Kinetic metrics of F-FDG in normal human organs identified by systematic dynamic total-body positron emission tomography

Purpose: To investigate the kinetic metrics of 2-[F]-fluoro-2-deoxy-d-glucose (F-FDG) in normal organs by using dynamic total-body (TB) positron emission tomography (PET). Methods: Dynamic TB-PET was performed for nine healthy volunteers. Time-to-activity curves (TACs) were obtained by drawing regions of interest in the organs. A two-tissue compartment model was fitted for each tissue TAC. Constant rates, including k, k, and k, and the metabolic rate of FDG (MRFDG) were obtained. The parameter statistics, including the average, standard deviation, coefficient of variance, and inter-site and inter-individual variances, were compared. Results: Constant rates and MRFDG varied significantly among organs and subjects, but not among sides or sub-regions within an organ. The mean k and k ranged from 0.0158 min in the right lower lung to 1.1883 min in the anterior wall of the left ventricle (LV) myocardium and from 0.1116 min in the left parietal white matter to 4.6272 min in the left thyroid, respectively. The k was lowest in the right upper area of the liver and highest in the septal wall of the LV myocardium. Mean MRFDG ranged from 23.1696 μmol/100 g/min in the parietal cortex to 0.5945 μmol/100 g/min in the lung. Four groups of organs with similar kinetic characteristics were identified: (1) the cerebral white matter, lung, liver, muscle, bone, and bone marrow; (2) cerebral and cerebellar cortex; (3) LV myocardium and thyroid; and (4) pancreas, spleen, and kidney. Conclusion: The kinetic rates and MRFDG significantly differed among organs. The kinetic metrics of FDG parameters in normal organs can serve as a reference for future dynamic PET imaging and research.