Characterization of the Serotonin 2A Receptor Selective PET Tracer [18F]MH.MZ in Patients With Neurodegenerative Diseases

This study is testing a new PET scan imaging agent that targets serotonin receptors in the brain, to help diagnose and better understand neurodegenerative diseases like Parkinson's disease, Lewy body dementia, Huntington's disease, and frontotemporal dementia. **You may be eligible if...** - You have a clinical diagnosis of Parkinson's disease, Lewy body disease, multiple system atrophy, Huntington's disease, frontotemporal dementia, or a related condition - Or you are a healthy volunteer matched in age and gender to a patient participant - You have a study partner available to accompany you to visits - If you have Parkinson's: you experience hallucinations or delusions at least weekly for 4 weeks that are severe enough to need treatment **You may NOT be eligible if...** - You are unwilling to participate - You have severe kidney problems (low filtration rate) - You have a history of serious allergy to gadolinium-based contrast agents - You have claustrophobia or another contraindication to MRI scanning Talk to your doctor to see if this trial is right for you.