The risk of liver tumors in dogs and man from radioactive aerosols

Life-span studies in progress using beagle dogs that inhaled relatively soluble or relatively insoluble forms of radionuclides will provide information from which we may project the risk to humans for liver cancer from inhaled radioactive material. Twenty-two liver tumors have been observed in dogs exposed to beta-emitting radionuclides, mainly 144Ce, and one liver tumor in a dog exposed to 238Pu. Two liver cancers were also observed in control dogs. The risk of liver cancer in dogs that inhaled beta-emitting radionuclides was calculated to be 90 liver cancers per million rads. The risk of liver cancers in dogs in our studies and in studies at the University of Utah, when compared to the incidence of liver tumors in humans exposed to Thorotrast, suggest that the risk of liver cancer from an inhaled beta-emitting radionuclide in people is about 30 liver cancers per million person-rads. 19 refs., 3 tabs