title: Iodine-123 labelled N-(2-fluoroethyl)-2 beta-carbomethoxy-3 beta-(4-iodophenyl)nortropane for dopamine transporter imaging in the living human brain.
abstract: There are several cocaine analogs which have potential for imaging the dopamine transporters (DAT). Earlier studies have shown that iodine-123 labelled 2 beta-carbomethoxy-3 beta-(4-iodophenyl)tropane ([123I]beta-CIT) and N-(3-fluoropropyl)-2 beta-carbomethoxy-3 beta-(4-iodophenyl)nortropane ([123I]beta-CIT-FP) are promising DAT imaging agents in the living human brain with single-photon emission tomography (SPET). Here we report a pilot comparison of [123I]beta-CIT and [123I]beta-CIT-FP with a new tropane derivative, [123I]N-(2-fluoroethyl)-2 beta-carbomethoxy-3 beta-(4-iodophenyl)nortropane ([123I]beta-CIT-FE), using SPET imaging in four healthy male subjects. Peak uptake of [123I]beta-CIT-FE into the basal ganglia occurred very rapidly (0.5 h after injection of tracer), after which the striatal washout obeyed a bi-exponential form. The specific DAT binding of [123I]beta-CIT-FE into the basal ganglia was somewhat less (0.785 +/- 0.117) than that of [123I]beta-CIT (0.922 +/- 0.004) or [123I]beta-CIT-FP (0.813 +/- 0.047). All these tracers have excellent imaging quality in healthy control subjects. However, the relatively fast washout of [123I]beta-CIT-FE and low temporal resolution of older SPET cameras may limit the use of this tracer to the measurement of the DAT density.
mesh_terms: D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D003042:Cocaine / Q000031:analogs & derivatives / Q000493:pharmacokinetics; D004298:Dopamine / Q000378:metabolism*; D050483:Dopamine Plasma Membrane Transport Proteins; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D008875:Middle Aged; D009419:Nerve Tissue Proteins; D009662:Nortropanes / Q000493:pharmacokinetics; D010865:Pilot Projects; D015899:Tomography, Emission-Computed, Single-Photon; D014326:Tropanes / Q000493:pharmacokinetics
chemical_list: D002352:Carrier Proteins; D050483:Dopamine Plasma Membrane Transport Proteins; D007457:Iodine Radioisotopes; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; C097058:N-(2-fluoroethyl)-2-carbomethoxy-3-(4-iodophenyl)nortropane; D009419:Nerve Tissue Proteins; D009662:Nortropanes; C493214:SLC6A3 protein, human; D014326:Tropanes; C087552:2-carbomethoxy-8-(3-fluoropropyl)-3-(4-iodophenyl)tropane; C069723:2beta-carbomethoxy-3beta-(4-iodophenyl)tropane; D003042:Cocaine; D004298:Dopamine