The contribution of ionizing radiation to cancer mortality in the United States

Although ionizing radiation has been well known as a carcinogen for more than 70 years, only a small part of the total cancer mortality burden in the United States can be attributed to radiation effects—less than 3%. Little can be done about much of the exposure to radiation that exists—about half of the total results from natural background radiation. More than 40% derives from medical and dental practice—mostly as diagnostic X-rays. Something less than 5% comes from nuclear weapons fallout from atmospheric tests and well under 1% from the use of nuclear energy for generating electric power. Substantial reduction of the total radiation burden on the population can be achieved only by reduction of X-rays used in medicine and dentistry. This will, however, involve careful consideration of the balance between radiation benefits and risks, as well as requiring that such X-ray exposures be reduced to the minimum required to achieve the necessary medical purpose.