Methods of Assay of the Relative Toxicity of Certain Bone-Seeking Radionuclides

Four methods of handling the dose-response relation in the data from the long-term experiment on the effects of certain radioisotopes administered intravenously to dogs at the University of Utah are presented and discussed. The results are cast in terms of the relative biological effectiveness of five radionuclides:^{226}{\rm Ra},{}^{239}{\rm Pu},{}^{90}{\rm Sr},{}^{228}{\rm Ra}$, and228Th for the production of bone cancers. One of the methods is based on quantal response (deaths from osteosarcomas), two are based on survival times, and the fourth is a modification of that proposed by Blair (which takes account of the induction period between dosage and the beginning of oncogenesis). There is evidence that Blair's approach has most merit.