Post-treatment imaging of head and neck cancer.

The expected changes on CT or MRI after treatment of a head and neck cancer are described; it is important not to confuse such expected changes with persisting or recurrent tumour, or a treatment complication. Post-treatment CT or MRI is of value when a recurrent tumour is suspected, to confirm the presence of such a lesion and to determine its extent; this is important information for determining the possibility of salvage therapy. More rarely, imaging maybe of use in the differentiation between tumour recurrence and a treatment complication. In patients with a high-risk profile for tumour recurrence after treatment, imaging is of value for surveillance of the patient, as an adjunct to clinical follow-up.The baseline study should be obtained about 3 to 4 months after the end of therapy. There is evidence that tumour recurrences can be detect earlier by systematic follow-up imaging.