Tesfamicael Biniam, Eckert Colton, Rana Suresh
The Oklahoma Proton Center, Oklahoma City, OK, USA.
Lynn Cancer Institute, Boca Raton Regional Hospital, Baptist Health South Florida, Boca Raton, FL, USA.
Int J Part Ther. 2022 Apr 22;9(1):90-95. doi: 10.14338/IJPT-21-00040.1. eCollection 2022 Summer.
The purpose of this work is to study the feasibility of using an XRV-124 scintillation detector in measuring the collinearity of the x-ray system and uniform scanning proton beam.
A brass aperture for Snout 10 was manufactured. The center of the aperture had an opening of 1 cm in diameter (4 cm for the film measurements). The 2D kV x-ray images of the XRV-124 were acquired such that the marker inside the detector is aligned to the imaging isocenter. After obtaining the optimal camera settings, a uniform scanning proton beam was delivered for various ranges (12 g/cm to 28 g/cm in step size of 2 g/cm). For each range, 10 monitor units (MU) of the first layer were delivered to the XRV-124 detector. Collinearity tests were repeated by using EDR2 and EBT3 films following our current quality assurance protocol in practice. The results from the XRV-124 measurements were compared against the collinearity results from EDR2 and EBT3 films.
The collinearity results were evaluated in the horizontal (x) and vertical (y) directions. The average deviation in collinearity in the x-direction was -0.24 ± 0.30 mm, 0.57 ± 0.39 mm, and -0.27 ± 0.14 mm for EDR2, EBT3, and XRV-124, respectively. In the y-direction, the average deviation was 0.39 ± 0.07 mm, 0.29 ± 0.14 mm, and 0.39 ± 0.03 mm for EDR2, EBT3, and XRV-124, respectively.
The measurement results from the XRV-124 and films are in good agreement. Compared to film, the use of the XRV-124 detector for collinearity measurements in uniform scanning protons is more efficient and provides results in real time.
本研究旨在探讨使用XRV - 124闪烁探测器测量X射线系统与均匀扫描质子束共线性的可行性。
制作了一个用于10号准直器的黄铜孔径板。孔径板中心的开口直径为1厘米（用于胶片测量时为4厘米）。采集XRV - 124的二维千伏X射线图像，使探测器内部的标记与成像等中心对齐。在获得最佳相机设置后，针对不同范围（从12 g/cm至28 g/cm，步长为2 g/cm）输送均匀扫描质子束。对于每个范围，向XRV - 124探测器输送第一层的10个监测单位（MU）。按照我们目前实际的质量保证方案，使用EDR2和EBT3胶片重复进行共线性测试。将XRV - 124测量结果与EDR2和EBT3胶片的共线性结果进行比较。
在水平（x）和垂直（y）方向评估共线性结果。对于EDR2、EBT3和XRV - 124，x方向共线性的平均偏差分别为 - 0.24±0.30毫米、0.57±0.39毫米和 - 0.27±0.14毫米。在y方向，EDR2、EBT3和XRV - 124的平均偏差分别为0.39±0.07毫米、0.29±0.1毫米和0.39±0.03毫米。
XRV - 124与胶片的测量结果吻合良好。与胶片相比，使用XRV - 124探测器进行均匀扫描质子束的共线性测量更高效且能实时提供结果。
