Imaging: staging and evaluation of lymphoma using nuclear medicine

The management of lymphoma is dependent on accurate staging of the disease and evaluation of histology and other risk factors. Advances in imaging techniques have improved the assessment of disease status and evaluation of the efficacy of different treatment modalities. While computed tomography remains the cornerstone of imaging for the assessment of disease status, it provides no understanding of the metabolic or functional parameters of the disease. Nuclear medicine techniques permit the evaluation of functional status, and nuclear medicine is likely to have its greatest impact in the detection of viable tumor in persistent masses. Nuclear imaging can be conducted using single photon agents, such as 67 Ga-citrate with SPECT (single photon emission computed tomography), or with positron emitters, such as 18 F-fluorodeoxyglucose (FDG) with PET (positron emission tomography). Many studies have indicated that FDG-PET is as good as or better than 67 Ga-SPECT for the detection of lymphoma. Thus, FDG-PET may be preferable to 67 Ga-SPECT for disease evaluation, staging, and follow-up. The superiority of FDG-PET compared with other imaging modalities strongly argues that it should be incorporated into the treatment paradigm. At present, FDG-PET scanning is not routinely available in all institutions; however, a role can be indicated for FDG-PET in several areas of lymphoma management, including initial staging, predicting response to therapy (during and following chemotherapy), and identification of residual tumor. This article examines the role of the different imaging techniques available and the use of these techniques in the staging and evaluation of patients with Hodgkin's and non-Hodgkin's lymphoma.