Development and evaluation of a rapid and efficient electrolytic preparation of 99mTc-labeled red blood cells

This paper reports a new, simple and reproducible method for routine preparation of 99 m Tc-labeled red blood cells (RBC). This method employs electrolytic generation of minute quantities of stannous ion to serve as the reducing agent for 99 m Tc-pertechnetate. The RBC are incubated with Sn(II), washed with saline, incubated with Na 99 m TcO 4, and washed again with saline. The entire procedure requires about 45 min and consistently provides labeling efficiencies above 90%. The half-clearance time in the blood in humans is approximately 24 hr. Activity released from the labeled RBC in vivo is largely in chelate form which is rapidly excreted in the urine. High quality blood pool images can be obtained for many hours after injection. In a damaged form, 99 m Tc-RBC provide spleen images of diagnostic quality. This 99 m Tc-RBC preparation appears to have good potential for routine use.