Tomographic Mapping of Kinetic Rate Constants in the Fluorodeoxyglucose Model Using Dynamic Positron Emission Tomography

A quick computing algorithm to calculate the rate constants (k*1, k*2, k*3) in the [18F]2-fluoro-2-deoxy-D-glucose (FDG) model was developed. The algorithm solved for the rate constants pixel by pixel using a conventional least-squares method and two tables consisting of a set of various rate constants, to shorten the computing time. Five planes of rate constant images were obtained. A combined study using the dynamic FDG method and the 15O-labeled gas continuous inhalation method was performed on seven healthy male volunteers aged 26-35 years. Results indicated an apparent discrepancy between CMRglu and CMRO2 in the cerebellum, where the low glucose utilization was correlated with a low FDG phosphorylation rate (k*3) despite a sufficient FDG transportation rate (k*1) from plasma to tissue.