Department of Radiation Oncology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan.
Department of Medical Imaging and Radiology, Shu-Zen Junior College of Medicine and Management, Kaohsiung, Taiwan.
Technol Cancer Res Treat. 2024 Jan-Dec;23:15330338241235058. doi: 10.1177/15330338241235058.
The aim of this study was to investigate whether variations in cranial angles and treatment accuracy during CyberKnife robotic radiosurgery necessitate adjustment of the margins of the planning target volume. Data from 66 patients receiving CyberKnife treatment for brain tumors were retrospectively analyzed. Patients were immobilized using a thermoplastic mask and headrest. The cranial angle was measured on planning CT and patients were divided into 2 groups: ≤10° (Group A) and >10° (Group B). Intrafractional motion was recorded using the CyberKnife tracking system over 50 min. Translational and rotational errors were compared between groups, and planning target volume margins were calculated. In Group A, significant translational error differences were found along with the X-axis over time ( < .02). In Group B, significant differences occurred along with the Z-axis ( < .03). No significant rotational or 3-dimensional vector differences were found in either group. Group A had significantly lower Y-axis ( < .045) and roll axis ( < .005) errors compared to Group B. Estimated planning target volume margins in Group A were 0.56 mm (X), 0.46 mm (Y), and 0.47 mm (Z). In Group B, margins were 0.62 mm (X), 0.48 mm (Y), and 0.46 mm (Z). Margins covering 95% of intrafraction motion were 0.49 to 0.50 mm (X, Y, Z) and 0.69 mm (3-dimensional vector) for Group A, and 0.48 to 0.60 mm and 0.79 mm for Group B. With a 1-mm margin, complete coverage was achieved in Group A while 2.1% of vectors in Group B exceeded 1 mm. Adjusting cranial angle to ≤10° during thermoplastic mask molding provided better or similar intrafractional stability compared to >10°.
本研究旨在探讨 CyberKnife 机器人放射外科治疗过程中颅角的变化和治疗精度是否需要调整计划靶区的边缘。回顾性分析了 66 例接受 CyberKnife 治疗脑肿瘤的患者数据。患者使用热塑面罩和头枕固定。在计划 CT 上测量颅角，将患者分为两组：≤10°（A 组）和>10°（B 组）。使用 CyberKnife 跟踪系统在 50 分钟内记录分次内运动。比较两组间的平移和旋转误差，并计算计划靶区边缘。在 A 组中，随着时间的推移，X 轴上的平移误差存在显著差异（ < .02）。在 B 组中，Z 轴上存在显著差异（ < .03）。两组均未发现明显的旋转或三维向量差异。与 B 组相比，A 组的 Y 轴（ < .045）和滚轴（ < .005）误差明显更低。A 组的计划靶区边缘估计为 0.56mm（X）、0.46mm（Y）和 0.47mm（Z）。B 组的边缘为 0.62mm（X）、0.48mm（Y）和 0.46mm（Z）。覆盖 95%分次内运动的边缘为 0.49 至 0.50mm（X、Y、Z）和 0.69mm（三维向量）的 A 组，以及 0.48 至 0.60mm 和 0.79mm 的 B 组。对于 1mm 的边缘，A 组完全覆盖，而 B 组有 2.1%的向量超过 1mm。在热塑面罩成型过程中，将颅角调整至≤10°可提供比>10°更好或相似的分次内稳定性。
