Radiation
A Radiation Resource Guide
The American College of Radiology has posted to its Web site a primer designed to help
medical professionals and emergency personnel manage a radiological disaster or terrorist
attack. The document offers guidance on preparedness, handling contaminated persons and
the consequences of radiation exposure. It also includes information on radiological
findings related to agents that could be used in a biological or chemical attack. The
primer, titled "Disaster Preparedness for Radiology Professionals: Response to
Radiological Terrorism," is at www.acr.org under "Disaster Planning
Information." The guide was developed by ACR with the American Society of Therapeutic
Radiology and Oncology and the American Association of Physicists in Medicine.
What is Radiation?
Radiation is energy that comes from a source and travels through some material or through
space. Light, heat and sound are types of radiation. The kind of radiation described here
is called ionizing radiation because it can produce charged particles (ions) in matter.
Ionizing radiation is produced by unstable atoms. Unstable
atoms differ from stable atoms because they have an excess of energy or mass or both.
Unstable atoms are said to be radioactive. In order to reach stability, these atoms give
off, or emit, the excess energy or mass.
These emissions are called radiation.
The kinds of radiation are electromagnetic (like light) and
particulate (i.e., mass given off with the energy of motion). Gamma radiation and X-rays are examples of
electromagnetic radiation. Beta and alpha radiation are examples of
particulate radiation. Ionizing radiation can also be produced by devices such as X-ray
machines.
How is Radiation a threat?
Regardless of where or how an accident involving radiation happens, three types of
radiation-induced injury can occur: external irradiation, contamination with radioactive
materials, and incorporation of radioactive material into body cells, tissues, or organs.
External Irradiation
External irradiation occurs when all or part of the body is exposed to penetrating
radiation from an external source. During exposure this radiation can be absorbed by the
body or it can pass completely through. A similar thing occurs during an ordinary chest
x-ray. Following external exposure, an individual is not radioactive and can be treated
like any other patient. (Refer to the sections on assessment and treatment in Hospital Emergency Care of the Radiation
Accident Patient.)
Contamination
The second type of radiation injury involves contamination with radioactive
materials. Contamination means that radioactive materials in the form of gases, liquids,
or solids are released into the environment and contaminate people externally, internally,
or both. An external surface of the body, such as the skin, can become contaminated, and
if radioactive materials get inside the body through the lungs, gut, or wounds, the
contaminant can become deposited internally. Refer to Managing Emergencies Involving Radiation
for additional information.
Incorporation
The third type of radiation injury that can occur is incorporation of radioactive
material. Incorporation refers to the uptake of radioactive materials by body cells,
tissues, and target organs such as bone, liver, thyroid, or kidney. In general,
radioactive materials are distributed throughout the body based upon their chemical
properties. Incorporation cannot occur unless contamination has occurred. (Refer to the
section on assessment and treatment of the contaminated patient in Hospital Emergency Care of the Radiation
Accident Patient.)
These three types of exposures can happen in combination and can be complicated by
physical injury or illness. In such a case, serious medical problems always have priority
over concerns about radiation, such as radiation monitoring, contamination control, and
decontamination. |