A Study of Brain Imaging With Nuclear Medicine Technology in Individuals With and at Risk for Parkinson's Disease

This study involves study participants who have been clinically diagnosed with parkinsonian syndrome or who are at-risk for parkinsonian syndrome, have a family history of parkinsonian syndrome or exposure to environmental toxins potentially associated with parkinsonian syndrome. Participants will have brain imaging to assess dopamine transporter density. The imaging data coupled with family history and environmental exposure data may provide important information about potential risk factors for parkinsonian syndrome.