Imaging to Better Understand and Diagnose Brain Disorders

Background: A radioligand is a radioactive substance that is used to diagnose diseases. A new ligand is called [11C]PS13. This has a small amount of radioactivity that can be detected by a positron emission tomography (PET) scan. If this ligand works well in this study, researchers may be able to use it to better understand and diagnose brain disorders. Objectives: To evaluate if [11C]PS13 can measure its receptor, which is involved in inflammation. To see if researchers get the same results when scanning a person twice. Eligibility: Healthy people ages 18 and older who are in Protocol 01-M-0254. Design: This study requires three visits of 2 5 hours each. Participants will have 2 PET scans with [11C]PS13. A needle will guide a small plastic tube (catheter) into an arm vein. The needle will be removed, leaving only the catheter in the vein. The ligand will be injected through the catheter. The PET scanner is shaped like a doughnut. Participants will lie on a bed that slides in and out of the scanner. Participants will wear a molded a plastic mask that fits the head. Another catheter will be put into an artery at the wrist or elbow area. Vital signs will be monitored during the PET scan. Participants will have a test during the PET scan to monitor heart function. Participants will have blood and urine tests. Participants will have 1 magnetic resonance imaging (MRI) scan. The MRI scanner is a metal cylinder surrounded by a strong magnetic field. Participants will lie on a table that slides in and out of the cylinder.