We plan to enroll up to 16 adult subjects in this study. We will enroll up to 8 patients with a diagnosis of probable idiopathic Parkinsons Disease (PD cohort) and up to 8 age and gender matched Healthy Controls (HC cohort). PET/CT imaging will be used to evaluate neuroinflammation in the brain using the investigational radiotracer [18F]NOS. Each subject will have one [18F]NOS positron emission tomography/computed tomography (PET/CT) scan performed. Patients will undergo approximately 60 minutes of dynamic scanning of the brain starting at approximately the time of injection of [18F]NOS. PET/CT imaging sessions will include an injection of 6.5 mCi (approximate range for most studies is anticipated to be 3.5-6.5 mCi) of [18F]NOS. Data will be collected to evaluate uptake of [18F]NOS in the brain and measurements will be compared between HCs and PD patients. Arterial blood samples will be taken during the scan session for measurement of radioactive counts and/or biometabolites. Subjects in both cohorts are required to have a brain MRI performed within 1 year of study enrollment. If the subject has not had a brain MRI that is deemed acceptable for use for this study, they will be asked to undergo a research brain MRI after they have consented for this study. We will draw a 10 mL venous blood sample prior to injection that will be used to measure inflammatory cytokines and mitochondrial molecules implicated in inflammation. The results of these research tests will not be given to the subject, will not be included in the medical record and will not be used in the subjects clinical management.

You may be eligible for this study if you meet the following criteria:

• Conditions: Parkinsons Disease
• Age: 99 years or below
• Gender: All