Department of Radiation Oncology, NYU Langone Health, NYU Grossman School of Medicine, New York University, New York, NY, USA.
J Appl Clin Med Phys. 2021 Feb;22(2):77-84. doi: 10.1002/acm2.13159. Epub 2021 Jan 13.
The treatment couch position of a patient in external beam radiation therapy (EBRT) is usually acquired during initial treatment setup. This procedure has shown potential failure modes leading to near misses and adverse events in radiation treatment. This study aims to develop a method to automatically determine the couch position before setting up a patient for initial treatment.
The Qfix couch-tops (kVue and DoseMax) have embedded reference marks (BBs) indicating its index levels and couch centerline. With the ESAPI, a C# script was programmed to automatically find the couch-top and embedded BBs in the planning CT and derive the treatment couch position according to treatment isocenter of a plan. Couch positions of EBRT plans with the kVue couch-top and SBRT plans using the DoseMax were calculated using the script. The calculation was evaluated by comparing calculated positions with couch coordinates captured during the initial treatment setup after image guidance. The calculations were further compared with daily treatment couch positions post image-guided adjustment for each treatment fraction.
For plans using the kVue couch-top for various treatment sites, the median (5-95 percentiles) differences between calculated and captured couch positions were 0.1 (-0.2 - 0.9), 0.5 (-1.1-2.0), 0.10 (-1.3-1.3) cm in the vertical, longitudinal, and lateral direction respectively. For the DoseMax couch-top, the median differences were 0.1 (-0.2-0.7), 0.2 (-0.3-1.1), and 0.2 (-0.7-0.9) cm in respective direction. The calculated positions were within 1 and 2 cm from the mean fraction positions for 95% patients on DoseMax and kVue couch-top respectively.
A method that automatically and accurately calculates treatment couch position from simulation CT was implemented in Varian Eclipse for Qfix couch-tops. This technique increases the efficiency of patient setup and enhances patient safety by reducing the risks of positioning errors.
在外部束放射治疗（EBRT）中，患者的治疗床位置通常在初始治疗设置期间获得。该过程显示出潜在的失效模式，导致放射治疗中的近失和不良事件。本研究旨在开发一种在为初始治疗设置患者之前自动确定治疗床位置的方法。
Qfix 治疗床（kVue 和 DoseMax）具有嵌入式参考标记（BB），指示其索引水平和治疗床中心线。使用 ESAPI，用 C#编写了一个脚本，用于自动在计划 CT 中找到治疗床和嵌入式 BB，并根据计划的治疗等中心点推导出治疗床位置。使用该脚本计算了具有 kVue 治疗床的 EBRT 计划和使用 DoseMax 的 SBRT 计划的治疗床位置。通过将计算出的位置与图像引导初始治疗设置后捕获的治疗床坐标进行比较来评估计算。进一步将计算结果与每个治疗部分的图像引导调整后的每日治疗床位置进行比较。
对于使用各种治疗部位的 kVue 治疗床的计划，计算出的和捕获的治疗床位置之间的中位数（5-95 百分位）差异分别为 0.1（-0.2-0.9）、0.5（-1.1-2.0）、0.10（-1.3-1.3）cm，分别在垂直、纵向和横向方向。对于 DoseMax 治疗床，中位数差异分别为 0.1（-0.2-0.7）、0.2（-0.3-1.1）和 0.2（-0.7-0.9）cm。对于 DoseMax 和 kVue 治疗床，分别有 95%的患者的计算位置与平均分次位置相差 1cm 和 2cm 以内。
已在瓦里安 Eclipse 中为 Qfix 治疗床实现了一种从模拟 CT 自动且准确计算治疗床位置的方法。该技术提高了患者设置的效率，并通过降低定位错误的风险提高了患者安全性。
