Serial FDG-PET/MR Imaging for Head and Neck Cancer Radiation Therapy: A Pilot Study

Radiation therapy (RT), with or without chemotherapy, can be an effective organ-preserving treatment strategy for many patients with head and neck cancer. Loco-regional failure, however, can occur in a significant minority of patients. Typically, treatment response is assessed months after radiotherapy to allow the tumor to regress and to avoid confounding acute therapy effects. This paper investigates the use of hybrid 18-Flurodeoxyglucose (
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F-FDG) positron emission tomography/ magnetic resonance (PET/MR) imaging for early visualization of tumor changes during treatment. Qualitative and quantitative comparison of changes in the anatomical and functional parameters is presented by multi-point serial scanning of head and neck cancer patients undergoing RT. Parameters derived from diffusion weighted imaging and PET imaging are found to trend differently in the patient with recurrence in comparison to patients without recurrence. By reporting feasibility and early findings of PET/MR within treatment, this study suggests that PET/MR has the potential to demonstrate mid-treatment tumor changes. A combination of anatomical and functional parameters can be used to guide potential treatment re-planning for patients who do not respond well to the initially planned treatment strategy.