On the Studies of the Problem of X-Ray Units Conducted from 1929 to 1937 : Centering on the Studies in American and British Radiological Societies

Abstract

The problem of the units of X-ray exposure originated from the fact that therapists wished to grasp the relationship between the quantity of irradiated X-ray and its effect on medical treatment, and to make a comparative study of each therapeutic result by the same measure. This problem was an interdisciplinary one between physics and radiotherapeutics. In 1925, the Radiological Society of North America settled the Committee on Standardization of X-ray Measurements to study the problem of measuring X-rays, and to guide the members of the Society. The committee was composed of physicists and radiologists in equal number. They developed a large-sized standard chamber and a portable one. L. S. Tayler transported the portable chamber to Europe and by using it he compared and exmined British, German and French standard chambers, confirming that each of them could be used as a common standard chamber. Based on these facts the ICRU presented the Annex to the recommendations of 1934 on the standard measuring apparatus. It was shown by physicists that the effect on the human body was not represented only by the quantity of irradiated X-rays and that a description of the quality of X-rays was indispensable. As radiologists' understanding deepend, they came to actively submit proposals to radiological societies in the 1930's. Taking their opinions into consideration, the ICRU recommendations which were practicable for medical purposes were issued in 1937. The effort of American and British radiological societies for a better solution beyond disciplines is suggestive in dealing with interdisciplinary issues.