 in Appendix B
to Part 20.1001-20.2401. The ALI values for inhalation... correspond to a
committed effective dose equivalent of 5 rems (0.05 Sv) or a committed dose
equivalent of 50 rems (0.5 Sv) to any individual organ or tissue, whichever is
more limiting. ... The committed effective dose equivalent (H) for each
radionuclide may be calculated /using the estimated radionuclide intake I by
inhalation during the calendar year (uCi) times 5 (the committed effective dose
equivalent from intake of 1 ALI (rems)) all divided by the ALI from column 2 of
Table 1./ ... (3) Committed effective dose equivalent may also be calculated
from exposures expressed in terms of DAC-hours. If the DAC in Appendix B to Part
20.1001-20.2401 for a radionuclide represents a stochastic value (i.e., the
corresponding ALI does not have the name of an organ below it), the DAC may be
used directly. If Appendix B to Part 20.1001- 20.2401 does not list a stochastic
DAC, which will be the case any time there is a stochastic ALI value in
parentheses, it is preferred (but not required) that the licensee calculate and
use a stochastic DAC. The stochastic DAC can be calculated from the stochastic
ALI /where DACstoc (uCi/mL) = ALIstoc divided by 2.4x10+9, the volume of air
inhaled by a worker in a workyear (mL)/ ... (4) The supplements to ICRP
Publication 30 list "weighted committed dose equivalent to target organs or
tissues per intake of unit activity" for inhalation in sieverts per
becquerel. The sum of the values given is the committed effective dose
equivalent. ICRP Publication 30 does not give the sum, but the licensee can
easily add the values given to calculate the sum. Then it is only necessary to
convert from sieverts per becquerel to rems per microcurie (3.7x10+6 x Sv/Bq =
rem/uCi). (5) When specific information on the physical and biochemical
properties of the radionuclides taken into the body or the behavior of the
material in an individual is known, the licensee may...use that information to
calculate the committed effective dose equivalent.
/In the U.S./ monitoring of the intake of radioactive material is required ...
if the intake is likely to exceed the annual limit on intake (ALI) during the
year for an adult worker or the committed effective dose equivalent is likely to
exceed 0.05 rem (0.5 mSv) for the occupationally exposed minor or declared
pregnant woman. ... The internal dose component needed for evaluating the total
effective dose equivalent is the committed effective dose equivalent. The
committed effective dose equivalent is the 50-year effective dose equivalent
that results when radioactive material is taken into the body, whether through
inhalation, ingestion, absorption through the skin, accidental injection, or
introduction through a wound. The contributions from all occupational intakes
for these modes of intake are added over the yearly time period for which the
total committed effective dose equivalent is being evaluated. ...
If ingestion has occurred, the methods for determining the committed effective
dose equivalent are similar to the methods used for estimating inhalation dose.
Four acceptable methods /to the NRC/ are described here. (1) Federal Guidance
Report No. 11 (Ref. 1) lists in its Table 2.2 the committed effective dose
equivalent per unit of intake by ingestion in sieverts per becquerel. These
values may be used directly after converting the units from sieverts per
becquerel to rems per microcurie ... (2) If the amount of ingested radioactive
material is known, the stochastic ingestion ALIs from Column 1 of Table 1 in
Appendix B to Part 20.1001-20.2401 may be used... /HT (Committed effective dose
equivalent from radionuclide (rems)) = I (Intake of radionuclide by ingestion
during the calendar year (uCi)) times 5 (committed effective dose equivalent
from annual intake of 1 ALI (rems) all divided by the ALI, oral from Column 1 of
Table 1/ .... (3) The supplements to ICRP Publication 30 (Ref. 2) list
"weighted committed dose equivalent to target organs or tissues per intake
of unit activity" for oral intake in sieverts per becquerel. The sum of the
values given is the committed effective dose equivalent. ICRP Publication 30
does not give the sum, but the licensee can easily add the values given to
calculate the sum. Then it is only necessary to convert from sieverts per
becquerel to rems per microcurie ... (4) NRC regulations (10 CFR 20.1204(c))
allow the committed effective dose equivalent to be calculated based on specific
information on the physical and biochemical properties of radionuclides taken
into the body of a specific worker.
