PDF(Pubmed)
Abstract：
OBJECTIVE: Beam delivery latency in respiratory-gated particle therapy systems is a crucial issue to dose delivery accuracy. The aim of this study is to develop a multi-channel signal acquisition platform for investigating gating latencies occurring within RPM respiratory gating system (Varian, USA) and ProBeam proton treatment system (Varian, USA) individually.
METHODS: The multi-channel signal acquisition platform consisted of several electronic components, including a string position sensor for target motion detection, a photodiode for proton beam sensing, an interfacing board for accessing the trigger signal between the respiratory gating system and the proton treatment system, a signal acquisition device for sampling and synchronizing signals from the aforementioned components, and a laptop for controlling the signal acquisition device and data storage. RPM system latencies were determined by comparing the expected gating phases extracted from the motion signal with the trigger signal\'s state turning points. ProBeam system latencies were assessed by comparing the state turning points of the trigger signal with the beam signal. The total beam delivery latencies were calculated as the sum of delays in the respiratory gating system and the cyclotron proton treatment system. During latency measurements, simulated sinusoidal motion were applied at different amplitudes and periods for complete beam delivery latency evaluation under different breathing patterns. Each breathing pattern was repeated 30 times for statistical analysis.
RESULTS: The measured gating ON/OFF latencies in the RPM system were found to be 104.20 ± 13.64 ms and 113.60 ± 14.98 ms, respectively. The measured gating ON/OFF delays in the ProBeam system were 108.29 ± 0.85 ms and 1.20 ± 0.04 ms, respectively. The total beam ON/OFF latencies were determined to be 212.50 ± 13.64 ms and 114.80 ± 14.98 ms.
CONCLUSIONS: With the developed multi-channel signal acquisition platform, it was able to investigate the gating lags happened in both the respiratory gating system and the proton treatment system. The resolution of the platform is enough to distinguish the delays at the millisecond time level. Both the respiratory gating system and the proton treatment system made contributions to gating latency. Both systems contributed nearly equally to the total beam ON latency, with approximately 100 ms. In contrast, the respiratory gating system was the dominant contributor to the total beam OFF latency.
METHODS: The multi-channel signal acquisition platform consisted of several electronic components, including a string position sensor for target motion detection, a photodiode for proton beam sensing, an interfacing board for accessing the trigger signal between the respiratory gating system and the proton treatment system, a signal acquisition device for sampling and synchronizing signals from the aforementioned components, and a laptop for controlling the signal acquisition device and data storage. RPM system latencies were determined by comparing the expected gating phases extracted from the motion signal with the trigger signal\'s state turning points. ProBeam system latencies were assessed by comparing the state turning points of the trigger signal with the beam signal. The total beam delivery latencies were calculated as the sum of delays in the respiratory gating system and the cyclotron proton treatment system. During latency measurements, simulated sinusoidal motion were applied at different amplitudes and periods for complete beam delivery latency evaluation under different breathing patterns. Each breathing pattern was repeated 30 times for statistical analysis.
RESULTS: The measured gating ON/OFF latencies in the RPM system were found to be 104.20 ± 13.64 ms and 113.60 ± 14.98 ms, respectively. The measured gating ON/OFF delays in the ProBeam system were 108.29 ± 0.85 ms and 1.20 ± 0.04 ms, respectively. The total beam ON/OFF latencies were determined to be 212.50 ± 13.64 ms and 114.80 ± 14.98 ms.
CONCLUSIONS: With the developed multi-channel signal acquisition platform, it was able to investigate the gating lags happened in both the respiratory gating system and the proton treatment system. The resolution of the platform is enough to distinguish the delays at the millisecond time level. Both the respiratory gating system and the proton treatment system made contributions to gating latency. Both systems contributed nearly equally to the total beam ON latency, with approximately 100 ms. In contrast, the respiratory gating system was the dominant contributor to the total beam OFF latency.
摘要：
目的：呼吸门控粒子治疗系统中的射束递送潜伏期是剂量递送准确性的关键问题。本研究的目的是开发一种多通道信号采集平台，用于研究RPM呼吸门控系统中发生的门控延迟（Varian，美国)和ProBeam质子治疗系统(瓦里安，美国）单独。
方法：多通道信号采集平台由几个电子元件组成，包括一个用于目标运动检测的字符串位置传感器，用于质子束传感的光电二极管，接口板，用于访问呼吸门测系统和质子治疗系统之间的触发信号，信号采集装置，用于对来自上述组件的信号进行采样和同步，以及用于控制信号采集装置和数据存储的笔记本电脑。通过比较从运动信号中提取的预期门控相位与触发信号的状态转折点来确定RPM系统延迟。通过比较触发信号与波束信号的状态转折点来评估ProBeam系统延迟。总的射束递送延迟被计算为呼吸门控系统和回旋加速器质子治疗系统中的延迟的总和。在延迟测量期间，在不同的振幅和周期下应用模拟的正弦运动，以评估不同呼吸模式下的完整波束传递延迟。每种呼吸模式重复30次用于统计分析。
结果：发现RPM系统中测得的门控ON/OFF延迟为104.20±13.64ms和113.60±14.98ms，分别。在ProBeam系统中测量的门控ON/OFF延迟为108.29±0.85ms和1.20±0.04ms，分别。总的波束开/关延迟被确定为212.50±13.64ms和114.80±14.98ms。
结论：借助开发的多通道信号采集平台，它能够研究呼吸门控系统和质子治疗系统中发生的门控滞后。平台的分辨率足以区分毫秒时间级别的延迟。呼吸门控系统和质子治疗系统都对门控延迟做出了贡献。两种系统对总波束开启延迟的贡献几乎相等，大约100毫秒。相比之下,呼吸门控系统是总波束关闭延迟的主要贡献者。
方法：多通道信号采集平台由几个电子元件组成，包括一个用于目标运动检测的字符串位置传感器，用于质子束传感的光电二极管，接口板，用于访问呼吸门测系统和质子治疗系统之间的触发信号，信号采集装置，用于对来自上述组件的信号进行采样和同步，以及用于控制信号采集装置和数据存储的笔记本电脑。通过比较从运动信号中提取的预期门控相位与触发信号的状态转折点来确定RPM系统延迟。通过比较触发信号与波束信号的状态转折点来评估ProBeam系统延迟。总的射束递送延迟被计算为呼吸门控系统和回旋加速器质子治疗系统中的延迟的总和。在延迟测量期间，在不同的振幅和周期下应用模拟的正弦运动，以评估不同呼吸模式下的完整波束传递延迟。每种呼吸模式重复30次用于统计分析。
结果：发现RPM系统中测得的门控ON/OFF延迟为104.20±13.64ms和113.60±14.98ms，分别。在ProBeam系统中测量的门控ON/OFF延迟为108.29±0.85ms和1.20±0.04ms，分别。总的波束开/关延迟被确定为212.50±13.64ms和114.80±14.98ms。
结论：借助开发的多通道信号采集平台，它能够研究呼吸门控系统和质子治疗系统中发生的门控滞后。平台的分辨率足以区分毫秒时间级别的延迟。呼吸门控系统和质子治疗系统都对门控延迟做出了贡献。两种系统对总波束开启延迟的贡献几乎相等，大约100毫秒。相比之下,呼吸门控系统是总波束关闭延迟的主要贡献者。
