电磁应答器引导的多叶准直器跟踪的首次临床应用。
The first clinical implementation of electromagnetic transponder-guided MLC tracking.
机构信息
Radiation Physics Laboratory, Sydney Medical School, University of Sydney, NSW 2006, Australia.
Radiation Physics Laboratory, Sydney Medical School, University of Sydney, NSW 2006, Australia and Northern Sydney Cancer Centre, Royal North Shore Hospital, Sydney, NSW 2065, Australia.
出版信息
Med Phys. 2014 Feb;41(2):020702. doi: 10.1118/1.4862509.
PURPOSE
We report on the clinical process, quality assurance, and geometric and dosimetric results of the first clinical implementation of electromagnetic transponder-guided MLC tracking which occurred on 28 November 2013 at the Northern Sydney Cancer Centre.
METHODS
An electromagnetic transponder-based positioning system (Calypso) was modified to send the target position output to in-house-developed MLC tracking code, which adjusts the leaf positions to optimally align the treatment beam with the real-time target position. Clinical process and quality assurance procedures were developed and performed. The first clinical implementation of electromagnetic transponder-guided MLC tracking was for a prostate cancer patient being treated with dual-arc VMAT (RapidArc). For the first fraction of the first patient treatment of electromagnetic transponder-guided MLC tracking we recorded the in-room time and transponder positions, and performed dose reconstruction to estimate the delivered dose and also the dose received had MLC tracking not been used.
RESULTS
The total in-room time was 21 min with 2 min of beam delivery. No additional time was needed for MLC tracking and there were no beam holds. The average prostate position from the initial setup was 1.2 mm, mostly an anterior shift. Dose reconstruction analysis of the delivered dose with MLC tracking showed similar isodose and target dose volume histograms to the planned treatment and a 4.6% increase in the fractional rectal V60. Dose reconstruction without motion compensation showed a 30% increase in the fractional rectal V60 from that planned, even for the small motion.
CONCLUSIONS
The real-time beam-target correction method, electromagnetic transponder-guided MLC tracking, has been translated to the clinic. This achievement represents a milestone in improving geometric and dosimetric accuracy, and by inference treatment outcomes, in cancer radiotherapy.
目的
我们报告了 2013 年 11 月 28 日在北悉尼癌症中心首次临床实施电磁应答器引导的叶片位置实时追踪的临床流程、质量保证以及几何和剂量学结果。
方法
基于电磁应答器的定位系统（Calypso）经过改装后，可将目标位置输出发送到自主研发的叶片位置实时追踪代码，该代码会调整叶片位置，使治疗射束与实时目标位置最佳对准。我们制定并执行了临床流程和质量保证程序。首例电磁应答器引导的叶片位置实时追踪临床应用是为一名接受双弧容积旋转调强放疗（RapidArc）治疗的前列腺癌患者实施的。在首例患者的首次分次治疗中，我们记录了室内时间和应答器位置，并进行了剂量重建，以估计实际递送剂量，以及如果不使用叶片位置实时追踪技术实际接收剂量。
结果
总室内时间为 21 分钟，其中 2 分钟用于射束传输。叶片位置实时追踪无需额外时间，也没有射束暂停。从初始设置来看，前列腺的平均位置为 1.2 毫米，主要是向前移位。使用叶片位置实时追踪技术进行的实际递送剂量重建分析显示，与计划治疗相比，等剂量线和目标剂量体积直方图相似，且部分直肠 V60 增加了 4.6%。没有运动补偿的剂量重建显示，即使运动幅度较小，部分直肠 V60 也比计划值增加了 30%。
结论
实时射束-靶标校正方法，即电磁应答器引导的叶片位置实时追踪，已在临床上得以实现。这一成果代表着在提高癌症放射治疗的几何和剂量学精度以及治疗效果方面迈出了重要一步。
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