RecruitingDrug trialThe University of Alabama at Birmingham (UAB) Neuroinflammation in Parkinson's Disease-TSPO- Positron Emission Tomography (PET) SubstudyThe primary objective of this substudy is to measure the concentration and the regional brain distribution of activated brain microglia/macrophages using the PET ligand \[18F\]DPA-714 in participants enrolled in the UAB Innate and Adaptive Immunity in Parkinson's Disease (Clinical Research Core) and Longitudinal \[18F\]DPA-714 Imaging in a Parkinson Disease Cohort studies. The PET tracer \[18F\]DPA-714 binds to the 18 kDa translocator protein (TSPO, also known as the peripheral benzodiazepine receptor) in the mitochondria of activated microglia/macrophages and provides a non-invasive measure of neuroinflammation. The amount and distribution of \[18F\]DPA-714 in the brain will be correlated to clinical data acquired through the separate ongoing UAB Innate and Adaptive Immunity in Parkinson Disease (Clinical Research Core) and Longitudinal \[18F\]DPA-714 Imaging in a Parkinson Disease Cohort studies. The primary objective of this study is to determine if patients with PD have higher levels of neuroinflammation than healthy controls as measured with \[18F\]DPA-714-PET/MRI.