Lymphoma staging systematically includes a CT scan of the cervical, thoracic and abdominopelvic regions. PET is indicated in diffuse large B cell lymphomas (DLBCL) and Hodgkin’s disease. Evaluation of the response to treatment is based on Cheson’s 1999 morphological criteria, which have been replaced by the 2007 IWC criteria, which combine morphological and metabolic responses. CT and FDG-PET are complementary in characterizing residual masses: if negative, a PET scan indicates the absence of residual disease, if positive; it directs a CT-guided biopsy to obtain the histological evidence. Monitoring clinical features and laboratory values is primordial following treatment. Imaging is performed as a second intention for investigating a relapse, if necessary associated with a PET scan. Multimodal imaging implies multidisciplinary consultation between haematologists, imaging specialists and histopathologists.