Splenic sequestration of 99mTc labeled, heat treated red blood cells.

The rates of blood clearance and splenic uptake as well as the total splenic uptake of heat damaged red blood cells labeled with 99mTc were determined in eight patients. Splenic uptake at two hours was 72.0 +/- 18.5%. Approximately 82.6% of the initial radioactivity was cleared from the blood by two hours, with a rapid T1/2 component of 6.3 +/- 4.7 minutes. The T1/2 of splenic uptake was 8.3 +/- 4.6 minutes, and splenic radioactivity reached a plateau by 30 minutes. The results indicate that the method of preparation is reliable, but its usefulness for evaluating spleen function remains to be determined.