Organ distribution of canine leukocytes labeled with 99mTc-sulfur colloid.

Previous reports have shown that scintigraphic localization of acute inflammation can be achieved using autologous leukocytes labeled in vitro with 99mTc-sulfur colloid (TcSC). The technique is limited, however, by a marked accumulation of radioactivity in the lungs and liver of normal animals. A modified procedure was developed using preparations of TcSC of small particle size to label blood leukocytes in vitro. Markedly decreased levels of lung and liver radioactivity and elevated levels of blood radioactivity were found after intravenous infusion of autologous canine leukocytes labeled by this method. These leukocytes could be used to image areas of acute inflammation resulting from induction of septic or sterile venous thrombi.