Conventional indices of the utilization of FDOPA in living human brain have not consistently revealed important declines in dopamine function with normal aging. However, most methods of kinetic analysis have assumed irreversible trapping of decarboxylated FDOPA metabolites in brain, an assumption that is violated even in PET recordings of short duration. Therefore, we have developed methods for the calculation of steady-state storage of FDOPA together with its decarboxylated metabolites (Vd, mlg−1), based upon improved kinetic analysis of 120-min emission recordings.Centre for Functionally Integrative Neuroscience,

Aarhus University, Denmark

Department of Nuclear Medicine, Graduate School of Medicine, The University of Tokyo, Japan

Department of Psychiatry and Psychotherapy, RWTH Aachen University, Germany

Department of Nuclear Medicine, University of Mainz, Germany

Department of Psychiatry, Charité Hopsital, Berlin, Germany

Department of Nuclear Medicine, University of Munich, Germany