In a retrospective study of a series of 30 adult patients during restaging of Hodgkin's disease after therapy, computed tomography (CT) and biopsy results were correlated with 67Ga SPECT in order to determine the value of SPECT imaging in monitoring recurrent mediastinal Hodgkin's disease. SPECT had an overall accuracy of 93% (28/30) and correctly identified active disease in 24 of 25, 96% of histopathologically proven recurrent Hodgkin's disease. Thus in this post-therapy setting, we have confirmed the high sensitivity of 67GA SPECT scans in patients selected for biopsy. Gallium-67 may prove particularly useful in detecting residual disease activity in patients in whom biopsy was positive but the interpretations of the CT scans were uncertain in regard to presence of tumors [8/30 (27%)]. In this group of patients, we found SPECT particularly helpful. A larger prospective series is under way to assess this possibility.