Committed dose equivalent (HT,50) means the dose equivalent to organs or tissues
of reference (T) that will be received from an intake of radioactive material by
an individual during the 50-year period following the intake. The committed dose
equivalent for a given organ is multiplied by a weighting factor to calculate
the effective dose equivalent. The organ dose weighting factors (Wt) are: gonads
0.25; breast 0.15, red bone marrow 0.12, lung 0.12, thyroid 0.03, bone surfaces
0.03, remainder 0.30, whole body 1.00. /from table/
Absorbed dose means the energy imparted by ionizing radiation per unit mass of
irradiated material. The units of absorbed dose are the rad and the gray (Gy).
Quality factors for converting absorbed dose to dose equivalent are: X-, gamma,
or beta radiation Q = 1; Alpha particles, multiple-charged particles, fission
fragments and heavy particles of unknown charge Q = 20; neutrons of unknown
energy Q = 10; high energy protons Q = 10 /from table/. The units of dose
equivalent are the rem and sievert (Sv).
Occupational Exposure Standards:
OSHA Standards:
No employer shall possess, use or transport radioactive material in such a
manner as to cause any employee, within a restricted area, to be exposed to
airborne radioactive material in an average concentration in excess of the
limits of 1 1/4 rems for the whole body (head and trunk, active bloodforming
organs, lens of eyes, or gonads), 18 3/4 rems for the hands and forearms and
feet and ankles , and 7 1/2 rems for the skin of whole body per calendar
quarter. The limits given are for exposure to the concentrations specified for
40 hours in any workweek of 7 consecutive days. In any such period where the
number of hours of exposure is less than 40, the limits specified in the table
may be increased proportionately. In any such period where the number of hours
of exposure is greater than 40, the limits specified in the table shall be
decreased proportionately(1).
In construction and related activities involving the use of sources of ionizing
radiation, the pertinent provisions of the Nuclear
Regulatory Commission Standards for Protection Against Radiation (10 CFR Part
20), relating to protection against occupational radiation exposure, shall
apply(1).
Threshold Limit Values:
The Physical Agents TLV Committee accepts the occupational exposure guidance of
the International Commission on Radiological Protection (ICRP). ... ICRP
Guidelines for Exposure to Ionizing Radiation: Effective Dose (a) in any single
year, 50 mSv, (b) averaged over 5 years, 20 mSv per year. Annual Equivalent Dose
to: (a) lens of the eye, 150 mSv, (b) skin, 500 mSv, (c) hands and feet, 500 mSv.
Embryo-Fetus exposures once the pregnancy is known - monthly equivalent dose 0.5
mSv - dose to the surface of women's abdomen (lower trunk) 2 mSv for the
remainder of the pregnancy - intake of radionuclide one twentieth of Annual
Limit on Intake (ALI). Radon Daughters, 4 Working Level Months (WLM/year).
The Physical Agents TLV Committee accepts the occupational exposure guidance of
the International Commission on Radiological Protection (ICRP). Ionizing
radiation includes particulate radiation (e.g., alpha particles and beta
particles emitted from radioactive materials, and neutrons from nuclear
reactors and accelerators) and electromagnetic radiation (e.g., gamma rays
emitted from radioactive materials and x-rays from electron accelerators and
x-ray machines) with energy greater than 12.4 electron-volts (eV) ... The
guiding principle of radiation protection is to avoid all unnecessary exposures.
ICRP has established principles of radiological protection. These are (1) the
justification of a work practice: No work practice involving exposure to
ionizing radiation should be adopted unless it produces sufficient benefit to
the exposed individuals or the society to offset the detriment it causes, (2)
the optimization of a workpractice: All radiation exposures must be kept as low
as reasonably achievable (ALARA), economic and social factors being taken into
account, and (3) the individual dose limits: The radiation dose from all
relevant sources should not exceed the /ICRP/ prescribed dose limits.
