Measurement of the Global Lumped Constant for 2-Deoxy-2-[ 18F]Fluoro-D-Glucose in Normal Human Brain Using [ 15O]Water and 2-Deoxy-2-[ 18F]Fluoro-D-Glucose Positron Emission Tomography Imaging : A Method with Validation Based on Multiple Methodologies

Abstract

PURPOSE: This study aims to determine a lumped constant (LC) value that can be applied to the 2-deoxy-2[ 18F]fluoro-D-glucose positron emission tomography (FDG-PET) study to yield a physiological value of cerebral metabolic rate of glucose (CMR glc) in normal brain. PROCEDURES: We developed a more robust method for determining the global FDG LC. Dynamic FDG and H 2 15O PET studied were acquired in 18 normal subjects. Arterial-venous difference of blood glucose level was measured. RESULTS: A global LC of 0.65 ± 0.15 was obtained if a 3-microparameter FDG model ( k 4 *=0)was assumed. Assumption of a 4-microparameter FDG model ( k 4 *≠0) in analyzing the FDG data resulted in a higher LC value of 0.81 ± 0.18. CONCLUSION: The value of LC used for quantitating CMR glc should match the assumption inherent to the method of data analysis. The LC results in this study agree well with recent findings in the literature.