Radiation Exposure and Emergencies
Basic Information for Healthcare Professionals

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By Dennis M. Crean, Jr., BA, Staff Writer

LEARNING OBJECTIVES

Upon completion of this course, you will be able to:

• Define the term “radiation” and describe its types and measurement.
• List several types of radiation emergencies.
• Discuss the health effects of acute and low-level exposure to radiation.
• Describe various healthcare responses to radiation emergencies.

RADIATION BASICS

What Is Radiation?

The term radiation in its most basic sense refers simply to a process in which energy moves through some medium as either waves or particles. Radiation exists naturally throughout the environment as well as being generated by human sources. Radiation falls into two major divisions: nonionizing and ionizing.

Nonionizing radiation is lower in energy; it can cause atoms in a molecule to vibrate. Common forms of nonionizing radiation energy include sound waves, visible light, and microwaves. Examples of human sources include power lines, radio and television broadcasting, and microwave ovens.

Ionizing radiation breaks the bonds in an atom by “stripping” electrons or even breaking up the nucleus, which releases energy in the form of radiation. This in turn can damage living cells and cause health affects. Ionizing radiation is the type generally thought of as “radiation.” Natural sources include radon, which is commonly found in soil, and cosmic (space) radiation, which enters the Earth’s atmosphere from space. Examples of human sources include medical X-rays, some industrial processes, nuclear power plants, and nuclear weapons (EPA, 2011).

Radiation across the electromagnetic spectum. (Source: Environmental Protection Agency.)

Ionizing radiation is emitted both as particles and waves. Alpha particles can travel only a few inches in air. They are not able to penetrate human skin or clothing but can be harmful if inhaled, swallowed, or absorbed through open wounds. Beta particles can travel only a few feet in air and are moderately penetrating, but clothing provides some protection. Gamma and X-ray radiation are emitted as waves and may travel many feet in air and many inches in human tissue. They readily penetrate most materials and are thus sometimes called “penetrating” radiation. (HPS, 2009)

Measuring Radiation

Radiation is commonly measured in the following three ways:

• Amount being given off from a radioactive source
• Amount, or dose, being absorbed by a person
• Risk that a person will suffer health effects (biological risk) from exposure to radiation (CDC, 2006b)

The amount of radiation being emitted by a radioactive material is measured using the conventional unit curie (Ci) or the Système Internationale (SI) unit becquerel (Bq). One Ci is equal to 37 billion Bq. Ci or Bq may be used to refer to the amount of radioactive materials released into the environment. For example, during the Chernobyl power plant accident that took place in the former Soviet Union, an estimated total of 81 million Ci of radioactive cesium (a type of radioactive material) was released.

When a person is exposed to radiation, energy is deposited in the tissues of the body. The amount of energy deposited per unit of weight of human tissue is called the absorbed dose. Absorbed dose is measured using the conventional unit “radiation absorbed dose” (rad) or the SI unit gray (Gy). One Gy is equal to 100 rad.

A person’s biological risk (that is, the risk that a person will suffer health effects from an exposure to radiation) is measured using the conventional unit rem or the SI unit sievert (Sv). One Sv is equal to 100 rem. To determine a person’s biological risk, the absorbed dose is multiplied by a “quality factor” (Q), which depends on the type of radiation and its ability to transfer energy to the cells of the body. Thus, risk in rem = rad X Q.

Some common ways that people are exposed to radiation and the associated doses are shown in the table below.

COMMON RADIATION EXPOSURES

Source of Exposure	Dose (in mrem)	Dose (in mSv)
Source: CDC, 2006b.
Exposure to cosmic rays during a roundtrip airplane flight from New York to Los Angeles	3	0.03
One dental X-ray	4–15	0.04–0.15
One chest X-ray	10	0.1
One mammogram	70	0.7
One year of exposure to natural radiation (from soil, cosmic rays, etc.)	300	3

Radiation Exposure and Contamination

Radiation exposure occurs whenever radiation energy penetrates the body, for example, when receiving a medical X-ray. A person can also be exposed by being close to radioactive material or a contaminated person, place, or thing.

