99mTechnetium-Heat damaged erythrocyte were used as spleen scanning agents in 12 patients from July, 1985 to April, 1986. We used this scan to evaluate situs inversus, asplenia, accessory spleen, hypersplenism, splenic infarction, tumor staging and evaluation of therapy, especially when the Tc-99m-tin colloid scans were not definite for diagnosis. The techniques applied to these scans were in vivo/in vitro-labeling method and heating-method to damage the erythrocytes. Liver- to-spleen uptake ratios were increased upto 100:1 and interference from the left lobe of the liver was eliminated. These scans were helpful to evaluate the spleen.