ACUTE MORTALITY OF MICE AND RATS EXPOSED TO MIXED GAMMA-NEUTRON RADIATIONS OR TO X RAYS
ARMED FORCES RADIOBIOLOGY RESEARCH INST BETHESDA MD
Pagination or Media Count:
Mortality data for C57BL mice and Sprague-Dawley rats were collected as a part of the program to biologically characterize AFRRI-TRIGA reactor radiations and to provide reference information for future studies. Unilateral whole body exposures to mixed gamma-neutron radiations from the reactor or to 250 kVp x rays were carried out over a range of midline tissue doses from 370 to 875 rads. The 30-day median lethal doses were calculated to be 589 and 432 rads for mice exposed to the x rays and to the reactor radiations, respectively. The corresponding values for the rat exposures were 740 and 434 rads. Using the LD5030 values as the end points for comparison, the reactor radiations were 1.4 and 1.7 times more effective in mice and rats, respectively, than were the x rays. The survival times of the mice and rats exposed to reactor radiations were significantly less than those of the animals exposed to similar doses of x rays.