Dose-response relationships for bone cancers from plutonium in dogs and people

The risk of bone cancers developing from internally deposited plutonium must be estimated from studies in laboratory animals because no plutonium-induced cancers have been observed in people. Studies of the effects of 226Ra and 239Pu injected into beagle dogs at the University of Utah and 238PuO2 inhaled by beagle dogs at the Inhalation Toxicology Research Institute provide a key link to understanding the longterm effects of inhaled alpha-emitting radionuclides in people. Injected radium and plutonium are rapidly deposited in bone whereas plutonium deposited in lung by inhalation is translocated to bone more slowly, depending on its chemical form. The development of bone cancers is a late occurring effect seen after either injection of plutonium or radium or inhalation of plutonium. The incidence of bone cancers from alpha radiation to the skeletons of dogs was compared to bone cancer incidences in radium dial painters to estimate bone cancer risk from inhaled plutonium in people. A risk factor of 1200 bone cancers/10(6) rad to skeleton (average dose) was estimated.