Detection of gastrointestinal blood loss with 99mTc-labeled, heat-treated red blood cells.

Abstract

Studies in dogs showed that heat-treated 99mTc-labeled red blood cells (HT/RBC) afford a highly sensitive means of detecting gastrointestinal bleeding as low as 0.12 ml/min., which could not be seen with unheated 99mTc-RBC, 99mTc-sulfur colloid, or 99mTc-DTPA. In addition, as the right upper quadrant and epigastrium remained free of activity, only one fifth to one tenth of the dose of 99mTc was needed. The safety of HT/RBC in humans has been documented, and the experiments in dogs suggest that it may have advantages over other agents in detecting gastrointestinal bleeding.