0. Types of Ionizing Radiation
Alpha Particles
Stopped by a sheet of paper
Radiation
Source
Beta Particles
Stopped by a layer of clothing
or less than an inch of a substance (e.g. plastic)
5. Types of Ionizing Radiation
Alpha particles. Alpha particles are ejected (thrown out of) the nuclei of some very heavy radioactive atoms (atomic number > 83). An alpha particle is composed of two neutrons and two protons. Alpha particles do not penetrate the dead layer of skin and can be stopped by a thin layer of paper or clothing. If an alpha emitting radioactive material gets inside the body through inhalation, ingestion, or through a wound, the emitted alpha particles can cause ionization that results in damage to tissue. It is less likely that a patient would be contaminated with an alpha emitter.
Beta particles. A beta particle is an electron ejected from the nucleus of a radioactive atom. Depending on its energy, beta radiation can travel from inches to many feet in air and is only moderately penetrating in other materials. Some beta radiation can penetrate human skin to the layer where new skin cells are produced. If high enough quantities of beta emitting contaminants are allowed to remain on the skin for a prolonged period of time, they may cause skin injury. Beta emitting contaminants may be harmful if deposited internally. Protective clothing (e.g., universal precautions) typically provides sufficient protection against most external beta radiation.
Gamma rays and x-rays (photons). Gamma rays and x-rays are able to travel many feet in air and many inches in human tissue. They readily penetrate most materials and are sometimes called “penetrating” radiation. Thick layers of dense materials are needed to shield against gamma radiation. Protective clothing provides little shielding from gamma and x radiation, but will prevent contamination of the skin with the gamma emitting radioactive material. Gamma and x radiation frequently accompanies the emission of beta and alpha radiation.
Gamma Rays
Stopped by inches to feet of concrete
or less than an inch of lead

1. Radiation Units Measure of Amount of radioactive material
Ionization in air
Absorbed energy per mass
Absorbed dose
weighted by type of radiation
Quantity
Activity
Exposure
Absorbed Dose
Dose Equivalent
Unit
curie (Ci)
roentgen (R)
rad
rem
6. Radiation Units
A curie is a very large amount of radioactivity. Contamination of individuals usually involve µCi to mCi quantities. Nuclear medicine patients are injected with µCi to mCi quantities of radioactive material for routine diagnostic exams.
The basic unit of radiation dose is the rad. The rad is defined as the deposition of 0.01 joule of energy (a small amount) per kilogram (kg) of tissue.
A rad of x-rays, a rad of gamma rays, and a rad of beta particles are about equally damaging to tissue. However, a rad of another type of ionizing radiation, such as alpha particles or neutrons, is much more damaging to tissue than a rad of gamma rays.
The rem was introduced to take into account this variation in tissue damage. This is important because a person may be exposed to more than one type of radiation. For example, it was found that 100 rad of gamma and beta radiation produced the same effect as 100 rad of x-rays. However, only 20 rad of neutrons and 5 rad of alpha particles produced the same effect as 100 rad of x-rays. Therefore, neutron and alpha radiations were more potent and required fewer rad to produce the same effect.
The number of rem is calculated by multiplying the number of rad by a radiation weighting factor that accounts for the relative amount of biological damage produced by a specific type of radiation. The radiation weighting factor for x-rays, gamma rays, and beta particles is 1. Thus, a rad of one of these radiations is equal to one rem. For other types of radiation (that are less likely to be present in accidents), the quality factor may be higher.
The International Scientific System (SI) assigns different units to the quantities:
1 R = 2.58 X 10-4 C kg-1 1 gray (Gy) = 100 rad
1 sievert (Sv) = 100 rem 1 becquerel (Bq) = 1 disintegration per second
For most types of radiation 1 R  1 rad  1 rem

