Annals of Disaster Medicine
| ISSN:1684-193X
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Updated
Oct 30, 2003
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Contents:
Volume 2, Supplement 1; October, 2003 |
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The
Essential Training of Disaster Medical Assistant Team on Radiological
Events |
Tzong-Luen Wang, MD, PhD |
From the Department of Emergency Medicine (Wang
TL), Shin-Kong Wu Ho-Su Memorial Hospital.
Correspondence to Dr. Tzong-Luen Wang, Department
of Emergency Medicine, Shin-Kong Wu Ho-Su Memorial Hospital, 95
Wen Chang Road, Taipei, Taiwan. E-mail M002183@ms.skh.org.tw
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Abstract
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Nuclear and radiation
events are special patterns of disasters. As the members of
disaster medical assistance team (DMAT), it is still essential
to have basic requirements to recognize and manage the situation
although some other specialized agencies may be also involved.
To treat the victims of the radiation exposure, either via nuclear
detonations or via terrorism, the safety of the personnel is
still the first priority. Because of possible limited equipment
for detecting the severity of radiation exposure, some general
rules to judge the situation by clinical evidences may be thus
important. To establish such objectives, we have to emphasize
the basic training for DMAT have to include the triage and management
in the initial stage of radiation incidents. The most essential
components include personal protection, the skills and knowledge
of evacuation and sheltering,
the clinical evaluation of severity, the key points on decontamination, and other modules
of management. Hands-on practice, repeated tabletop drills and
real field exercises are always required to accomplish the goal.
On the other hand, familiarity with response plan and good inter-agency
cooperation are still the crucial step to eliminate the hazards
of such disasters.
Key words--- Radiation; Nuclear
Events; Terrorism; DMAT; Disaster Response
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Introduction
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Radiation
incidents are among of hazardous events emergency responders might
have to deal with.1,2 Because strict requirements are
used in the shipment of radioactive materials, accidental spills
or releases of these substances seldom occur.1,2
Most of emergency responders or disaster medical assist team (DMAT)
members have limited experiences in dealing with such accidents.
The consequence of the hazard will be expected to be serious due
to lack of practice and experiences.
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Types of Radiation Incidents |
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There may be three general types of
radiation incidents, that is, external exposure that is irradiation
from a source distant or in close proximity to the body, and contamination
defined as unwanted radioactive material in or on the body.2-8
External irradiation occurs when all or part
of the body is exposed to penetrating radiation from an external
source.2-8 During exposure this radiation can be absorbed by the body
or it can pass completely through. A similar thing occurs during
an ordinary chest x-ray. Following external exposure, an individual
is not radioactive and can be treated like any other patient.
The second type of radiation injury involves contamination
with radioactive materials.2-8 Contamination means
that radioactive materials in the form of gases, liquids, or solids
are released into the environment and contaminate people externally,
internally, or both. An external surface of the body, such as
the skin, can become contaminated, and if radioactive materials
get inside the body through the lungs, gut, or wounds, the contaminant
can become deposited internally.
The third type of radiation injury that can occur is incorporation
of radioactive material.2-8 Incorporation refers to
the uptake of radioactive materials by body cells, tissues, and
target organs such as bone, liver, thyroid, or kidney. In general,
radioactive materials are distributed throughout the body based
upon their chemical properties. Incorporation cannot occur unless
contamination has occurred.
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The Role of DMAT |
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As
described previously, the function of the Disaster Medical Assistant
Team (DMAT) includes triage of victims at the disaster site, providing
sophisticated medical care in austere conditions and maintaining
casualty clearing or staging locations just outside the site of
the disaster. The DMATs can also provide
care at a reception area when the patient evacuation part is activated. Along with the training at both team level
and local/national level exercises, the DMAT members provide medical
care at special events and develop palns
for deployment to various disasters. However, in some special
disaster conditions such as radiological events, the DMAT should
have more specified training and equipments. Therefore, some specialized
team for different specified disaster may be developed.
