Radiation 101

Radiation is energy that can be characterized as waves or particles trying to become stable. Radioactive materials contain energized atoms that are unstable and release energy. This energy may damage certain critical cellular structures, causing a cell to malfunction or die and may also interact with water molecules in the body to create unstable, hyperoxide molecules causing further damage. (See the sidebar for characteristics of ionizing radiation.)

Every year, people worldwide are exposed to naturally occurring background radiation from the sun, outer space, and radioactive materials in the soil. The average U.S. resident receives a background radiation dose from all sources of about 100 millirems.⁶ Man-made sources of radiation include some industrial measurement devices and radiotherapeutics used for medical diagnoses and treatment. Sources of radioactive materials include nuclear power plants, nuclear waste processors, university research centers, medical radiotherapy clinics, and even industrial complexes.¹

The gray (Gy) is a unit of measure for absorbed dose and reflects the amount of energy deposited into a mass of tissue (1 Gy = 100 rads). The U.S. annual occupational exposure allowed by the Department of Energy for those who work with and around radioactive materials is 0.05 Gy [1] (or 15,000 millirems).⁶

Weapons of mass destruction

There are four general scenarios you consider when classifying radiological weapons of mass destruction (WMD).⁷ The four scenarios are examined here in order of least likely to occur to more likely to occur.

Nuclear bombs or improvised nuclear devices (IND), also known as suitcase nukes, require high-grade radioactive fissionable materials and the scientific and technical sophistication to assemble the components for detonation. Nuclear devices create a tremendous blast, extreme heat, and a significant dose of radiation to those in close proximity (two miles for an IND and more than 50 miles for a 1 kiloton nuclear bomb).^1,8 The purchase and transportation of fissionable materials are highly regulated in most countries, which significantly limits their availability. This type of an event is extremely unlikely.

In the history of the nuclear power industry, industrial accidents involving nuclear power plants have been rare. Nuclear plants have a number of redundant safety systems to take a plant off-line as well as well-exercised emergency plans involving local authorities (police, fire, and EMS). Their physical structures have been bolstered to prevent accidental releases, even from a terrorist attack.

There have been a few reports of hidden, or “silent,” sources, defined as a radioactive source that is lost or abandoned, or intentionally placed in areas to expose people. By placing a source on mass transportation, such as under a subway seat or in a large movie theater, a large numbers of casualties could occur over time.

Finally, radiological dispersion devices, or dirty bombs, combine an ordinary explosive with a radioactive material. Although there has been no documented use to date, it is believed that a dirty bomb could be constructed with radiologic materials found in common use. Materials such as Cesium 137 and Cobalt 60, frequently found in medical teletherapy, and Iridium 192, found in industrial instrumentation, can be purchased legitimately or illegitimately, or stolen.^1,2

While it is unlikely that a dirty bomb would cause large numbers of actual radiation casualties, detonation of one would likely result in panic and economic disruption.²

How radiation affects the body

Exposure occurs when all or part of the body is exposed to penetrating radiation. We subject patients to exposures every day when we perform a CT scan or an X-ray. The radiation is either absorbed or passes completely through. Once removed from the source, the patient is not radioactive and can be treated like any other patient.^5,7,9

Contamination is radioactive material where it does not belong. It can be a solid, liquid, or gas — or even dust particles that float through the air and eventually settle on the ground or some other surface. External contamination is radioactive material on the outside of the body, usually on the skin or on clothing. It can be easily removed by removing clothing and washing the skin with soap and water. Internal contamination involves the deposition of radioactive material inside the body through inhalation, ingestion, or penetrating wounds.^5,7

Incorporation is the uptake of radioactive materials by body cells, tissues, and target organs, such as bone, the liver, the thyroid, or the kidney, causing chemical changes at the cellular level. Incorporation cannot take place unless contamination occurs.⁵ Cells that replicate rapidly, such as spermatocytes, blood elements, and intestinal crypt cells, are very sensitive. Lymph tissue and bone marrow are the most radiation-sensitive tissues. The most radiation sensitive organs are the skin, intestines, kidneys, and gonads.^6,9