2. Radiation Doses and Dose Limits
Flight from Los Angeles to London mrem
Annual public dose limit mrem
Annual natural background mrem
Fetal dose limit mrem
Barium enema mrem
Annual radiation worker dose limit 5,000 mrem
Heart catheterization (skin dose) ,000 mrem
Life saving actions guidance (NCRP-116) ,000 mrem
Mild acute radiation syndrome ,000 mrem
LD50/60 for humans (bone marrow dose) ,000 mrem
Radiation therapy (localized & fractionated) ,000,000 mrem
7. Radiation Doses and Dose Limits
Radioactive material has always been a natural part of the earth. It has existed for millions of years in the crust of the earth, in building materials, in the food we eat, the air we breathe, and in nearly everything that surrounds us. Radiation from these materials, as well as cosmic radiation from the sun and universe, makes up the natural background radiation to which we are constantly exposed. On the average, persons are exposed to about 300 millirem per year from natural sources (NCRP Report No. 101).
The guidance from NCRP Report No. 116, Limitation of Exposure to Ionizing Radiation, states that for life saving or equivalent purposes, workers may approach or exceed 50,000 mrem to a large portion of the body. Emergency exposures are considered once-in-a-lifetime. This is below the threshold for the acute radiation syndrome, discussed later.
If an individual is exposed to more than 100 rem at one time, predictable signs and symptoms will develop within a few hours, days, or weeks depending on the magnitude of the dose. About half of all people exposed to a single dose of 350 rem will die within 60 days (LD50/60) without medical intervention. The large doses used in medicine for radiation therapy, while higher than this dose, are given to only part of the body and are typically given over a period of weeks.
Heart catheterization is a skin dose; barium enema is an effective dose. (NRPB Report R-200, 1986)
The dose limits are highlighted in orange.

3. Radioactive Material
Radioactive material consists of atoms with unstable nuclei
The atoms spontaneously change (decay) to more stable forms and emit radiation
A person who is contaminated has radioactive material on their skin or inside their body (e.g., inhalation, ingestion or wound contamination)
8. Radioactive Material
The difference between radioactive material and radiation should be explained.
Radioactivity is a mechanism whereby an unstable nucleus rearranges itself to become more stable. The process often involves the ejection of charged particles from the atomic nuclei. This ejection of particles (beta or alpha) is often accompanied by the emission of gamma rays from the nucleus or x-rays from the atom’s electron shells. Beta particles, alpha particles, gamma rays and x-rays are all forms of radiation that can be emitted from radioactive atoms.
Radioactive contamination is simply radioactive material (often attached to dust or dirt) that is either on the skin or clothes of the patient or has been taken into the body via inhalation, ingestion, or through a wound.
Usually most of the external contamination can be removed from the patient by carefully removing the patient’s clothing.

4. Half-Life (HL) Physical Half-Life Biological Half-Life
Time (in minutes, hours, days or years) required for the activity of a radioactive material to decrease by one half due to radioactive decay
Biological Half-Life
Time required for the body to eliminate half of the radioactive material (depends on the chemical form)
Effective Half-Life
The net effect of the combination of the physical & biological half-lives in removing the radioactive material from the body
Half-lives range from fractions of seconds to millions of years
1 HL = 50% 2 HL = 25% 3 HL = 12.5%
9. Half-Life
In any sample of radioactive material, the amount of radioactive material constantly decreases with time because of radioactive decay.
The physical half-life is the amount of time required for a given amount of radioactive material to be reduced to half the initial amount by radioactive decay.
The biological half-life is the time required for the human body to eliminate half of the radioactive material taken into it. For many radioactive materials, the elimination from the body occurs via urination. However, depending on the chemical composition of the radioactive material, other pathways can also help to eliminate the radioactive material from the body.
The effective half-life is a measure of the time it takes for half the radioactive material taken into the body to disappear from the body. Both the physical half-life and the biological half-life contribute to the elimination of the radioactive material from the body. The combination of these two half-lives is called the effective half-life.
After one half-life, half of the material remains. After a second half-life, a half of a half, i.e. 25% of the initial amount remains. After 10 half-lives, about 1/1000 remains. After 20 half-lives, only one millionth of the material remains.