In the United States, many special teams have been developed in
response for weapons of mass destruction. 9
Some of them that are responsible for radiological events include
AFRAT ( Airforce Radiation Assessment Team) for on-site detection,
identification and quantification of any ionizing radiation hazard;
ARG (Accident Response Group) for technical response for nuclear
emergencies; DOE (Department of Energy) for responding to nuclear
terrorism and events; ERAMS (Environment Radiation Ambient Monitoring
System) for measuring radioactivity and other contaminants in
the environment; NEST (Nuclear Emergency Search Team) providing
specialized technical expertise to resolve nuclear terrorist incidents;
REACT/TS (Radiation Emergency Assistance Center/Training Site)
offering a 24-hour emergency response program to support the medical
management of radiation accidents, and RERT (Radiological Emergency
Response Team) for environment monitoring and risk assessment. 9
According to the present systems in Taiwan,
the supervision for the radiological event is the responsibility
of Atomic Energy Committee. However, if any radiological or nuclear
terrorism occurs, the role of investigation should also depend
on the Bureau of Investigation or National Security Bureau. The
inter-cooperation between the different agencies deserves to be
well established at the usual time.
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Basic Training in Managing Radiological Events for General DMAT |
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Basic Concepts in Radiological
Terrorism |
To
cause the threatening effects, radiological or nuclear events may
be as much as biological terrorism.1-3,10-12
In 1994 Czech police seized 4 kg of highly enriched
uranium and at almost the same time German police seized more than
400 g of plutonium. Two men were seized with 1.16 kg of weapons
grade uranium in Turkey in 2001. The real attacks were two recent incidents
in 2001 when terrorist groups attempted to trespass Russian nuclear
storage sties. There has been reported to be 175 cases of nuclear
trafficking, 18 involving highly enriched uranium or plutonium since
1993 according to the International Atomic Energy Agency. Even more
alarming are reports that small fully built nuclear weapons are
missing from the Russian arsenal. In 1996 the Russian general Alexander
Lebed claimed that 40 of these so called
suitcase weapons were stolen.
In summary, the methods by terrorists were reported to stolen stale-owned weapons
or weapon components, improved nuclear devices fabricated from special
nuclear material, and attack on nuclear reactors / spent nuclear
fuel or radiological dispersal devices. In addition, so-called “dirty
bomb” that was delivered via conventional bomb has also been
reported as a weapon. 1-3,10-12
As DMAT, the first that we have to know is to recognize the possible
exposure. First, every member should be alert to the manifestations
of acute radiation syndrome following a predictive pattern after
substantial exposure. Victims may also present individually over
a longer period of time after exposure to contaminated sources hidden
in the community. There may be specific syndromes of concern, especially
with a 2 to 3 weeks prior history of nausea and vomiting, including
thermal burn-like lesions without documented heat exposure, immunological
dysfunction with secondary infections, bleeding tendency and hair
loss.2,13,14 Because
the high alertness is the first important issue for such nuclear
events, every member should be familiar with the details of clinical
manifestations and their possible variations. |
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Understanding the Exposure |
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The exposure may
be recognized by knowing large radiation exposures such as a nuclear
bomb or catastrophic damage to a nuclear power station, or small
radiation source causing intermittent exposures those are usually
met in the medical or industrial facilities. The DMAT should keep
in mind that the exposure to radiation may result from any combination
of external sources, skin contamination with radioactive materials
(so-called external contamination) and internal radiation from absorbed,
inhaled, or ingested radioactive material (or so-called internal
contamination).2,13,14
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Inter-agency Cooperation |
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For the members
of the DMAT, their task works include continuous medical care for
the victims in the disasters. However, the specific events such
as radiation / nuclear disasters must include many other specialized
organizations such as Atomic Energy Committee and the Bureau of
Investigation. Inter-agency cooperation should be established in
the response plan at the usual time and practiced accordingly in
the event time. In Taiwan, there is still no a highly supervised
departments in central government that is full responsible for most
of the disaster responses, as the FEMA works in the United States.
