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 18F-fluorodeoxyglucose (FDG) with a conventional gamma-camera and a special collimator to 67Ga scintigraphy in 26 patients with malignant lymphoma during chemotherapy. The scintigraphic appearance of involved sites was essentially the same with both tracers: in patients eventually achieving complete remission, tracer distribution had normalized after two courses; high uptake reflected treatment failure; faint uptake was associated with variable outcome. For (re)staging, 67Ga may be preferable (higher contrast). To document the initial response, we performed FDG scintigraphy during the first course (n = 11). Effective treatment sharply reduced metabolic tumor activity within days and prior to volume response, whereas abnormal uptake persisted in treatment failure. Planar FDG scintigraphy may be a tool to assess the potentially prognostic initial response rate, preventing over-treatment and allowing a timely switch to more aggressive therapy.