Radioactive contamination occurs when radioactive material is deposited on or in an object or a person. Radioactive materials released into the environment can cause air, water, surfaces, soil, plants, buildings, people, or animals to become contaminated. A person exposed to radiation is not necessarily contaminated. For a person to be contaminated, radioactive material must be on or inside the body.

When radioactive materials—in the form of dust, powder, or liquid—come into contact with a person’s skin, hair, or clothing, he or she is considered externally contaminated. External contamination can be removed by shedding contaminated clothing and/or completely washing off the source of radioactivity. Internal contamination occurs when people swallow or breathe in radioactive materials, or when radioactive materials enter the body through an open wound or are absorbed through the skin.

Internal contamination continues until the radioactive material decays, is flushed from the body by natural processes, or is removed by medical countermeasures. Some types of radioactive materials stay in the body and are transported in the blood to cells, tissues, and organs. Other types are eliminated from the body in blood, sweat, urine, and feces. (CDC, 2006a)

TYPES OF RADIATION EMERGENCIES

Radioactive materials can be released into the environment as the result of an accident, an event in nature, or an act of terrorism. Examples of such releases might include:

• A nuclear power plant accident
• A nuclear bomb explosion
• An accidental release from a medical or industrial device
• Nuclear weapons testing
• An intentional release of radioactive material as an act of terrorism
• A spill or leak of radioactive material during transport

Nuclear Reactor Accidents

Radiation reactor incidents occur almost exclusively at fixed facilities, like nuclear reactors or nuclear power plants. Typically, facility operators and local officials have formal response plans and practice response operations. In some cases, such as the accident at the Fukushima Daiichi nuclear power plant in Japan in 2011, such response plans may be insufficient to address the scope of the emergency.

For accidents at fixed facilities, there is likely to be a window of time before the release of radiation into the environment (as opposed to a nuclear bomb or sabotage, which will likely come without advanced warning).

Accidents at a nuclear reactor can lead to both exposure to radioactivity as well as to contamination. Workers close to the reactor could be contaminated due to external exposure to highly radioactive materials within the reactor or to radioactivity released and dispersed locally in a radioactive cloud, or plume. They may also suffer internal contamination due to ingestion or inhalation.

The general public could be similarly contaminated due to radioactivity released and dispersed widely in the plume. Some radioactive material may attach itself to dust particles in the air and can be carried long distances in the wind. When these particles are caught in precipitation (e.g., rain or snow), they are deposited directly onto the ground and may potentially contaminate drinking water sources and growing food supplies.

Nuclear Bomb Explosion

A nuclear bomb explosion results from the joining or splitting of atoms (called fusion or fission) to produce an intense pulse or wave of heat, light, air pressure, and radiation. When a nuclear device is exploded, it produces a huge fireball that vaporizes everything around, including soil and water, and carries it upward into a mushroom cloud. Radioactive materials in the mushroom cloud then cool, condense, and form into particles (known as “fallout”) that disperse back to the ground. Fallout can be carried long distances on wind currents and end up miles from the site of the explosion, causing the contamination of anything it lands on, including people, plants, and water. (CDC, 2006a)

A nuclear blast causes great destruction, death, and injury, and has a wide area of impact. People may experience skin burns, eye damage due to looking at the blast, and high levels of radiation exposure, including acute radiation syndrome (ARS) (see “Acute Radiation Syndrome” below). Effects may range from mild to severe. Exposure to very large doses of external radiation may cause death within a few days or months. External exposure to lower doses of radiation and internal exposure from breathing or eating food contaminated with radioactive fallout may lead to an increased risk of developing cancer and other health effects.

Terrorist Act

Radioactive material could be dispersed in an act of terrorism. This might include the detonation of a nuclear bomb, which could have the same effects as those described above.

Terrorists might also employ a “dirty bomb,” which is a mix of an explosive such as dynamite with radioactive material. Such a device is not the same as a nuclear bomb and will not create an atomic blast and the associated widespread impact. The main effect of a dirty bomb would likely be bodily injury and radiation exposure limited to those close to the blast site. Any radioactive dust and smoke spread farther away could also be dangerous if inhaled. (CDC, 2006a)

Another potential terrorist act would be to intentionally hide a radioactive device in a public location or release radioactive material into the food or water supply so as to expose people to its effects. Such exposure would likely not result in contamination, and the effects would depend on many factors, such as a person’s proximity to the source, length of exposure, and nature of the source.

