直线扫描内CT及其动态Bowtie研究

项目名称： 直线扫描内CT及其动态Bowtie研究

项目编号： No.61471070

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 无线电电子学、电信技术

项目作者： 刘丰林

作者单位： 重庆大学

项目金额： 85万元

中文摘要： 一方面新型低成本、可移动CT成像设备是发展中国家偏远地区、战场、军事机构等亟需；另一方面CT新技术需优先考虑降低辐射剂量。项目提出一种射线源和平板探测器相对平行移动扫描的内CT方法和一种高密度液体材料的动态Bowtie(BT)滤波新技术，在简化CT扫描仪系统结构的同时采用动态BT降低辐射剂量和探测器动态范围需求，从而降低系统成本。1次(1T)直线运动CT扫描与数字射线分层照相扫描运动相同，初步研究表明采用2次(2T)和3次(3T)直线运动扫描时重建CT图像效果理想；动态BT为在液体滤波器(HBT)中放置气泡型滤波器(LBT),LBT与扫描对象外形相关，当LBT与CT扫描同步旋转时实现动态滤波，初步研究表明该动态BT能较大降低探测数据动态范围。项目组将在现有研究基础上，继续针对锥束变视场内CT图像重建算法、动态BT实现方法等开展相关理论、仿真和试验研究，期望形成一套新型CT的理论和方法。

中文关键词： XCT成像；成像原理；成像方法；图像重建；医学CT系统

英文摘要： New techniques for movable ultra-low-cost x-ray CT scanners are in instant and great needs for military, war areas, developing countries, especially for rural areas. And for the new CT techniques, methods for radiation dose reduction should be taken into consideration. In this project, we proposed a translation based interior CT scheme which is inspired by the recently developed compressive sensing and interior tomography techniques, and proposed a dynamic bowtie scheme for cone-beam CT which consists of a high-density bowtie (HBT) filled in with heavy liquid and a low-density bowtie (LBT) immersed in the liquid of the HBT. In the CT scheme, the source and detector are translated in opposite directions for ROI reconstruction with one or more localized linear scans, among which the one-translation scan is similar to the digital tomosynthesis. The popular slip ring is replaced by a translation based setup, and the instrumentation cost is reduced by a relaxation of the imaging speed requirement. The dynamic bowtie filter can reduce the dose and in the meantime reduce the required dynamic range of detectors which would decrease the cost of detectors. Our initial study shows that the CT and dynamic bowtie methods are feasible. In this project plan, we will further the theory, simulations and experiments of the CT and dynamic bowtie.

英文关键词： Interior tomography;CT algorithm;CT methodology;image reconstruction;Dynamic Bowtie