This study is testing a new tool called [11C]MODAG-005, which helps doctors see a protein called alpha-synuclein in the brain using a special scanner, PET/CT. This tool is being tested for safety and if it works well. The study involves people with Parkinson's disease (PD), a condition that affects movement, and multiple system atrophy (MSA), which affects movement and other body functions. Healthy people of the same age are also included to compare results.
**Key Points:**
- Participants with PD or MSA will have two scans: one at the start and one 7 to 48 days later. Healthy participants will have one scan.
- A small group with PD or MSA will take a medicine called anle138b (Emrusolmin) before their second scan.
- The study lasts up to 12 weeks, and doctors will check on participants' health and safety often.
This study helps to understand if [11C]MODAG-005 can tell apart PD and MSA from healthy people and study its reliability. Participants should be in good overall health and not have certain medical conditions to join. The study aims to make these scans safer and more useful for diagnosing PD and MSA.