Department of Mechanics, Marvdasht Branch, Islamic Azad University, Marvdasht, Iran.
Department of Electrical Engineering, College of Engineering, Shiraz Branch, Islamic Azad University, Shiraz, Iran.
J Adv Res. 2016 Mar;7(2):225-32. doi: 10.1016/j.jare.2015.04.006. Epub 2015 Apr 20.
A miniature X-ray source has been optimized for electronic brachytherapy. The cooling fluid for this device is water. Unlike the radionuclide brachytherapy sources, this source is able to operate at variable voltages and currents to match the dose with the tumor depth. First, Monte Carlo (MC) optimization was performed on the tungsten target-buffer thickness layers versus energy such that the minimum X-ray attenuation occurred. Second optimization was done on the selection of the anode shape based on the Monte Carlo in water TG-43U1 anisotropy function. This optimization was carried out to get the dose anisotropy functions closer to unity at any angle from 0° to 170°. Three anode shapes including cylindrical, spherical, and conical were considered. Moreover, by Computational Fluid Dynamic (CFD) code the optimal target-buffer shape and different nozzle shapes for electronic brachytherapy were evaluated. The characterization criteria of the CFD were the minimum temperature on the anode shape, cooling water, and pressure loss from inlet to outlet. The optimal anode was conical in shape with a conical nozzle. Finally, the TG-43U1 parameters of the optimal source were compared with the literature.
一种微型 X 射线源已被优化用于电子近距离放射治疗。该设备的冷却流体为水。与放射性核素近距离治疗源不同，该源能够在不同的电压和电流下运行，以匹配肿瘤深度的剂量。首先，针对钨靶-缓冲层厚度对能量的关系进行了蒙特卡罗（MC）优化，以使 X 射线衰减最小。其次，根据蒙特卡罗在水中 TG-43U1 各向异性函数对阳极形状的选择进行了优化。进行这种优化是为了使任何角度（0°至 170°）的剂量各向异性函数更接近 1。考虑了三种阳极形状，包括圆柱形、球形和圆锥形。此外，通过计算流体动力学（CFD）代码，对电子近距离放射治疗的最佳靶-缓冲形状和不同的喷嘴形状进行了评估。CFD 的特征化标准是阳极形状、冷却水和进出口压力损失的最小温度。最佳阳极呈圆锥形，并带有圆锥形喷嘴。最后，将最优源的 TG-43U1 参数与文献进行了比较。
