Beam control system and output fine-tuning for safe and precise delivery of FLASH radiotherapy at a clinical linear accelerator.
Beam control system and output fine-tuning for safe and precise delivery of FLASH radiotherapy at a clinical linear accelerator.
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DOI：
10.3389/fonc.2024.1342488
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发表时间：
2024
影响因子：
4.7
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中科院分区：
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我们之前已经采用了临床直线加速器（Elekta Precise，Elekta AB）进行超高剂量率（UHDR）电子输送。为了提高未来临床FLASH放射治疗试验的可靠性，本研究的目的是引入和评价升级的射束控制系统和射束调谐过程，以实现安全和精确的UHDR输送。射束控制系统被设计成基于1）由监控器检测器测量的监控单元（MU）的预设数量、2）由脉冲计数二极管测量的脉冲的预设数量、或3）预设输送时间来中断射束。对于UHDR传输，光耦合器有助于加速器闸流管触发脉冲的外部控制。建立了光束调谐过程以最大化输出。我们评估了输送的稳定性，以及三个系统（监测探测器、脉冲计数器和计时器）的独立中断能力。此外，我们探索了一种新的方法，以提高剂量精确度的交付同步的触发脉冲与充电周期的脉冲形成网络（PFN）。枪电流和磁控管频率的改进的射束调谐导致在等中心距离处的剂量最大值处的平均剂量率分别为>160戈伊/s或>200戈伊/s，在射束路径中有或没有外部监测室。递送显示出良好的重复性（总膜剂量的标准偏差（SD）为2.2%）和再现性（膜剂量的SD为2.6%）。DPP的估计变化导致SD为1.7%。在初始脉冲的输出依赖于PFN的延迟时间。在采用PFN同步的50次测量过程中，监测器检测器计算的MU输送数量与预设MU之间的绝对百分比误差为0.8 ± 0.6%（平均值± SD）。我们提出了一种升级的束流控制系统和束流调谐过程，用于在临床直线加速器的等中心距离处安全稳定地提供数百戈伊/s的UHDR电子。该系统可以中断基于监视器单元的射束，并利用PFN同步来提高剂量输送中的剂量测定精度，这代表了可靠的临床FLASH试验的重要进步。
We have previously adapted a clinical linear accelerator (Elekta Precise, Elekta AB) for ultra-high dose rate (UHDR) electron delivery. To enhance reliability in future clinical FLASH radiotherapy trials, the aim of this study was to introduce and evaluate an upgraded beam control system and beam tuning process for safe and precise UHDR delivery. The beam control system is designed to interrupt the beam based on 1) a preset number of monitor units (MUs) measured by a monitor detector, 2) a preset number of pulses measured by a pulse-counting diode, or 3) a preset delivery time. For UHDR delivery, an optocoupler facilitates external control of the accelerator’s thyratron trigger pulses. A beam tuning process was established to maximize the output. We assessed the stability of the delivery, and the independent interruption capabilities of the three systems (monitor detector, pulse counter, and timer). Additionally, we explored a novel approach to enhance dosimetric precision in the delivery by synchronizing the trigger pulse with the charging cycle of the pulse forming network (PFN). Improved beam tuning of gun current and magnetron frequency resulted in average dose rates at the dose maximum at isocenter distance of >160 Gy/s or >200 Gy/s, with or without an external monitor chamber in the beam path, respectively. The delivery showed a good repeatability (standard deviation (SD) in total film dose of 2.2%) and reproducibility (SD in film dose of 2.6%). The estimated variation in DPP resulted in an SD of 1.7%. The output in the initial pulse depended on the PFN delay time. Over the course of 50 measurements employing PFN synchronization, the absolute percentage error between the delivered number of MUs calculated by the monitor detector and the preset MUs was 0.8 ± 0.6% (mean ± SD). We present an upgraded beam control system and beam tuning process for safe and stable UHDR electron delivery of hundreds of Gy/s at isocenter distance at a clinical linac. The system can interrupt the beam based on monitor units and utilize PFN synchronization for improved dosimetric precision in the dose delivery, representing an important advancement toward reliable clinical FLASH trials.
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影响因子：
4.7
作者：
Konradsson E;Arendt ML;Bastholm Jensen K;Børresen B;Hansen AE;Bäck S;Kristensen AT;Munck Af Rosenschöld P;Ceberg C;Petersson K
通讯作者：
Petersson K
影响因子：
5.7
作者：
Gaide, Olivier;Herrera, Fernanda;Bourhis, Jean
通讯作者：
Bourhis, Jean
使用临床直线加速器的电子超高剂量率闪光照射研究：直线加速器修改、剂量测定和放射生物学结果
影响因子：
3.8
作者：
Xie，De-Huan;Li，Yi-Chuan;Qian，Chao-Nan
通讯作者：
Qian，Chao-Nan
双梁电流变压器设计，用于监视和报告电子超高剂量速率（闪光）梁参数。
影响因子：
2.1
作者：
Liu, Kevin;Palmiero, Allison;Chopra, Nitish;Velasquez, Brett;Li, Ziyi;Beddar, Sam;Schueler, Emil
通讯作者：
Schueler, Emil
影响因子：
3.8
作者：
通讯作者：
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