The total disaster response plan will depend upon the Executive
Yuan. It may be so urgent for us to set up a well-prepared response
plan which includes the inter-agency interactions for good response
for such a special event. |
Radiological Protection |
The radiological
protection should include respiratory protection, skin protection
and body sheltering. As we know, the respiratory protection levels are classified A, B, and C, classified
by the degree of protection.2,14
Level C protection is generally sufficient where airborne particulates
are the chief concern, whereas the personnel who have to invade
the hot zone should be equipped with level A. There are several
basic concepts for respiratory protection. Fit-tested cartridge-filtered
respirators or powered-air purifying respirators should be used
when available. Any respiratory protection that is designed to protect
responders against chemical or biological agents will likely offer
benefits in a radiation event.
The alternative method is to use ordinary surgical masks to provide
good protection against inhaling particulates, and allow excellent
ventilation for working at high breathing rates. If available, high
efficiency particulate air (HEPA) filter masks such as the common
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.
On must always consider other, greater hazards when selecting breathing
protection. If authorities suspect that particulates such as anthrax
or other such bacterial agents are present, an N-95 mask is required.2,14,15
Neither common surgical nor N-95 masks protect against gases and
vapors, however. If chemical agents are suspected, level B or higher
protection is required, for both the lungs and the skin. This means
fitted, full-face respirators and chemical-resistant coveralls. |
Skin Protection |
Current weather conditions, as well as
the environment at the event, will drive the selection of anti-contamination
clothing. Normal barrier clothing and gloves give excellent personal
protection against airborne particles. Disposable medical scrub
suits or high-density polyethylene coveralls and hood should be
used if they are available. The choice of clothing will often be
driven by other more immediate hazards, such as fire, heat, or chemicals.
Protection for these hazards covers any additional threat that radioactive
material could pose.
As stated above, transport of the severely injured to available
acute care medical facilities should not be delayed due to suspected
or confirmed radiological contamination on the patient. If a critically
injured but contaminated patient must be transferred immediately,
make preparations for limitation of contamination at the destination
facility. |
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Body Protection |
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Radioactive materials may contaminate
the deceased. Appropriate radiation survey assistance can confirm
or rule out such a situation. If a body is known or suspected to
be contaminated, personnel engaged in handling of the body should
be issued personal protective equipment. As stated above, it is
important for responders and mortuary personnel to be aware of other,
more acutely hazardous agents that may co-contaminate the remains
in question. Appropriately higher levels of protection should be
used as needed.2,3,14
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Radiation Dosimetry |
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Two types of devices may be used.2,14
The first type is a clip-on badge containing either film or other
radiation-sensitive material (AKA a thermoluminescent
dosimeter or TLD). The second type of device is a reusable electronic
dosimeter, which can be read visually or by other reading devices.
Some devices of this type also “chirp” like the traditional
Geiger counter. Radiation protection personnel will distribute and
explain how to use such devices. |
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Evacuation and Sheltering
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Although evacuation is always the work of Urban Rescue
and Search team and emergency medical technicians, the DMAT members
are still usually involved in the task even the latter team be activated
6 hours after the disaster has been recognized because of the long-lasting
characteristics of the radiation events. It is thereof important
for DMAT members to be familiar with the methods of evacuation and sheltering.
There are three general principles that form the basis for making
decisions on intervention.2,3,14
First, all possible efforts should be made to prevent serious deterministic
health effects (such as bone marrow depression and skin burns).
There is no specific dose level at which intervention should be
undertaken although, at levels of dose that would cause serious
deterministic effects, some kind of intervention would be almost
mandatory. The second principle is that the intervention should
be justified in the sense that the protective measure should do
more good than harm. While this may seem obvious, inappropriate
actions have been taken in accidental situations to reduce dose
at an extremely high social and monetary cost. The third principle
is that the levels at which an intervention is introduced and at
which it is later withdrawn should be optimized. After an intervention
is applied (e.g., evacuation or sheltering of a population), there needs
to be optimization of the action to determine the scale and duration.
Costs and benefits of such actions will change over time. If people
have been relocated and the radioactivity decays sufficiently, the
persons may be allowed to go back home.
Population dose assessment during the early phases of accident management
is at best difficult. Early decisions regarding evacuation or sheltering are challenging.
