Immobilization Devices for Proton Therapy in Head and Neck Cancer: The Role of Radiation Therapists

Abstract

Head and neck cancers present significant therapeutic challenges in radiation oncology due to the proximity of multiple radiosensitive organs and critical structures. Proton therapy has emerged as a specialized technique to minimize unintended doses to surrounding normal tissues, leveraging the physical properties of the Bragg peak to achieve maximal dose deposition at a precise depth. However, the therapeutic advantages of proton therapy are strictly dependent on highly accurate and reproducible patient immobilization. This review highlights the clinical importance of immobilization in proton therapy for head and neck malignancies and describes the essential roles of radiation therapists in device preparation and treatment simulation. By examining the technical processes of patient positioning and the utilization of various immobilization systems—including thermoplastic masks, specialized head and neck cushions (e.g., cushions), bite blocks, and related supportive accessories—this article summarizes a CT simulation workflow based on clinical experience and evidence from relevant literature. Effective immobilization is shown to reduce patient motion and breathing-induced variations, thereby minimizing range uncertainty and ensuring positional reproducibility across the entire treatment course. Furthermore, appropriate immobilization strategies decrease radiation exposure to organs at risk, directly enhancing the precision and safety of proton therapy. Consequently, the selection of appropriate devices, combined with the meticulous technical practice of skilled radiation therapists, remains a cornerstone of treatment accuracy and patient safety in this complex anatomical region.