5. Examples of Radioactive Materials
Physical
Radionuclide Half-Life Activity Use
Cesium-137* yrs x106 Ci Food Irradiator
Cobalt yrs ,000 Ci Cancer Therapy
Plutonium ,000 yrs Ci Nuclear Weapon
Iridium days Ci Industrial Radiography
Hydrogen yrs Ci Exit Signs
Strontium yrs Ci Eye Therapy Device
Iodine days Ci Nuclear Medicine Therapy
Technetium-99m hrs Ci Diagnostic Imaging
Americium yrs Ci Smoke Detectors
Radon days pCi/l Environmental Level
* Potential use in radiological dispersion device
10. Examples of Radioactive Materials
Radioactive materials emit ionizing radiation. They are used in medical diagnosis (nuclear medicine), medical therapy (cancer treatment), industry (food irradiation), and for research.
Many radioactive materials, including radioactive waste, are commercially shipped in special containers.
A radionuclide is chemically identical to and behaves in the body the same way as the non-radioactive form of the element. For example, radioactive iodine (e.g. I-131) is concentrated in the thyroid in the same way as non-radioactive iodine (i.e. I-127).
Quantities of radioactive material (i.e. activity) range from trivial amounts in typical laboratories, to much larger quantities, such as in nuclear reactors.
Half-lives can range from seconds to millions of years.
The nuclides that are in orange are those that are considered to be potential nuclides that could be present in a radiological dispersal device.

6. Types of Radiation Hazards
Internal
Contamination
External Exposure -
whole-body or partial-body (no radiation hazard to EMS staff)
Contaminated -
external radioactive material: on the skin
internal radioactive material: inhaled, swallowed, absorbed through skin or wounds
External
Contamination
External
Exposure
11. Types of Radiation Hazards
Patients who have only been exposed to the radiation from a radioactive source or a machine, such as an x-ray machine or a linear accelerator, are not contaminated and do not pose any radiation contamination or exposure potential for hospital personnel.
Radiation safety precautions are not needed for patients who have only been exposed and are not contaminated.
Patients with radioactive material on them or inside their bodies are said to be contaminated.
Contaminated patients require care in handling to effectively remove and control the contamination.
Analogy - You can think of radiation exposure and radioactive material in terms of a trip to the beach. Sand is like radioactivity. The sun is like radiation exposure. Once you go inside, you are not in the sun any longer and there is no more exposure (radiation stops). On the other hand, most of the sand came off when you walked off the beach, however, some sand remains on your skin until you physically remove it (brush or wash it off). The same is true for radioactivity contamination on the skin. A small amount may remain on the skin and need to be washed off.

7. Causes of Radiation Exposure/Contamination
Accidents
Nuclear reactor
Medical radiation therapy
Industrial irradiator
Lost/stolen medical or industrial radioactive sources
Transportation
Terrorist Event
Radiological dispersal device (dirty bomb)
Attack on or sabotage of a nuclear facility
Low yield nuclear weapon
12. Causes of Radiation Exposure and Contamination
Accidents - There are several settings or scenarios in which radiation accidents may occur: nuclear reactor accidents; medical radiation therapy accidents or errors in treatment dose; accidental overexposures from industrial irradiators; lost, stolen or misused medical or industrial radioactive sources; and accidents during the transportation of radioactive material.
Terrorist Use of Nuclear Materials - The use of radioactive materials in an RDD or a nuclear weapon by a terrorist is a remote but plausible threat. The medical consequences depend on the type of device used in a terrorist event. An attack on or sabotage of a nuclear facility, such as an irradiation facility or a nuclear power plant, could result in the release of very large amounts of radioactive material.
Radiological Dispersal Device (RDD) - A RDD disperses radioactive material for the purpose of terrorism. A RDD that uses a conventional explosive (e.g., TNT or a plastic explosive) to disperse the radioactive material is called a “dirty bomb”. A dirty bomb is NOT an atomic bomb. The initial explosion may kill or injure those closest to the bomb, while the radioactive material remains to expose and contaminate survivors and emergency responders.
Low Yield Nuclear Weapon - A low yield nuclear weapon or partial failure of a high yield weapon could cause a low yield nuclear detonation. For example, if one considers the consequences of a 0.1 kiloton yield nuclear detonation (less than 1/100 the size of the weapon used on Hiroshima), then the following would occur within one minute surrounding ground zero. The effects listed below do not take into account that multiple injuries caused by the interaction of the various types of injury will increase the probability of fatality. (NCRP Report No. 138)
- The range for 50% mortality from trauma from the blast is approximately 150 yards.
- The range for 50% mortality from thermal burns is approximately 220 yards.
- The range for 400 rad from gamma and neutron radiation would be approximately 1/3 mile.
- The range for 400 rad in the first hour from radioactive fallout would be almost 2 miles in the downwind direction.
- As the size of the weapon increases, the effects encompass a greater distance. This will result in the release of widespread contamination and substantial air blast and heat.

