Measurement of functioning hepatocyte mass via [99mTc]galactosyl-neoglycoalbumin

Technetium-99m-galactosyl-neoglycoalbumin (TcNGA) is a synthetic radiolabeled ligand specific for hepatic binding protein (HBP), a receptor that resides exclusively on hepatocytes. In vivo measurement of receptor concentration was obtained via kinetic analysis of liver and blood time-activity data obtained during the hepatic clearance of intravenously administered TcNGA. The purpose of this study was to assess receptor concentration as a measure of the functioning hepatocyte mass. Therefore, TcNGA and dual-injection indocyanine green maximal removal rate (ICG Rmax) studies were performed on nine patients with hepatic cirrhosis associated or not with hepatocellular carcinoma. Receptor concentration was compared with ICG Rmax, which is a validated method for the estimation of the functioning hepatocyte mass. The correlation coefficient was 0.76 (P = 0.017). It is concluded that HBP concentration ([HPB]o) as measured by functional imaging is a measure of functioning hepatocyte mass. This implies that measurement of an individual's receptor concentration by using nuclear medicine techniques provides an objective index of hepatic functional mass and supports attempts to rigorously evaluate [HBP]o for its clinical efficacy.