The objective of this protocol is to analyze the sensitivity and specificity of 18F-DTBZ PET to the differential diagnosis of Parkinson's disease (PD) and other parkinsonism disorders, including multiple system atrophy (MSA), corticobasal degeneration (CBD), and progressive supranuclear palsy (PSP).

40 patients with PD, 40 patients with MSA, 20 patients with CBD, and 20 patients with PSP, will be enrolled. Each evaluable subject involved in this study must fulfill all the inclusion and exclusion criteria according the subject grouping, each subject will have 3 visits in this study, as one screening visit, one imaging visit, and one safety evaluation visit.

Safety measurement will be evaluated by medical history, vital signs, physical examinations,

Inclusion Criteria:

1. Forty subjects with a diagnosis of PD whom must:

   i.Male or female patients, age range 20~80. ii.Patients should be fulfilled Criteria of diagnosis of Parkinson disease8 of "possible" or "probable" PD (Appendix I).

   iii.Patients who provide a written informed consent prior to study entry. If the patient is incapable of informed consent, the caregiver may consent on behalf of the patient (the patient must still confirm assent).

2. Forty subjects with a diagnosis of MSA whom must:

   i.Male or female patients, age range 20~80. ii.Patients should be fulfilled the Consensus diagnostic criteria of "possible" or "probable" MSA14 (Appendix II).

   iii. Patients who provide a written informed consent prior to study entry. If the patient is incapable of informed consent, the caregiver may consent on behalf of the patient (the patient must still confirm assent).

3. Twenty subjects with a diagnosis of PSP whom must:

   i.Male or female patients, age range 20~80. ii.Patients should be fulfilled the NINDS-SPSP clinical criteria for the diagnosis of PSP of "possible" or "probable" PSP35 (Appendix III).

   iii.Patients who provide a written informed consent prior to study entry. If the patient is incapable of informed consent, the caregiver may consent on behalf of the patient (the patient must still confirm assent).

4. Twenty subjects with a diagnosis of CBD whom must:

   i.Male or female patients, age range 20~80. ii.Patients should be fulfilled the Kumar's criteria of CBD36 (Appendix IV). iii.Patients who provide a written informed consent prior to study entry. If the patient is incapable of informed consent, the caregiver may consent on behalf of the patient (the patient must still confirm assent).

Exclusion Criteria:

1. Pregnant or becoming pregnant during the study or current breast feeding.

2. Any subject who has a clinically significant abnormal laboratory values, and/or clinically significant or unstable medical or psychiatric illness.

   i.Clinically significant hepatic, renal, pulmonary, metabolic, or endocrine disturbances.

   ii.Current clinically significant cardiovascular disease. (cardiac surgery or myocardial infarction within the last 6 months; unstable angina; decompensated congestive heart failure; significant cardiac arrhythmia; congenital heart disease.

3. History of drug or alcohol abuse within the last year, or prior prolonged history of abuse.

4. History or presence of QTc prolongation.

5. History of intracranial operation, including thalamotomy, pallidotomy, and/or deep brain stimulation.

6. Any documented abnormality in the brain by CT or MRI of brain, which might contribute to the motor function, such as hydrocephalus, multiple infarction and encephalomalacia, will be excluded. Mild cortical atrophy and non-specific white matter changes will be allowed.

7. Patients who have the evidence of secondary parkinsonism (multiple infarcts, intoxication, and hydrocephalus, etc) or other neurodegenerative diseases, such as spinocerebellar atrophy (SCA), Wilson's disease, hydrocephalus, multiple infarction, serious head injury and definite history of neurotoxin exposure, are excluded.

8. General PET exclusion criteria.