Radiation can affect the body in a number of ways, and harmful health consequences may not be seen for many years.⁷ Effects depend on the amount of radiation absorbed by the body (the dose), the type of radiation, the route of exposures, and the length of time a person is exposed. Effects can be mild, such as reddening of the skin, or serious, such as cancer and even death.¹⁰ Special populations that are more radiation-sensitive include those under 12 years of age. and pregnant women because of their rapidly growing tissues, those over the age of 60 because of declining immune systems and co-morbidities, and those with pre-existing conditions that may result in immunosuppression, blood loss, or infectious complications. The human embryo and fetus are particularly sensitive to ionizing radiation, and the health consequences of exposure can be severe, even at radiation doses too low to immediately affect the mother. Consequences can include growth retardation, malformations, impaired brain function, and cancer. At higher doses, the health effects depend on dose and the stage of gestation.^9,11

Nursing considerations

The Joint Commission requires facilities it accredits to exercise emergency plans for radiologic incidents that use the Incident Command System (ICS).⁹ Plans should involve hospital radiation experts, such as the radiation safety officer, health physicists, and medical physicists. These experts can help hospital staff document the presence of radioactive materials, activity levels, and accident details; collect samples that document contamination; assist in decontamination procedures; conduct and document dose calculations; and dispose of radioactive wastes.

Other federal guidelines exist. For example, the Occupational Safety and Health Administration recently published mass casualty guidelines addressing protection for first responders during releases of chemicals, radiological particles, and biological agents (overt releases) that produce victims who may need decontamination before medical care is administered.¹²

Protecting yourself

First and foremost, remember that no healthcare provider has ever received a significant radiation exposure by treating a contaminated patient.^5,9 Protection involves limiting your radiation exposure, using personal protective clothing, and controlling contamination. You can reduce your exposure through time, distance, and shielding. Limit time near a radiation source, increase your distance from the source, and use shielding between you and the radiation source.⁷

Protective clothing in a radiation emergency is similar to that used in universal precautions and includes gowns, caps, masks, splash shields, and waterproof boots.^5,7,9 All open seams and cuffs should be taped using masking or adhesive tape. Two pairs of gloves should be worn. The first pair, preferably colored, should be worn under the arm cuff of the outer gown and secured by tape. The second pair of gloves should be easily removable and replaced if they become contaminated. The outer gloves should preferably be white to clearly show if the outer glove has been removed and not replaced. A radiation dosimeter should be assigned to each team member and attached to the outside of the surgical gown at the neck, where it can be easily removed and monitored by a radiation safety officer. Waterproof aprons can be worn when using liquids for decontamination.^5,7

The Nuclear Regulatory Commission limits the exposure of pregnant workers to 5 mGY for the entire pregnancy.⁹ Therefore, during a radiation emergency, pregnant hospital workers should be reassigned to areas where exposure is unlikely.

Remember, unlike most hazardous materials, radioactive material can be easily detected, even in small quantities, with a simple and readily available survey meter, such as a Geiger counter.⁷ The purpose of donning extra clothes is to give yourself a layer of clothing to keep your own clothes and body from becoming contaminated.

Organizing for an incident

Detailed response procedures are beyond the scope of this module; however, the website of the Radiation Emergency Assistance Center/ Training Site (REAC/TS) at the Oak Ridge Associated Universities http://orise.orau.gov/reacts has demonstrations of using protective clothing, prepping a treatment area, removing contaminated clothing, surveying for contamination, and decontamination procedures for wounds and intact skin. See the sidebar for more information.

If your hospital receives advance notification, you should carry out your hospital’s radiation emergency plan. Your primary goal should be to provide patient care while limiting the spread of contamination. Preparation is great if you have the time, but if an unstable patient arrives, the priority is to stabilize the patient.

Select a treatment area near an outside entrance. Remove equipment that will not be needed and assemble additional required items. This will include a survey meter (Geiger counter), extra 4x4s, ABD pads, small and large sample bags, surgical drapes, tape, and irrigation solution. You will also need a number of large, plastic-lined waste containers. Treatment beds should be covered with several layers of waterproof sheets that can be removed as you decontaminate the area.

Check your survey meter to obtain and record a background reading. This reading will be used to compare readings with the patient. The goal for removing contamination is to get as close to the background level as possible. The average background reading is 20 to 60 counts per minute.⁵

REAC/TS gives the following guidelines:⁵

General:

• If in doubt, assume contamination.
• Avoid contact with contaminants.
• Do not eat, drink, or smoke in areas where radioactive materials are located.
• Wear protective clothing.

