Analysis of Kinetic Rate Constants in [¹⁸F] Fluorodeoxyglucose Model Using a Least Square Fitting Package SALS (Statistical Analysis with Least Squares)

Abstract

The analysis of kinetic rate constants in the compartment model for [¹⁸F] fluorodeoxyglucose (FDG) was undertaken. Four kinetic rate constants were determined with a least square fitting package SALS (Statistical Analysis with Least Squares), using the measured data of ¹⁸F activity as a function of time. SALS calculations were found to be easy and quick with high precision. The rate constants and the curves fitted by the k₃ and the k₄ models were compared in situations with various degree of cerebral glucose metabolism during positron emission tomography (PET) studies. The k₄ model in the determination of cerebral metabolic rate for glucose (CMR_glu) was much superior than the k₃ model in any given situation as it always underestimates the metabolic rate. However, the k₃ model produces less variation when the cerebral radioactivity curve shows steady rising pattern.