Solid tumours contain varying degrees of hypoxia. Studies show hypoxia to be associated with poor local control and survival, as hypoxia is a cause of resistance to radio- and chemotherapy and the development of a more aggressive tumour.

Previous attempts to measure hypoxia have been biased because the techniques have been invasive, not repeatable or difficult to apply on a routine basis. There is great interest in trying to measure hypoxia in tumours as this could lead to individualized hypoxia-modifying therapy and prediction of treatment response. Additionally the investigators' knowledge of change in hypoxia over time is limited, but of great interest as individualised treatment, such as intensity-modulated radiation therapy (IMRT) is emerging.

18F-FAZA, appears promising. It is a nitroimidazole, which gets trapped in hypoxic cells and can be detected by a positron emission therapy (PET) scan. Compared to other nitroimidazoles, 18F-FAZA has superior biokinetics and thereby is believed to provide a faster and clearer image of hypoxia.

The investigators' hypothesis is that 18F-FAZA can be used as a prognostic marker in HNSCC.

Inclusion Criteria:

• Histological proven squamous cell carcinoma of the pharynx, larynx, oropharynx and hypopharynx
• Curative intent and no prior treatment
• Age >= 18 years
• stage T1-4 N0-N3 M0.
• Informed consent according to local guidelines and national law
• The patient is able (psychological, sociological, geographical and physical) to carry through the treatment and follow-up
• Fertile women must use contraceptive devices (IUD or oral contraceptives)

Exclusion Criteria:

• No serious concurrent medical disease
• No metastasis
• No prior disease that can affect the treatment, evaluation or outcome of current disease
• No pregnant or breastfeeding woman

head and neck cancer patients