Occurrence of hemangiosarcomas in beagles with internally deposited radionuclides.

In a series of related experiments to evaluate the relative toxicity of inhaled radionuclides, beagles were exposed to aerosols containing relatively soluble (chloride) or relatively insoluble (fused clay) forms of 144-Ce and 90Sr. With the solubled 144-CeCl3, significant radiation doses were delivered to the lungs, liver, and skeleton whereas, after 90-SrCl2 exposure, the radiation dose was delivered predominantly to the skeleton. In dogs exposed to 144-Ce and 90-Sr in fused clay particles, radiation doses were delivered mostly to the lungs and tracheobronchial lymph nodes. In most dogs dying within 2 years after exposure, deaths were attributable to nonneoplastic radiation-induced lesions in the target organ systems. At later times after exposure, neoplasms were the major cause of death, again occurring mostly in target organs or the adjacent tissues. Lung liver, and bone-related neoplasms, including five hepatic hemangiosarcomas, developed after 144-CeCl3 exposure. Among the bone-related sarcomas seen in dogs exposed to 144-CeC3 or 90-SrC2, the incidence of hemangiosarcomas was over 40%. Among the 20 dogs dying with pulmonary neoplasms after exposure to 144-Ce or 90Sr in fused clay particles, all had hemangiosarcomas and several also had other neoplasms. This high after exposure and differs from results in other laboratories where beagles have been exposed to both alpha and beta-emitting radionuclides.