Radioactive Spill during Transport

Radioactive material may be released during an accidental spill. For instance, since many states do not permit the storage of radioactive waste and it must be shipped to distant locations, a spill could take place due to an accident during transport. A spill of radiaoactive material may also be caused by damage to a package containing radioactive material.

Strict packaging and labeling requirements are used when shipping radioactive materials to help prevent an accidental radiation release. The risk of exposure or contamination during a spill is dependent on whether any radioactive material is dispersed from the spill site. In all likelihood, healthcare providers along these routes do not ever expect to activate a response plan to such an emergency.

HEALTH EFFECTS OF RADIATION

Any living tissue in the human body can be damaged by ionizing radiation. The severity and types of damage are based on the amount and duration of radiation exposure.

Effects Due to Acute Exposure

Short-term, high-level (or acute) exposure to radiation can cause burns and acute radiation syndrome (ARS, also called “radiation poisoning” or “radiation sickness”). It can also cause premature aging and death. (Medical patients receiving radiation treatments also often experience acute effects because they are receiving relatively high “bursts” of radiation during treatment.)

There is no firm basis for setting a “safe” level of exposure. However, there do appear to be threshold exposures for the various acute effects.

THRESHOLD EXPOSURE FOR ACUTE EFFECTS

Exposure (rem)	Health Effect	Time to Onset (without treatment)
Source: EPA, 2011.
5–10	Changes in blood chemistry
50	Nausea	Hours
55	Fatigue
70	Vomiting
75	Hair loss	2–3 weeks
90	Diarrhea
100	Hemorrhage
400	Possible death	Within 2 months
1,000	Destruction of intestinal lining Internal bleeding Death	1–2 weeks
2,000	Damage to central nervous system Loss of consciousness Death	Minutes Hours to days
Acute effects are cumulative. For example, a dose that produces damage to bone marrow will have produced changes in blood chemistry and be accompanied by nausea.

ACUTE RADIATION SYNDROME (ARS)

Acute Radiation Syndrome is caused when the entire body (or most of the body) is exposed to a high dose of penetrating radiation in a very short period of time. The survivors of the nuclear bombing of Hiroshima and Nagasaki as well as first responders to the reactor accident at Chernobyl in 1986 suffered ARS.

The three classic acute radiation syndromes are bone marrow syndrome (sometimes referred to as hematopoietic syndrome), gastrointestinal syndrome, and cardiovascular/central nervous system syndrome (see table below).

ACUTE RADIATION SYNDROMES (ARS)

	Bone Marrow (Hematopoietic)	Gastrointestinal	Cardiovascular/ Central Nervous System
Source: CDC, 2006b.
Dose	> 0.7 Gy (70 rads) (Mild symptoms may occur as low as 0.3 Gy or 30 rads.)	> 10 Gy (1,000 rads) (Some symptoms may occur as low as 6 Gy or 600 rads.)	> 50 Gy (5,000 rads) (Some symptoms may occur as low as 20 Gy or 2,000 rads.)
Prodromal Stage	Symptoms are anorexia, nausea, vomiting. Onset occurs 1 hour to 2 days after exposure. Stage lasts for minutes to days.	Symptoms are anorexia, severe nausea, vomiting, cramps, diarrhea. Onset occurs within a few hours after exposure. Stage lasts about 2 days.	Symptoms are extreme nervousness, confusion; severe nausea, vomiting, watery diarrhea; loss of consciousness; burning sensations of the skin. Onset occurs within minutes of exposure. Stage lasts for minutes to hours.
Latent Stage	Stem cells in bone marrow are dying, although patient may appear and feel well. Stage lasts 1 to 6 weeks.	Stem cells in bone marrow and cells lining GI tract are dying, although patient may appear and feel well. Stage lasts less than 1 week.	Patient may return to partial functionality. Stage may last for hours but often is less.
Manifest Illness Stage	Symptoms are anorexia, fever, malaise. Drop in all blood cell counts occurs for several weeks.	Symptoms are malaise, anorexia, severe diarrhea, fever, dehydration, electrolyte imbalance.	Symptoms are return of watery diarrhea, convulsions, coma. Onset occurs 5 to 6 hours after exposure.
Recovery/ Prognosis	In most cases, bone marrow cells will begin to repopulate the marrow. Full recovery for a large percentage of individuals from a few weeks up to two years after exposure. Primary cause of death is infection and hemorrhage. Survival decreases with increasing dose; death may occur in some at 1.2 Gy (120 rads); at 2.5–5 Gy (250–500 rads) 50% of the population will die within 60 days. Most deaths occur within a few months after exposure.	A dose of about 10 Gy (1,000 rads) will kill 100% of the exposed population. Death occurs within 2 weeks of exposure due to infection, dehydration, electrolyte imbalance.	Death occurs within 3 days of exposure.

