Brain regional α-[11C]methyl-L-tryptophan trapping, used as an index of 5-HT synthesis, in healthy adults: absence of an age effect

Purpose Previous functional neuroimaging studies suggest that selective aspects of the brain serotonin (5-HT) system change during the aging process. Here, we assessed the effects of aging on the brain regional α-[11C]methyl-L-tryptophan (α-[11C]MTrp) trapping rate constant (K*; μl·g−1·min−1), which, with certain assumptions, could be taken as a proxy of 5-HT synthesis.