The Principles of Radiation Safety

Since humankind harnessed the power of the atom, the hazards of radiation have always been real. A radiation leak does not have to be on the same scale as that of the Chernobyl nuclear plant disaster in the former Soviet Union. Even small leaks of radioactive material can lead to serious health effects, including nausea, weakness, hair loss, skin burns and even cancer and changes in DNA.

Radiation Essentials

• Radiation is energy emitted in the form of microscopic particles known as photons. Radiation is invisible to the human eye, and can be measured only with a special device such as an ionization chamber or a Geiger counter. Although radiation can occur naturally -- e.g., in the form of uranium and thorium in rock and soil -- it is more dangerous when radioactive material produced through nuclear fission leaks. Such radiation can come from nuclear reactors, nuclear weapons and fission-created radioactive substances such as cobalt-60, or Co-60; iodine-131, or I-131; cesium-137, or Cs-137; and from X-rays and particle accelerators.

First-Aid

• Being aware of what to do when you are exposed to radiation may one day save your own life or those of other people. First, quickly leave the area where exposure occurred. Take off your contaminated clothing and place it in a sealed container, if possible, to prevent further contamination. Next, wash your body vigorously with soap and water. If your exposure was severe or of long duration, seek emergency medical treatment.

Potassium Iodide

• Some medicines can help you get some types of radiation out of your body. One is potassium iodide, or KI, which is available in tablet form. This medication can be effective, but only in preventing thyroid cancer in cases of exposure to radioactive iodine. Ideally, take potassium iodide three hours before exposure to radioactive iodine or, if that is not possible, within 10 hours after exposure. According to the World Health Organization, adults and adolescents should receive 130 mg of the substance, children ages 3 to 12 should get 65 mg of potassium iodide, and infants older than 1 month should be given 32.25 mg, or a half-tablet. Give babies under 1 month of age a quarter-tablet.

Health Effects

• The health effects of exposure to radiation depend on the nature of the exposure, taking into account factors such as duration and severity. Exposure to radiation is measured in gray, symbol Gy, which is a unit of radiation dosage. Temporary sterility in men occurs at a radiation level of 0.15 Gy, while a person becomes permanently sterile if exposed to radiation of 3.5 to 6 Gy. Depression of the blood-forming process is observed at 0.5 Gy, while bone marrow syndrome develops at a radiation exposure of 3 Gy to 5 Gy. In addition, exposure to radiation may lead to bleeding from the nose, mouth, gums and rectum. Dehydration, diarrhea and fainting can also occur. Other symptoms of radiation sickness include fatigue, hair loss, nausea and vomiting, open sores on the skin, and ulcers in the esophagus, stomach or intestines. The person may also vomit blood and feel weak.

Protection

• Radiation protection rests on three pillars: time, distance and shielding. Essentially, the less time a person is exposed to radiation, the lower is the dose he receives. Distance from the source of radioactive material also matters: in general, the greater the distance, the less the exposure. Shielding refers to the creation of a "biological shield," or materials that can absorb the radiation to help reduce human exposure. Water, graphite and concrete are used to shield against neutron radiation, while lead and steel are employed as shields from gamma radiation.