PET STUDIES ON BRAIN MONOAMINE TRANSPORTERS WITH CARBON-11-BETA-CIT IN PARKINSONS-DISEASE

The cocaine analog 2 beta-carbomethoxy-3 beta-[4-iodophenyl]tropane (b eta-CIT) labeled with C-11 was used to study dopamine reuptake sites w ith PET. Methods: Three normal subjects and nine patients with Parkins on's disease were investigated. Each of them underwent a dynamic PET s can (25 timeframes over 80 min) with [C-11]beta-CIT. A dose of 102.5-2 11.3 MBq (2.77-5.71 mCi) of this ligand was administered intravenously and a PET examination with an ECAT 931/08 PET camera was carried out. Ratios between the striatal/cortical/thalamic/midbrain and cerebellar uptake of this radioligand were calculated. Results: The highest accu mulation of [C-11]beta-CIT was observed in the caudate and putamen, th ough there was some uptake in the thalamus and the midbrain. Cortical uptake was negligible. Carbon-11-beta-CIT accumulated significantly le ss in the putamen of the Parkinson's patients than in the normal subje cts. The putamen-to-cerebellum ratio in the Parkinson's patients was 1 .59 +/- 0.04 and 1.80 +/- 0.13 (p = 0.028) in the normal subjects. In the caudate, there was no significant difference between the Parkinson 's patients and the normal subjects. Conclusion: These results imply t hat [C-11]beta-CIT is a useful compound for carrying out a PET examina tion of the function of the presynaptic monoaminergic neurons both in normal and pathological brains.