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 (99mTc, 111In, 67Ga, 131/125I, 153Sm) and PET isotopes (68Ga, 18F). 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.