CUTANEOUS RADIATION SYNDROME (CRS)

Cutaneous radiation syndrome can result from acute radiation exposure to the skin, especially due to beta radiation or X-rays. This can also occur when radioactive materials contaminate a patient’s clothes.

Damage to the basal cell layer of the skin by radiation can cause inflammation, erythema (redness), and dry or moist desquamation. Hair follicles may also be damaged, causing epilation (hair loss). A transient and inconsistent erythema (associated with itching) can occur within the first few hours. Then, a latent phase may occur and last from a few days up to several weeks, characterized by intense reddening, blistering, and ulceration of the irradiated site.

In most cases, the skin will heal by regenerative means; however, very large radiation 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.

Effects Due to Low-Dose or Chronic Radiation Exposure

Long-term, low-level (chronic) exposure to radiation can lead to cancer, often considered its primary health effect, due to radiation’s ability to disrupt cells and molecules. Because children are growing more rapidly, with more cells dividing, they stand a greater risk for such health effects. Radiation can also cause changes in DNA, leading to genetic mutations that are passed on to offspring.

Radioactive elements can accumulate in human organs as a result of internal contamination. For instance, ingested radioactive iodine (I-131) will concentrate in the thyroid and can lead to thyroid cancer (see figure below). Similarly, radioactive strontium and radium accumulate in calcium-rich areas, such as bones and teeth, and can lead to bone cancer.

Internal exposure to radioactive iodine-131 through ingestion.
(Source: HHS/National Cancer Institute/Division of Cancer Epidemiology and Genetics.)

RADIATION AND PREGNANCY

Fetuses are highly sensitive to radiation, whether due to external exposure through the mother’s abdomen or to the mother’s internal contamination. Health effects depend on which systems are developing at the time of exposure.

In the first 2 weeks of pregnancy, when the fetus is made up of only a few cells, radiation damage to even one cell can cause the death of the embryo. During early development (weeks 2 to 15), the fetus may face severe consequences, including stunted growth, deformities, abnormal brain function, or cancer that may develop later in life. From week 16 to birth, health effects are unlikely unless the fetus is exposed to a large dose of radiation.

ESTIMATING LOW-DOSE HEALTH EFFECTS

Scientists estimate only a small risk of health effects due to low doses of radiation. For instance, in a group of 10,000 people, 2,000 of them might die of cancer from all non-radiation causes. Accumulated exposure to 1 rem of ionizing radiation in small doses over a lifetime would increase that number by about 5 or 6 people. (Most people receive about 0.3 rem every year from natural sources of radiation.)

Among fetuses, scientists estimate that if 1,000 fetuses between 8 and 15 weeks old were exposed to 1 rem of radiation, 4 fetuses would become mentally retarded. For fetuses between 16 and 25 weeks, it is estimated that 1 of them would become mentally retarded.

Regarding genetic effects, scientists estimate about 50 severe hereditary effects in a group of 1 million live-born children whose parents were both exposed to 1 rem. In comparison, all other causes of genetic effects result in as many as 100,000 severe hereditary effects in 1 million live-born children. These genetic effects include those that occur spontaneously (“just happen”) as well as those that have non-radioactive causes. (EPA, 2011)

INDIVIDUAL RESPONSE TO A RADIATION EMERGENCY

Evacuation and Shelter

In the event of a radiation emergency, such as a nuclear power plant accident or the explosion of a dirty bomb, those nearby may be advised to evacuate the immediate area, “shelter in place,” or go to an emergency shelter. Local authorities will generally alert the public with radio and television messages. Utility companies operating nuclear plants are also required by law to have plans in place for contacting people in the community during an emergency and publicizing its evacuation plans and routes.

