PET/CT is a noninvasive, imaging modality that has become widely used in the management of patients with malignant lymphomas. This technology has been demonstrated to be more sensitive and specific than either 67 gallium scintigraphy or computeraized tomography, providing a more accurate distinction between scar or fibrosis and active tumor. PET/CT scans have been evaluated in pretreatment staging, restaging, monitoring during therapy, posttherapy surveillance, assessment of transformation and more recently, as a surrogate marker in new drug development.