Head and Neck Squamous Cell Carcinoma (HNSCC)PET-CT Pilot Study

Inclusion Criteria: * Non-nasopharynx head and neck mucosal squamous cell carcinoma * Radiologically evident gross disease * Radiotherapy alone for curative intent * Age equal to or more than 18 years old * To be eligible for the second study PET-CT scan: FDG avid tumour (or minimum SUV of 2.5) on the first study PET-CT scan Exclusion Criteria: * Nasopharynx cancer * H\&N SCC skin * Distant metastases (already known or if found on baseline CT-thorax) * Prior malignancy within the last 5 years (exclude non-H\&N SCC, BCC skin) * Prior chemotherapy within the last 5 years or concurrent chemotherapy/EGFR inhibitors * Prior head and neck radiotherapy * Inability to lie supine for study duration * Pregnancy * Inability to provide informed consent