[en] Fluorodeoxyglucose F18/diagnostic use ; Gallium Radioisotopes/diagnostic use ; Humans ; Lymphoma, Non-Hodgkin/radiography/radionuclide imaging ; Neoplasm, Residual/diagnosis ; Radiopharmaceuticals/diagnostic use ; Tomography, Emission-Computed ; Treatment Outcome
[en] Incomplete regression of a lymphomatous mass after chemotherapy and/or radiotherapy constitutes a major problem in the treatment of lymphoma. In patients with persisting tumor, it could be reasonable to use salvage therapy and possibly hematopoietic stem cell transplantation at the time of minimal disease rather than at the time of clinically overt relapse. The authors reviewed the most appropriate imaging techniques for the assessment of response to treatment. The limitations of CT and MRI for predicting the nature of residual masses are well known. 67Ga scintigraphy has become a standard procedure for the posttreatment evaluation of patients with lymphoma, but it appears that 18F-FDG PET may be a more effective method. Personal experience in the field of PET scan is reported. Although PET should be considered the noninvasive imaging modality of choice, a histological confirmation of residual disease is always necessary before starting salvage therapy. 18F-fluorodeoxyglucose is not a tumor specific radiotracer.