Iodine-123 labelled N-(2-fluoroethyl)-2β-carbomethoxy-3β-(4-iodophenyl)nortropane for dopamine transporter imaging in the living human brain

Here we report a pilot comparison of [123I]β-CIT and [123I]β-CIT-FP with a new tropane derivative, [123I]N-(2-fluoroethyl)-2β-carbomethoxy-3β-(4-iodophenyl)nortropane ([123I]β-CIT-FE), using SPET imaging in four healthy male subjects. Peak uptake of [123I]β-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]β-CIT-FE into the basal ganglia was somewhat less (0.785±0.117) than that of [123I]β-CIT (0.922±0.004) or [123I]β-CIT-FP (0.813±0.047). All these tracers have excellent imaging quality in healthy control subjects. However, the relatively fast washout of [123I]β-CIT-FE and low temporal resolution of older SPET cameras may limit the use of this tracer to the measurement of the DAT density. (orig./UG)