用于放射治疗质量保证的像素分段充液线阵的研制和运行
Development and operation of a pixel segmented liquid-filled linear array for radiotherapy quality assurance
摘要：
设计、制造和测试了用于放射治疗质量保证的液体异辛烷（C $_{8}$ H $_{18}$）填充电离线阵。探测器由128个像素组成，每个像素的面积为1.7 mm $\times$ 1.7 mm，间隙为0.5 mm。小像素尺寸使探测器非常适合高梯度射束轮廓，如强度调制放射治疗（IMRT）和放射外科中存在的那些。作为读出电子设备，我们使用由CCLRC开发的带有Xchip的X射线数据采集系统（XDAS）。为了优化器件的操作，已经进行了关于收集效率对极化电压和剂量率的依赖性的研究。在第一次测试中，我们研究了剂量率和能量依赖性以及信号再现性。在固体水中，剂量率依赖性低于2.5%，直至5 Gy min $^{-1}$，能量依赖性低于2.1%，直至20 cm深度。几个矩形领域的输出因子和半影已被测量的线性阵列，并与0.125厘米的$^{3}$空气电离室和射线照相胶片，分别获得的结果进行了比较。最后，我们已经获得了配置文件的调强放射治疗领域和虚拟楔形。这些配置文件也进行了比较与射线照相胶片测量。所有的比较都显示出良好的对应关系。在测试期间（约三个月），信号再现性在2%以内。该装置已被证明具有良好的空间分辨率和信噪比的在线验证治疗光束的能力。
英文摘要：
A liquid isooctane (C$_{8}$H$_{18}$) filled ionization linear array for radiotherapy quality assurance has been designed, built and tested. The detector consists of 128 pixels, each of them with an area of 1.7 mm $\times$ 1.7 mm and a gap of 0.5 mm. The small pixel size makes the detector ideal for high gradient beam profiles like those present in Intensity Modulated Radiation Therapy (IMRT) and radiosurgery. As read-out electronics we use the X-Ray Data Acquisition System (XDAS) with the Xchip developed by the CCLRC. Studies concerning the collection efficiency dependence on the polarization voltage and on the dose rate have been made in order to optimize the device operation. In the first tests we have studied dose rate and energy dependences, and signal reproducibility. Dose rate dependence was found lower than 2.5 % up to 5 Gy min$^{-1}$, and energy dependence lower than 2.1 % up to 20 cm depth in solid water. Output factors and penumbras for several rectangular fields have been measured with the linear array and were compared with the results obtained with a 0.125 cm$^{3}$ air ionization chamber and radiographic film, respectively. Finally, we have acquired profiles for an IMRT field and for a virtual wedge. These profiles have also been compared with radiographic film measurements. All the comparisons show a good correspondence. Signal reproducibility was within a 2% during the test period (around three months). The device has proved its capability to verify on-line therapy beams with good spatial resolution and signal to noise ratio.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
