FOR 13 YEARS, radioactive colloids have been successfully used for the measurement of hepatic blood flow in man.32Labeled dyes, such as rose bengal I 131 have been employed to assess the function of the parenchymal cells of the liver. These techniques have not become widely used, because alterations in liver blood flow occur relatively late in hepatic diseases and because the labeled dye studies convey essentially the same information as the conventional liver function test with sulfobromophthalein (Bromsulphalein). In contrast, the technique of scintillation scanning following injection of these labeled materials has steadily increased in popularity since the first successful demonstration of intrahepatic metastases by Friedell et al in 1957.15With this method, the size, shape, and position of the liver can be assessed and focal intrahepatic lesions demonstrated. This diagnostic information cannot be provided by any known radiographic technique. Many authors have reported their results in