. The aim of this prospective study was to determine the benefits of hybrid 18F-FDG PET/CT in detecting a subclinical locoregional recurrence of HNSCC and distant metastases. The study patients were considered cured of HNSCC on the basis of 12 mo of negative findings on conventional follow-up. We also assessed the diagnostic accuracy of 18F-FDG PET/CT in these patients.