The value of Ga-67 scintigraphy and F-18 fluorodeoxyglucose positron emission tomography in staging and monitoring the response of lymphoma to treatment
Gallium-67 scintigraphy (GS) has the ability to provide important diagnostic and prognostic information for the evaluation of patients with lymphoma. GS is superior to morphologic imaging techniques because of its affinity to viable lymphoma cells. The value of GS lies not in the initial diagnosis but primarily in assessing the results of treatment and in the follow-up of patients with lymphoma. Nevertheless, GS has not gained the expected wide acceptance, possibly because of the meticulous technique required and the expertise needed for optimal interpretation. The introduction of positron emission tomography (PET) with F-18 fluorodeoxyglucose (FDG) as a tumor-seeking agent, which provides images of superior quality, may have an impact on the current role of GS in the management of patients with lymphoma. FDG-PET seems to share with GS the advantages of a tumor viability agent. It appears to be more sensitive for detecting nodal and extranodal sites of disease than GS and may have predictive value during and after therapy for lymphoma. These potential clinical and economic advantages of FDG-PET need to be confirmed in systematic, large-scale prospective studies.