Dose distribution from x-ray microbeam arrays applied to radiation therapy: An EGS4 Monte Carlo study
Dose distribution from x-ray microbeam arrays applied to radiation therapy: An EGS4 Monte Carlo study
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DOI：
10.1118/1.1951043
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发表时间：
2005-08-01
期刊：
影响因子：
3.8
通讯作者：
Dilmanian, FA
中科院分区：
文献类型：
--
作者：
De Felici, M;Felici, R;Dilmanian, FA
我们提出了EGS4蒙特卡罗计算方法，用于放射治疗研究中单个x射线铅笔束、平面微束和平行平面微束阵列沉积的剂量的空间分布。计算了吸收剂量分布曲线，包括微束阵列剂量分布的峰谷比。微米级分辨率。我们确定了这些发现对光子和电子输运主要参数的依赖性。结果说明了电子范围和沉积在束内的剂量与电子输运的截止能量的关系，以及对束流能量、阵列尺寸和束流间距的剂量分布的影响。本文还研究了单束和平行平面微光束阵列的光束偏振效应。结果表明，虽然水影内3 cm × 3 cm微束阵列的极化效应足以在阵列的外侧测量（200 keV X射线束沉积剂量差的16%），但在阵列中心无法检测到，因此与放射治疗目的无关。最后，我们表明，为了正确地比较金属氧化物半导体场发射晶体管探测器确定的剂量谱与计算方法预测的剂量谱，重要的是要充分模拟器件的Si有源元素的尺寸和材料。(c) 2005年美国医学物理学家协会。
We present EGS4 Monte Carlo calculations of the spatial distribution of the dose deposited by a single x-ray pencil beam, a planar microbeam, and an array of parallel planar microbeams as used in radiation therapy research. The profiles of the absorbed dose distribution in a phantom, including the peak-to-valley ratio of the dose distribution from microbeam arrays, were calculated. at micrometer resolution. We determined the dependence of the findings on the main parameters of photon and electron transport. The results illustrate the dependence of the electron range and the deposited in-beam dose on the cut-off energy, of the electron transport, as well as the effects on the dose profiles of the beam energy, the array size, and the beam spacing. The effect of beam polarization also was studied for a single pencil beam and for an array of parallel planar microbeams. The results show that although the polarization effect on the dose distribution from a 3 cm X 3 cm microbeam array inside a water phantom is large enough to be measured at the outer side of the array (16% difference of the deposited dose for x-ray beams of 200 keV), it is not detectable at the array's center, thus being irrelevant for the radiation therapy purposes. Finally we show that to properly compare the dose profiles determined with a metal oxide semiconductor field emission transistor detector with the computational method predictions, it is important to simulate adequately the size and the material of the device's Si active element. (c) 2005 American Association of Physicists in Medicine.