Toxicity of inhaled 239PuO2 in aged Beagle dogs. VI

Studies to determine the effects of age at exposure on the metabolism, dosimetry, and biological effects of inhaled particles of 239PuO2 are in progress in aged Beagle dogs (8.0 to 10.5 years of age at exposure). Forty-eight dogs inhaled 239PuO2 particles with an activity media aerodynamic diameter of 1.5 μm to achieve initial lung burdens ranging from 0.02 to 0.66 μCi 239Pu/kg body weight (0.74 to 24 kBq/kg). Twelve dogs exposed to the aerosol diluent serve as controls. Thirty-nine exposed dogs have died, including four in the past year. The principal causes of death have been radiation pneumonitis and pulmonary fibrosis. Four control dogs have died. The nine surviving exposed dogs and eight controls are continuing to be observed. 1 reference, 2 figures, 1 table