Inhaled (147)Pm and/or Total-Body Gamma Radiation: Early Mortality and Morbidity in Rats,

摘要

Rats were given doses of 60Co gamma radiation and/or lung burdens of 147Pm (in fused aluminosilicate particles) within lethal ranges in an experiment to determine and compare morbidity and mortality responses for the radiation insults within 1 year after exposure. Radiation-induced morbidity was assessed by measuring changes in body weights, hematologic parameters, and pulmonary-function parameters. Gamma radiation caused transient morbidity, reflected by immediately depressed blood cell levels and by reduced body weight gain in animals that survived the acute gamma radiation syndrome. Inhaled promethium caused a loss of body weight and diminished pulmonary function, but its only effect on blood cell levels was lymphocytopenia. Combined gamma irradiation and promethium lung burdens were synergistic, in that animals receiving both radiation insults had higher morbidity and mortality rates than would be predicted based on the effect of either kind of radiation alone. Promethium lung burdens enhanced the effect of gamma radiation in rats within the first 30 days of exposure, and gamma radiation enhanced the later effect of promethium lung burdens. A model, based on a statistical tool called the hazard function, was applied to the data from rats exposed to either promethium aerosols or total-body gamma radiation and accurately predicted the LD 50/365 lung doses for rats exposed to combined radiation insults.