PET/CT in the Evaluation of Relapsed or Refractory Hodgkin Lymphoma.

18F-fluorodeoxyglucose-positron emission tomography (FDG-PET) has been the most important advance in the assessment of Hodgkin lymphoma (HL) since the introduction of computed tomography (CT). In the frontline management of HL, FDG-PET combined with low-dose CT has emerged as the modality of choice for staging and treatment response assessment. Substantial data have accumulated over the past several years supporting the use of PET/CT in the evaluation and management of relapsed or refractory HL, as well. In this article, we review the role of PET/CT after the frontline treatment of HL, as well as the prognostic utility of PET/CT before autologous and allogeneic stem cell transplantation. We also review the use of PET/CT as a part of response-adapted treatment strategies in relapsed or refractory HL and implications for current and future clinical practice.