When providing emergency care:

• Set up a controlled area large enough to hold the anticipated number of victims.
• Prevent tracking of contaminants by covering the floor areas with paper if your hospital plan calls for it. Some hospitals with nonporous floors like linoleum have made the decision not to cover them.
• Monitor and restrict access to the controlled area with security personnel.
• Use a buffer zone or secondary control line for added security.
• Use a radiation meter and assess anyone or anything leaving the controlled area to prevent further contamination, taking special care with hands, feet, and face. People exhibiting radiological contamination must remain in their controlled area until they can be sufficiently decontaminated or wrapped in sheets if their medical condition requires their emergent movement to another section of the hospital.
• Use strict isolation precautions, including double bagging of all wastes and protective clothing.
• Control waste by using large, plastic-lined containers for clothing, linens, dressings, etc.
• Control ventilation to prevent airborne contamination.
• Survey hands and clothing with radiation meters at frequent intervals. Change instruments, outer gloves, drapes, etc., when they become contaminated or when preparing to touch “clean” areas.
• Use waterproof materials to limit the spread of contaminated liquids, for example, waterproof surgical drapes.

Triage

Triage evaluates and sorts victims for priority in treatment to do the greatest good for the most people.⁹ In many radiological events, the vast majority of people involved will be exposed to very low doses of radiation (if they are exposed at all). In these cases, there will be no immediate effects, with a potential for delayed effects depending on the dose received. Remember that if a patient has only been exposed and does not have radioactive material on his or her  person, there is no need to take any unusual precautions.⁵ Such patients can be cared for like any other emergency case.

People who are uninjured or minimally injured and stable should be evaluated at the scene. Removal of clothing and washing the skin with warm soap and water is 95% effective in removing contamination.¹

Some people may be exposed to doses large enough to cause immediate effects. The onset of nausea, vomiting, fatigue, and anorexia within hours usually indicates a significant and lethal radiation dose.^7,9

Most patients in the immediate vicinity of a dirty bomb will present with symptoms of blast or burn (chemical or thermal) injury in addition to radiation exposure.⁹ Patients who have combined injury will experience a greater morbidity than patients who received the same dose of radiation without trauma.

Assessment and treatment of serious medical problems is the No.1 priority.^5,7 Never delay critical interventions because you are concerned about contamination. Patients with life-threatening presentations, such as a compromised airway or severe hemorrhage, should receive enough immediate treatment to preserve life and to stabilize them. While the health team conducts the standard ABCs of triage, the radiation safety officer will quickly survey the patient. A quick survey tells you if you are dealing with a contaminated patient.

Once stabilized, patients should have all their clothes removed for a more definitive survey. Care should be taken not to spread the contamination around. Clothing should be cut off, not ripped, from head to foot (away from the airway) and rolled outward so that the outer surface, which  is most likely more contaminated, is rolled away from the patient. Before log rolling the patient, you should change your gloves because you have touched the patient’s outer garments and are likely contaminated. Sheets and clothing should be double bagged, labeled, and removed from the treatment room to prevent them from causing inaccurate survey readings.

Decontamination involves removing external contamination. It is conducted first in open wounds, then in or near body orifices, and finally on intact skin.5 Open wounds are a direct pathway for internal contamination and should be decontaminated as soon as medical priorities permit. Decontamination of intact skin can be delayed because most radioactive materials are not readily absorbed through intact skin in the first hour after contact.

Decontamination involves simple irrigation or gentle washing with soap and water starting at the outside of the area and circling inward. First washes have the greatest chance of removing large amounts of contaminated material. Do not scratch or abrade intact skin while trying to clean it or you risk internal contamination. Care must be taken not to spread contamination through splashes or water spills. Field dressings and embedded particles should be removed using tongs to maintain as much distance between a possible source and your fingers as you can. Decontamination should continue until efforts are no longer giving you lower survey readings. Decontaminated wounds should be bandaged with sterile waterproof dressings.⁵

The dose received is determined by dosimeter readings; biological changes are determined by methods including lab tests and accident reconstruction models.^9,13 Dose can be estimated by observing the onset of signs and symptoms, especially vomiting, and observation of lymphocyte depletion.^1,7 Elements of the history most important in helping with dose calculations are presence of nausea; vomiting (start date, time, and severity); tachycardia; fatigue; weakness; abdominal pain; headache; fever; and drug therapy and the results of any cytogenetics. Note any recent nuclear medicine tests. See table for the specimens that help assess radiation injury.

