The use of 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) in conjunction with 
computed tomography has recently become important in the initial staging, evaluation of response, 
and treatment of malignant lymphomas. PET has shown high sensitivity in early and late response 
assessment during treatment, and early diagnosis of lymphoma manifestations. PET is most helpful in 
evaluating how well DLBCL and Hodgkin's lymphoma patients are responding to treatment. PET- CT 
in staging is extremely sensitive at identifying lymphoma lesions, and it is used to help doctors decide 
on treatment options, resulting in better therapy selection this imaging technique is often used to 
assess individual chemo sensitivity and adjust treatment accordingly. FDG-PET may also be used to 
assess residual masses after treatment is over. Patients with a negative FDG-PET scan should be 
considered in full remission, according to a recent update. FDG-PET/CT is no longer used in routine 
follow-up following a full metabolic response to treatment, but it is still a useful tool for excluding 
recurrence if patients experience clinical symptom suggestive of disease relapse.