Role of(～(18)F)2-fluoro-2-deoxyglucose positron emission tomography in upper gastrointestinal malignancies

The role of whole-body FDG [(～(18)F)2-fluoro-2-deoxy-glucose] positron emission tomography(PET)scan-ning as an imaging modality in the management of patients with malignancy has evolved enormously over the past two decades.FDG-PET has demonstrated signifi cant effi cacy in the staging,prognostication and detection of occult metastatic disease in malignancies of the gastrointestinal tract,in addition to assessment of the response to cytotoxic chemotherapy in a more timely manner than has traditionally been possible by more conventional imaging tools.The sensitivity and specif icity of FDG-PET for the detection and staging of malignancy depend not only on the site and size of the primary tumor and metastases,but also on histologi-cal cell type,reflecting underlying disparities in glucose metabolism.The metabolic response to neo-adjuvant chemotherapy or to chemo-radiotherapy in cancers of the gastro-esophageal junction or stomach has been demonstrated in several prospective studies to correlate signifi cantly with both the histological tumor response to treatment and with consequent improvements in overall survival.This may offer a future paradigm ofpersonalized treatment based on the PET response to chemotherapy.FDG-PET has been less successful in efforts to screen for and detect recurrent upper gastro-intestinal malignancies,and in the detection of low vol-ume metastatic peritoneal disease.Efforts to improve the accuracy of PET include the use of novel radiotrac-ers such as(～(18)F)FLT(3-deoxy-3-fluorothymidine)or 11C-choline,or fusion PET-CT with concurrent high-res-olution computed tomography.This review focuses on the role of FDG-PET scanning in staging and response assessment in malignancies of the upper gastrointesti-nal tract,specif ically gastric,esophageal and pancreas carcinoma.