Deferoxamine mesylate enhancement of 67Ga tumor-to-blood ratios and tumor imaging.

To improve the tumor-to-blood ratio in 67Ga tumor imaging, the effect of administration of deferoxamine mesylate (DFO) was evaluated. DFO improved 67Ga tumor-to-blood ratios in tumor-bearing rats. Administration of DFO 12 h after 67Ga injection did not decrease the concentration of radioactivity in the tumor of rats, but administration of DFO 4 h after 67Ga decreased the concentration of radioactivity in the tumor. Serum unsaturated iron binding capacity in rats was transiently increased by DFO administration, but when DFO was administered before 67Ga injection the tumor uptake showed rather decreased levels. In human studies, DFO accelerated the excretion of 67Ga from the blood, but tumor images were not necessarily improved.