Dynamic SPECT in two healthy volunteers to determine the optimal time for in vivo D2 dopamine receptor imaging with 123I-IBZM using the rotating gamma camera.

Dynamic SPECT was performed in two healthy male volunteers with a single slice brain dedicated camera (Strichman Medical Equipment 810, first study) and a rotating gamma camera (Siemens Dual Rota ZLC37, second study) to obtain information about the optimal imaging time for the dopamine D2 receptor specific ligand 123I-(S)-(-)-2-hydroxy-3-iodo-6-methoxy-N[(1-ethyl-2-pyrrolidinyl) methyl]-benzamide (123I-IBZM). Count rates in the basal ganglia and in several cerebral cortical regions were used to define specific and aspecific binding, respectively. On the basis of the first study, 90-150 min seemed the optimal time for rotating gamma camera 123I-IBZM-SPECT.

In vitro and in vivo D2-dopamine receptor binding with [123I]S(-) iodobenzamide ([123I]IBZM) in rat and human brain.

As a promising dopamine D2-receptor imaging agent for single photon emission computerized tomography (SPECT), [123I](S)-(-)-2-hydroxy-3-iodo-6-methoxy-N [(1-ethyl-2-pyrrolidinyl)methyl]benzamide ([123I]IBZM) has recently been synthesized in a modified way along with its precursor, S(-)BZM, and the stereoisomer R(+)BZM. The present study applied this new product to investigate in vitro and in vivo D2-receptor binding in rat brain and in postmortem human brain. In vitro saturation binding curves with [123I]IBZM for rat crude striatal membrane preparations yielded an affinity constant (Kd) of 0.

In vivo characterisation of 3-iodo-6-methoxybenzamide 123I in humans.

3-Iodo-6-methoxybenzamide (123I-IBZM), a new Dopamine D2 receptor ligand, was used in conjunction with SME 810 brain tomography to study six subjects (one normal volunteer, four schizophrenics and one DAT patient). Initial Dynamic SPET was followed by multislice SPET. High-resolution images of the D2 receptor distribution in the basal ganglia were obtained.