目的:使用新型基于胶片的体模评估3种靶标在单次递送中的患者特异性质量保证(PSQA)。
方法:体模被设计为可以作为球体自由旋转,并且可以在一次递送中测量3个目标。在确定了头骨中3个目标的坐标后,计算了赤道和子午线的旋转角度,以实现最佳的体模设置,确保胶片平面与3个目标相交。该计划是使用基准跟踪在Cyberknife系统上交付的。扫描并处理经照射的膜。使用3个γ标准分析所有膜。
结果:在体模上提供了15个具有3种不同方式的射波刀测试计划。在配准辐照的胶片和剂量平面时,应用了自动和基于标记的配准方法。伽玛分析使用3%/1mm,2%/1毫米,和1%/1毫米标准,阈值为10%。对于自动注册方法,通过率为98.2%±1.9%,94.2%±3.7%,80.9%±6.3%,分别。对于基于标记的配准方法,通过率为96.4%±2.7%,91.7%±4.3%,和78.4%±6.2%,分别。
结论:使用TG218建议,对一种新型球形体模进行了Cyberknife系统评估,并获得了可接受的PSQA通过率。体模可以测量真实的复合剂量,并为PSQA提供高分辨率的结果,使它成为机器人放射外科的有价值的设备。
结论:这是首次在Cyberknife系统上同时研究3个目标的PSQA。
OBJECTIVE: To evaluate patient-specific quality assurance (PSQA) of 3 targets in a single delivery using a novel film-based phantom.
METHODS: The phantom was designed to rotate freely as a sphere and could measure 3 targets with film in a single delivery. After identifying the coordinates of 3 targets in the skull, the rotation angles about the equator and meridian were computed for optimal phantom setup, ensuring the film plane intersected the 3 targets. The plans were delivered on the CyberKnife system using fiducial tracking. The irradiated films were scanned and processed. All films were analysed using 3 gamma criteria.
RESULTS: Fifteen CyberKnife test plans with 3 different modalities were delivered on the phantom. Both automatic and marker-based registration methods were applied when registering the irradiated film and dose plane. Gamma analysis was performed using a 3%/1 mm, 2%/1 mm, and 1%/1 mm criteria with a 10% threshold. For the automatic registration method, the passing rates were 98.2% ± 1.9%, 94.2% ± 3.7%, and 80.9% ± 6.3%, respectively. For the marker-based registration approach, the passing rates were 96.4% ± 2.7%, 91.7% ± 4.3%, and 78.4% ± 6.2%, respectively.
CONCLUSIONS: A novel spherical phantom was evaluated for the CyberKnife system and achieved acceptable PSQA passing rates using TG218 recommendations. The phantom can measure true-composite dose and offers high-resolution results for PSQA, making it a valuable device for robotic radiosurgery.
CONCLUSIONS: This is the first study on PSQA of 3 targets concurrently on the CyberKnife system.