SHELTER IN PLACE

The safest initial response for those outside the immediate vicinity of the emergency may simply be to take shelter in place. The walls of a building may block any harmful radiation and reduce exposure. Thus, it is important to stay inside and protect against radioactive materials from entering the building. The CDC (2006a) advises the following:

• Close and lock all windows and doors, and close fireplace dampers.
• Turn off fans, air conditioners, and forced-air heating units that bring air in from the outside.
• Go to a room in the middle of the home or workplace, or go to the basement, if possible. (A shelter should have as few windows as possible.)

It is also recommended to have on hand basic emergency supplies, whether for radiation, severe weather, or any other emergencies. These include food, water, clothing, bedding, radio, flashlights, batteries, etc.

EVACUATING

Since each situation is different, it is important to wait for appropriate information before evacuating. For instance, the direction any radioactive plume is moving will dictate which areas should be evacuated and how people can best avoid the plume. Local authorities will advise the public when to go to an emergency shelter, where the shelter is located, and in which direction to travel when evacuating the area of the incident. Some people may be told not to evacuate, such as children in a school that is miles away and upwind from the incident.

For those evacuating to emergency shelters, they should bring any medicines and a change of clothes. Shelter will have most other supplies that people need. Most emergency shelters will not accept pets.

Limiting Exposure and Contamination

A release of radioactive material can expose people and contaminate their surroundings and personal property. However, it is difficult for people to know when they have contacted radioactive materials because radiation cannot be seen, smelled, felt, or tasted.

People who become externally contaminated may then contaminate other people or surfaces that they touch. Those who are internally contaminated can also expose others through their bodily fluids, which may contain radioactive materials.

For example, people who have radioactive dust on their clothing may spread the radioactive dust when they sit in chairs, hug other people, or even walk through a house. Contaminants can easily fall from clothing and contaminate other surfaces. Homes can also become contaminated with radioactive materials in bodily fluids from internally contaminated people. Making sure that others do not come in contact with bodily fluids from a contaminated person will help prevent contamination of other people in the household.

The CDC (2006a) provides the following recommendations. These steps depend on the nature of the emergency and a person’s location when the incident occurs.

Potassium Iodide (KI) Prophylaxis

In the event of a radiation emergency that involves the release of radioactive iodine (such as an accident at a nuclear power plant or a nuclear bomb explosion), non-radioactive potassium iodide (KI) may be recommended. Taking KI or other iodine substances will saturate the thyroid with iodine, thereby decreasing the amount of radioactive iodine that can be absorbed by it and minimizing or avoiding the subsequent risk of thyroid cancer. KI is most effective if given a few hours before exposure, but it is also effective if given within several hours after exposure. (KI does not provide protection from other types of radiation exposure.)

The need for prophylaxis and/or treatment with potassium iodide will be determined by officials managing the event, and instructions to the general public will be given based on the assessment of risk. Potassium iodide should be taken only on the advice of emergency management officials, public health officials, or a personal physician. There are health risks and side effects associated with taking KI, and it may be harmful to those with an allergy to iodine or certain skin disorders.

The U.S. Food and Drug Administration (FDA) has approved a tablet form and a liquid form of KI for use after a radiation emergency. They have established recommended dosages for all age groups; exceeding this dosage may cause adverse health effects. KI is sold without a prescription.

HEALTHCARE RESPONSE TO A RADIATION EMERGENCY

Provider Protection

Healthcare providers should always utilize appropriate personal protective equipment (PPE) when evaluating and treating patients known or suspected to be contaminated with radioactive material. Additionally, a personal radiation dosimeter should be worn by all providers, including first responders, to monitor radiation exposure.

Film badge (left) and ring badge (right) dosimeters. (Source: OSHA.)

Pregnant healthcare providers should not be permitted to work in pre-decontamination or decontamination areas, areas where internally contaminated patients are cared for or housed, or areas where there are elevated levels of environmental radiation.

