[18F]FTC-146 is a sigma-1 receptor detector and is an experimental radiotracer. Several studies have implicated involvement of sigma-1 receptors in generation and perpetuation of chronic pain conditions, while others are investigating anti sigma-1 receptor drugs for treatment of chronic pain. Using [18F]-FTC-146 and PET/MRI, we hope to learn what is the best approach to identify the source of pain generation and characterize the disease in pediatric patients with chronic pain.

It is estimated that 20% to 35% of children and adolescents worldwide are affected by chronic pain. As a result of chronic pain, children may miss school, withdraw from social activities, and develop internalizing behaviors. Therefore, accurately identifying the cause of a child's pain is important for both proper treatment of the pain and to prevent problems secondary to the chronic pain. Evidence in the literature points strongly toward an involvement of the sigma-1 receptor in neurogenic inflammation, which is known to be an important pathophysiological mechanism for maintenance and perpetuation of chronic neuropathic pain. The investigators hope to image and identify activated pain pathways in pediatric pain paitents using a radiolabeled biomarker for increased S1R expression. By localizing and quantifying areas of increased S1R expression to sites of augmented nociceptive activity using hybrid molecular/anatomic imaging techniques, we will objectively identify sites of neurogenic inflammatory activity and pain generation. The ability to image the changes associated with chronic pain generating pathologies provides us with a tool to identify and measure the intensity of the pathology. Imaging S1R expression in chronic pain states in pediatric patients would be both novel in its application and extremely powerful in better characterizing pediatric pain.

Inclusion Criteria:

• 11-18 years old.
• Chronic pain (nociceptive, neuropathic or mixed pain) lasting at least 2 months.
• Pain level of at least 4/10 on a 0-10 Comparative Pain Scale (reported at time of screening).
• Covid Vaccination status: Vaccinated or unvaccinated subjects who received a negative test result from the Covid test within 72 hours of the scan.

Exclusion Criteria:

• MRI incompatible
• Pregnant or nursing
• Non-English speaker
• Claustrophobic