Positron emission tomography/CT in the management of lymphoma

•. Fluorine-18 fluorodeoxyglucose (18FDG) positron emission tomography (PET)/CT is well established in the staging, response assessment and residual mass assessment of high-grade lymphomas.•. PET/CT can be complementary to bone marrow biopsy in the evaluation of bone marrow/bone involvement.•. Early response assessment with PET/CT has prognostic value.•. Residual mass assessment with PET/CT avoids unnecessary further treatment and/or invasive investigations.Metabolic imaging with fluorine-18 fluorodeoxyglucose (18FDG) positron emission tomography (PET)/CT is now established in the management of malignant high-grade lymphomas. This review summarises and illustrates the evidence for the use in staging, response assessment and residual mass assessment. Common pitfalls in the interpretation of PET/CT in this context are highlighted. Current developments and future directions of metabolic imaging in lymphoma are discussed, including the emerging use of diffusion-weighted whole-body MRI.