Failure of Y 90 to Escape from Skeletally-Fixed Sr. 90 ∗

Abstract

Summary

The data presented demonstrate that Y⁹⁰ produced in vivo from long term skeletal deposits of Sr⁹⁰ in young dogs does not escape from the local areas of bone in which it is produced. This is in agreement with previous experimental evidence(5). The implications of this finding are as follows: First, the combined energy of the Sr⁹⁰ and Y⁹⁰ beta rays irradiates the skeleton. Hence, dosimetric data determined in vitro can be directly applied to in vivo conditions. Second, the Sr⁹⁰ deposited in the growing skeleton is probably intracrystalline. This is in agreement with the x-ray diffraction findings of McDonald(6). Work is in progress to see whether this effect occurs in older dogs where there is less bone growth and less crystal formation.