8. Scope of Event Event Number of Deaths Most Deaths Due to Radiation
None/Few
Radiation
Accident
Radioactive
Few/Moderate
Blast Trauma
Dispersal
(Depends on
size of explosion &
Device
13. Scope of Event
428 major radiation accidents have been reported worldwide in the years 1944 to These accidents caused 126 deaths due to radiation. Their effects were dependent on exposure, contamination and the number of people involved. There were an additional 8 non-radiation deaths that would likely have resulted in eventual death due to the radiation. (REAC/TS Registry, 2002)
There have been no uses of radioactive dispersal devices. The outcome of such an event would depend on the size of the explosion, the radioactive material involved, the activity (amount) of the radioactive material, the number of people in the vicinity and the effectiveness of the emergency response.
There have been no low-yield nuclear weapon detonations by terrorists. The outcome from such an event would depend on the yield, the location of the detonation and the number of people in the vicinity.
proximity of persons)
Low Yield
Large
Blast Trauma
Nuclear Weapon
(e.g. tens of thousands in
Thermal Burns
an urban area even from
Radiation Exposure
0.1 kT weapon)
Fallout
(Depends on Distance)

9. Radiation Protection Reducing Radiation Exposure
Time
Minimize time spent near radiation sources
To Limit Caregiver Dose to 5 rem
Distance Rate Stay time
1 ft R/hr min
2 ft R/hr hr
5 ft R/hr hr
8 ft R/hr hr
Distance
Maintain maximal practical distance from radiation source
14. Reducing Radiation Exposure
There are three methods for reducing radiation exposure: time, distance, and shielding. All three of these methods can be used to keep radiation exposure to a minimum.
The longer a person is exposed to a radiation source, the higher will be the dose received. To minimize the dose, reduce the time of exposure to the radiation. For example, ED nurses who do not have to stand beside a contaminated patient can minimize exposure by stepping close to the patient only when assistance is needed and stepping away as soon as they are done.
In addition to minimizing the exposure time, the nurse can further reduce exposure by taking advantage of distance. Radiation dose rate falls off very quickly as the distance between the radiation source and the individual is increased. Time and distance are effective methods of minimizing dose.
Another method of minimizing dose is through the use of shielding. Radiology personnel use leaded aprons to shield themselves from the x-rays that are scattered from the patient undergoing an x-ray procedure. Leaded aprons are not recommended and usually provide little shielding protection from the types of radiation expected from contaminated patients. An effective way to use shielding is to place radioactive materials removed from patients into lead containers called “pigs.” The thick lead walls of these containers absorb the radiation from the radioactive material.
Shielding
Place radioactive sources in a lead container

10. Detecting and Measuring Radiation
Instruments
Locate contamination - GM Survey Meter (Geiger counter)
Measure exposure rate - Ion Chamber
Personal Dosimeters - measure doses to staff
Radiation Badge - Film/TLD
Self reading dosimeter (analog & digital)
21. Detecting and Measuring Radiation
You cannot see, smell, taste, feel, or hear radiation, but we have very sensitive instrumentation to detect it at very low levels. Radiation monitoring instruments detect the presence of radiation. The radiation measured is usually expressed as exposure per unit time, using various units of measure, milliroentgen per hour (mR/hr) and counts per minute (CPM). Anything with “milli” in front of it is SMALL! The most commonly used instruments to detect the presence of radiation include:
Geiger- Mueller Survey Meter. The Geiger-Mueller (GM) survey meter (also known as a Geiger counter) will detect low levels of gamma and most beta radiation. The instrument typically has the capability to distinguish between gamma and most beta radiation. This instrument is used to quickly determine if a person is contaminated. GM survey meters are very sensitive and other instruments may be needed to measure higher levels.
Ionization Chamber Survey Meter. This device can accurately measure radiation exposure. These meters measure from low levels (mR/hr) to higher levels (many R/hr). To find the dose an individual is receiving, multiply the dose rate by the time that they are exposed.
Personal Dosimeters. These devices measure the cumulative dose of radiation received by persons wearing them. Film and TLD badges must be analyzed by the company that supplies them and so the dose received is not typically known for several days. However, self reading dosimeters allow the wearer to immediately see the total dose they have received.

