[en] Among the life-span studies conducted with beagle dogs, bone cancer has been in two studies the predominant effect at death. These studies involved dogs that inhaled ⁹⁰SrCl₂, which is very soluble in body fluids; and dogs that inhaled ²³⁸PuO₂, which is initially insoluble but eventually becomes fragmented and more soluble. Both radionuclides were deposited in the skeleton after dissolution in the lung and absorption into the bloodstream. All dogs in the ⁹⁰Sr study are dead, and all living dogs in the ²³⁸Pu study are at least 7 years postexposure. Results from these two studies were compared to determine the relative biological effectiveness (RBE) of chronic beta and alpha radiation delivered from these two radionuclides. These data also were used to estimate the risk of bone cancer in man by using comparisons with data from the ⁹⁰Sr-, ²³⁹Pu-, and ²²⁶Ra-injected dogs at the University of Utah and data on humans who ingested ²²⁶Ra or were injected with ²²⁴Ra. Such comparisons provided a link between studies in laboratory animals and the available human data. In this way risks of bone cancer in humans from inhaled plutonium or strontium were estimated, even though currently no human cases of bone cancer are known to have resulted from the inhalation of either of these radionuclides. 15 refs., 7 figs., 7 tabs