Toxicity of 90Y inhaled in a relatively insoluble form by beagle dogs. IX

Studies on the metabolism, dosimetry and biological effects of inhaled 90Y in fused aluminosilicate particles in the Beagle dog are in progress to assess the consequences of inhaling an energetic beta-emitting radionuclide that has a short effective half-life in the lung. A radiation dose-pattern study in which 12 dogs were sacrificed in pairs at 0, 2, 4, 6, 8 and 12 days after exposure has been completed. A longevity study is in progress in which 89 dogs were exposed to initial lung burdens ranging from 80 to 5200 μCi/kg body weight and 12 control dogs were exposed to stable yttrium in fused aluminosilicate particles. The short half-life and the relative insolubility of the 90Y in this vector at the doses achieved resulted in a radiation insult to the lung and surrounding structures at a relatively high, but rapidly decreasing dose rate. To date, 42 dogs with cumulative doses to lung from 6600 to 70,000 rads have died from 7.5 to 2627 days after exposure. Forty-seven exposed dogs and 12 control dogs remain alive 2374 to 2930 days after exposure and will continue to be studied for the remainder of their life span