A linear compartment model analysis on the liver scintigraphy with 99mTc-GSA

99mTc-galactosyl human serum albumin (99mTc-GSA) is a newly developed receptor-binding agent, specific for the asialoglycoprotein receptor, which resides exclusively on the plasma membrane of mammalian hepatocytes. Liver scintigraphy using 99mTc-GSA was performed on 40 patients with liver diseases. Dynamic data were obtained by a gamma camera during 20 minutes after intravenous injection of 3 mg (185 MBq) of 99mTc-GSA. Rate constant P(2)* (1/min) of 99mTc-GSA transferred from hepatic blood to receptor was determined, assuming linear compartment model. P(2)*·Km that was given by the product of P(2)* and Michaelis constant Km was significantly correlated with the maximum removal rate by the nonlinear compartment model taken into account of the Michaelis-Menten type (r2=0.972, n=40). P(2)*·Km by graphical method was also well correlated with P(2) (r2=0.988, n=40). It was concluded that the linear compartment model was applicable to liver scintigraphy with 99mTc-GSA, moreover, the graphical method could easily evaluate the maximum removal rate. (author)