In 1951, Cassen and his associates and Mayneord et al, published the method of Area Scanning technique and apparatus. Since that time, numerous reports on hepatic scanning have appeared. Today, this technique has become widely used. With this method, the size, configuration, and position of the liver can be assessed and focal intrahepatic lesions, such as primary and secondary tumors, abscesses, and cysts, can be demonstrated. As radioactive agents for hepatic scanning, 131I rose bengal, 131I human serum albumin, colloidal198Au, 99Mo and99mTc have been used, and the scan image has been produced by either the imprint or the photoscan method. Many workers now prefer to use radioactive colloidal gold rather than131I rose bengal for hepatic scanning, because colloidal gold is rapidly taken up and permanently held in the Kupffer cells of the liver, whereas131I rose bengal is rapidly excreted via the biliary system, resulting in areas of radioactivity within the gallbladder and small bowel which can be easily confused with abnormalities of the hepatic parenchyma. This study has been performed by using colloidal198Au as a radioactive agent for hepatic scanning. Hepatic scanning was performed with a Model 1700P Nuclear-Chicago Isotope Scanner with a 2×2 inch thallium activated sodium iodide crystal and a 37-holes focusing collimator. Scans of liver tumors (61 cases) are examined and also the fundamental investigation has been performed. This study indicates that a space occupying lesion centrally located in right or left lobe should be at least 3 cm. in diameter to be detected. But we believe that, if liver scanning is performed at the same time using peritoneoscopy and liver function tests, the diagnostic accuracy must be high. Scans of livers affected with diffuse pathologic changes such as, acute hepatitis, chronic hepatitis and cirrhosis also frequently show characteristic abnormalities. Tow hundred and sixty seven cases of liver diseases are included in the series. These scans are divided into five scan patterns, basing on characteristic changes in configuration of liver; (1) Normal, (2) Left Lobe Enlargement, (3) Globular, (4) Enlargement Without abnormality, (5) Enlargement with abnormality (Fig. 1) Correlation of scan patterns to liver diseases is shown (Table 2). As one of characteristic abnormalities, splenic visualization is noted in the hepaticscans of patients with liver diseases, namely, in 9 of the 30 cases with acute hepatitis, in 20 of the 35 cases with chronic hepatitis and 32 of the 35 cirrhotic patients. The splenic visualigation of the hepatic scans has the correlation to the liver fiborosis follwing biopsy finding, but has not to liver cell degeneration, cell infiltration and proliferation of Kupifer's cell. A method to know the function, especially the phagocytic activity, of reticuloendothelial system in liver and spleen is devised. According to this method, the liver spleen uptake ratio (L/S ratio) of intravenously administered198Au colloid in various liver diseases. The correlation of the clinical features in various liver disorders, especially protracted chronic hepatitis and liver cirrhosis, to the L/S ratio is studied. The accounted L/S ratios are distributed from 16 to 22 in the normal cases. The L/S ratios are gradually lowered in order of acute hepatitis, chronic hepatitis, liver cirrhosis and Banti's syndrome. Thes tendency is remrkable in liver cirrhosis and Banti's syndrme and most of them show under 5 of the L/S ratio. On experimental materials (Wistar rats), fibrosis in liver is gradually sever in the order of the liver damaged group by CCl4, by Campbell's method, by yellowed rice, while the L/S ratio is gradually lowered follwing the same order. This decreastng of the L/S ratio depends on the degree of the fibrosis in liver.