[Malignant lymphoma].

18-Fluoro-deoxyglucose positron emission tomography (FDG-PET) has become widely used in the management of patients with malignant lymphomas. FDG-PET has been evaluated in pretreatment staging, restaging, monitoring during therapy, and posttherapy surveillance. The Ann Arbor staging system was initially based on physical examination and bone marrow evaluation, but more recently, CT scans or 67gallium scintigraphy have been incorporated. FDG-PET may provide complementary information to conventional staging methods, and may be of particular value prior to therapy for patients who appear to have stage I or II disease and for whom radiation therapy is being considered. FDG-PET has technical limitations, variability of FDG avidity among different lymphoma histologic subtypes, and in a large number of etiologies shows false-negative and false positive results. Most studies of FDG-PET involve patients with Hodgkin's disease or diffuse large B-cell lymphoma. FDG PET in lymphoma is being incorporated into the response assessment in lymphoma as published by the Imaging Subcommittee of International Harmonization Project in Lymphoma. New guidelines, the Revised Response Criteria for Malignant Lymphoma, are presented incorporating PET, IHC, and flow cytometry for definitions of response in non-Hodgkin's and Hodgkin's lymphoma. They should reduce the variability among studies. Standardized definitions of end points are provided. Standardized FDG-PET will hopefully lead to improved outcome for patients. PET as a biomarker has the potential to change the current model of drug development.