11. Patient Management - Decontamination
Carefully remove and bag patient’s clothing and personal belongings (typically removes 95% of contamination)
Survey patient and, if practical, collect samples
Handle foreign objects with care until proven non-radioactive with survey meter
Decontamination priorities:
Decontaminate wounds first, then intact skin
Start with highest levels of contamination
Change outer gloves frequently to minimize spread of contamination
24. Patient Management – Decontamination
Patient decontamination should be performed after stabilization of the patient. Removal of clothing usually occurs in the field, prior to transport to the hospital.
The approach to decontamination as described in the slide will minimize contamination of and exposure to attending personnel.
If internal contamination is suspected, take nasal swipes and 24 hour urine and fecal collections.
Unfamiliar embedded objects in patient’s clothing or wounds may be radioactive sources. Handle with long forceps, handle only briefly, and keep distant from staff and patients until proven, with a survey meter, not to be radioactive. If radioactive objects are recovered, they should be placed in a lead container using tongs or forceps and then placed at a distance from staff and patients.

12. Patient Management - Decontamination (Cont.)
Protect non-contaminated wounds with waterproof dressings
Contaminated wounds:
Irrigate and gently scrub with surgical sponge
Extend wound debridement for removal of contamination only in extreme cases and upon expert advice
Avoid overly aggressive decontamination
Change dressings frequently
Decontaminate intact skin and hair by washing with soap & water
Remove stubborn contamination on hair by cutting with scissors or electric clippers
Promote sweating
Use survey meter to monitor progress of decontamination
25. Patient Management - Decontamination (Cont.)
Protection of non-contaminated wounds with waterproof dressings will minimize the potential for uptake of radioactive material.
To decontaminate wounds, irrigate and gently scrub with a surgical sponge. Normal wound debridement should be performed. Excision around wounds solely to remove contamination should only be performed in extreme cases and upon the advice of radiological emergency medical experts.
Many times, radioactive material will exude from wounds into gauze dressings so frequent changing of dressings may aid wound decontamination. The dressing also serves to keep the contamination in place.
Remove contaminated hair if necessary, using scissors or electric clippers. To avoid cutting the skin and providing an entry for internal contamination, do not shave.
Usual washing methods are effective for removal of radioactive material. Overly aggressive decontamination may abrade the skin, which would increase absorption of radioactive material, and should be avoided.
Sweating can remove radioactive material from pores. Cover the area with gauze and put a glove or tape plastic over the area to promote sweating.
Use a GM survey meter to monitor the effectiveness of the cleaning method.

13. Patient Management - Decontamination (Cont.)
Cease decontamination of skin and wounds
When the area is less than twice background, or
When there is no significant reduction between decon efforts, and
Before intact skin becomes abraded.
Contaminated thermal burns
Gently rinse. Washing may increase severity of injury.
Additional contamination will be removed when dressings are changed.
Do not delay surgery or other necessary medical procedures or exams…residual contamination can be controlled.
26. Patient Management - Decontamination (Cont.)
Cease decontamination of the skin and wounds when the area is less than twice the background reading on the survey meter or there is no significant reduction between washings. Under no circumstances should decontamination cause the skin to become abraded.
Contaminated thermal burns can be gently rinsed while ensuring that there will be no further damage to the skin. Additional contamination will be removed with the exudate as dressings are changed.
Do not delay surgery or other necessary medical procedures because of contaminated skin or wounds. Staff will be protected from becoming contaminated by using universal precautions. Sheets and dressings will keep contamination in place.

14. Treatment of Internal Contamination
Radionuclide-specific
Most effective when administered early
May need to act on preliminary information
NCRP Report No. 65, Management of Persons Accidentally Contaminated with Radionuclides
Radionuclide Treatment Route
Cesium-137 Prussian blue Oral
Iodine-125/131 Potassium iodide Oral
Strontium-90 Aluminum phosphate Oral
Americium-241/ Ca- and Zn-DTPA IV infusion,
Plutonium-239/ nebulizer
Cobalt-60
27. Treatment of Internal Contamination
Deposition of radioactive materials in the body (i.e., internal contamination), is a time-dependent, physiological phenomenon related to both the physical and chemical natures of the contaminant.
The rate of radionuclide incorporation into organs can be quite rapid. Thus, time can be critical and treatment (decorporation) urgent.
Several methods of preventing incorporation (e.g., catharsis, gastric lavage) might be applicable and can be prescribed by a physician.
Some of the medications or preparations used in decorporation might not be available locally and should be stocked.
NCRP Report No. 65, Management of Persons Accidentally Contaminated with Radionuclides, addresses the strategies to limit the exposure from internal contamination by radioactive materials. Radiation Protection Dosimetry published a Guidebook for the Treatment of Accidental Internal Radionuclide Contamination of Workers (1992) that provides additional information on patient management.
In January 2003, the Food and Drug Administration (FDA) determined that Prussian blue had been shown to be safe and effective in treating people exposed to radioactive elements such as Cesium-137.
In August 2004, the FDA determined that two drugs, pentetate calcium trisodium injection (Ca-DTPA) and pentetate zinc trisodium injection (Zn-DTPA), are safe and effective for treating internal contamination with plutonium, americium, or curium. The drugs increase the rate of elimination of these radioactive materials from the body.

