Clinical comparison of cardiac blood pool visualization with technetium-99m red blood cells labeled in vivo and with technetium-99m human serum albumin.

Technetium-99m red blood cells (Tc-RBC) labeled by an in vivo technique were compared with two preparations of Tc-99m human serum albumin (HSA) for cardiac blood-pool imaging. Relative distribution of the tracers was analyzed on end-diastolic frames of gated blood-pool studies and on whole-body (head to mid-thigh) anterior pinhole images. The Tc-RBC demonstrated greater relative percentage localization in the cardiac blood pool, higher target-to-background ratios in the left ventricle, and less liver concentration. For cardiac blood-pool imaging, Tc-RBC labeled by the in vivo approach appears to be superior to the two Tc-HSA preparations studied.