PET in Lymphoma

The management approach in Hodgkin (HL) and high-grade non-Hodgkin lymphomas (NHLs) has shifted toward reducing the toxicity and long-term adverse effects associated with treatment while maintaining favorable outcomes in low-risk patients. The availability of more effective therapies for lymphoma provides a rationale for accurate diagnostic tests and updated patient evaluation, staging, and response criteria. In this regard, positron emission tomography (PET) using fluorodeoxyglucose (FDG) with computed tomography (CT) has proved effective as a metabolic imaging tool with compelling evidence supporting its superiority over conventional modalities, particularly in staging and early evaluation of response, and is now integrated into the routine staging and restaging algorithm of lymphomas. A semiquantitative parameter for measuring tumor glucose metabolism, the maximum standardized uptake value (SUVmax), reflects aggressiveness of neoplasm and is proven to be an important survival predictor. Several quantitative metrics including metabolic tumor volume (MTV) and total lesion glycolysis (TLG) appears to be dependable and reproducible prognostic indicators. Additionally, the 5-point Deauville score (DS) has been recommended as a qualitative method for evaluating interim and end-of-treatment PET/CT results. This chapter summarizes the data on the proven and potential utility of PET/CT imaging for staging, response assessment, and restaging, describing current limitations of this imaging modality.