15. Facility Recovery
Remove waste from the Emergency Department and triage area
Survey facility for contamination
Decontaminate as necessary
Normal cleaning routines (mop, strip waxed floors) typically very effective
Periodically reassess contamination levels
Replace furniture, floor tiles, etc. that cannot be adequately decontaminated
Decontamination Goal: Less than twice normal background…higher levels may be acceptable
29. Facility Recovery
If you have in-house radiation safety staff, they will supervise decontamination efforts.
Environmental Services staff should remove waste from the Emergency Department and triage area and take it to a holding place until it can be surveyed for radioactive material before disposal.
A radiation survey of the facility will identify any areas that need decontamination. Normal cleaning routines are typically very effective. If there is residual contamination after normal cleaning, items such as furniture and floor tiles can be replaced.
The decontamination goal is for the equipment and floors to be less than twice the normal background reading. Higher levels of fixed contamination should not deter the use of emergency facilities during periods of critical need.

16. Radiation Sickness Acute Radiation Syndrome
Occurs only in patients who have received very high radiation doses (greater than approximately 100 rem) to most of the body
Dose ~ 15 rem
no symptoms, possible chromosomal aberrations
Dose ~ 50 rem
no symptoms, minor decreases in white cells and platelets
30. Radiation Sickness - Acute Radiation Syndrome
Radiation sickness [acute radiation syndrome (ARS)] is an acute illness following exposure to a very large dose of ionizing radiation. It is produced if a large dose of radiation reaches enough sensitive tissue within the body. The acute radiation syndrome follows a roughly predictable course over a period of time ranging from a few hours to several weeks.
For doses of approximately 15 rem, the patient should be asymptomatic, but an increased number of chromosomal aberrations may be detectable in circulating lymphocytes.
For doses of approximately 50 rem, the patient should be asymptomatic, but show minor decreases in white cells and platelets.

17. Acute Radiation Syndrome (Cont.) For Doses > 100 rem
Prodromal stage
nausea, vomiting, diarrhea and fatigue
higher doses produce more rapid onset and greater severity
Latent period (Interval)
patient appears to recover
decreases with increasing dose
Manifest Illness Stage
Hematopoietic
Gastrointestinal
CNS
Time of Onset
31. Acute Radiation Syndrome (Cont.)
The signs and symptoms that develop in the ARS occur in four distinct phases: prodromal (initial), latent period, manifest illness stage and recovery or death.
Prodromal phase. Depending on the dose of radiation, patients may experience a variety of symptoms including loss of appetite, nausea, vomiting, fatigue, and diarrhea. After extremely high radiation doses, additional symptoms such as prostration, fever, respiratory difficulties, and increased excitability may develop.
Latent period. This is a transitional period in which many of the initial symptoms partially or completely resolve. It may last for a few hours or up to a few weeks depending on the radiation dose. The latent period shortens as the initial dose increases.
Manifest Illness Stage. These three phases occur with increasing radiation exposure and are described on the following slides.
The severity of the symptoms increases with dose, amount of the body exposed (whole body vs. partial body exposure), and the penetrating ability of the radiation. The severity is also affected by factors such as age, gender, genetics, medical conditions, etc.
Severity of Effect

18. Acute Radiation Syndrome (Cont
Acute Radiation Syndrome (Cont.) Hematopoietic Component - latent period from weeks to days
Dose ~ 100 rem
~10% exhibit nausea and vomiting within 48 hr
mildly depressed blood counts
Dose ~ 350 rem
~90% exhibit nausea/vomiting within 12 hr, 10% exhibit diarrhea within 8 hr
severe bone marrow depression
~50% mortality without supportive care
Dose ~ 500 rem
~50% mortality with supportive care
Dose ~ 1000 rem
90-100% mortality despite supportive care
32. Acute Radiation Syndrome (Cont.)
Radiation in very large whole body doses can cause death of the individual exposed. The clinical progression of the symptoms is dose dependent, as is the body system that exhibits the most profound effects. For very high whole body doses, the duration of time from exposure to onset of symptoms is shortened and the effects exhibited are dose dependent.

