Background: with the evolution of curative treatment regimen, the rate of complete remission achieved in patients with diffuse aggressive non-Hodgkin lymphoma is continuously rising. It is achievable at the end of primary treatment in about 60-80%. On the other hand relapse is very common in the 1 st two years after end of primary treatment in diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma, that is to say, about 20-25% of patients relapse after complete response. Use of routine surveillance imaging for relapse detection is still an area of controversy. Evidence is still lacking to support the utility of routine imaging (namely CT scan) in detection of pre-clinical relapse in diffuse aggressive non-Hodgkin lymphoma (NHL). This work aims at adding further evidence to the pool of studies available in the literature which might encourage, or disapprove the rule of CT as a routine imaging procedures in lymphoma patients who achieved CR. Objectives: I. To clarify whether surveillance CT scan has a significant role in early detection of asymptomatic relapse in B-Cell lymphoma patients. II. To assess the contribution of image-based relapse detection to the overall survival of B-Cell lymphoma patients. Design: this is a retrospective cohort study in which 50 Patients with B-Cell lymphoma diagnosed between 2014 and 2016 were selected from the