Other Occupational Permissible Levels:
For NRC licencees monitoring of the intake of radioactive material is required
by 10 CFR 20.1502(b) if the intake is likely to exceed 0.1 ALI (annual limit on
intake) during the year for an adult worker or the committed effective dose
equivalent is likely to exceed 0.05 rem (0.5 mSv) for the occupationally exposed
minor or declared pregnant woman. Regularory Guide 8.34 - Monitoring Criteria
and Methods to Calculate Occupational Radiation Doses ... describes methods
acceptable to the NRC staff for calculating occupational doses when the intake
is known. The Regulatory Guide lists important considerations for evaluating
bioassay measurements that includes chemical toxicity in the case of uranium
(see 10 CFR 20.1201(e))
For NRC licensees monitoring of an individual's external radiation exposure is
required by 19 CFR 20.1502(a) if the external occupational dose is likely to
exceed 10% of the dose limit appropriate for the individual (i.e., adult, minor,
or declared pregnant woman). External radiation monitoring is also required by
10 CFR 20.1502(a)(30 for any individual entering a high or very high radiation
area. Criteria acceptable to the NRC staff that may be used by licensees to
determine when monitoring is required is available in Regularory Guide 8.34 -
Monitoring Criteria and Methods to Calculate Occupational Radiation Doses.
This part contains the requirements and provisions for the medical use of
byproduct material and for issuance of specific licenses authorizing the medical
use of this material. These requirements and provisions provide for the
radiation safety of workers, the general public, patients, and human research
subjects. The requirements and provisions of this part are in addition to, and
not in substitution for, others in this chapter. The requirements and provisions
of parts 19, 20, 21, 30, 71, 170, and 171 of this chapter apply to applicants
and licensees subject to this part unless specifically exempted. Nothing in this
part relieves the licensee from complying with applicable FDA, other Federal,
and State requirements governing radioactive drugs or devices.
/In the U.S.,/ the NRC licensee /must/ control the occupational dose to
individual adults, except for planned special exposures under 10 CFR 20.1206, to
the following dose limits. (1) An annual limit, which is the more limiting of (i)
The total effective dose equivalent being equal to 5 rems (0.05 Sv); or (ii) The
sum of the deep-dose equivalent and the committed dose equivalent to any
individual organ or tissue other than the lens of the eye being equal to 50 rems
(0.5 Sv). (2) The annual limits to the lens of the eye, to the skin of the whole
body, and to the skin of the extremities, which are: (i) A lens dose equivalent
of 15 rems (0.15 Sv), and (ii) A shallow-dose equivalent of 50 rem (0.5 Sv) to
the skin of the whole body or to the skin of any extremity. (b) Doses received
in excess of the annual limits, including doses received during accidents,
emergencies, and planned special exposures, must be subtracted from the limits
for planned special exposures that the individual may receive during the current
year and during the individual's lifetime. (c) The assigned deep-dose equivalent
must be for the part of the body receiving the highest exposure. The assigned
shallow-dose equivalent must be the dose averaged over the contiguous 10 square
centimeters of skin receiving the highest exposure. The deep-dose equivalent,
lens-dose equivalent, and shallow-dose equivalent may be assessed from surveys
or other radiation measurements for the purpose of demonstrating compliance with
the occupational dose limits, if the individual monitoring device was not in the
region of highest potential exposure, or the results of individual monitoring
are unavailable. (d) Derived air concentration (DAC) and annual limit on intake
(ALI) values are presented in table 1 of appendix B to part 20 and may be used
to determine the individual's dose and to demonstrate compliance with the
occupational dose limits. ? (f) The licensee /must/ reduce the dose that an
individual may be allowed to receive in the current year by the amount of
occupational dose received while employed by any other person.
