Abstract
Survival for upper gastrointestinal tumors remains poor, likely in part due to treatment resistance associated with intratumoral hypoxia. In this review, we highlight advances in nuclear medicine imaging that allow for characterization of in vivo tumor hypoxia in esophageal, pancreatic, and liver cancers. Strategies for adaptive radiotherapy in upper gastrointestinal tumors are proposed that would apply information gained through hypoxia imaging to the creation of personalized radiotherapy treatment plans able to overcome hypoxia-induced treatment resistance, minimize treatment-related toxicities, and improve patient outcomes.