D. Diagnostic and Therapeutic Radiation Exposure

Review of Thirty Years Study of Hiroshima and Nagasaki Atomic Bomb Survivors I. DOSIMETRY

Abstract

Diagnostic and therapeutic radiology were studied as possible contaminants in the evaluations of A-bomb survivors in the ABCC-JNIH Adult Health Study for radiation effects. Hiroshima and Nagasaki subjects received X-ray examinations elsewhere within three months of their ABCC visits at rates of 23 and 12%, respectively. Medical X-ray examinations were more frequent among survivors than comparison subjects. Hiroshima and Nagasaki radiologic practice steadily increased since 1948, and differed markedly by city. From 1946-70 the Hiroshima and Nagasaki X-ray bone marrow doses were 2, 300 and 1, 000 g-rads, respectively. By 1970, cumulated medical X-ray doses approximated A-bomb doses at distances from the hypocenters of 2, 000 m in Hiroshima and 2, 800 m in Nagasaki. ABCC X-ray examination doses per subject are routinely updated for comparison with A-bomb doses. Each subject's reported fluoroscopy, photofluorography and radiation therapy exposure elsewhere are for future reference. Dental radiography, though increasing, was not currently an important contributor to survivors' overall exposure. Radiation therapy exposures of 137 subjects were confirmed, and doses estimated for most. Two-thirds the treatments were for malignancies; therapy differed markedly by city; and five cancers possibly arose from earlier radiation therapy.
This underscores the importance of considering diagnostic and therapeutic radiology when attributing diseases to the atomic bombs.