EARLY TREATMENT RESPONSE IN MALIGNANT-LYMPHOMA, AS DETERMINED BY PLANAR FLUORINE-18-FLUORODEOXYGLUCOSE SCINTIGRAPHY

Clinical oncology needs flexible techniques for routine monitoring of treatment response. We therefore compared planar F-18-fluorodeoxygluco se (FDG) with a conventional gamma-camera and a special collimator to 67 Ga scintigraphy in 26 patients with malignant lymphoma during chemo therapy. The scintigraphic appearance of involved sites was essentiall y the same with both tracers: in patients eventually achieving complet e remission, tracer distribution had normalized after two courses; hig h uptake reflected treatment failure; faint uptake was associated with variable outcome. For (re)staging, Ga-67 may be preferable (higher co ntrast). To document the initial response, we performed FDG scintigrap hy during the first course (n = 11). Effective treatment sharply reduc ed metabolic tumor activity within days and prior to volume response, whereas abnormal uptake persisted in treatment failure. Planar FDG sci ntigraphy may be a tool to assess the potentially prognostic initial r esponse rate, preventing over-treatment and allowing a timely switch t o more aggressive therapy.