Early disposition of inhaled monodisperse and polydisperse 239PuO2 in dogs

The temporal pattern of radiation dose to tissues of Beagle dogs which have inhaled 239PuO2 aerosols is being studied. Twenty-six dogs each have received single inhalation exposures (0.07 μCi/kg body weight) to one of the following 239PuO2 aerosols: 0.7, 1.4 or 2.85 μm (AD) monodisperse aerosol or 1.1 μm (AMAD) polydisperse aerosol. Sequential sacrifice of male and female pairs of dogs is to be performed at 4 hours, 4, 8, 16, 32, 64, 128, 365, 512 and 730 days and 4, 6, and 8 years after exposure. Excreta collections are performed for the first 21 days after exposure and then 3 day collections are taken at 6, 12, 18 and 24 weeks and at 6 month intervals thereafter. Information derived from this study will be instrumental in developing a description of the radiation dose to tissues and organs as related to particle size of the inhaled aerosol and, taken together with information developed on the spatial distribution of radiation dose in the lung, will provide a basis for interpretation of biological response as measured in the accompanying dose-response study. This study is in progress and data are currently available on the 239Pu content of tissues of dogs sacrificed through 64 days after inhalation. Work is continuing on radiochemical determination of 239Pu in dog tissues and urine and feces samples