uptake on sulfur colloid (SC) imaging. 2. To assess the function of the reticuloendothelial system in patients with suspected liver disease. The decision to perform a liver biopsy or to continue treatment with a hepatotoxic agent may be influenced by the severity of liver disease that is seen on liver-spleen imaging. B. Liver Blood Pool Imaging This study is highly specific for cavernous hemangio mas of the liver. The sensitivity for detecting large lesions of the liver (>2 cm—3cm) is also high. Hem angiomas as small as 0.5 cm may be detected with SPECT. C. HepaticPerfusionImaging This study is useful for demonstrating that hepatic artery catheters used to infuse chemotherapeutic agents are optimally positioned to perfuse liver tumors and to avoid perfusion of normal extrahepatic tissues (e.g., stomach). D. Splenic Imaging This study is used to detect functional splenic tissue. This study is often performed: 1. In children to rule out congenital asplenia or polysplenia. 2. In adults whose thrombocytopenia has been previ ously treated with splenectomy. 3. To characterizean incidentally noted mass as ftmc tional splenic tissue.