" TN SP QrCre Seo akyAyr ty BSR RADIATION STANDARDS, INCLUDING FALLOUT 289 his management during his therapy with greater precision. We don’t see where the end of this is going to come. Thisis one of the reasons why I personally feel that the exact figure as to the amountof radiation exposure used in medicineis of secondary importance. We ought to use the amount that will do the most good for our people. The amounts generally involved have a very small degree of hazard compared to the good that is derived for the individual person. But of course we ought to do it with the least wastage of radiation and the avoidance of radiation that is unproductive. I personally feel again that educational methods will have by far the greatest impact on this in the future and moderate regulatory measures will be of someassistance. Thank you. (Dr. Chamberlain’s prepared statement follows:) eS MEDICAL RADIATION HXXPOSURE (By Richard H. Chamberlain, M.D.) In evaluating radiation dosages from other sources, it is appropriate to discuss the exposure of the population to ionizing radiation used for the beneficial purposes of medicine and dentistry. During the past 2 years much thought and effort has been expended on appruisals of the amounts of radiation delivered to the gonads and other portions of the body from this source. Even more attention has been given to reasonable methods of reducing the radiation dosage without losing the vital benefts of radiological diagnosis and therapy. The pertinent features may be discussed under the following three points: 1. Epidemiological estimates of dosage values. 2. Control and improvement measures. (a) Educational. (6) Regulatory. (¢) Research. 3. Perspective and prospects in medical exposures. 1. EPIDEMIOLOGICAL ESTIMATES OF DOSAGE VALUES Early attempts at estimates of average population exposures were largely confined to gonadal exposures and were largely based on fragmentary data from published papers of experiences in a few hospitals and local regions. They reflected the best that could be obtained from such sources, but left much uncertainty in the validity of the 150-millirad-per-year average figure which was derived for gonadal radiation dosage up to age 30 in the United States. In the past few years, very comprehensive analyses have been attempted in several other countries, notably Sweden, the United Kingdom, and Denmark. The Adrian Committee report from the United Kingdom is based on a large-scale study of measured doses and patient procedure distribution. It was well designed for proper statistical sampling. It indicates that in the United Kingdom the average gonadal exposure per year for medical purposes is between 15 and 25 millirads, with about 20 millirads as the probable figure. Figures from other Western European countries range from about 25 to 60 millirads. The Japanese estimate is about 40 millirads. No comparable study or estimate has been made in the United States, and to duplicate the United Kingdom study here would require a huge undertaking. From general comparisons of the development of radiological procedures in the United States and those countries that have re- ported, however, we would not expect great discrepancies. It seems reasonable to assume, therefore. that our own exposures are probably closer to 25 to 50 millirads per year than the preliminary estimate of 150 millirads. It is not clearly known, as yet what may be significant in the assessment of somatic exposures. Investigations of dose and procedures may result in fairly homogeneous coverage of the hody as averaged over lurge segments of the population. If this is trne, the tigures for somatic exposure are likely to be roughly comparable to these for gonadal exposure. Among the difficulties encountered in arriving at meaningful figures are the proper corrections for such factors as the individual prognosis relevant to the large proportion of use of major radiological procedures in patients with serious illnesses and limited life expectancy. ERASBSERICH issTadatenet Subp hae eseTE