Individuals within an affected geographic area can receive widely
varying doses. Often it is best to recommend sheltering and showering
as an initial intervention until the situation (e.g., source, meteorology)
becomes clear. Initial decisions may need to be based upon field
measurements. Sheltering is 10-80% effective in reducing dose depending
upon the duration of exposure, building design and ventilation.14-16
If there is a passing plume of radioactivity, sheltering may be
preferable to evacuation. When sheltering, ventilation
should be tuned off to reduce influx of outside air. Sheltering
may not be appropriate if doses are projected to be very high or
long in duration. Sheltering has the advantage that people have
access to food, water and communications.
Evacuation is much more disruptive and expensive than sheltering.
Care needs to be taken to assess the meteorology and potential changes
to avoid moving people into the path of oncoming fallout. Evacuation
planning needs to consider schools, hospitals, prisons, food availability,
communications and housing. It should be noted that if persons are
outside and there is a major release of radioiodine or radioactive
particulate material, they should be instructed to make use of any
possible respiratory protection such as folded wet handkerchiefs
or towels. When they reach shelter, they should change clothes and
if possible shower.
Individual dose assessment is usually not possible in the early
phases of a terrorist event. Individual doses may only be approximated
in the first few hours or days. Relatively accurate individual dose
estimates may take up to a month or more and are retrospectively
performed based upon physical dosimetry,
accident reconstruction or biological markers and clinical examination.
Intake of long-lived radionuclides poses
additional problems. Doses are often calculated in terms of “committed
dose”. This usually refers to the dose an individual would
be expected to receive from that intake over the next 50 years.
While this may make sense for a young worker, it has little relevance to workers with less than an additional
50-year life expectancy. Another issue is that doses from intakes
of radionuclides are often calculated
on the basis of models. There may be significant individual deviations
from these estimates. With significant exposures, individual information
should be used. This is particularly important if there has been
an intervention (such as administration of potassium iodide) that
substantially affects the clearance and biological half-life of
the radionuclide. |
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Triage |
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In a radiological event, the first thing
that the first responders, emergency medical technicians or DMAT
members have to do is rapid triage.2,14-16 It is necessary
to assess any trauma or medical conditions prior to consideration
of radiological exposure. The triage is of extreme importance in
the chaos or mass casualties of an event such as terrorism. Even
after triage by the first responder or emergency medical technicians,
the DMAT should keep triage again and again because the patients’
condition may be complicated and dynamic.
As mentioned before, the rapid triage for such cases may depend
upon the symptoms. In other words, refer the cases with time to
vomiting less than 4 hours to immediate evaluation and the cases
with time to vomiting longer than 4 hours to delayed evaluation if no concurrent
injury.2,13-15 |
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Patients Decontamination |
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Skin or wound contamination is almost
never immediately life threatening to the patient or to medical
personnel. Therefore, treating conventional trauma injuries is the
first priority. Decontaminate the patient only after medical stabilization.2,3
Ideally, emergency medical services personnel or DMAT members will
decontaminate patients at the scene of an incident prior to transport.
As this will not always occur, decontamination procedures should
be part of the operational plans and procedures of all health care
facilities. Removal of outer clothing and shoes can reduce contamination
by as much as 90%. Assess for radiological contamination by slowly
passing a radiation detector over the entire body, insuring that
the same distance is maintained in subsequent surveys. Cover open
wounds prior to decontamination of surrounding skin. Remove contaminated
clothing and place it in marked plastic bags, moving it to a secure
location within a contaminated area. Wash bare skin and hair thoroughly,
and if practical, secure and appropriately dispose of the effluent.14,15 |
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Skin Decontamination |
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It remains essential to decontaminate
skin to decrease the risk of acute injury, lower the risk of internal
contamination, and reduce the potential of contaminating medical
personnel and the environment. After removing the patient’s
clothing, wash the patient with soap and water to emulsify and dissolve
the contamination. Gentle brushing removes some contamination bound
to skin protein and also a portion of the keratinized layer.14
Because the frequency of replacement of the stratum cornea, contamination
that is not removed and not absorbed by the body immediately will
be shed off within several days. The decontamination should be gentle
and effective enough to remove as much contamination as possible
without damaging the skin. Since it may prove difficult to remove
all contamination, decontaminating to two times background radiation
level should suffice. If after the third attempt, this goal is not
reached, and further attempts reduce the contamination by less then
10%, cease further efforts and handle the patient following standard
blood borne precautions to minimize the possible spread of the contaminant.