Healthcare providers should be organized in order to minimize exposures to team members by frequently monitoring individual team member radiation doses and rotating teams and team members away from high radiation dose fields.

First Response

In radiation emergencies, first responders must consider certain specific issues, including the use of additional personal protective equipment and triaging, treating, and transporting potentially contaminated individuals (DHHS, 2011).

The choice of PPE is made by incident commanders and is proportional to the level of risk. In addition to a personal radiation dosimeter, PPE may include both respiratory and dermal protective equipment, which can guard against external and internal contamination via inhalation, ingestion, or absorption through open wounds. However, PPE cannot protect against exposure from high-energy penetrating forms of radiation associated with such emergencies. Responders should thus follow worker exposure guidelines to limit total exposure time. They can also reduce exposure by remaining in shielded areas.

After performing life-saving tasks, first responders manage radiation-related problems. Triage protocols may begin with evaluating people for contamination and be followed by decontamination (see “Decontamination” below). For those requiring further care, medical facilities should be notified of the number, type, and severity of casualties to be transported.

Transport of those who are exposed but not contaminated does not require protection of the vehicle or personnel. Transport of those who are contaminated does require protective measures, including covering any litter and gurney with sheets/blankets, removing the victim’s contaminated outer clothing, closing all open compartments within the vehicle, and using disposable equipment when possible. (The above are general recommendations; detailed local protocols should always be followed.)

Decontamination

Beyond the steps listed above for individual self-decontamination, decontamination of victims of radiation emergencies may be carried out by healthcare personnel. Decontaminating the skin and body will lower the risk of acute dermal injury, internal contamination, and contamination of medical personnel and the environment.

The U.S. Department of Health and Human Services (2011) provides detailed protocols for decontamination procedures. Following is a brief summary of general recommendations. In the case of mass casualty events and a large number of individuals seeking treatment, these recommendations may require major modification.

• Begin by carefully removing all of patients’/victims’ clothing or have patients/victims undress themselves, working from head to toe.
• Place all property of each patient/victim in a single, airtight container (e.g., property bag); label and store the bag properly.
• Perform a whole-body radiation survey (see “Performing a Survey for Radiation Contamination” below).
• Conduct decontamination in the following order: whole body, radioactive shrapnel, open wounds, body orifices (nose, mouth, ears), and localized intact contaminated skin starting with area of highest contamination noted on radiation body survey.

When treating shrapnel and open wounds, it is important to consider them contaminated until proven otherwise. It should also be assumed that embedded foreign bodies and wound contamination will produce uptake (internal contamination), and such patients should be assessed for internal contamination as well. When decontaminating open wounds, providers can limit the spread of radioactivity by carefully capturing water run-off during wound irrigation and by using waterproof dressings.

Since uptake of radioactive material may be faster through membranes than through intact skin, it is important to decontaminate body orifices before intact skin. Orifices should first be assessed to determine likelihood and extent of internal contamination. An ear syringe can be used to rinse the external auditory canal (only if the tympanic membrane is intact). Tooth brushing, frequent mount rinsing, and gargling with 3% hydrogen peroxide solution can be encouraged for oral decontamination. The eyes can be gently irrigated with copious amounts of saline or water if corneal contamination is present and the globe is intact.

To decontaminate localized areas of the skin, healthcare providers first mark (using a waterproof felt tip marker) any areas of high-level contamination found during the whole-body radiation survey. Decontamination should begin with areas of highest contamination by either gently brushing the skin surface or washing with tepid water and soap without damaging or abrading the skin. Recontamination can be avoided by directing contaminated waste water away from the patient and using serial washcloths, gauze pads, or surgical sponges. When removing all contamination from the skin is not feasible or desirable, residual contamination can be covered with waterproof dressings/drapes in order to limit its spread.

