X射线CT转台单侧两次螺旋扫描单层重排重建算法  

Single-Slice-Rebinning Reconstruction Algorithm with One-Sided Two Helical Scans for X-Ray CT System

作　　者：李磊[1] 韩玉[1] 席晓琦[1] 王林元[1] 闫镔[1] 包尚联[2] 

机构地区：[1]国家数字交换系统工程技术研究中心,河南郑州450002 [2]北京大学重离子物理研究所,北京100871

出　　处：《光学学报》2016年第9期342-350,共9页Acta Optica Sinica

基　　金：国家自然科学基金(61372172)

摘　　要：锥束计算机断层成像(CT)在临床医学及工业无损检测等诸多领域获得了越来越广泛的应用。但是,受面阵探测器尺寸等硬件条件限制,锥束CT的成像视野有限,难以满足实际应用中对大尺寸物体成像的需求。为了扩展锥束CT的视野,提出了锥束CT转台单侧两次螺旋扫描单层重排重建算法。该算法在转台的同一侧进行两次螺旋扫描,通过统一成像几何条件,将两组螺旋锥形束投影重排为多层平行束投影,利用平行束投影的对称性去除数据的横向截断,得到一组完全覆盖物体横截面的平行束投影数据,再通过滤波反投影方式得到重建图像。实验结果表明,该方法的成像视野扩展率可达2.56,且成像质量与传统全覆盖算法相当。X-ray computed tomography （CT） has been widely applied as a powerful tool in both clinical medicine and industrial non-destructive test areas. With the development of flat panel detector in detection efficiency and anti- radiation property, the cone beam CT based on the cone beam source and the flat panel detector has been broadly used. However, the field of view of cone-beam CT is restricted by the hardware conditions such as detector size, and thereby the accessibility for larger size object applications is limited. In order to enlarge the field of view of cone beam CT, a one-sided two helical-scan single slice-rebinning reconstruction algorithm is proposed. By performing one-sided two helical scans and normalizing the imaging geometries, two groups of helical cone-beam proiections are recombined into one muhi-slice parallel-beam projection, whose symmetrical feature is utilized to remove the transverse truncation in the data obtained, then the parallel beam projection data covering the complete object cross- section is obtained, and thus the images are reconstructed by back projection. The experimental results show that the proposed algorithm can extend the field of view by 2.56 times with comparable imaging quality compared to the traditional algorithm.

关 键 词：X射线光学 计算机断层成像 转台单侧两次螺旋扫描 图像重建 数据重排 

分 类 号：TP391[自动化与计算机技术—计算机应用技术] O434.1[自动化与计算机技术—计算机科学与技术]