Evaluation of [11C]ZTP-1 to Image PDE4B

Background: PDE4B is a protein in cells that helps turn off certain chemical signals after they ve done their job. It controls inflammation, immune responses, and some brain signaling. Measuring PDE4B levels in the body can help doctors manage a disease or know if a treatment is working. Researchers want to find out if a new tracer (a radioactive substance injected during imaging scans) can help them measure PDE4B in people more effectively. Objective: To test a new tracer (\[11C\]ZTP-1) during imaging scans of the brain and body in healthy people. Eligibility: Healthy people aged 18 and older. They must have been screened under protocols 01M-0254 or 17M0181. Design: Participants will have either 1 or 2 clinic visits. During their first visit, all participants will have a positron emission tomography (PET)/computed tomography (CT) scan. Prior to the scan, they will have blood and urine tests and a test of their heart function. The study tracer will be given through a tube attached to a needle inserted into a vein in the arm. They will lie on a padded bed that fits inside a doughnut-shaped machine; the machine uses x-rays to create images of the inside of the body. Some participants will have a PET/CT scan of their whole body. They will need only 1 visit. The visit will last up to about 8 hours. Some participants will have a PET/CT scan of only their brain. They will also have a magnetic resonance imaging (MRI) scan of the brain. They may need to return for a second visit for the MRI scan. Participants will receive a follow-up call to check on their well-being after their PET/CT scans.