Patient Management for Acute Exposure

For patients with acute radiation exposure, additional treatment recommendations include:

• Supportive care in a clean environment (if available, the use of a burn unit may be effective)
• Prevention and treatment of infections
• Stimulation of hematopoiesis (red blood cell formation) by use of growth factors
• Stem cell transfusions or platelet transfusions (if platelet count is too low)
• Psychological support
• Careful observation and documentation for erythema, hair loss, skin injury, mucositis, parotitis, weight loss, or fever
• Confirmation of initial radiation dose estimate using chromosome aberration cytogenetic bioassay when possible (although resource intensive, this is the best method of dose assessment following acute exposures)
• Consultation with experts in radiation accident management

Certain drugs are also used to treat some instances of internal contamination. This includes the use of potassium iodide (see “Potassium Iodide (KI) Prophylaxis” above) as well as the following treatments. Since not all treatments are effective for all types of radiation contamination, it is important to follow the guidance of doctors and public health authorities.

PRUSSIAN BLUE (RADIOGARDASE)

Prussian blue, typically taken in capsule form, has been used since the 1960s to treat those who have been internally contaminated with radioactive cesium (and nonradioactive thallium). Originally produced as a dye, this substance traps these elements in the intestines and prevents their reabsorption into the body while they are being excreted in bowel movements. Prussian blue also reduces the biological half-life (the time required for one half of a substance to be expelled from the body by natural metabolic processes) from 110 to 30 days, thereby decreasing the body’s exposure time to radiation.

Prussian blue (or Radiogardase) is available only by prescription and should be taken only under a physician’s supervision. It is considered safe for most adults, including pregnant women, and children ages 2–12 years. Upset stomach and constipation are the most common side effects, and individuals suffering from constipation or other stomach or intestinal problems should notify their doctor of this before taking Prussian blue.

DPTA

DPTA is a chelating agent used since the 1960s to treat internal contamination. It is currently approved for use in cases involving radioactive plutonium, americium, and curium. As a chelating agent, DPTA binds to these radioactive materials and is then excreted from the body in the urine. There are two forms: calcium (Ca-DPTA) and zinc (Zn-DPTA). Within the first 24 hours after contamination, Ca-DPTA is 10 times more effective, and after 24 hours, the two forms are equally effective.

DPTA is administered by direct injection, intravenous drip, or an inhaled mist or spray. It can be given to adults and children of all ages, with the dose based on size and weight. The length of treatment depends on the level of radioactive contamination. There are limited contraindications, and side effects may include nausea, vomiting, diarrhea, chills, fever, itching, muscle cramps, headache, lightheadedness, chest pain, and a metallic taste in the mouth.

FILGRASTIM (NEUPOGEN)

Filgrastim (trade name Neupogen) was approved by the FDA in 1991 for cancer patients to help in the recovery of bone marrow damage due to chemotherapy or radiation therapy. Neupogen can be used in patients exposed to very high doses of radiation in order to stimulate the growth of white blood cells, thereby reducing the risk of infection.

Neupogen is administered by injection or intravenous infusion. It may be prescribed for most adults, however children, pregnant women, and breastfeeding women should take it with caution. There are limited contraindications, and side effects may include fever, diarrhea, skin rash, weakness, and mild to moderate bone pain.

Monitoring Radiological Incidents

The U.S. Environmental Protection Agency (EPA) monitors and tracks radiation across the nation, both at the time of any radiation emergency and on an ongoing basis.

The agency’s Radiological Emergency Response Team (RERT) can travel to the scene of an incident in order to detect localized radiation. Hand-held equipment is used to measure levels of radiation that may threaten the safety of responders or the public. Air samplers are placed away from the immediate incident to monitor the spread of radioactive materials. Mobile Environmental Radiation Laboratories (MERLs) are also deployed to sites in the United States in order to test samples taken from the environment.

The EPA’s RadNet system consists of a nationwide network of sampling stations that operates constantly to monitor samples of air, drinking water, precipitation, and other media where radiation may be present. By plotting sampling results, RadNet can detect the path of a contaminant plume due to large-scale radiation releases due to emergencies, such as that at the Fukushima nuclear plant in Japan in 2011.

The safety of food products is monitored by the U.S. Food and Drug Administration (FDA). This includes regulating, tracking, and radiation screening of food shipments into the country as well as inspecting and analyzing food and animal feed domestically. The FDA also works with other agencies as part of the Food Emergency Response Network (FERN).

FREQUENTLY ASKED QUESTIONS