Dynamic Contrast Enhanced Computed Tomography (CT) for Head and Neck Cancer

Inclusion Criteria: * Age 18 or older * Willing to provide informed consent * ECOG performance status 0-2 * Histologically confirmed squamous cell carcinoma (includes variants such as verrucous carcinoma, spindle cell carcinoma, carcinoma NOS) of the head and neck * Tumor stage: Any (T1-T4) * Nodal stage: * N2 or N3 (≥ 3 cm) on pre-treatment imaging for radiotherapy cohort (higher likelihood of requiring neck dissection); * N1-N3 for surgery cohort. N0 admissible for T4 tumors. * Patient assessed at head and neck multidisciplinary clinic (with assessment by radiation oncologist and surgeon), with recommendation for definitive chemoradiation therapy (n=15) or surgery (n=15) Exclusion Criteria: * Prior history of head and neck cancer within 5 years * Prior head and neck radiation at any time * Metastatic disease, or imaging findings suspicious for metastases * Prior invasive malignant disease unless disease-free for at least 5 years or more, with the exception of non-melanoma skin cancer. * Pregnant or lactating women * Contraindication to DCE-CT (e.g. contrast allergy)