Specific binding to dopamine transporters may serve as a tool to detect early loss of nigrostriatal dopaminergic neurons in patients with Parkinson's disease. Objective: To determine striatal dopamine transporter binding using the cocaine analogue [I-123]N-(3i o d o p r o p e n -2 -y l ) -2 ␤ -c a r b o m e t h o x y -3 ␤ -( 4chlorophenyl) tropane ([I-123]IPT) and single photon emission computed tomography. Patients and Methods: We studied 9 control subjects (mean age, 58 years; range, 41-69

more »

... rs) and 28 patients with early Parkinson's disease (Hoehn and Yahr stages I [n = 14] and II [n = 14] [symptom duration, Ͻ5 years]; mean age, 55.5 years; range, 36-71 years). Single photon emission computed tomography was performed 90 minutes after injection of 120 to 150 MBq of radioactive [I-123]IPT. Results: Specific striatal [I-123]IPT binding (mean ± SD) was significantly reduced in patients with early Parkinson's disease (ipsilateral striatum: 4.09 ± 0.97; range, 2.46-6.40; contralateral striatum: 3.32 ± 0.76; range, 1.80-5.13) compared with controls (left striatum: 7.28 ± 0.94;