18F-FDG versus 11C-choline PET/CT for the imaging of advanced head and neck cancer after combined intra-arterial chemotherapy and radiotherapy: the time period during which PET/CT can reliably detect non-recurrence

Purpose The purpose of this prospective study was to evaluate the usefulness of 18F-fluorodeoxyglucose (FDG) and 11C-choline positron emission tomography (PET)/computed tomography (CT) for detecting recurrences of advanced head and neck cancer after combined intra-arterial chemotherapy and radiotherapy. Additionally, we surveyed the time period during which an effective negative predictive value could be maintained after the first follow-up PET/CT examination and estimated the optimal timing of a second PET/CT examination for detecting late recurrences.