Tc-99m labeled leukocytes: preparation and use in identification of abscess and tissue rejection.

Abstract
A simple and reproducible method for the preparation and labeling of leukocytes with 99mTc was developed. Leukocytes were separated from blood, incubated with stannous pyrophosphate, and then with 20-30 mCi (740-1110 MBq) of 99mTcO4-. In leukocytes separated from human blood, the labeling efficiency was 81% .+-. 6% (n = 4). Experiments on dogs with abscesses showed accumulation of the Tc-99m-labeled leukocytes in the infected sites, indicating the viability of the labeled leukocytes. Additional studies showed that rat lymphocytes that were labeled with 99mTc, using the same technique, localized in heart transplant tissue that was being rejected.