title: [123I] beta-CIT, a tracer for dopamine and serotonin re-uptake sites: preparation and preliminary SPECT studies in humans.
abstract: beta-CIT (2 beta-carbomethoxy-3 beta-(4-iodophenyl)tropane) is a new ligand that has a high affinity to dopamine and serotonin re-uptake sites. [123I] beta-CIT was prepared by reacting the corresponding trimethylstannyl precursor with no-carrier-added 123I. Iodogen was used as an oxidizing agent. The labeling mixture was purified by filtration through a mini-column. The purity of the product was confirmed by analytical HPLC. The total radiochemical yield was 67 +/- 5%. The radiochemical purity was > 95% and the specific activity was > 107 GBq/mol (> 2900 Ci/mmol). The final product was confirmed to be free of endotoxins before intravenous administration. Two healthy male volunteers were injected iv with 120-160 MBq of [123I] beta-CIT and scanned with a 3-head gamma-camera (Siemens MultiSPECT3). Dynamic SPECT scans were performed for up to 2 hours. There was a high accumulation of radioactivity in the striatum and in the thalamus, and some in the medial prefrontal area. Thus, we have developed an easy method to prepare [123I] beta-CIT with a high specific radioactivity and in a sufficient radiochemical yield. Specific [123I] beta-CIT binding in striatal and thalamic regions was demonstrated in humans. [123I] beta-CIT is a potential marker of the dopamine and serotonin transporters and can be used to study the pathophysiology of Parkinson's disease, as well as neuropsychiatric disorders.
authors.affiliation: Department of Clinical Physiology and Nuclear Medicine, Kuopio University Hospital, Finland.
authors.forename: K A
authors.initials: KA
authors.lastname: Bergström
authors.forename: J T
authors.initials: JT
authors.lastname: Kuikka
authors.forename: A
authors.initials: A
authors.lastname: Ahonen
authors.forename: E
authors.initials: E
authors.lastname: Vanninen
mesh_terms: D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging*; D002352:Carrier Proteins / Q000378:metabolism; D003042:Cocaine / Q000031:analogs & derivatives*; D004298:Dopamine / Q000378:metabolism; D050483:Dopamine Plasma Membrane Transport Proteins; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism; D026901:Membrane Transport Proteins; D008875:Middle Aged; D009419:Nerve Tissue Proteins; D012701:Serotonin / Q000378:metabolism; D050486:Serotonin Plasma Membrane Transport Proteins; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D002352:Carrier Proteins; D050483:Dopamine Plasma Membrane Transport Proteins; D007457:Iodine Radioisotopes; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins; D012701:Serotonin; C069723:2beta-carbomethoxy-3beta-(4-iodophenyl)tropane; D003042:Cocaine; D004298:Dopamine