Moslemi Vahid, Erfanian Vahid, Ashoor Mansour
Radiation Applications Research School, Nuclear Science and Technology Research Institute, P.O. Box: 113653486, Tehran, Iran.
Mechanical Engineering Department, Amirkabir University of Technology, P.O. Box: 158754413, Tehran, Iran.
Heliyon. 2020 Jan 22;6(1):e03279. doi: 10.1016/j.heliyon.2020.e03279. eCollection 2020 Jan.
The system matrix (SM) being a main part of statistical image reconstruction algorithms establishes relationship between the object and projection space. The aim was to determine it in a short duration time, towards obtaining the best quality of contrast images. In this study, a new analytical method based on Cavalieri's principle as subdividing common regions has been proposed in which the precision of the amounts of estimated areas was improved by increasing the number of divisions (NOD), and consequently the total SM's time was increased. An important issue is the tradeoff between the NODs and computational time. For this purpose, a Monte Carlo simulated Jaszczak phantom study was performed by the Monte Carlo N-Particle transport code version 5 (MCNP5) in which the tomographic images of resolution and contrast phantoms were reconstructed by maximum likelihood expectation maximization (MLEM) algorithm, and the influence of NODs variations was investigated. The results show that the lowest and best quality have been obtained at the NODs of 0 and 8, respectively and in the optimum case, the SM's total time at NOD of 8 was 925 s, which was much lower than those of the conventional Monte Carlo simulations and experimental test.
系统矩阵（SM）作为统计图像重建算法的主要部分，建立了物体空间与投影空间之间的关系。目的是在短时间内确定它，以获得最佳质量的对比度图像。在本研究中，提出了一种基于卡瓦列里原理细分公共区域的新分析方法，通过增加分割数（NOD）提高了估计面积量的精度，从而增加了总系统矩阵时间。一个重要问题是分割数与计算时间之间的权衡。为此，使用蒙特卡罗N粒子输运代码版本5（MCNP5）进行了蒙特卡罗模拟的贾兹扎克体模研究，其中通过最大似然期望最大化（MLEM）算法重建分辨率体模和对比度体模的断层图像，并研究了分割数变化的影响。结果表明，分别在分割数为0和8时获得了最低和最佳质量，在最佳情况下，并研究了分割数变化的影响。结果表明，分别在分割数为0和8时获得了最低和最佳质量，在最佳情况下，分割数为8时系统矩阵的总时间为925秒，远低于传统蒙特卡罗模拟和实验测试的时间。
