Asialoglycoprotein receptor-targeted radiopharmaceuticals for measurement of liver function.

The number of Asialoglycoprotein (ASGP) receptors on the hepatocytes of patients with liver disease is reduced and is thus considered a good indicator for the evaluation of liver function. ASGP receptor-targeted radiopharmaceuticals permit a non-invasive way to evaluate total and regional hepatic function and hepatic functional reserve visually and quantitatively. Over the past three decades, a variety of ASGP receptor-targeted probes have been developed with different molecular backbones (albumin, polymer, small-molecular-weight ligand), different glycol-residues (galactose, lactose, N-acetyl-galactosamine) and different chelating systems suitable for radiolabeling with SPECT isotopes ((99m)Tc, (111)In, (67)Ga, (131/125)I, (153)Sm) and PET isotopes ((68)Ga, (18)F). In this review, we present an overview of ASGP receptor-targeted radiopharmaceuticals, discuss their chemistry, biodistribution, catabolism and challenge as well as application for measurement of liver function.