Initial care

If a patient has received an acute dose greater than 1 Gy (100 rad), efforts must be made to close wounds, cover burns, reduce fractures, and perform surgical definitive treatments within 48 hours after injury, before pancytopenia, immunosuppression, and delayed healing occur. After 48 hours, surgical interventions should be delayed until hematopoietic recovery has occurred, which usually takes about three months.⁹

Definitive care options

Patients with higher exposures will require hospitalization. Because they will be immunosuppressed, consider the use of a burn unit. Treatment is symptomatic and should target the prevention of infection. Antibiotics should be given to sterilize the gut and treat opportunistic infections. Hematopoietic growth factors to stimulate blood cell production should be given within the first 24 to 48 hours and then daily.^6,13

Acute radiation syndrome

Acute radiation syndrome (ARS) is characterized by the following: the radiation dose must be large (greater than 0.7 Gy or 70 rads); the dose usually must be external; the radiation must be penetrating; the entire body or a significant portion of it must have received the dose; and the dose must be delivered in a short time. ARS usually has four stages, whose length and severity depend on the dose received:

• Prodromal stage: the classic symptoms for this stage are nausea, vomiting, and possibly diarrhea beginning from within minutes to up to days after the exposure.
• Latent stage: In this stage, the patient generally looks and feels better. This stage can last for a few hours or a few weeks.
• Manifest illness state: Symptoms are dose-dependent and determined by the type of specific syndrome the patient is exhibiting. This stage may last from hours up to several months.
• Recovery or death: For those who recover, the process may last from several weeks up to two years. Those who do not recover will die within several months of exposure.

Where you can learn more

Several websites contain excellent information that can be used to augment your knowledge or serve as “just in time” learning if you are confronted with a radiation emergency.

• Radiation basics: http://orise.orau.gov/reacts/guide/index.htm
• Radiation emergencies: www.bt.cdc.gov/radiation/
• Hospital triage in the first 24 hours after a nuclear or radiological incident: http://orise.orau.gov/reacts/files/triage.pdf
• Acute radiation syndrome: www.bt.cdc.gov/radiation/arsphysicianfactsheet.asp
• Prenatal radiation exposure: www.bt.cdc.gov/radiation/prenatalphysician.asp
• Software to record radiological incidents and assess dose rates: www.afrri.usuhs.mil/
• Procedures for patient care in case of terrorism with ionizing radiation: www.afrri.usuhs.mil/www/outreach/pdf/pcktcard.pdf
• Procedures for managing radiation emergencies: http://orise.orau.gov/reacts/guide/index.htm

Several universities and federal agencies offer Web-based classes that provide continuing education credit at no cost. Examples include:

• The Emergency Management Institute (part of the Federal Emergency Management Agency of the Department of Homeland Security) offers a wide variety of courses: http://training.fema.gov/EMIWeb/IS/crslist.asp.
• The Centers for Disease Control and Prevention has offered two Web-based courses on treatment of radiological patients. The “Role of Public Health in a Nuclear or Radiological Terrorist Incident” can be found at www2a.cdc.gov/phtnonline/registration/detailpage.asp?res_id=1133 and “Medical Response to Nuclear and Radiological Terrorism” is at www2a.cdc.gov/PHTNOnline/registration/detailpage.asp?res_id=905.
• The University of Albany offers “Terrorism, Preparedness and Public Health: An Introduction,” a six-module course that includes a section on radiological weapons: www.ualbanycphp.org/learning/registration/detail_Terrorism.cfm.
• The Health Alert Network site contains links to recent CDC news releases and to the Public Health Training Network, both providing up-to-date information to medical professionals. The site also maintains a jurisdictional map with links to state and federal public health agencies and an archive of health messages:  www2a.cdc.gov/han/Index.asp.

Serious medical problems always have priority over radiological concerns, and  immediate attention is given to life-threatening problems. As mentioned, no healthcare provider has ever received a significant radiation exposure by treating a contaminated patient. Initial and definitive care is symptom driven and supportive. Most importantly, managing a radiation incident involves preparation, planning, practice, and the realization that contaminated patients do not present an immediate threat, but simply require special handling. While it is impossible to prevent radiological incidents, it is possible to raise awareness and set in place emergency plans and systems that allow for activities to prepare for and respond to future radiological emergencies.