Recurrent head and neck cancer: The case shown below is from a 23 year old female with moderately differentiated squamous cell carcinoma of the left ethmoid sinus. Following pre-operative chemo and radiation therapy, residual tumor was surgically removed. Four months later a PET/CT exam showed local recurrence in the posterior nasal cavity. Fusion images such as these shown below provide the greatest degree of anatomic correlation with the metabolic information derived from the FDG PET exam.