Toxicity of inhaled 239PuO2 in immature Beagle dogs. VII

Immature Beagle dogs have been exposed by inhalation to a monodisperse aerosol of 239PuO2 (1.5 μm AMAD) to compare the biological effects with those observed in dogs exposed to a similar aerosol as young or aged adults. The study includes 96 dogs exposed to 239PuO2 and 12 controls. The lung burdens of the plutonium-exposed dogs ranged from 0.00030 to 0.80 μCi/kg body weight (0.011-30 kBq/kg). No dogs died during this year. Seven dogs were diagnosed as having developing lung disease, mainly fibrosis, and one had a developing lung tumor. With 20 dogs having estimated cumulative radiation doses in excess of 1000 rad (10 Gy), the biological response of the dogs exposed as juveniles appears to be less than that seen in mature dogs. However, major uncertainties still exist in the current estimations of radiation dose, particularly regarding the local distribution of alpha radiation dose. 1 reference, 4 figures, 1 table