To avoid survey errors, it has to be sure that the same meter to
skin distance is used in all surveys. If washing will not remove
stubborn hand and distal extremity skin contamination, wrap the
contaminated area, and over time, sweating will decrease contamination.
To decontaminate hair, use any commercial shampoo without conditioner
because the latter bind material to hair protein and make removal
more difficult. Consider clipping hair to remove contaminants but
avoid removing eyebrows because they may not regrow. |
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Wound Decontamination |
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The patterns of wound affect the absorption
and decontamination of radioactive substances.2,3,14-16
Abrasions may disrupt the skin barrier to increase absorption potential.
However, they are usually easy to remove due to easily accessible
contaminants. Lacerations are easy to decontaminate after the contaminated
tissue is excised. Puncture wounds are difficult to decontaminate
because of poor approach to the contaminants and difficulty in determining
the depth and degree of contamination. Solubility, acidity/alkalinity,
tissue reactivity, and particle size affect the absorption of the
contaminants. Smaller particles have potential to be phagocytized
and thus kept internal tissue readily.
Victims may have wounds containing radioactive materials following
the detonation of a radiologic dispersal
device.2,14,16
Metallic shrapnel should be handled with forceps and, if found to
be radioactive, placed in a lead container or at least six feet
away from personnel. When an extremity is severely contaminated
and adequate shrapnel removal can not be allowed, amputation may
be indicated. It is necessary only the injuries are so extensive
with trivial functional recovery or the radiation dose is likely
to result in limb necrosis as a consequence. Decisions on amputation
should be delayed until long-term risks are clearly defined. Remember
the phrase “decontaminate but do not mutilate”.
For skin and wound decontamination, use a cleaning solution. Suggested
solutions are soap and water or normal saline, povidone iodine and water, and hexachlorophene 3% detergent
cleanser and water. |
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Internal decontamination treatment |
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Immediate care should focus primarily
on preventing internal contamination. As discussed earlier, skin
or wound contamination is almost never immediately life threatening
to the patient or to medical personnel. Therefore, treating conventional
trauma injuries is the first priority.2,14,16 As soon
as the patient’s condition permits, take steps to determine
whether internal contamination has occurred. Nasal swab samples
for radioactivity should be obtained as early as possible. However,
under some circumstances, inhalation exposures may not yield a positive
nasal swab. If contamination is present, especially in both nostrils,
inhalation of a contaminant may be assumed. Collect urine and feces
specimens to help determine whether internal contamination has occurred.
The reason to treat persons with internal contamination is to reduce
the radiation dose from absorbed radionuclides and thus the risk of long-term biological effects
(i.e., cancer). Minimize internal contamination by 1) reducing the
absorption of radionuclides and their
deposition in target organs, and 2) increasing excretion of the
radionuclides from the body. A number
of procedures are available for respiratory and gastrointestinal
contamination. The benefit of removing the radioactive contaminant
using modalities associated with significant side effects must be
weighed against the short and long-term effects of contamination
without treatment. The radioactivity and toxicity of internalized
radionuclides must also be considered.
Risk estimates combine professional judgment with the statistical
probability of radiation-induced diseases occurring within a patient’s
lifetime.
According to the task force from Department of Homeland Security
Working Group,14
immediate potential treatments include:
1. Consider oral potassium iodide for those whom
radioiodine is suspected as the potential contaminant.
2. Perform gastric lavage within
1-2 hours of ingestion of a single large amount till the washings
are free of radioactive material.
3. Prescribe antacids (such as aluminum hydroxide and magnesium carbonate-containing
formulas) as indicated to reduce gastrointestinal absorption if
radionuclides are ingested. Accordingly,
aluminum containing antacids are especially effective in reducing
uptake of strontium and reduces uptake up to 50-85%.
