摘要
多层螺旋CT中,采用大螺距可以大大提高扫描速度,在工业和医学中颇受青睐。但在给定探测器尺寸条件下,螺距过大会出现明显的伪影。Noo等1999年提出的单层重排算法(SSRB)能够适应较大的螺距,且有较高的重建图像质量。本文采用新的重排方法对SSRB算法进行了改进,理论分析及仿真实验表明,相同探测器大小时,改进的SSRB算法(ISSRB)可适用的螺距是SSRB的(1+tan^2δ)倍(δ射线源半张角),且有相近或更高的图像质量。
Large pitch was used to speed up scanning in helical cone-beam CT, but its reconstruction remains a challenging problem. The Single-Slice ReBinning method （SSRB）, proposed by Noo et al, can obtain high image quality at large pitch, but artifacts appear when pitch is too large for given detector. In this paper, a new approximate reconstruction scheme, i.e. Improved Single-Slice ReBinning method （ISSRB） is described. It modified the key rebinning step of SSRB. Theoretical considerations and reconstruction of simulation data are presented in comparison to SSRB in the paper. Results show that the pitch of proposed method is （1＋tan^2δ） times larger than that of SSRB for given detector size, and the reconstruction image quality is comparable or even better.
出处
《CT理论与应用研究（中英文）》
2008年第1期7-13,共7页
Computerized Tomography Theory and Applications
关键词
锥束CT
单层重排
螺距
图像质量
computed tomography
helical cone-beam
single-slice rebinning
image reconstruction