/In the U.S./ NUREG-1736, Consolidated Guidance: 10 CFR Part 20 - Standards for
Protection Against Radiation, consolidates /NRC/ guidance into a single
comprehensive source by reference to numerous guidance documents. It complements
the NUREG-1556 series, Consolidated Guidance about Materials Licenses. Since
Part 20 applies to all NRC licensees, in varying degrees, it extends beyond the
materials scope of NUREG-1556. Each section in this document provides the
following:" A statement of the requirement (reflecting revisions published
in the Federal Register through October 13, 1999); A discussion of the
requirement; A statement of the requirement's applicability; A guidance
statement; A list of existing regulatory guidance (Regulatory Guides, NUREG
reports); A list of existing implementation guidance (Information Notices,
health physics positions, Part 20 questions and answers, etc.). NUREG-1736,
Consolidated Guidance: 10 CFR Part 20 - Standards for Protection Against
Radiation, also identifies prior guidance that is now outdated and in some cases
subject to withdrawal or revision.
For occupational exposure the ICRP recommends a limit on effective dose of 100
mSv in a 5-year period, giving an average value of 20 mSv in a single year, with
the further provision that the effective dose should not exceed 50 mSv in any
single year. Where workers may be exposed to both external radiation and intake
of radionuclides, the annual dose limit applies to the sum of the effective
doses from external radiation and the committed effective dose from intakes of
radionuclides occurring within the year. In the case of intakes of mixtures of
radionuclides, and in the absence of external radiation exposure, the total
intake during one year should be controlled so as not to give rise to a
committed effective dose greater than 20 mSv.
The NCRP recommends that the annual occupational effective dose be limited to /a
maximum of/ 50 mSv not including medical and natural background. Alternatively,
if the flexibility inherent in the above recommendation is not required, the
implementation of an annual limit of 10 mSv is recommended. The NCRP recommends
that all new facilities and the introduction of all new practices should be
designed to limit annual exposure to individuals to a fraction of the 10 mSv per
year limit implied by the cumulative dose limit.
Individuals whose cumulative effective dose exceeds the age related limit should
be restricted in their exposures to no more than 10 mSv per year until the age
related lifetime limit is met.
To prevent deterministic effects severe enough to be clinically significant, the
following annual equivalent dose limits are recommended for occupational
exposure: 150 mSv for the crystalline lens of the eye and 500 mSv for localized
areas of the skin, the hands and feet. These limits apply whether an individual
tissue or organ is exposed selectively or together with other tissues or organs.
The NCRP recommends that exposures of persons under the age of 18 years be
permitted only under conditions presenting high assurance of maintaining the
resulting annual effective dose to less than 1mSv and dose equivalent to the
lens of the eye to less than 15 mSv and to the hands, feet and skin to less than
50 mSv (excluding medical and natural background radiation exposure.)
The NCRP has recommended that for all sources of ionizing radiation other than
medical and natural background exposure to individual members of the general
public be limited to an annual effective dose of 1 mSv. The NCRP has also
recommended a maximum annual effective dose limit of 5 mSv to provide for
infrequent annual exposures.
The sensitivity of the embryo-fetus for both mental retardation and cancer
should be considered in all situations involving irradiation of the
embryo-fetus. Therefore, for occupational situations, the NCRP recommends a
monthly equivalent dose limit of 0.5 mSv to the embryo-fetus (excluding medical
and natural background radiation) once the pregnancy is known.
Normally, only actions involving life saving justify acute exposures that are
significantly in excess of the annual effective dose limit. The use of
volunteers for exposures during emergency actions is desirable. Older workers
with low lifetime accumulated effective doses should be chosen from among the
volunteers, whenever possible. Exposures during emergency actions that do not
involve life saving should, to the extent possible, be controlled to the
occupational dose limits. Where this cannot be accomplished, it is recommended
that a limit of 0.5 Sv effective dose and equivalent dose of 5 Sv to the skin be
applied. When, for life saving..., the equivalent dose may approach or exceed
0.5 Sv to a large portion of the body in a short time, the workers need to
understand the potential for acute effects and have an appreciation of the
substantial increase in their lifetime risk of cancer.