4. Give cathartics to decrease distention time and radiation dose
of materials in the bowel if large ingestions are suspected. It
is suggested that biscodyl or phosphate
soda enema will empty the colon in a few minutes. Oral agents of
suppositories will take one or more hours to work and considered
as second choice. Magnesium sulfate can be also suggested to produce
insoluble sulfate compounds with some radionuclides
such as radium.
5. Perform radionuclide specific therapies as guidelines.
6. Pulmonary lavage is rarely indicated
and is considered only after inhalation of extreme amounts of long-lived
insoluble radionuclides with the possible
result of major pulmonary sequelae. |
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Conclusion |
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Training plays an important role in DMAT
development. Although a special team may be developed for specific
events such as radiation or nuclear events mentioned above, the
general DMAT teams are still possibly engaged in the rescue and
medical care in such incidents. For a collective group that does
not work together daily at the usual time and gather to work under
tough circumstances at the casualties, qualified training has
to be ongoing. In addition to knowing their role and the teamwork
approach, hands-on practice with the basic load supply and the
equipment cache provides familiarity with the rapid set-up and
also allows constant check-up of those items that are in need
of repair or maintenance. And these modules have also to meet
the basic requirements for the possible special incidents such
as radiation. This article just summarizes many literatures and
provides some possible basic requirements of DMAT training for
nuclear / radiation events mentioned above. |
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References |
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1. |
Durham B. The background and history of manmade disasters.
Topics in Emerg Med 2002;24:1-14 |
2. |
Mettler FA Jr, Voelz GL. Current concepts: major radiation exposure-what
to expect and how to respond. NEJM 2002;346:1554-61 |
3. |
Gusev I, Guskova AK, Mettler FA Jr, eds. Medical management of radiation
accidents. 2nd ed. Boca Raton, Fla.: CRC Press, 2001 |
4. |
Jarrett D, ed. Medical management of radiation casualties: handbook.
AFRRI special publication 99-2. Bethesda, Md.: Armed Forces Radiobiology
Research Institute, 1999. (Also available at http://www.afrri.usuhs.mil
.) |
5. |
How to recognize and initially respond to an accidental radiation
injury. Vienna, Austria: International Atomic Energy Agency, 2000 |
6. |
Diagnosis and treatment of radiation injuries. Safety reports
series no. 2. Vienna, Austria: International Atomic Energy Agency,
1998 |
7. |
Browne D, Weiss JF, MacVittie TJ, Pillai MV. Treatment of radiation
injuries. New York: Plenum Press, 1990 |
8. |
Ricks RC, Berger ME, O'Hara FM, eds. The medical basis
for radiation accident preparedness: the clinical care of victims.
Boca Raton, Fla.: Parthenon Publishing, 2002 |
9. |
Weapons of mass destruction response. Available at http://cphpbr.uthscsa.edu/wmd.pdf
|
10. |
Hogan DE, Kellison TRN. Nuclear Terrorism. Am J Med Sci 2002;323:341-9
|
11. |
Clauw D, Engel CC Jr, Aronowitz R, et al. Unexplained Symptoms
After Terrorism and War: An Expert Consensus Statement. J Occupational
Environ Med 2002;45:1040-8 |
12.. |
Harrison TW, Gustafson EM, Dixon JaneK. Radiologic Emergency:
Protecting Schoolchildren and the Public. AJN 2003;103:41-9 |
13. |
Terrorism with ionizing radiation general guidance: pocket guide.
Available at http://www.oqp.med.va.gov/cpg/cpg.htm |
14.. |
Department of Homeland Security working group on radiological dispersal
device (RDD) preparedness: medical preparedness and sub-group. May
2003 version. Available at http://www.va.gov/emshg/docs/ Radiologic_Medical_Countermeasures_051403.pdf |
15. |
Skorga P, Persell DJ, Arangie P, et al. Caring for Victims of Nuclear
and Radiological Terrorism. Nurse Practitioner 2003;28:24-41 |
16.. |
Udeani JC, Aguilera P. Management of Nuclear Casualties. Topics
Emerg Med 2002;24:40-6
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