Radiation and Society

Abstract

Radioactivity and radiation have always existed, yet it is less than a century since we have become aware of their presence in nature and been able to exploit the knowledge of natural and man made radiation to improve our health and well being. It has been estimated that natural radiation accounts for more than 80% of the radiation exposure of the general population, with medical exposure accounting for most of the rest. There appears to be no reproducible evidence of harmful effects associated with increases in background radiation up to six times the usual levels. In the absence of smoking, the age adjusted lung cancer death rates in the USA and in the high background region of China are in the range of 2–3 per 100 000. Although many studies have shown that very high exposure of miners to the naturally radioactive gas radon and its daughter products result in a marked increase in lung cancer, there is no evidence for an increase in lung cancer among non-smokers exposed to radon related levels commonly found in the home. Furthermore, most cancerous lesions in non-smokers are located in the deeper portions of the lung, whereas lung cancer due to radon and its daughters would be expected to arise in the bronchial epithelium. Among 22 000 hyperthyroid patients treated with ¹³¹I, whose whole body dose averaged 10 rem, there was no increased incidence of leukemia compared with 14 000 treated with surgery or drugs. A 20 year followup of 35 000 patients who received ¹³¹I uptake tests for evaluation of thyroid function revealed that those studied for reasons other than a suspected tumour had considerably fewer thyroid cancers than would have been expected in a control group. In epidemiologic studies positive results suggesting radiation damage are interesting and reported, whereas negative studies generally are not. Therefore the literature would tend to overestimate the damaging effects of radiation even if the true effect were not different from zero. If the possible deleterious effects of radiation exposure are exaggerated, society will be denied its beneficial role.