Patients with head and neck cancer greater than 3 cm will imaged with PET scan and CT scan in order to determine areas of the tumour that are hypoxic. Following surgical removal, samples of the tumour will be evaluated for the expression of hypoxia genes. The preoperative imaging will be compared to the "gold standard" measures of hypoxic response at the level of gene transcription and a new hypoxia marker with the hypoxyprobe detection system (pimonidazole).