 2-18F-fluoro-2-deoxyD-glucose positron emission tomography FDG PET has proven to be a valuable clinical tool for the staging and surveillance of lymphoma.1-6 Occasionally, lymph nodes in the mesentery and retroperitoneum can be difficult to distinguish from normal bowel activity on PET scans despite three-plane and cine maximal image projection MIP imaging. This uncertainty limits the clinical usefulness of PET in some cases of lymphoma.7-8 In addition, bowel activity can also hinder interpretation of PET scans in other types of solid tumors including melanoma and colorectal cancer.6,9,10 Our goal is to determine how well diphenoxylateatropine 5mg0.05mg Lomotil decreases bowel activity and how this decrease impacts clinical decision-making, specifically for lymphoma staging and surveillance. This is a prospective, randomized, double-blinded study involving 60 patients undergoing PET scans for newly diagnosed or recurrent, untreated lymphoma. 