Cobalt-60 gamma Irradiation of Sheep: Correlations of Sixty-Day Median Lethal Dose Studies with Selected Biochemical, Hematologic, and Pathologic Findings

摘要

Ninety-seven female sheep, 2-1/2 to 4 years of age, were exposed to bilateral whole body 60Co gamma radiation at a dose rate of 11.0 R/min. Doses ranging from 180 to 415R midline air exposure (MAE) were administered at 11 different dose levels. Probit analysis of mortality data revealed a 60-day 50 percent (LD50(60)) lethal dose value of 367R. Death distribution, hematologic, and gross and histopathologic findings implicated bone marrow failure as the major contributing factor causing death of the animals. The onset of death correlated with the onset of severe neutropenia and thrombocytopenia. Preexposure body weights served as a useful guide for predicting which animals would be most radiation sensitive. The course of radiation sickness in sheep was monitored throughout the experiment by selected hematological, biochemical, and electrolyte studies. (Author)