To study the safety and possible side effects of using the imaging agent 4-\[18F\]Fluoro-1-Naphthol (also called \[18F\]4FN) in PET/CT scans for participants with chronic GVHD.
Chronic GVHD involving the joints, defined as any limitation of range of motion measured by Photographic Range Of Motion (PROM). Criteria can be found at (Jagasia, et al. 2015).
Able to give written informed consent.
≥18 years of age
Creatinine clearance ≥ 30 mL/min/1.73m2
Unable to comply with all study procedures (for example, participants who are unable to come to all follow up visits because they live far away from the transplant center)
Pregnant or lactating women: pregnant women are excluded from this study because the effects of [18F]4FN in pregnancy are not known.
Subjects with contraindications to the use of [18F]4FN including confirmed allergy.
Participants with a body weight of 400 pounds or more, or a body habitus which precludes their entry into the bore of the PET/CT scanner, because the hardware is not intended to support that weight.