Effect of external whole-body x-irradiation on gallium-67 retention in mouse tissues.

irradiation. In contrast to decreased uptake in soft tissues, 6Ga concentration in whole femur increased after irradiation. Blood levels decreased rapidly in irradiated mice (67Ga injected 24 hr after 450 R) between 1 and 2 hr after administration of the radionuclide. Two hours after injection, its concentration was approximately 15% of that in nonirradiated, control animals. We conclude that decreased 67Ga retention in mice after x-irradiation is in part due to an effect on a relatively radiosensitive, as yet unidentified blood or serum component that normally binds the radioisotope. Other as yet un