Modification of distribution of gallium 67 in man by administration of iron

In mice bearing tumours, the clearance of 67Ga from blood and the attainment of high tumour-to-normal soft-tissue concentration ratios are accelerated if the serum unsaturated iron-binding capacity (UIBC) is low. A preliminary clinical trial is described, concerning the administration of iron as a means of creating favourable imaging distributions within 6 h of injection of 67Ga. Iron was given intramuscularly at a dosage in the range 50-100 mg, depending on the patient's UIBC and generally about 3 h post 67Ga. In 14 patients receiving iron, consistent and substantial reductions in 67Ga plasma concentrations and in UIBC were demonstrated. In seven of these, the 6 h 67Ga images revealed lesions at contrasts which were nearly equivalent to their contrasts in later (48 h) pictures: there were an additional two cases where the lesion was not detected until 48 h. The 6 h results were relatively free of the bowel appearances which sometimes confuse later studies, and examinations generally benefited from the advance information gained at 6 h.