The ICRP's occupational dose guidelines in the event of a radiological attack
may be summarized as follows: For first responders undertaking rescue operations
that involve saving life, no dose restrictions are recommended in principle if,
and only if, the benefit to others clearly outweighs the rescuer's own risk.
Otherwise, for rescue operations involving the prevention of serious injury or
the development of catastrophic conditions, every effort should be made to avoid
deterministic effects on health - by keeping effective doses below 1000 mSv to
avoid serious deterministic health effects, or below ten times the maximum
single year dose limit to avoid other deterministic health effects. ... For
first responders undertaking other immediate and urgent rescue actions to
prevent injuries or large doses to many people, all reasonable efforts should be
made to keep doses below twice the maximum single year dose limits. For actions
undertaken by workers engaged in recovery operations, the doses received should
be treated as part of normal occupational exposure and the normal occupational
dose limits apply; namely a limit on effective dose of 20 mSv/yr, averaged over
5 yrs (100 mSv in 5 years) with the further provision that the effective dose
should not exceed 50 mSv in any single year, and annual equivalent dose limits
of 150 mSv for the lens of the eye, 500 mSv for the skin... and 500 mSv for the
hands and feet. Taking account of the unavoidable uncertainties surrounding
first-response measures and the specific protection measures recommended for
female workers who may be pregnant or nursing an infant, the ICRP strongly
advocates that female workers in those conditions should not be employed as
first responders undertaking life-saving or other urgent actions at the site of
a radiological attack. Those rescuers undertaking actions in which the dose may
exceed the single year dose limit should be volunteers, and should be well
prepared for dealing with the aftermath of the radiological attack, i.e., they
should be clearly and comprehensively informed in advance of the associated
health risk and, to the extent feasible, be trained in the actions that may be
required, including the use of protective measures ... . The ICRP's occupational
dose guidelines in the event of a radiological attack may be summarized as
follows: For first responders undertaking rescue operations that involve saving
life, no dose restrictions are recommended in principle if, and only if, the
benefit to others clearly outweighs the rescuer's own risk. Otherwise, for
rescue operations involving the prevention of serious injury or the development
of catastrophic conditions, every effort should be made to avoid deterministic
effects on health - by keeping effective doses below 1000 mSv to avoid serious
deterministic health effects, or below ten times the maximum single year dose
limit to avoid other deterministic health effects. ... For first responders
undertaking other immediate and urgent rescue actions to prevent injuries or
large doses to many people, all reasonable efforts should be made to keep doses
below twice the maximum single year dose limits. For actions undertaken by
workers engaged in recovery operations, the doses received should be treated as
part of normal occupational exposure and the normal occupational dose limits
apply; namely a limit on effective dose of 20 mSv/yr, averaged over 5 yrs (100
mSv in 5 years) with the further provision that the effective dose should not
exceed 50 mSv in any single year, and annual equivalent dose limits of 150 mSv
for the lens of the eye, 500 mSv for the skin... and 500 mSv for the hands and
feet. Taking account of the unavoidable uncertainties surrounding first-response
measures and the specific protection measures recommended for female workers who
may be pregnant or nursing an infant, the ICRP strongly advocates that female
workers in those conditions should not be employed as first responders
undertaking life-saving or other urgent actions at the site of a radiological
attack. Those rescuers undertaking actions in which the dose may exceed the
single year dose limit should be volunteers, and should be well prepared for
dealing with the aftermath of the radiological attack, i.e., they should be
clearly and comprehensively informed in advance of the associated health risk
and, to the extent feasible, be trained in the actions that may be required,
including the use of protective measures ...
