基于可分离替代函数优化的CT重建  

CT reconstruction based on separable surrogate optimization

作　　者：侯晓文 郭金川[1] 陈伟 江浩川 HOU Xiaowen;GUO Jinchuan;CHEN Wei;JIANG Haochuan(College of Physics and Optoelectronic Engineering,Shenzhen University,Shenzhen 518060,Guangdong Province,P.R.China;MinFound Medical Systems Co.Ltd.,Hangzhou 310018,Zhejiang Province,P.R.China)

机构地区：[1]深圳大学物理与光电工程学院,广东深圳518060 [2]明峰医疗系统股份有限公司,浙江杭州310018

出　　处：《深圳大学学报（理工版）》2023年第6期681-687,共7页Journal of Shenzhen University(Science and Engineering)

基　　金：国家自然科学基金资助项目(11674232);浙江省科技厅领雁计划资助项目(2022C03072);中核集团领创科研基金资助项目。

摘　　要：针对应用迭代坐标下降算法,且基于q广义高斯马尔科夫随机场正则化模型的计算机断层成像(computed tomography, CT)目标函数优化中存在的耗时过长问题,提出一种基于可分离替代函数的优化方法.根据目标函数特性,采用优化转换策略,将目标函数的优化转换为可分离替代函数的优化,使得待重建CT图像各个像素可以同时更新,再结合图形处理器(graphics processing unit, GPU)技术并行运算能力,最终极大降低了迭代重建所需时间.实验结果表明,与迭代坐标下降算法相比,通过本研究算法重建的CT图像具有相同的空间分辨率和噪声水平,计算耗时仅为迭代坐标下降算法的1/20.本算法在极低的计算耗时下,保持了迭代坐标下降算法优异的图像性能,为临床应用所面临的耗时过长问题提供解决途径.In response to the time-consuming problem of optimizing the objective function in computed tomography(CT)using the iterative coordinate descent algorithm and the regularization model of q-generalized Gaussian Markov random field,an optimization method based on separable surrogate is proposed.According to the characteristics of the objective function,the optimization transformation strategy is adopted to transform the optimization of the objective function into that of the separable surrogate,so that each pixel of the CT image to be reconstructed can be updated simultaneously.Combined with the parallel computing ability of the graphics processing unit(GPU)technology,the time required for iterative reconstruction is greatly reduced.The experimental results show that compared with the iterative coordinate descent algorithm,the CT image reconstructed by the proposed algorithm has the same spatial resolution and noise level,and the calculation time is only 1/20 of that of the iterative coordinate descent algorithm.The proposed algorithm maintains the excellent image performance of the iterative coordinate descent algorithm with extremely low calculation time,problem of excessive time consumption faced by the application of the iterative reconstruction algorithm.

关 键 词：医学成像技术 计算机断层成像 迭代重建 优化转换 并行运算 q广义高斯马尔科夫随机场 计算耗时 

分 类 号：R445.3[医药卫生—影像医学与核医学] O434.19[医药卫生—诊断学]