This study is a prospective, randomized, open-label, single-center exploratory trial. A total of 40 newly diagnosed, untreated head and neck cancer patients （stage I-IVa, AJCC 8th edition） will be enrolled and randomly assigned in a 1：1 ratio to either the experimental group or the control group. The experimental group will receive radiotherapy immobilization using optical surface guidance technology combined with an open-face mask, while the control group will undergo conventional positioning with a closed head-neck-shoulder thermoplastic mask. The primary objective is to compare the six-dimensional setup errors derived from cone-beam CT （CBCT） registration and intrafraction motion between the two groups. The secondary objective is to compare dosimetric parameters of organs at risk （including lens, eyeball, spinal cord, brainstem, temporal lobe, parotid gland, submandibular gland, thyroid gland, mandible, and temporomandibular joint） between the two groups. The safety of the optical surface-guided open-face mask technique will be evaluated by monitoring radiotherapy-related adverse effects during and after treatment. This study aims to investigate whether optical surface guidance combined with open-face immobilization can improve patient comfort, provide more precise radiotherapy, and enhance the protection of normal tissues.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
40
Patients undergo simulation and treatment using an open-face head-neck-shoulder thermoplastic mask. Before and during each fraction, the surface-guided system monitors the patient's surface position in real-time. Positioning is adjusted based on SGRT data and verified by pre-treatment CBCT.
Patients undergo simulation and treatment using a standard closed head-neck-shoulder thermoplastic mask. Positioning is performed using traditional laser marks and skin tattoos, with position verified by pre-treatment CBCT. No optical surface system is used for active monitoring.
Sun Yat-sen Memorial Hospital, Sun Yat-sen University
Guangzhou, Guangdong, China
RECRUITINGSix-Dimensional Setup Error
Translational errors （X, Y, Z in mm） and rotational errors （Rx, Ry, Rz in degrees） measured via CBCT bone-window registration to planning CT.
Time frame: First three times and weekly before each fraction during the entire radiotherapy course （typically 5-7 weeks）.
Intrafraction Motion
Magnitude of patient movement during the delivery of a fraction, detected by real-time SGRT monitoring or post-treatment CBCT.
Time frame: First three times and weekly before each fraction during the entire radiotherapy course （typically 5-7 weeks）.
Dosimetric Parameters of Organs at Risk
Dose-volume histogram metrics （e.g., Dmean, Dmax, D2%, V30） for specified OARs including spinal cord, brainstem, parotids, mandible, etc., derived from the treatment planning system.
Time frame: During the entire radiotherapy course （typically 5-7 weeks）.
Patient Comfort and Satisfaction
Questionnaire scores assessing patient-reported comfort, anxiety, and satisfaction related to mask immobilization.
Time frame: Weekly during the entire radiotherapy course （typically 5-7 weeks）.
Acute Radiation-Induced Toxicity
Incidence and severity of skin reactions, mucositis, xerostomia, etc., graded according to CTCAE v5.0.
Time frame: Weekly during treatment （typically 5-7 weeks) and at 1-month post-treatment follow-up.
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