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Abstract：
OBJECTIVE: To propose a straightforward and time-efficient quality assurance (QA) approach of beam time delay for respiratory-gated radiotherapy and validate the proposed method on typical respiratory gating systems, Catalyst™ and AlignRT™.
METHODS: The QA apparatus was composed of a motion platform and a Winston-Lutz cube phantom (WL3) embedded with metal balls. The apparatus was first scanned in CT-Sim and two types of QA plans specific for beam on and beam off time delay, respectively, were designed. Static reference images and motion testing images of the WL3 cube were acquired with EPID. By comparing the position differences of the embedded metal balls in the motion and reference images, beam time delays were determined. The proposed approach was validated on three linacs with either Catalyst™ or AlignRT™ respiratory gating systems. To investigate the impact of energy and dose rate on beam time delay, a range of QA plans with Eclipse (V15.7) were devised with varying energy and dose rates.
RESULTS: For all energies, the beam on time delays in AlignRT™ V6.3.226, AlignRT™ V7.1.1, and Catalyst™ were 92.13 ± $ \\pm $ 5.79 ms, 123.11 ± $ \\pm $ 6.44 ms, and 303.44 ± $ \\pm $ 4.28 ms, respectively. The beam off time delays in AlignRT™ V6.3.226, AlignRT™ V7.1.1, and Catalyst™ were 121.87 ± $ \\pm $ 1.34 ms, 119.33 ± $ \\pm $ 0.75 ms, and 97.69 ± $ \\pm $ 2.02 ms, respectively. Furthermore, the beam on delays decreased slightly as dose rates increased for all gating systems, whereas the beam off delays remained unaffected.
CONCLUSIONS: The validation results demonstrate the proposed QA approach of beam time delay for respiratory-gated radiotherapy was both reproducible and time-efficient to practice for institutions to customize accordingly.
METHODS: The QA apparatus was composed of a motion platform and a Winston-Lutz cube phantom (WL3) embedded with metal balls. The apparatus was first scanned in CT-Sim and two types of QA plans specific for beam on and beam off time delay, respectively, were designed. Static reference images and motion testing images of the WL3 cube were acquired with EPID. By comparing the position differences of the embedded metal balls in the motion and reference images, beam time delays were determined. The proposed approach was validated on three linacs with either Catalyst™ or AlignRT™ respiratory gating systems. To investigate the impact of energy and dose rate on beam time delay, a range of QA plans with Eclipse (V15.7) were devised with varying energy and dose rates.
RESULTS: For all energies, the beam on time delays in AlignRT™ V6.3.226, AlignRT™ V7.1.1, and Catalyst™ were 92.13 ± $ \\pm $ 5.79 ms, 123.11 ± $ \\pm $ 6.44 ms, and 303.44 ± $ \\pm $ 4.28 ms, respectively. The beam off time delays in AlignRT™ V6.3.226, AlignRT™ V7.1.1, and Catalyst™ were 121.87 ± $ \\pm $ 1.34 ms, 119.33 ± $ \\pm $ 0.75 ms, and 97.69 ± $ \\pm $ 2.02 ms, respectively. Furthermore, the beam on delays decreased slightly as dose rates increased for all gating systems, whereas the beam off delays remained unaffected.
CONCLUSIONS: The validation results demonstrate the proposed QA approach of beam time delay for respiratory-gated radiotherapy was both reproducible and time-efficient to practice for institutions to customize accordingly.
摘要：
目的：为呼吸门控放射治疗提出一种直接且时间有效的束时间延迟质量保证（QA）方法，并在典型的呼吸门控系统上验证所提出的方法，Catalyst™和AlignRT™。
方法：QA装置由运动平台和嵌入金属球的Winston-Lutz立方体体模（WL3）组成。首先在CT-Sim和两种类型的QA计划中扫描该设备，该计划专门针对光束开启和光束关闭时间延迟，分别,是设计的。利用EPID获取WL3立方体的静态参考图像和运动测试图像。通过比较运动和参考图像中嵌入金属球的位置差异，确定了波束时间延迟。所提出的方法已在具有Catalyst™或AlignRT™呼吸门控系统的三个直线加速器上进行了验证。为了研究能量和剂量率对光束时间延迟的影响，使用Eclipse（V15.7）设计了一系列具有不同能量和剂量率的QA计划。
结果：对于所有能量，AlignRT™V6.3.226、AlignRT™V7.1.1和Catalyst™中的光束时间延迟为92.13±$\\pm$5.79ms,123.11±$\\pm$6.44ms，和303.44±$\\pm$4.28ms，分别。AlignRT™V6.3.226、AlignRT™V7.1.1和Catalyst™中的波束关闭时间延迟为121.87±$\\pm$1.34ms，119.33±$\\pm$0.75ms，和97.69±$\\pm$2.02ms，分别。此外，随着所有门控系统的剂量率增加，光束延迟略有下降，而光束关闭延迟不受影响。
结论：验证结果表明，所提出的用于呼吸门控放射治疗的束时间延迟QA方法既可重复又有效，可用于机构进行相应定制。
方法：QA装置由运动平台和嵌入金属球的Winston-Lutz立方体体模（WL3）组成。首先在CT-Sim和两种类型的QA计划中扫描该设备，该计划专门针对光束开启和光束关闭时间延迟，分别,是设计的。利用EPID获取WL3立方体的静态参考图像和运动测试图像。通过比较运动和参考图像中嵌入金属球的位置差异，确定了波束时间延迟。所提出的方法已在具有Catalyst™或AlignRT™呼吸门控系统的三个直线加速器上进行了验证。为了研究能量和剂量率对光束时间延迟的影响，使用Eclipse（V15.7）设计了一系列具有不同能量和剂量率的QA计划。
结果：对于所有能量，AlignRT™V6.3.226、AlignRT™V7.1.1和Catalyst™中的光束时间延迟为92.13±$\\pm$5.79ms,123.11±$\\pm$6.44ms，和303.44±$\\pm$4.28ms，分别。AlignRT™V6.3.226、AlignRT™V7.1.1和Catalyst™中的波束关闭时间延迟为121.87±$\\pm$1.34ms，119.33±$\\pm$0.75ms，和97.69±$\\pm$2.02ms，分别。此外，随着所有门控系统的剂量率增加，光束延迟略有下降，而光束关闭延迟不受影响。
结论：验证结果表明，所提出的用于呼吸门控放射治疗的束时间延迟QA方法既可重复又有效，可用于机构进行相应定制。
