[I-123] BETA-CIT SINGLE-PHOTON EMISSION TOMOGRAPHY IN PARKINSONS-DISEASE REVEALS A SMALLER DECLINE IN DOPAMINE TRANSPORTERS WITH AGE THAN IN CONTROLS

In vivo studies using single-photon emission tomography (SPET) and pos itron emission tomography have shown an age-related decline in the num ber of striatal dopamine transporters in healthy subjects. We examined ten healthy subjects and 33 de novo patients with Parkinson's disease (PD) using [I-123]2 beta-carbomethoxy-3 beta-(4-iodophenyl)tropane ([ I-123]beta-CIT) SPET, A clear age-related loss of dopamine transporter s was found in the healthy subjects. In the PD group, controlling for the contribution of disease severity, we found a small (compared with controls) but significant decrease with aging, though only in the ipsi lateral regions. This aging effect was especially pronounced in younge r patients. We conclude that the use of age-correct SPET data in PD, b ased on studies with healthy subjects, may lead to an under- or an ove restimation of the striatal binding measures.