Role of positron emission tomography (PET) in head and neck cancer.

F-18 fluorodeoxyglucose positron emission tomography is now part of the initial stage III and IV cancer work-up and each time that metastasis or the presence of a second cancer is suspected that may contraindicate major surgery. Similarly, this exam should be undertaken when the conventional work-up is negative but there is isolated metastatic adenopathy. In therapeutic follow-up, a 3- or 4-month delay must be respected to prevent false-positive exams caused by inflammation. Although FDG-PET seems very promising in determining target volumes in radiotherapy, its implementation raises a number of problems that can only be resolved through the collaboration of all of the different specialists.