Esophagus, Stomach, and Small Bowel Malignancies

In this chapter we try to synthesize the emerging role of functional imaging techniques in esophagic and gastric tumors as well as in small bowel malignancies. In relation to small bowel malignancies, we focused on gastrointestinal stromal tumors (GIST) and carcinoid tumors. Positron emission tomography/computed tomography (PET/CT) represents an essential nuclear medicine technique showing superiority against conventional diagnostic imaging methods in the detection of lymphatic and distant metastases, detection of recurrences, and evaluation of tumor response to different treatments in these tumors. We mainly give attention to the most common PET radiotracer (18F-FDG), but other new PET radiotracers are also mentioned such as 68Ga-labeled somatostatin analogs (DOTA-TOC, DOTA-TATE, and DOTA-NOC) that are basically used in the evaluation of carcinoid tumors.