Technetium-99m labeling of polymorphonuclear leukocytes: preparation with two different stannous agents.

A technique for in vitro labeling of human polymorphonuclear leukocytes with Tc-99m is described. Titration of stannous fluoride and stannous pyrophosphate concentrations for pretinning was performed, and optimal amounts of the stannous agents were added to polymorphonuclear leukocytes efficiently isolated from 100 ml of blood. Labeling with 10-15 mCi Tc-99m resulted, after three washings of cell suspensions, in yields of 1.6-4.8 mCi, corresponding to 20.5-33.5% of added tracer. Cell-bound activity in the final cell suspensions was 92.3% +/- 1.9 of the added dose. Cell function was not impaired by the labeling technique. Sterility and exclusion of bacterial endotoxins in the final cell suspensions were demonstrated. The method may prove of diagnostic value in the isolation, labeling, and reinjection of autologous leukocytes for scintigraphic imaging of acute inflammatory lesions.