不含旋转角度微分的螺旋锥束CT重建  

Rotation Angle Derivative-free Image Reconstruction in Cone-beam Helical CT

作　　者：马建华[1] 陈武凡[1] 

机构地区：[1]南方医科大学生物医学工程学院,广州430074

出　　处：《中国图象图形学报》2008年第4期647-653,共7页Journal of Image and Graphics

基　　金：国家重点基础研究发展计划973项目(2003CB716101)

摘　　要：近年来,Katsevich提出一种基于滤波反投影的螺旋锥束CT重建算法,并给出相应的重建公式改进形式,可以有效地解决长物体成像问题。基于Katsevich算法框架,提出了新的螺旋锥束CT精确重建算法。该算法利用数学上严格的推导,将Katseivch重建公式中关于旋转角度的微分运算完全回避,使得成像质量得到较大改善,减少了重建伪影。同时,新算法仍然基于平移不变滤波且数据冗余加权在滤波过程之后进行,保持了数值计算的灵活性。为验证本文算法的有效性,对计算机模拟数据进行仿真实验,实验结果表明,新重建算法的重建图像质量较Katsevich重建算法有较大提高。Recently,Katsevich proposed an exact FBP algorithm and its improved version for image reconstruction in helical cone-beam CT. In this paper,we present a new FBP image reconstruction algorithm based on the Katsevich＇s original algorithm paradigm. This proposed algorithm can achieve good image quality improvement and fewer artifacts since it successfully avoids the direct derivatives with respect to rotation angle, The new algorithm still performs a 1 D shift-invariant filtering of the modified data on the detector plane and the redundancy weight is applied after filtering, allowing a more efficient numerical implementation. Results in these studies confirm the observation that the proposed algorithm can improve the image resolution over Katsevich＇ s original algorithm with noiseless and noise projection data.

关 键 词：计算机断层成像 螺旋锥束 Hilbert滤波 

分 类 号：TP301.6[自动化与计算机技术—计算机系统结构]