Dopamine D2 receptor imaging with I-123 IBZM in patients with Parkinson Disease

In this paper the authors evaluate I-123 IBZM SPECT as a tool for cerebral D2 receptor imaging in patients with Parkinsonian symptoms. Fifteen patients were studied according to the following protocol: 5 mCi of I-123-IBZM was administered intravenously. Dynamic acquisition was performed 0-20 minutes after injection, and three SPECT series were performed after injection with a single-head rotating gamma camera. Transaxial, coronal, and sagittal sections were reconstructed. Visual and quantitative evaluation was performed with the region of interest technique. Signal intensity within the basal ganglia (BG), frontal cortex (FC), and cerebellum (CB) was measured and ratios were calculated. Age, sex, clinical features, and type of pharmacologic dopaminergic regime were correlated with SPECT data. In 11 of 15 patients, high specific uptake of I-123-IBZM in the BG could be visualized, where BG-CB ratios were highest at the third SPECT series, indicating high D2 receptor density and availability. However, a significantly reduced uptake was found in three of 15 patients who were on a therapeutic regimen with the D2 receptor ligand Lisurid