Toxicity of inhaled 239PuO2 in Beagle dogs. A. Monodisperse 0.75-μm AMAD particles. B. Monodisperse 1.5-μm AMAD particles. C. Monodisperse 3.0-μm AMAD particles. VIII

Beagle dogs were exposed to monodisperse aerosols of 239PuO2 of 0.75-, 1.5-, or 3.0-μm activity median aerodynamic diameter (AMAD) to obtain information on the relative importance of homogeneity of alpha irradiation doses to the lung. The dogs' graded initial lung burdens ranged from 0.0002 to 2.6 μCi (0.0074 to 96 kBq) 239Pu/kg of body weight. Thirty-six dogs exposed to the aerosol diluent are the controls. Twenty-four exposed dogs have died to date in the study with 0.75-μm AMAD particles, 57 in the study with 1.5-μm AMAD particles, and 50 in the study with the 3.0-μm AMAD particles. Three control dogs have died. The dogs exposed to 239Pu that have died to date have died with radiation pneumonitis and fibrosis and/or lung cancer. Surviving dogs have lived up to 3100 days after exposure. 6 figures, 1 table