Usefulness of 201TL SPECT/CT relative to 18F-FDG PET/CT in detecting recurrent skull base nasopharyngeal carcinoma.

Abstract

This study was designed to compare (201)Tl single photon emission computed tomography (SPECT)/CT with 18-fluoro-2-deoxyglucose ((18)F-FDG) PET/CT in diagnosing recurrent skull base nasopharyngeal carcinoma (NPC). Twenty-seven patients were recruited. Both (201)Tl SPECT/CT and (18)F-FDG PET/CT for each patient were performed at least 4 months later after initial therapy. The sensitivity and specificity for (201)Tl SPECT/CT were 66.7% and 100%, and those for (18)F-FDG PET/CT were 86.7% and 75.0%. Lesion/background ratios were obtained for the 10 lesions that were both SPECT and PET true positive. For the 8 patients with recurrences in nasopharyngeal regions, PET lesion/background ratios were all higher than SPECT lesion/background ratios. For the 2 patients with intracranial metastases, SPECT lesion/background ratios were higher than PET lesion/background ratios. (201)Tl SPECT/CT is as effective as (18)F-FDG PET/CT in detecting recurrent NPC. For intracranial recurrence, (201)Tl SPECT, because of its high intracranial lesion/background ratio, is probably better than (18)F-FDG PET.