2284 - Exploratory Study on SGRT in Precise Radiotherapy of Intracranial Tumors without Mask Fixation: A Randomized Controlled Study
Presenter(s)
L. Yang1, R. Cai1, F. Bai2, L. Zixuan3, and L. N. Zhao4; 1Department of Radiotherapy, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China, 2Department of Radiation Oncology, Xijing Hospital, Fourth Military Medical University, xi'an, Shaanxi, China, 3Department of Radiation Oncology, Xijing Hospital, Fourth Military Medical University. Xi’an, China, Xi'an, Shaanxi Province, China, 4Department of Radiation Oncology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
Purpose/Objective(s): To explore the setup accuracy and clinical value of surface - guided radiotherapy (SGRT) in radiotherapy for intracranial tumors without facial mask fixation, and to evaluate its comprehensive effects on target margins coverage optimization and improvement of patient experience.
Materials/Methods: Prospectively, intracranial tumor patients who received radiotherapy in our center from October 2023 to February 2025 were included. They were randomly divided into two groups using a digital table method. One group was fixed with individualized head - neck - shoulder foam rubber and monitored for real - time motion by SGRT (SGRT group), while the other group was fixed with head - neck - shoulder foam rubber and facial mask and underwent the routine IGRT treatment process (IGRT group). Before each fractionated treatment, CBCT verification was performed for all patients. The three - dimensional translational errors (LR, AP, SI) and rotational errors (Roll, Pitch, Yaw) of the two groups were recorded, and the differences in target volume displacement of tumors near the brainstem and functional areas were analyzed. Patient comfort was investigated through a three - time treatment experience questionnaire (including pain, anxiety, and claustrophobia scores).
Results: A total of 78 patients were included, with 43 males and 35 females, and the median age was 48.5 (range 35 - 68 years old), with 39 patients in each group. Translational errors (mm) in the SGRT and IGRT groups: In the LR direction:0.3±0.2 vs 1.1±0.4(p<0.001); in the AP direction: 0.4±0.3 vs 1.3±0.5(p=0.002); in the SI direction: 0.6±0.3 vs 1.8±0.6(p<0.001). Rotational errors (°): Pitch: 0.2±0.1 vs 0.9±0.3(p=0.001); Roll: 0.3±0.2 vs 1.1±0.4(p<0.001); Yaw:0.2±0.1 vs 0.8±0.3(p=0.004). In 95% of the fractionated treatments in the SGRT group, the comprehensive vector displacement (translation/rotation) was=1.2mm/1.0° , which was significantly better than=2.5mm/2.0°in the traditional IGRT group(p<0.001). The target margins conformity index increased by 15% (HI 1.18 vs 1.36 ). The subjective experience of patients was significantly improved, and the incidence of nervousness decreased by 82%. For tumors near the brainstem (n=12), the planning target margins (PTV) expansion margin caused by rotational errors in the SGRT group could be reduced by 2.3mm.
Conclusion: SGRT - guided setup significantly reduces translational and rotational errors during radiotherapy, breaks through the correction limitations of traditional facial masks for rotational errors, achieves sub - millimeter radiotherapy accuracy for intracranial tumors, and at the same time avoids the risk of facial mask compression. Its technical advantages are particularly significant in complex anatomical sites (such as tumors adjacent to the brainstem), providing a new strategy for reducing target margins expansion and optimizing brain function protection.