STRIATAL F-18 DOPA UPTAKE - ABSENCE OF AN AGING EFFECT

L-[F-18]6-Fluoro-DOPA (L-[F-18]6-fluoro-3,4-dihydroxyphenylalanine; FDOPA) has been used with quantitative positron emission tomography (PET) to assess presynaptic nigrostriatal dopaminergic function in life. The relationship of estimated kinetic rate constants for striatal FDOPA uptake [K(i)(FDOPA)] to the normal aging process has been the subject of conflicting reports. Resolution of this issue has been hampered by methodological differences in previous FDOPA/PET investigations. We studied 19 healthy normal subjects (aged 27-77 years) and measured striatal K(i)-(FDOPA) according to each of the earlier methods. While significant correlations (p < 0.005) existed between K(i)(FDOPA) values estimated by the various techniques, none correlated with normal aging. We conclude that normal striatal K(i)(FDOPA) values estimated using quantitative FDOPA/PET are uncorrelated with the aging process.