A method to increase the nominal range resolution of a stack of parallel-plate ionization chambers
A method to increase the nominal range resolution of a stack of parallel-plate ionization chambers
复制标题
一种提高平行板电离室堆叠标称距离分辨率的方法
DOI：
10.1088/0031-9155/59/18/5501
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发表时间：
2014
影响因子：
3.5
通讯作者：
Parodi K
中科院分区：
文献类型：
--
作者：
Rinaldi I;Brons S;Jäkel O;Voss B;Parodi K
基于61个平行板电离室(PPIC)和聚甲基丙烯酸甲酯(PMMA)吸收器板的堆叠，组装了一种探测器原型，用于离子束治疗的透射式成像。PPIC叠层中吸收片的厚度决定了探测器的标称范围分辨率。在目前的设置中，使用了3 mm的PMMA板。因此，堆叠的61个有效通道的信号提供了探测器中的布拉格曲线的离散近似。在这项工作中，提出了一种提高电离室堆叠距离分辨率的数据处理方法。在MIRR中，布拉格曲线的最大值的位置是根据相邻PPIC通道中的测量信号的比率来推断的。该方法是基于蒙特卡罗模拟得到的Bragg曲线，并用用碳离子束在PPIC堆上获得的楔形PMMA体模的实验数据来验证的。定量评估了初始束流能量和模体不均匀性对镜面反射率的影响。讨论并量化了与信号噪声有关的系统误差和不精确度。结果表明，使用MIRR后，实验数据的距离分辨率提高了0.7 mm PMMA当量或0.8 mm水当量厚度。
A detector prototype based on a stack of 61 parallel-plate ionisation chambers (PPIC) interleaved with absorber plates of polymethyl methacrylate (PMMA) was assembled for transmission imaging purposes in ion beam therapy. The thickness of the absorber sheets in the PPIC stack determines the nominal range resolution of the detector. In the current set-up, 3 mm PMMA slabs are used. The signal of the 61 active channels of the stack thereby provides a discrete approximation of the Bragg curve in the detector. In this work, a data processing method to increase the range resolution (MIRR) in a stack of ionization chambers is presented. In the MIRR the position of the maximum of the Bragg curve is deduced from the ratio of measured signals in adjacent PPIC channels. The method is developed based on Bragg curves obtained from Monte Carlo simulations and validated with experimental data of a wedge-shaped PMMA phantom acquired with the PPIC stack using carbon ion beams. The influence of the initial beam energy and of phantom inhomogeneities on the MIRR is quantitatively evaluated. Systematic errors as well as inaccuracies related to signal noise are discussed and quantified. It is shown that with the MIRR an increased range resolution of 0.7 mm PMMA equivalent or 0.8 mm water equivalent thickness is achieved for the considered experimental data.
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影响因子：
3.8
作者：
Jäkel, O;Jacob, C;Hartmann, GH
通讯作者：
Hartmann, GH
使用测距望远镜进行碳离子扫描射线照相的实验研究
影响因子：
3.5
作者：
Rinaldi I;Brons S;Jäkel O;Voss B;Parodi K
通讯作者：
Parodi K
影响因子：
1.8
作者：
Schulte, R;Bashkirov, V;Woody, C
通讯作者：
Woody, C
使用重离子 CT 测量电子密度分布
DOI：
--
发表时间：
2004
期刊：
影响因子：
--
作者：
Y. Ohno;T. Kohno;N. Matsufuji;T. Kanai
通讯作者：
T. Kanai