Inclusion Criteria:

- Histologically confirmed squamous cell carcinoma of the oral cavity, oropharynx,
hypopharynx and larynx.

- Primary non-resected tumor and/or patients refused surgery

- Stage T1-4, N0-3; for cancer of the glottis T3-4 or T any N1-3

- Decision of curative radiotherapy or radiochemotherapy made by a Multidisciplinary
Group of Head and Neck Tumors at UZ Gent and UZ Gasthuisberg Leuven

- Karnofsky performance status >= 70 %

- Age >= 18 years old

- Informed consent obtained, signed and dated before specific protocol procedures

Exclusion Criteria:

- Treatment combined with brachytherapy

- Prior irradiation to the head and neck region

- Surgery of the primary tumor except lymph node dissection prior to radiotherapy

- induction chemotherapy

- history of prior malignancies, except for cured non-melanoma skin cancer, curatively
treated in-situ carcinoma of the cervix or other cancer curatively treated and with
no evidence of disease at least 5 years

- Distant metastases

- Creatinine clearance (Cockroft-Gault) =< 60 milliliter/minute before treatment or
creatinine value > 1,3 milligram/deciliter

- Known allergy to the CT-contrast agents

- Pregnant or lactating women

- Mental condition rendering the patient unable to understand the nature, scope and
possible consequences of the study

- Patient unlikely to comply with protocol, i.e. uncooperative attitude, inability to
return for follow-up visits and unlikely to complete the study