Mouse-Strain Differences in Response to Radiation

Summary 1. The acute radiation mortality of mice exposed to x-rays shows that there are radiosensitive regions in the mouse head. 2. The L.D.-50% at 12 days for acute mortality due to whole-body exposure to x-rays is essentially the same for 4 mouse strains and is about 528 r. 3. The sensitivity of the head region varies with mouse strain. In the most sensitive strain, the dba, the M.L.D. for head exposure is the same as for whole-body exposure. Up to more than a 4-fold decrease in head sensitivity in the strains is found in the following order: dba, Marsh, C57 black, and C3H mice.