/In the U.S./ to receive, possess, or administer medical radionuclides, an
institution must be issued a license that commits the institution to observe Nuclear
Regulatory Commission rules and regulations, as set forth in 10 CFR Parts 20 and
35 and expanded on in "Regulatory Guides." Typically, a hospital must
have a radiation safety committee, a radiation safety officer, a high-level
administrative commitment to the provisions of the radiation safety program,
written policies and procedures for radiation safety and isotope utilization
that are substantially identical to NRC model guidelines, and sufficient
resources and manpower to carry out the program. ... To receive and administer
radionuclides, a physician must be named on the license as an authorized user.
This requires either specialty board certification or completion of several
hundred hours of prescribed course work in addition to a medical degree.
/In the U.S./ the Nuclear Regulatory
Commission does not regulate all aspects of medical radionuclides.
Accelerator-produced radionuclides, such as thallium-201, gallium-67, and
indium-11, are controlled by state regulation. ... Shipping and receiving of
radionuclides are regulated by the Department of Transportation. Disposal of
non-reactor-produced radionuclides is regulated by the Environmental Protection
Agency. States may agree to regulate reactor-produced nuclides on their own.
Such Agreement States must have state regulations that meet or exceed federal
regulations. ... Most nuclear medicine
procedures are performed in Agreement States, under the direction of state
regulations.
/In the U.S./ radiation regulation and control of nuclides used for
brachytherapy is similar to that for diagnostic nuclear
medicine. Because a majority of nuclides are reactor produced, the regulatory
environment is primarily determined by the NRC, with Agreement States following
suit. However, accelerator-produced nuclides are regulated by state law. The
Department of Transportation sets packaging and labeling requirements for
transport of therapeutic radionuclides. The QM requirements of 10 CFR Part 35,
apply to brachytherapy and to therapeutic unsealed radionuclides. No treatment
may be delivered without a written directive from a physician named on the
authorized user list of the facility license; the patient's identity must be
confirmed by two independent means before administration; each administration
must be carried out in accordance with the directive; and any unintended
deviation (misadministration) from the written directive should be identified
and reported to the NRC and to the patient, and corrective action should be
taken.
In U.S. Agreement States, the state regulates all external beam therapy. Typical
state laws specify radiation shielding design levels for facility construction,
required interlocks, area radiation monitors, warning labels, and access
control. Some states may specify qualifications, training, and licensure of
equipment operators and (rarely) radiological physicists, as well as content and
frequency of accelerator calibrations. The level of oversight varies
considerably from state to state.
The Atomic Energy Act of 1946 as amended in 1954 (42 USC 2011 et seq.)
established the Atomic Energy Commission (AEC) to promote the "utilization
of atomic energy for peaceful purposes to the maximum extent consistent with the
common defense and security and with the health and safety of the public."
When EPA was formed, the AEC's authority to issue generally applicable
environmental radiation standards was transferred to EPA. Other federal and
state organizations must follow these standards when developing requirements for
their areas of radiation protection. EPA also received the Federal Radiation
Council's authority under the Atomic Energy Act to develop guidance for federal
and state agencies containing recommendations for their use in developing
radiation protection requirements and to work with states to establish and
execute radiation protection programs.
Since the late 1940s, the U.S. Federal government has assumed ultimate
responsibility for the management and disposal of defense generated radioactive waste.
In 1957 the National Academy of Science recommended naturally occurring salt
formations as promising disposal media for these wastes.
... In the 1970 report, Disposal of Solid Radioactive Wastes
in Bedded Salt Deposits, the NAS concluded that salt formations are satisfactory
for long-range disposal of radioactive waste.
