In proton-based radiotherapy, proton radiography could allow for direct measurement of the water-equivalent path length (WEPL) in tissue, which can then be used to determine relative stopping power (RSP). Additionally, proton radiographs allow for imaging in the beam’s-eye-view. In this work, a proton radiography technique using a flat-panel imager and a pencil-beam scanning (PBS) system is demonstrated in phantom. Proton PBS plans were delivered on a Varian ProBeam system to a flat-panel imager. Each proton plan consisted of energy layers separated by 4.8 MeV, and a field size of 25 cm × 25 cm. All measured data is binned into a layer-by-layer delivery in post processing. To build a calibration curve correlating detector response to WEPL, the plans were delivered to slabs of solid water of increasing thickness. Pixel-by-pixel detector response in the time/energy domain is then fit as a function of WEPL. Tissue equivalent phantoms are imaged for evaluation of WEPL accuracy. A sp...

中文翻译：

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质子笔束扫描系统的平板成像器依赖能量的质子射线照相

在基于质子的放射治疗中，质子射线照相可以直接测量组织中的水等效路径长度（WEPL），然后可以用来确定相对停止功率（RSP）。此外，质子射线照相可以在光束的视野内成像。在这项工作中，以幻影展示了使用平板成像仪和铅笔束扫描（PBS）系统的质子射线照相技术。Proton PBS计划已在Varian ProBeam系统上交付给平板成像仪。每个质子计划都由相隔4.8 MeV的能量层组成，场大小为25 cm×25 cm。在后处理中，所有测得的数据都被分装到逐层传送中。为了建立使检测器对WEPL的响应相关的校准曲线，计划被发送到了厚度不断增加的固体水中。然后，将时域/能量域中的逐像素检测器响应拟合为WEPL的函数。对组织等效体模成像以评估WEPL准确性。一个...