A novel liver function evaluation system using radiopharmacokinetic modeling of technetium-99m-DTPA-galactosyl human serum albumin.

Background A new kinetic model of technetium-99m-labeled diethylenetriaminepentaacetic acid-galactosyl human serum albumin (Tc-99m-GSA) was developed to show the speed of asialoglycoprotein receptor-mediated endocytosis.Materials and methods Ten healthy volunteers and 17 patients with liver cirrhosis were intravenously injected with 185 MBq of Tc-99m-GSA, and dynamic planar images were acquired. The absolute amounts of Tc-99m-GSA in the liver and extrahepatic blood were estimated from the time-activity curves for the liver, heart, and lungs. A two-compartment model was represented with two parameters as variables to estimate the uptake index (UI) of Tc-99m-GSA transport through the hepatic cell membrane from the total plasma at any given time.Results The dynamic curve of Tc-99m-GSA uptake by the liver was generated. Analysis of individuals with normal livers and patients with liver cirrhosis showed statistically significant differences in their UI. The UI for normal livers was high and that for cirrhotic livers was low. Linear regression correlation of UI with albumin, prealbumin, and prothrombin time was 0.841, 0.746, and -0.723, respectively.Conclusion UI reflects the cellular transport of asialoglycoproteins as ascertained by the two-compartment model on the basis of GSA dynamic images. It is useful for measuring liver function.