Parkinson's disease can be difficult to diagnoses as there are Parkinsonian feature of other cause or uncertainty in the early stage of Parkinson's disease (PD). Miss clinical diagnosis or delayed diagnosis rates were reported 15-20% in Parkinson's disease in the early stage. 

The purposes of this study were 1) to compare diagnostic accuracy of 18F FP-CIT PET/CT and 2) to validate of clinical effectiveness of 18F FP-CIT PET/CT in suspicious early Parkinson disease.