Accurate confirmation and verification of the range of spot scanning proton beams is crucial for correct dose delivery. Current methods to measure proton beam range using ionization chambers are either time-consuming or result in measurements with poor spatial resolution. The large-volume liquid scintillator detector allows real-time measurements of the entire dose profile of a spot scanning proton beam. Thus, liquid scintillator detectors are an ideal tool for measuring the proton beam range for commissioning and quality assurance. However, optical artefacts may decrease the accuracy of measuring the proton beam range within the scintillator tank. The purpose of the current study was to 1) develop a geometric calibration system to accurately calculate physical distances within the liquid scintillator detector, taking into account optical artefacts; and 2) assess the accuracy, consistency, and robustness of proton beam range measurement using the liquid scintillator detector with our geometric calibration system. The range of the proton beam was measured with the calibrated liquid scintillator system and was compared to the nominal range. Measurements were made on three different days to evaluate the setup robustness from day to day, and three sets of measurements were made for each day to evaluate the consistency from delivery to delivery. All proton beam ranges measured using the liquid scintillator system were within half a millimeter of the nominal range. The delivery-to-delivery standard deviation of the range measurement was 0.04 mm, and the day-to-day standard deviation was 0.10 mm. In addition to the accuracy and robustness demonstrated by these results when our geometric calibration system was used, the liquid scintillator system allowed the range of all 94 proton beams to be measured in just two deliveries, making the liquid scintillator detector a perfect tool for range measurement of spot scanning proton beams.

中文翻译：

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使用体积液体闪烁体探测器对点扫描质子束进行快速范围测量

点扫描质子束范围的准确确认和验证对于正确的剂量输送至关重要。当前使用电离室测量质子束范围的方法要么耗时，要么导致测量空间分辨率较差。大容量液体闪烁体探测器允许实时测量点扫描质子束的整个剂量分布。因此，液体闪烁体探测器是测量质子束范围以进行调试和质量保证的理想工具。然而，光学人工制品可能会降低测量闪烁体罐内质子束范围的准确性。当前研究的目的是 1) 开发几何校准系统以准确计算液体闪烁体探测器内的物理距离，考虑到光学人工制品；2) 使用液体闪烁体探测器和我们的几何校准系统评估质子束范围测量的准确性、一致性和稳健性。质子束的射程是用校准的液体闪烁体系统测量的，并与标称射程进行比较。在三个不同的日子进行测量以评估每天的设置稳健性，每天进行三组测量以评估从交付到交付的一致性。使用液体闪烁体系统测量的所有质子束范围都在标称范围的半毫米以内。测距的交货到交货标准偏差为 0.04 毫米，日常标准偏差为 0.10 毫米。