19. Acute Radiation Syndrome (Cont.) Gastrointestinal and CNS Components
Dose > 1000 rem - damage to GI system
severe nausea, vomiting and diarrhea (within minutes)
short latent period (days to hours)
usually fatal in weeks to days
Dose > 3,000 rem - damage to CNS
vomiting, diarrhea, confusion, severe hypotension within minutes
collapse of cardiovascular and CNS
fatal within 24 to 72 hours
33. Acute Radiation Syndrome (Cont.)
Doses greater than 1000 rem will progress on a medically unalterable course.

20. Treatment of Large External Exposures
Estimating the severity of radiation injury is difficult.
Signs and symptoms (N,V,D,F): Rapid onset and greater severity indicate higher doses. Can be psychosomatic.
CBC with absolute lymphocyte count
Chromosomal analysis of lymphocytes (requires special lab)
Treat symptomatically. Prevention and management of infection is the primary objective.
Hematopoietic growth factors, e.g., GM-CSF, G-CSF (24-48 hr)
Irradiated blood products
Antibiotics/reverse isolation
Electrolytes
Seek the guidance of experts.
Radiation Emergency Assistance Center/ Training Site (REAC/TS)
Medical Radiobiology Advisory Team (MRAT)
34. Treatment of Large External Exposures
The faster the onset of signs and symptoms and the greater the severity of the drop in the lymphocytes and other blood elements will indicate higher radiation doses. (N, V, D, F) refers to nausea, vomiting, diarrhea and fatigue.
The complete blood cell with absolute lymphocyte count should be taken initially and about every 6 hours thereafter (Purple top tube containing EDTA). The concentration of lymphocytes in circulation can be altered by trauma and can complicate the use of this as an indicator for radiation exposure.
For chromosomal analysis, use a dark green top tube (sodium heparin tube). The light green top tube (lithium heparin with gel) is not acceptable.
Treat patients symptomatically as they occur for nausea, vomiting, diarrhea, fatigue, electrolyte imbalance, and pancytopenia. Treatment should focus on prevention of infection. Antibiotics should be given to sterilize the gut and treat opportunistic infections.
Hematopoietic growth factors should be given within the first 24 to 48 hours and then daily.
Patients with higher exposures will require hospitalization.
The telephone numbers for REAC/TS and MRAT are given in a subsequent slide.

21. Localized Radiation Effects - Organ System Threshold Effects
Skin - No visible injuries < 100 rem
Main erythema, epilation >500 rem
Moist desquamation >1,800 rem
Ulceration/Necrosis >2,400 rem
Cataracts
Acute exposure >200 rem
Chronic exposure >600 rem
Permanent Sterility
Female >250 rem
Male >350 rem
35. Localized Radiation Effects - Organ System Threshold Effects
Partial body radiation can cause localized effects if the dose is sufficiently high.
Radiation doses to the skin can cause reddening of the skin, blistering, and ulceration. Higher doses are required for blistering and ulceration than for skin reddening. This photo is from a patient who had 3 angioplasty procedures under fluoroscopic guidance. It shows deep necrosis of the skin 22 months after an exposure of ~2000 rem.
A patient may present with injuries from exposure to a lost or stolen high-activity commercial radiation source. The patient may not be aware that he or she was exposed. Such a patient may have localized burn-like skin injuries without a history of heat exposure. Epilation, a tendency to bleed, nausea and vomiting and/or other symptoms of the acute radiation syndrome may be present.
Cataracts have developed in some early radiation workers who received high doses to the lens of their eyes.
Loss of fertility has occurred in both males and females whose gonads were exposed to very high doses of radiation.

