基于切片轮廓重投影的锥束CT射束硬化校正方法  

Beam hardening correction method for Cone-Beam computed tomography based on reprojection of slice contours

作　　者：黄魁东[1] 张定华[1] 孔永茂[1] 王凯[1] 

机构地区：[1]西北工业大学现代设计与集成制造技术教育部重点实验室,西安710072

出　　处：《仪器仪表学报》2008年第9期1873-1877,共5页Chinese Journal of Scientific Instrument

基　　金：国家科技支撑计划重点项目(2006BAF04B02);教育部博士点基金(新教师)(20070699049);西北工业大学青年科技创新基金(W016221)资助项目

摘　　要：根据锥束CT射束硬化机理,提出一种基于切片轮廓重投影的锥束CT射束硬化校正新方法。该方法从原始投影图像重建的序列切片图像中得到中心切片和斜切片的轮廓信息,然后根据实际扫描时的锥束CT成像系统参数建立重投影坐标系,通过射线与切片轮廓重投影到平板探测器上的求交计算,得到射线穿越物体长度与投影灰度之间的对应关系,最后拟合射束硬化曲线并校正射束硬化伪影。仿真与实际校正结果均表明,该方法可简单有效地消除锥束CT的射束硬化伪影。According to the principle of beam hardening in Cone-Beam Computed Tomography （CBCT）, a new beam hardening correction method for CBCT based on re-projection of slice contours is presented. Firstly, contour information of center slice and aslant slice are acquired from the serial slice images that reconstructed from original projection images, then the re-projection coordinates are set up by using the practical scan parameters of CBCT imaging system. After that, the numerical relation between the length of X-ray traversing object and the value of projection gray is founded by re-projecting the contours to the flat panel detector. Finally, an exponential function is designed for fitting the beam hardening curve and made use of correcting beam hardening artifact. The experimental correction results of both simulation and practical scan show that the method can mostly remove the beam hardening artifact in CBCT simply and effectively.

关 键 词：射束硬化 锥束CT 切片轮廓 重投影 伪影校正 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]