Radiation Injuries Health Article

Occupational radiation exposure

Specialists in industrial and occupational health are increasingly aware of the rising number of injuries related to on-the-job radiation exposure. One study of Swedish workers exposed to high levels of low-frequency magnetic fields found an increased incidence of kidney, liver, and pituitary gland tumors among the men, and a higher rate of leukemia and brain tumors among the women.

Sadly, the delayed effects of occupational radiation exposure have also delayed the adoption of necessary protection for workers at risk. A study of the high rate of lung cancer among Navajo Indians who worked in uranium mines during World War II did not bring about even partial protection for the miners until 1962. It was not until 1990 that Congress passed the Radiation Exposure Compensation Act to provide care for the injured miners. he effects of cosmic radiation on human beings are also being investigated because of concern for the safety of air crew. Although findings are still inconclusive as of 2002, recent reports of an increased incidence of cancer among airline pilots and cabin crew members have led epidemiologists to study the long-term effects of cosmic radiation at the altitudes of modern aircraft flight.

Radiation exposure from nuclear accidents, weaponry, and terrorist acts

Between 1945 and 1987, there were 285 nuclear reactor accidents, injuring over 1,550 people and killing 64. The most striking example was the meltdown of the graphite core nuclear reactor at Chernobyl in 1986, which spread a cloud of radioactive particles across the entire continent of Europe. Information about radiation effects is still being gathered from that disaster, however 31 people were killed in the immediate accident and 1,800 children have thus far been diagnosed with thyroid cancer. In a study published in May 2001 by the British Royal Society, children born to individuals involved in the cleanup of Chernobyl and born after the accident are 600% more likely to have genetic mutations than children born before the accident. These findings indicate that exposure to low doses of radiation can cause inheritable effects.

Since the terrorist attack on the World Trade Center and the Pentagon on September 11, 2001, the possibility of terrorist-caused nuclear accidents has been a growing concern. All 103 active nuclear power plants in the United States are on full alert, but they are still vulnerable to sabotage such as bombing or attack from the air. A nofly zone of 12 miles below 18,000 feet has been established around nuclear power plants by the Federal Aviation Administration (FAA). There is also growing concern over the security of spent nuclear fuel—more than 40,000 tons of spent fuel is housed in buildings at closed plants around the country. Unlike the active nuclear reactors that are enclosed in concrete-reinforced buildings, the spent fuel is stored in non-reinforced buildings. Housed in cooling pools, the spent fuel could emit dangerous levels of radioactive material if exploded or used in makeshift weaponry. Radioactive medical and industrial waste could also be used to make "dirty bombs." Since 1993, the Nuclear Regulatory Commission (NRC) has reported 376 cases of stolen radioactive materials.

One response on the part of health care workers has been stepped-up training in radiation disaster management. Emergency department personnel are being trained as of 2002 to use radiologic monitoring and other specialized equipment for treating victims of a terrorist attack involving radiation.

Causes & symptoms

Radiation can damage every tissue in the body. The particular manifestation will depend upon the amount of radiation, the time over which it is absorbed, and the susceptibility of the tissue. The fastest growing tissues are the most vulnerable, because radiation as much as triples its effects during the growth phase. Bone marrow cells that make blood are the fastest growing cells in the body. A fetus in the womb is equally sensitive. The germinal cells in the testes and ovaries are only slightly less sensitive. Both can be rendered useless with very small doses of radiation. More resistant are the lining cells of the body—skin and intestines. Most resistant are the brain cells, because they grow the slowest.

The length of exposure makes a big difference in what happens. Over time the accumulating damage, if not enough to kill cells outright, distorts their growth and causes scarring and/or cancers. In addition to leukemias, cancers of the thyroid, brain, bone, breast, skin, stomach, and lung all arise after radiation. Damage depends, too, on the ability of the tissue to repair itself. Some tissues and some types of damage produce much greater consequences than others.

There are three types of radiation injuries.

• External irradiation: as with x-ray exposure, all or part of the body is exposed to radiation that either is absorbed or passes through the body.
• Contamination: as with a nuclear accident, the environment and its inhabitants are exposed to radiation. People are affected internally, externally, or with both internal and external exposure.
• Incorporation: dependent on contamination, the bodies of individuals affected incorporate the radiation chemicals within cells, organs, and tissues and the radiation is dispersed throughout the body.

Immediately after sudden irradiation, the fate of those affected depends mostly on the total dose absorbed. This information comes mostly from survivors of the atomic bomb blasts over Japan in 1945.

• Massive doses incinerate immediately and are not distinguishable from the heat of the source.
• A sudden whole-body dose over 50 Sv produces such profound neurological, heart, and circulatory damage that patients die within the first two days.
• Doses in the 10–20 Sv range affect the intestines, stripping their lining and leading to death within three months from vomiting, diarrhea, starvation, and infection.
• Victims receiving 6–10 Sv all at once usually escape an intestinal death, facing instead bone marrow failure and death within two months from loss of blood coagulation factors and the protection against infection provided by white blood cells.
• Between 2–6 Sv gives the person a fighting chance for survival if he or she is supported with blood transfusions and antibiotics.
• One or two Sv produces a brief nonlethal sickness with vomiting, loss of appetite, and generalized discomfort.