SPECT Imaging of Dopamine Transporter with I-123 IPT in Normal Controls and Parkinson's Patients

ABSTRACT

OBJECTIVES: Dopamine transporter concentrations have been known to decrease in Parkinson's disease(PD). The aim of the present study was to evaluate the correlation between SPECT measurements of [I-123]N-(3-iodopropene-2-yl)-2beta-carbomethoxy-3beta-(4-chlorophenyl) tropane(IPT) as an imaging agent for measuring changes in transporter concentrations with PD. PATIENTS AND METHODS:IPT labelled with 4.87+/-1.29mCi(180.19+/-47.73 MBq) of [I-123] was intravenously injected into 23 patients(age58+/-12) with PD and three normal controls(NC)(age37+/-7) as bolus. Brain SPECT were then performed at 1 hour and 2 hours after injection on a double headed camera. The statistical parameters were the contrast ratio of left basal ganglia(BG) and right basal ganglia to occipital cortex(OCC) per milli curies of injected radiotracer at 1 hour and 2 hours. The correlations were evaluated between these parameters and Hoehn-Yahr classification of the patients. RESULTS: The(BG-OCC)/OCC/mCi ratios at 1 hour and 2 hours for PD and NC were 0.14+/-0.07 and 0.27+/-0.07(1 hour) and 0.12+/-0.07 and 0.34+/-0.04(2 hour), respectively. The(BG-OCC)/OCC/mCi ratios of Parkinson's disease were decreased with higher grade of Hoehn-Yahr classification of the patients. The ratio between BG and OCC for PD were clearly separated from NC and may be useful outcome measures for clinical diagnosis. CONCLUSION: The findings suggest that IPT may be a very useful tracer for early diagnosis and treatment of PD and study of dopamine re-uptake site.