Interaction of technetium 99m-labeled teboroxime with red blood cells reduces the compound’s extraction and increases apparent cardiac washout

Background 99mTc-labeled teboroxime shows high myocardial extraction in both in vivo animal and in vitro cell culture and isolated heart studies. Whereas in vivo studies show rapid myocardial clearance of teboroxime, in vitro cell culture and isolated heart studies show slower washout comparable to that of201Tl. Binding of teboroxime to blood components may contribute to these conflicting results.