Relative Biological Efficiency of 1000-Kvp and 250-Kvcp X-Rays: III. Determinations Based on the LD 50/28 and the Killing Time of the Mouse

Abstract

The relative biological efficiency, [eta] , of 1000 kvp X-rays compared with 250 kvcp X-rays was determined from the results of mortality studies with adult CAF1 and CAF2 mice. For the LD50/28, [eta] (tissue dose) and its 95% confidence limits were: 0.839 (0.807 to 0.873). It was determined that [eta] based on the killing time (range, 4 to 16 days) was the same as [eta] based on the LD50/28. No difference in the biological mode of action of the 2 beams was noted.