The management of diffuse large B-cell lymphoma depends on the initial diagnosis including molecular and immunophenotypic characteristics, Ann Arbor staging, and International Prognostic Index (IPI score). Treatment approaches with different chemotherapy regimens used is discussed in detail. The role of radiation as a consolidation is discussed including: (1) the prerituximab randomized trials that challenged the role of radiation, (2) recent prospective studies (UNFOLDER/RICOVER-60), and (3) retrospective studies; the last 2 showed a potential benefit of radiation both for early and advanced stage. The document also discusses the role of positron emission tomography/computed tomography for predicting outcome and potentially guiding therapy. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 3 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.