This study mainly aims to prospectively evaluate the changes of reactive astrogliosis in Parkinsonism patients of Chinese population by the novel 18F-labeled MAO-B PET tracer.

18F-SMBT-1, the novel 18F-labeled MAO-B PET tracer, was evaluated reactive astrogliosis in Alzheimer's disease successfully. In this prospective study, we assess the changes of reactive astrocytes in cerebral gray matter and white matter on Parkinson's disease by 18F-SMBT-1 PET/CT imaging among Chinese population.

Inclusion Criteria:

• Aged from 40 to 90 years old.
• Clinically diagnosed as Parkinsonism, including Parkinson's disease and atypical Parkinsonism syndromes.
• Can cooperate with 18F-FDG PET/CT, 18F-FP-CIT PET/CT and 3D T1-weighted structural MR scans.
• Complete clinical data, including modified Hoehn and Yahr staging scale and the Movement Disorders Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS).

Exclusion Criteria:

• Cannot cooperate with PET/CT or MR examination.
• Associated with brain diseases such as stroke, brain trauma, brain tumor, and cranial surgery.

The study population are recruited from the Department of Neurology of the First Affiliated Hospital of University of Science and Technology of China (USTC).