... Plans for development of a Waste
Isolation Pilot Plant (WIPP) (40 CFR Part 194) for long-term storage of
transuranic radioactive wastes (TRU)
followed in the next two decades. In 1975, a salt formation east of Carlsbad,
NM, was explored and in 1980 Congress authorized construction of the WIPP /at
that site/. The Department of Energy National Security and Military Applications
of Nuclear Energy Authorization Act of
1979 provided authorization for the development of the WIPP. ... The 1982 NuclearWaste Policy Act also supported the
use of mined geologic repositories for the safe storage and/or disposal of
radioactive waste... . The 1992 Waste
Isolation Pilot Plant Land Withdrawal Act (40 CFR Part 194) effected a
legislative withdrawal of the land surrounding WIPP for purposes of developing
and building a TRU waste repository,
required EPA to establish a process to certify that the WIPP facility was
technically adequate to meet the disposal standards established at 40 CFR Part
191, and reevaluate the WIPP every five years to determine whether it should be
recertified. ... As directed by WIPP LWA, EPA finalized the standards for the
the disposal of spent nuclear fuel,
transuranic, and high-level radioactive wastes
and developed criteria to implement and interpret the generic standards
specifically for the WIPP. This Criteria for Certification and Re-certification
of the Waste Isolation Pilot Plant's
(WIPP) Compliance with the 40 CFR 191 Disposal Regulations at 40 CFR Part 194.
The Criteria were upheld in their entirety on June 6, 1997, and EPA certified
the DOE submission for a Compliance Certification Application for WIPP on May
13, 1998. Since TRU may be mixed radioactive and chemical waste,
DOE was required to obtain a RCRA Permit (40 CFR Parts 264 and 270) from the New
Mexico Environmental Department. The WIPP received its first shipment of TRU
radioactive waste in March 1999.
The Low-Level Radioactive Waste Policy
Act of 1980 as amended in 1985 (42 USC 2021b et. seq.) requires each State /in
the U.S./ to be responsible for providing disposal capacity for commercial low
level radioactive waste generated
within its borders by January 1, 1986. It encouraged States to form regional
compacts to develop new disposal facilities. The LLRWPA was amended in 1985 to
provide States more time to develop facilities and to provide incentives for
volume reduction of low level radioactive waste.
Yucca Mountain, Nevada: In 1980, DOE performed an analysis of disposal
alternatives for spent nuclear fuel (SNF)
and high level waste (HLW). ... In
1987, the U.S. Congress enacted the NuclearWaste Policy Act Amendments that
directed DOE to consider Yucca Mountain as the primary site for the first HLW
and SNF repository in the U.S. The Waste
Isolation Pilot Plant Land Withdrawal Act of 1992 exempted Yucca mountain from
disposal standards at 40 CFR Part 191. The Energy Policy Act of 1992 directed
EPA to promulgate public health and safety standards for protection of the
public from releases from radioactive materials stored or disposed of in the
repository at the Yucca Mountain site. Based on a National Academy of Sciences
report, Technical Bases for Yucca Mountain Standards, and information received
from the public, EPA proposed the Environmental Radiation Protection Standards
for Yucca Mountain, Nevada on August 27, 1999. If approved, Yucca Mountain will
be the nation's first deep geological disposal facility for the permanent
disposal of HLW and SNF.
The recommendations in the American National Standards Institute standard, ANSI
Z88.2-1992, "American National Standard For Respiratory Protection,"
are endorsed by the NRC and may be used by licensees in establishing a
respiratory protection program with the /several/exceptions. /including
limitations that do not permit or greatly restrict the use of quarter-facepiece
respirators and supplied air respirators and self-contained breathing apparatus
(SCBA) that operate in the demand mode./
Applicability of OSHA's Respiratory Protection Rules: If an NRC licensee is
using respiratory protection to protect workers against nonradiological hazards,
the OSHA requirements apply. If the NRC has jurisdiction and is responsible for
inspection, the ... NRC will inform the licensee and OSHA if the NRC observes an
unsafe condition relative to nonradiological hazards. In general, .... if a
licensee is in compliance with the NRC regulations in Subpart H, the licensee is
considered to be in compliance with the corresponding and comparable OSHA
regulations on respiratory protection. ... In situations involving mixed
hazards, such as airborne radioactive materials and nonradioactive hazardous
materials, compliance with 10 CFR Part 20 alone may not provide sufficient
protection.