[A new method for pharmacokinetic analysis of 99mTc-GSA using two-compartment and two-parameter model]

Area of Science:

• Nuclear Medicine
• Medical Imaging
• Hepatology

Background:

• Technetium-99m-diethylenetriaminepentaacetic acid-galactosyl-human serum albumin (99mTc-GSA) targets asialoglycoprotein receptors in hepatocytes.
• Assessing liver dysfunction often relies on invasive tests or less precise imaging indices.

Purpose of the Study:

• To evaluate a novel two-compartment, two-parameter (2C2P) model for 99mTc-GSA liver scintigraphy.
• To determine the correlation between parameters derived from the 2C2P model and established liver function tests.

Main Methods:

• Twenty-six patients with liver dysfunction underwent 99mTc-GSA liver scintigraphy.
• A 2C2P model was applied, analyzing time-activity curves from the heart and liver to estimate parameters k1, k2, k1/k2, and VLmg.
• Results were compared with conventional 99mTc-GSA indices (HH15, LHL15, LU15) and serum liver function tests.

Main Results:

• The 2C2P model successfully estimated transfer rate constants (k1, k2) and maximum binding capacity (VLmg).
• Parameters k1/k2 and VLmg showed positive correlations with multiple serum liver function tests, including platelets, total bilirubin, cholinesterase, GOT, LDH, ALP, and gamma GTP.
• The new model's parameters demonstrated a strong correlation with overall liver function.

Conclusions:

• The 2C2P model provides a non-invasive and simplified approach to 99mTc-GSA liver scintigraphy.
• This method shows significant potential for accurately evaluating liver function and may serve as a valuable diagnostic tool.