Measurement of background radiation for epidemiologic studies.

Abstract

Methods being used in a survey of cancer incidence and its relation to background radiation in New England communities are outlined. The measurement of background radiation for epidemiologic purposes is discussed in terms of the application of technics capable of detecting geographic variation in human exposure to both external and internal natural sources of radioactivity at very low levels. The equivalent uranium content was calculated for 58 geological formations in New Hampshire, 5 in Maine, and 24 in Vermont. From this an average equivalent uranium value for the minor civil division, weighted by the proportion overlying each geological formation, was obtained. Illustrations are provided showing the distribution of geological formations and their respective equivalent uranium concentrations in minor civil divisions of New Hampshire. The findings suggest that even within small civil divisions there may be marked differences in terrestrial radiation. Radiometric analysis of small amounts of hiological material, such as individual teeth, are being used to estimate the body burden of radium and other emitters in largescale population studies. A method is described for assaying Ra/sup 226/, Ra/sup 224/, Ra/sup 223/, and Po/sup 210/ in a single tooth. (T CO)