CANCER RISK FACTORS: RADIATION RISK FACTORS
Human studies show that the more radiation a person is exposed to, the higher is the risk of developing cancer, especially if the radiation exposure is to bone marrow, where the blood cells are made. People who received radiation to shrink enlarged tonsils or to treat acne have a higher risk of developing cancer of the thyroid and parathyroid glands located in the neck. Survivors of the bombings of Hiroshima and Nagasaki have had an increased incidence of leukemia, lymphoma, Hodgkin's disease, multiple myeloma, and other cancers. People who used to paint radium on wristwatch dials have a high incidence of osteogenic sarcoma, a bone cancer. Chronic exposure of fair-skinned, easily sunburned people to sunlight (ultraviolet light) will lead to a higher rate of skin cancer.
There has been mounting concern that people who work in or live near nuclear power plants have a higher risk of developing cancer. In the United Kingdom a higher incidence of childhood leukemia has been reported in children living near several nuclear facilities, most notably a fuel reprocessing plant located at Sellafield in northwest England. The results of another study involving over 8,000 men who worked in the Oak Ridge National Laboratory in Tennessee between 1943 and 1972 show that these men had a higher risk of developing cancers, especially leukemia. Another study shows no such increase in cancer incidence.
Women with tuberculosis who received many chest X rays to follow the progress of treatment had an increased incidence of breast cancer with as little as 17 cGy total dose. A cGy, or centiGray, is a defined amount of energy absorbed by a certain amount of body tissue. One chest X ray using modern equipment delivers about 0.14 cGy. Riding in an airplane at 35,000 feet for six hours exposes a person to 0.01 cGy.
A study by Matanoski published in the Proceedings of the 1980 International Conference on Cancer indicates that radiologists, besides their well-known increased risk of developing cancer, may also have a 30 percent increased risk of death from cardiovascular disease and stroke due to radiation exposure. Workers in many industries are chronically exposed to low-dose radiation and hence may be at risk for heart disease and cancer. We may therefore have to reexamine standards for acceptable radiation levels in industry.