22. Special Considerations
High radiation dose and trauma interact synergistically to increase mortality
Close wounds on patients with doses > 100 rem
Wound, burn care and surgery should be done in the first 48 hours or delayed for 2 to 3 months (> 100 rem)
Hours
~3 Months
Emergency
Surgery
Hematopoietic Recovery
No Surgery
After adequate
hematopoietic recovery
Permitted
36. Special Considerations
Patients who have suffered trauma (from an explosive or burn) combined with an acute high level exposure to penetrating radiation will have increased morbidity as compared to patients who have received the same dose of radiation without trauma.
If a patient has received an acute dose greater than 100 rad, efforts must be made to close wounds, cover burns, reduce fractures, and perform surgical stabilizing and definitive treatments within the first 48 hours after injury.
After 48 hours, surgical interventions should be delayed until hematopoietic recovery has occurred.

23. Chronic Health Effects from Radiation
Radiation is a weak carcinogen at low doses
No unique effects (type, latency, pathology)
Natural incidence of cancer ~ 40%; mortality ~ 25%
Risk of fatal cancer is estimated as ~ 5% per 100 rem
A dose of 5 rem increases the risk of fatal cancer by ~ 0.25%
A dose of 25 rem increases the risk of fatal cancer by ~ 1.25%
37. Chronic Health Effects from Radiation
High radiation doses have been linked to a modest increase in the incidence of cancer in exposed populations, such as the atomic bomb survivors. At low doses, below about 20 rem, the potential for cancer causation is uncertain and generally believed to be quite small.
The natural incidence of cancer in the population of the United States, over a lifetime, is estimated to be approximately 40% and the risk of mortality is approximately 25%. [Reference - SEER (Surveillance, Epidemiology and End Results) Program of the National Cancer Institute]
Risk of fatal cancer from ICRP Publication 60, pg. 177, 1991; 5% per 100 rem.
There are several sets of recommendations for acceptable doses to emergency workers performing life saving actions. While these doses are 5 to 10 times higher than annual occupational dose limits, it represents a modest increase in cancer risk during life saving measures.
EPA / NRC rem
NCRP / ICRP Approach or exceed 50 rem
(EPA, Manual of Protective Action Guides and Protective Actions for Nuclear Incidents, 1992)
(NCRP Report 116, Limitation on Exposure to Ionizing Radiation, 1993)
(IRCP Report 60, 1990 Recommendations of the International Commission on Radiological Protection, 1991)

24. What are the Risks to Future Children? Hereditary Effects
Magnitude of hereditary risk per rem is ~10% that of fatal cancer risk
Risk to caregivers who would likely receive low doses is very small - 5 rem increases the risk of severe hereditary effects by ~ 0.02%
Risk of severe hereditary effects to a patient population receiving high doses is estimated as ~ 0.4% per 100 rem
38. What are the Risks to Future Children? Hereditary Effects
Concern over radiation-induced hereditary (genetic) effects is quite common due to a century of misrepresentation, by the media and the entertainment industry, of radiation’s ability to produce hereditary effects.
The natural incidence of malformations and genetic disease at 1-2 years of age is 6-10%. (Mossman KL, Hill LT: Radiation Risks in Pregnancy , Obsts Gynecol 60: , 1982)
No direct evidence of hereditary effects exceeding normal incidence have been observed in any of the studies of humans exposed to radiation, even with high doses.
Risk of severe hereditary effects from UNSCEAR Hereditary Effects of Radiation, pg. 2, 2001; % per gray.

25. Fetal Irradiation No significant risk of adverse developmental effects below 10 rem
Weeks After
Fertilization
Period of
Development
Effects
<2
2-7
7-40
All
Pre-implantation
Organogenesis
Fetal
Little chance of malformation
Most probable effect, if any, is death of embryo
Reduced lethal effects
Teratogenic effects
Growth retardation
Impaired mental ability
Growth retardation with higher doses
Increased childhood cancer risk (~ 0.6% per 10 rem)
39. Fetal Irradiation
Termination of pregnancy is NOT justified based upon radiation risks for fetal doses less than 10 rem.
Excess childhood cancer risk is ~0.06% per rem. Normal childhood cancer incidence is 0.075%.
Fetal doses greater than 50 rem can cause significant fetal damage, the magnitude and type of which is a function of dose and stage of pregnancy.
For fetal doses between 10 and 50 rem, decisions regarding termination of pregnancy should be made based upon individual circumstances.