锥形束CT中简单动态滤波策略的数值验证  

Numerical Validation of A Simple Dynamic Beam Filtration Strategy in Cone Beam CT

作　　者：王鹤然 谢吉雄 朱炯滔 张欣 谭雨航 苏婷 葛永帅 WANG Heran;XIE Jixiong;ZHU Jiongtao;ZHANG Xin;TAN Yuhang;SU Ting;GE Yongshuai(Shenzhen Institutes of Advanced Technology,Chinese Academy of Sciences,Shenzhen 518055,China;University of Chinese Academy of Sciences,Beijing 100049,China;Research Center for Advanced Detection Materials and Medical Imaging Devices,Shenzhen Institutes of Advanced Technology,Chinese Academy of Sciences,Shenzhen 518055,China;Paul C.Lauterbur Research Center for Biomedical Imaging,Shenzhen Institutes of Advanced Technology,Chinese Academy of Sciences,Shenzhen 518055,China;Key Laboratory of Biomedical Imaging Science and System,Chinese Academy of Sciences,Shenzhen 518055,China)

机构地区：[1]中国科学院深圳先进技术研究院,深圳518055 [2]中国科学院大学,北京100049 [3]中国科学院深圳先进技术研究院先进探测材料与医学成像器件研究中心,深圳518055 [4]中国科学院深圳先进技术研究院劳特伯生物医学成像研究中心,深圳518055 [5]中国科学院医学成像科学与技术系统重点实验室,深圳518055

出　　处：《集成技术》2025年第2期71-85,共15页Journal of Integration Technology

基　　金：国家自然科学基金项目(12305349,12235006,12027812);深圳市科技计划项目(JSGGKQTD20210831174329010);广东省基础与应用基础研究基金项目(2021TQ06Y108)。

摘　　要：对于锥束计算机断层扫描(cone beam computed tomography,CBCT),人们一直希望能够在扫描过程中动态地调节X射线的强度和分布,以适应患者内部的解剖结构。这样就可以达到减少图像伪影和降低辐射剂量的目的。然而,目前的动态滤波装置,如动态Bowtie滤波器,其结构较为复杂难以真正应用到临床,因此,本研究旨在设计一种结构简单的动态滤波策略,以减少CBCT成像中的图像伪影同时降低辐射剂量。本研究所设计的动态滤波策略随着CBCT的旋转而动态变化,具体而言,该动态滤波策略是将两个不同部分集成在一起:滤片部分和Bowtie部分。该动态滤波策略设置有两种工作模式,一种是动态滤片与动态Bowtie的组合,称为动态滤片-动态Bowtie(Dynamic filter-Dynamic bowtie,DFDB);另一种是动态滤片与静态Bowtie的组合,称为动态滤片-静态Bowtie(Dynamic filter-Static bowtie,DFSB)。本研究分别针对3个人体部位(肩部、胸部和膝部)进行了数值仿真模拟,且使用蒙特卡罗模拟平台MC-GPU生成每个体模对应的剂量分布图。结果表明,使用所提出的DFDB和DFSB动态滤波方案可以显著减少图像伪影,从而改善CBCT图像质量。根据扫描部位的不同,辐射剂量的降低幅度达到约30%。因此,本研究所提出的简单动态滤波策略DFDB和DFSB,可以有效提升图像质量同时降低辐射剂量,且拥有足够简单的结构(尤其是DFSB),在一定程度上推进了动态滤波策略的临床应用。For cone beam computed tomography(CBCT),there has long been a desire to modulate the intensity and distribution of the X-rays to accommodate the patient’s anatomy as the gantry rotates from one projection to another.This would reduce both image artifacts and radiation dose.However,the current beam modulation setups,such as dynamic bowtie filters,may be too complex for practical use in clinical applications.This study aimed to investigate a simplified dynamic beam filtration strategy for CBCT imaging to reduce image artifacts and radiation dose.In this study,the beam filtration was designed to vary dynamically as the CBCT gantry rotates around the object.Specifically,two distinct components were integrated:the sheet filter part and the bowtie filter part.The dynamic beam filtration setup has two working schemes,one is a combination of dynamic sheet filter and dynamic bowtie filter,denoted as dynamic filterdynamic bowtie(DFDB);the other is a combination of dynamic sheet filter and static bowtie filter,denoted as dynamic filter-static bowtie(DFSB).Numerical imaging experiments were performed for three human body parts:the shoulder,chest,and knee.In addition,the Monte Carlo simulation platform MC-GPU was used to generate the dose distribution maps.Results showed that the proposed DFDB and DFSB beam filtration schemes can significantly reduce the image artifacts and thus improve the CBCT image quality.Depending on the scanned object,the total radiation dose could be reduced by 30%.The proposed simple dynamic beam filtration strategy,especially the DFSB approach,could be beneficial in the future to improve the CBCT image quality with reduced image artifacts and radiation dose.

关 键 词：动态滤波 辐射剂量降低 硬化伪影减少 锥束CT 

分 类 号：R814.4[医药卫生—影像医学与核医学]