影响同步辐射X射线螺旋显微CT的若干因素研究  

Effects of some factors on X-ray spiral micro-computed tomography at synchrotron radiation

作　　者：王玉丹[1,2] 彭冠云[1] 佟亚军[1] 周光照[1,2] 任玉琦[1,2] 杨群[1,2] 肖体乔[1] 

机构地区：[1]中国科学院上海应用物理研究所,上海201204 [2]中国科学院研究生院,北京100049

出　　处：《物理学报》2012年第5期174-182,共9页Acta Physica Sinica

基　　金：国家重点基础研究发展计划(批准号:2010CB834301);中国科学院对外合作重点项目(批准号:GJHZ09058);国家自然科学基金(批准号:10805071;10705020);上海市基础研究重点项目(批准号:08JC1411900)资助的课题~~

摘　　要：同步辐射X射线是扁平光,传统显微CT难以对长样品实现快速、高分辨、低剂量三维成像,螺旋扫描的引入可以很好地解决这一难题.本文采用数字模拟和实验的方法较为系统地研究了螺距、光斑竖直高度和180°投影数对成像质量、速度的影响.模拟结果表明,在螺距不大于2的前提下,180°投影数增大,误差减小,CT成像速度变慢;光斑竖直高度增大,速度加快;螺距增大,速度加快,且误差在允许范围内;选取合适的参数值使旋转平移比为整数,误差最小.同时,优化参数并在上海光源实现螺旋显微CT,从实验上验证了模拟结果.研究表明,通过优化各参数,同步辐射螺旋显微CT可以实现快速高质量三维成像,为以后的实际应用提供了依据.It is difficult to obtain low-dose three-dimensional images of a long sample with high spatial resolution in a single scan using conventional X-ray micro-CT technique because the synchrotron X-ray beam is prolate. Spiral scanning is induced into synchrotron X-ray micro-CT （SR ~t-CT） to resolve this problem. We investigate the effects of some factors on imaging quality and scanning speed by simulation and experiment, such as pitch, vertical beam width and projections per 180~. When the pitch is not greater than 2, it is found that the relative error and the CT scanning speed decrease while the projections per 180~ increases. The scanning speed increases with vertical beam width. Furthermore, as pitch becomes greater, the scanning speed becomes faster. The relative error is minimized by choosing the appropriate parameters to make the ratio between rotation and vertical transfer be an integer. The simulated results are confirmed by the synchrotron-based spiral micro-CT （SRS u-CT） experiments performed at the Shanghai Synchrotron Radiation Facility and parameters are optimized. The results presented herein provide a theoretical and experimental basis for future applications of SRS u-CT.

关 键 词：同步辐射X射线 螺旋CT 相对误差 投影数 

分 类 号：O434.1[机械工程—光学工程]