Molecular Imaging of Head and Neck Cancers

Fluorine-18 (18F)-fluorodeoxyglucose (FDG) positron emission tomography - computed tomography (PET/CT) is an essential tool in the evaluation of head and neck cancers (HNC). 18F-FDG PET/CT can detect the primary site of malignancy in patients with cervical lymph node metastases from an unknown origin and guide treatment. Compared to traditional imaging, 18F-FDG PET/CT has higher sensitivity in detecting distant metastases and potential second primary malignancy, which significantly impacts management. 18F-FDG PET/CT also helps in evaluating recurrent or persistent disease that can be treated with salvage surgery and enables safe avoidance of planned post-radiation neck dissection with a high negative predictive value. For response evaluation, the Hopkins criteria and Neck Imaging Reporting and Data System (NI-RADS) are helpful for a standardized evaluation and recommendation. 18F-FDG PET/CT is also integrated in radiotherapy planning for accurate target delineation. PET/magnetic resonance (PET/MR) is advantageous in HNC because of high soft-tissue resolution of MR imaging and molecular information provided by the PET component. Hypoxia imaging in head and neck cancers has also been evaluated with novel molecular imaging agents. Sentinel lymph node biopsy with SPECT/CT and gamma probe guides early-stage HNC surgeries. This chapter highlights the role of molecular imaging in the management of HNC.