Neuroimaging of the dopamine transporter in Parkinson's disease:: first study using [99mTc]-TRODAT-1 and SPECT in Brazil

Background: Dopamine transporter (DAT) neuroimaging radiotracers were developed to estimate dopamine neuronal loss in vivo in Parkinson's disease (PD). Objective: To evaluate DAT density in vivo using [Tc-99m]-TRODAT-1 and single photon computerized tomography (SPECT) in a population of Brazilian PD. Method: Fifteen PD patients and 15 matched healthy controls scanned with [Tc-99m]-TRODAT-1 (INER-Taiwan) and SPECT. Estimates of striatum DAT density were calculated using binding potential (BP). Patients were assessed with PD scales. Results: PD patients had significantly lower striatal DAT-BP (mean SD) (0.38 +/- 0.12) compared to controls (BP=0.84 +/- 0.16; p < 0.01). A 100% sensitivity and 100% specificity was obtained to discriminate PD cases from controls. Negative correlations between striatal DAT-BP and PD severity (rho= -0.7, p < 0.001) and motor scales (rho= -0.80, p < 0.001) were found. Conclusion: [Tc-99m]TRODAT-1 SPECTs scanning was able to discriminate PD patients from controls. The technique is a powerful instrument to measure DAT density that can be used in clinical and research settings in Brazil.