Toxicity of inhaled 91YCl3 in beagle dogs

The metabolism, dosimetry and effects of inhaled 91YCl3 in beagle dogs are being studied. Forty-two dogs with 91Y initial body burdens from 14 to 1300 μCi/kg body weight and 12 control dogs are being maintained for lifetime observation. Four additional dogs with a mean initial body burden of 180 μCi/kg body weight were placed in a sacrifice study. Thirty-six of the exposed dogs and 7 of the control dogs have died. Dogs with the highest activity levels died with bone marrow damage and pancytopenia. Three dogs died with nasal cavity carcinomas and three with pulmonary carcinomas and one with hepatic hemangiosarcoma that all appear related to radiation injury. Control dogs died of miscellaneous neoplastic and chronic diseases. Observations are continuing on 10 surviving exposed dogs and six surviving unexposed dogs