Relative biological effectiveness of internal emitters.

Abstract

Permissible levels of exposure to radioactive materials have been based in large part upon two sets of comparisons. In the first, the radiotoxic hazards of the various isotopes are evaluated relative to radium in experimental animals. In the second, extrapolations are made to man through radium as the common link, since the latent effects of that element are known from individuals who have carried small but measurable body burdens for many years. In this work the mouse has proved to be a very useful experimental animal, particularly when relatively large populations are required. The data accumulated in such studies make possible an evaluation of the relative biological effectiveness (RBE) of different radioisotopes according to a number of criteria. The effects of several alpha-emitters upon survival and upon the incidence of malignant bone tumors in mice have been reported previously (1). Subsequent experiments with several beta-emitters have now progressed to the point where preliminary comparisons can...