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报告题目: A Block-tridiagonal Shift-variant Preconditioner for Iterative Cone Beam CT Reconstruction
报告人：郭洪斌 研发总监
奕瑞（iRay）科技 美国研发中心
报告时间：2025年5月26日下午16:00
报告地点：红瓦楼826
报告内容简介：In X-ray computed tomography (CT), iterative image reconstruction offers a promising approach to reduce radiation dose while preserving diagnostic image quality. Although extensive studies on both phantom and clinical datasets have validated the advantages of iterative methods, their high computational cost remains a significant barrier to replacing the widely-used analytical technique of filtered backprojection (FBP) in routine clinical practice. Iterative reconstruction involves repeated forward and backprojections, and reducing the number of iterations is crucial for improving efficiency.
In two-dimensional CT, a well-designed shift-variant preconditioner by Fessler and Booth has demonstrated substantial acceleration. Several preconditioning strategies have been proposed for three-dimensional cone-beam CT. In this work, we introduce a novel block tridiagonal preconditioner tailored to the structure of the system matrix in 3D cone-beam reconstruction. This preconditioner approximates the dominant matrix structure with minimal computational overhead. Experimental results demonstrate that the preconditioned conjugate gradient (PCG) algorithm significantly outperforms the conventional conjugate gradient (CG) method in convergence speed, offering a practical path toward more efficient iterative reconstruction in clinical CT applications.
报告人简介：郭洪斌 （Hongbin Guo）2000年获复旦大学计算数学博士学位。 随后在亚利桑那州立大学（ASU）长期从事计算数学理论及其在医疗图像方面的应用研究（博士后和研究教授）。2010年进入工业界，在UIUC研究园区的InstaRecon从事CT的图像重建产品的算法研究，特别是投影和反投影的快速算法以及迭代重建算法的加速收敛的研究。2013年进入FMI medical systems先后任首席科学家和总工程师十年。2023年起任奕瑞（iRay）科技美国研发中心研发总监，带领团队研发高端CT系统。
报告邀请人：徐定华