The main objective of this study is to establish a standardized method for [18F] - FD17 PET imaging in α-synucleinopathy patients, and to analyze its physiological distribution in healthy individuals as well as its pathological distribution in α-synucleinopathy patients, including Parkinson's disease (PD), multiple system atrophy (MSA), and idiopathic rapid-eye-movement sleep behavior disorder (iRBD). Specifically, [18F] - FD17 PET imaging focuses on evaluating the deposition of α-synuclein and exploring the diagnostic value of [18F] - FD17 PET in PD, MSA, and iRBD patients. In addition, for PD, MSA and RBD patients, dopamine transporter(DAT)-PET imaging was performed to evaluate the distribution and density of DAT in brain. The study aims not only to clarify the specific binding mode of the imaging agent in different α-synucleinopathies, but also to evaluate its efficacy and potential application prospects in early diagnosis , providing new methods for the diagnosis and treatment of neurodegenerative diseases. This study is expected to contribute to early pathological detection and accurate diagnosis in clinical practice.

Inclusion Criteria:

• 1: Normal cognitive function, CDR score=0（for healthy subjects）

  2: Without neurological disorders, major chronic diseases, malignant tumors, or acute infectious diseases (for healthy subjects）

  3: Without the family history of neurological disorders related to motor or cognitive impairments(for healthy subjects）

  4: Clinical diagnosis of idiopathic PD (for PD patients)

  5: Clinical diagnosis of MSA (for MSA patients)

  6: Clinical diagnosis of idiopathic RBD (for RBD patients)

  7: An informed consent form signed in writing by the subject or their legal guardian or caregiver.

  8: Must be abled to be accompanied by nursing staff

  9: Must be able to understand and sign a informed consent form before any evaluation and examination

  10: Must have medical records to prove that they have undergone surgical sterilization (such as hysterectomy, bilateral oophorectomy, or tubal ligation) or menopause for more than one year.(for female subjects)

  11: Must adopt isolation contraception measures within 3 months after the start of this study.(for female subjects)

  12: Willing and capable to cooperate with all projects of this study.

Exclusion Criteria:

• 1: Other severe neurological disorders. Gastrointestinal, cardiovascular, liver, kidney, hematological, tumor, endocrine, respiratory, immunodeficiency, and other serious diseases.

  2: Received ionizing radiation outside the scope of this experiment, resulting in an annual radiation exposure dose exceeding 50 mSv in the past year,

  3: History of drug abuse or alcoholism

  4: Pregnant or lactating women

  5: Poor venous conditions, unable to tolerate repeated venipuncture

  6: Received experimental drug or device treatment with unclear efficacy or safety in last 1 month.

  7: Any situation that the investigators believe may cause harm or potential harm in any aspect related to this study

10 PD subjects ,10 MSA subjects, 10 RBD subjects ,and 5 healthy control subjects