A quality assurance for respiratory gated proton irradiation with range modulation wheel.
A quality assurance for respiratory gated proton irradiation with range modulation wheel.
复制标题
使用范围调制轮进行呼吸门控质子照射的质量保证。
DOI：
10.1002/acm2.12526
复制
发表时间：
2019
期刊：
影响因子：
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通讯作者：
Ogino H.
中科院分区：
文献类型：
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作者：
Yasui K;Shimomura A;Toshito T;Tanaka K;Ueki K;Muramatsu R;Katsurada M;Hayashi N;Ogino H.
本研究的目的是为具有距离调制轮(RMW)的呼吸门控质子束提供周期性质量保证(QA)方法，并阐明呼吸门控质子束的特性和长期稳定性。使用二维探测器阵列和固体水模测量绝对剂量、扩展布拉格峰(SOBP)宽度和质子射程用于每月质量保证。利用倾斜入射到固体水模侧面的束流测量了SOBP宽度和质子射程，并比较了有无门控质子束的情况。为了测量年度质量保证的束通/断延迟时间，我们采集了束通/断信号和剂量监测检测脉冲。我们分析了15个月内每月QA的结果，并通过机器信号分析调查了延迟时间。近端、中点和远点的剂量偏差分别为−0.083±0.25%、0.026±0.20%和−0.083±0.35%。有无呼吸门控的最大剂量偏差在远端−为0.95%，其他偏差在±0.5%以内。近端剂量和SOBP中心剂量在15个月期间显示出相同的趋势。200M MeV/SOBP 16M的束流开/关延迟时间分别为140.5±100.8ms和22.3ms±113.0ms。160M EV/SOBP 10M延迟时间分别为167.5±15.1M和19.1M±99.8M。我们的带有RMW的束流输送系统对呼吸门控质子治疗显示出足够的稳定性，并且该系统不表现出对能量和呼吸波形的依赖。束流开启/关闭的延迟时间在预期范围内。建议的质量保证方法将有助于管理呼吸门控质子束和其他束流输送系统的质量。
The purpose of this study was to provide periodic quality assurance (QA) methods for respiratory‐gated proton beam with a range modulation wheel (RMW) and to clarify the characteristics and long‐term stability of the respiratory‐gated proton beam. A two‐dimensional detector array and a solid water phantom were used to measure absolute dose, spread‐out Bragg peak (SOBP) width and proton range for monthly QA. SOBP width and proton range were measured using an oblique incidence beam to the lateral side of a solid water phantom and compared between with and without a gating proton beam. To measure the delay time of beam‐on/off for annual QA, we collected the beam‐on/off signals and the dose monitor‐detected pulse. We analyzed the results of monthly QA over a 15‐month period and investigated the delay time by machine signal analysis. The dose deviations at proximal, SOBP center and distal points were −0.083 ± 0.25%, 0.026 ± 0.20%, and −0.083 ± 0.35%, respectively. The maximum dose deviation between with and without respiratory gating was −0.95% at the distal point and other deviations were within ±0.5%. Proximal and SOBP center doses showed the same trend over a 15‐month period. Delay times of beam‐on/off for 200 MeV/SOBP 16 cm were 140.5 ± 0.8 ms and 22.3 ± 13.0 ms, respectively. Delay times for 160 MeV/SOBP 10 cm were 167.5 ± 15.1 ms and 19.1 ± 9.8 ms. Our beam delivery system with the RMW showed sufficient stability for respiratory‐gated proton therapy and the system did not show dependency on the energy and the respiratory wave form. The delay times of beam‐on/off were within expectations. The proposed QA methods will be useful for managing the quality of respiratory‐gated proton beams and other beam delivery systems.