Five- to Eight-Day Radiation Death in Mice

Abstract

There are several modes of acute radiation death, and their number seems to be increasing as more species and more irradiation conditions are being studied. With mice, after whole-body irradiation (X or 7) with the doses commonly used (a few hundred to a few thousand roentgens), the picture seems to be dominated by and Each of these two modes is associated with a survival time which is invariant (or nearly invariant) with dose, although it varies somewhat according to strain, sex, and general laboratory conditions. Intestinal death occurs after 3.5 to 4.3 days (average), and marrow death after about 9 to 15 days. Individual mice die between 4 and 9 days after irradiation. Also, if appropriate doses are used, the mean survival time decreases with dose from 9 to 4 days. In fact, the decrease is so regular that it can be used for bioassay (1). Two interpretations are suggested: 1. Survival times are distributed around the two modal values with considerable scatter, and an individual dying at, say, 6 days succumbs to a late intestinal or an early marrow death; in this sense, the change in mean survival time would be due to a shift in the relative percentage of the two modes of death. 2. There exists a mode of death, neither intestinal nor marrow, associated with a dose-variant survival time between 4 and 9 days.