X射线CT正交基材料分解成像方法及其在校正金属伪影中的应用  

Orthogonal Multi-Material Decomposition for X-Ray CT and Application in Metal Artifact Correction

作　　者：罗婷 赵星[2,3] 赵云松[2,3] 李陶 Luo Ting;Zhao Xing;Zhao Yunsong;Li Tao(Academy of Information Network Security,People's Public Security University of China,Beijing 100038,China;School of Mathematical Sciences,Capital Normal University,Beijing 100048,China;Beijing Advanced Innovation Center for Imaging Technology,Capital Normal University,Beijing 100048,China;School of Mathematics and Statistics,Beijing Technology and Business University,Beijing 100048,China)

机构地区：[1]中国人民公安大学信息网络安全学院,北京100038 [2]首都师范大学数学科学学院,北京100048 [3]首都师范大学检测成像北京市高等学校工程研究中心,北京100048 [4]北京工商大学数学与统计学院,北京100048

出　　处：《光学学报》2024年第8期37-51,共15页Acta Optica Sinica

基　　金：国家自然科学基金(61827809);中央高校基本科研业务费专项资金(2022JKF02015)。

摘　　要：针对被测样品的组成物质已知且彼此不混合的情况,提出了一种结合能谱信息的单能谱计算机断层扫描(CT)图像重建方法。该方法利用已知物质作为基材料对CT投影数据的采集过程进行数学建模,然后对该非线性模型进行基材料图像的迭代求解。在求解中,通过将基材料“不混合”的性质转化为向量正交性,实现了迭代过程的快速收敛。本文方法充分考虑了X射线的能谱和被测样品材料的属性,可显著地校正传统CT图像中的硬化伪影和金属伪影,有效地提高该类样品的CT成像质量。实验验证了所提方法的有效性。Objective X-ray computed tomography(CT) imaging technology,with nondestructive testing capabilities,has been widely used in industry,medicine,and other fields.When X-ray CT imaging is performed on samples containing highabsorption materials such as metals,the reconstructed images often contain metal artifacts due to beam hardening,scattering,and other factors,which severely degrade the quality of CT imaging.More recently,dual/multi-spectral CT has been proposed as an effective means of reducing beam-hardening and metal artifacts.However,it needs multiple scans of the object or specialized multi-spectral CT equipment.In this paper,we studied the multi-material decomposition reconstruction technique with traditional CT scanned data to reduce beam-hardening and metal artifacts.Methods The problem of multi-material decomposition reconstruction in traditional single-spectral CT is inherently highly underdetermined,leading to non-unique solutions.To obtain physically meaningful true solutions,it is necessary to incorporate additional constraints.In a type of scenario,the constituent materials of the scanned object are known and immiscible.The reconstructed image vectors are orthogonal if these materials are selected as basis materials needed in multi-material decomposition reconstruction.Based on this finding,an orthogonal multi-material decomposition reconstruction technique(OMDRT) combined with the X-ray energy spectrum was proposed.In the proposed OMDRT method,the order of basis materials was sorted based on the decreasing sequence of their attenuation coefficients.With triple-material decomposition reconstruction as an example,the proposed OMDRT method includes steps as follows:1) triple-material decomposition reconstruction;2) generation of the first material' mark images from reconstructed image;3) triple-material decomposition reconstruction with the first material' mark images;4) generation of the first and second materials' mark images from reconstructed images;5) triple-material decomposition reconstruction w

关 键 词：成像系统 X射线计算机断层扫描 硬化伪影 金属伪影 基材料分解 

分 类 号：TP391.4[自动化与计算机技术—计算机应用技术]