The purpose of this study is to learn if a special type of imaging drug, called a “radioactive tracer” can help doctors see sites of pheochromocytoma or paraganglioma more clearly when used with a procedure called Positron Emission Tomography/Computed Tomography (PET/CT).” Eligible participants will complete the following research procedures: • Up to 2 18F-FTT PET/CT scans: before starting a new treatment for pheochromocytoma or paraganglioma and 1-21 days after start of treatment (The second scan is OPTIONAL). • Optional research collection of tissue from a surgical specimen or clinical biopsy (if applicable). Participants who agree to the scan after treatment, may be in the study for up to 6 weeks. The active part of participation during this time will only include PET/CT scan visits. Participants will be asked for permission to store and use data related to your participation in this study for future use. Participants will be compensated up to $150.00 per FTT PET/CT scan for participation in the study, for a potential total of $300.00 if they are undergoing two scans.

You may be eligible for this study if you meet the following criteria:

• Conditions: Pheochromocytoma and Paraganglioma
• Age: 18 years - 99 years
• Gender: All