摘要
圆轨道锥束CT(computed tomography)重建中,随着锥角增大,锥角伪影和数据缺失伪影越来越严重,影响FDK算法(由Feldkamp-Davis-Kress名字命名)重建区域的大小和图像质量。本文分析了短扫描FDK算法(short scanFDK,SS-FDK)重建时的数据完整性,提出了根据重建切片高度自适应地将重建切片分成若干区域,对每个区域采用SS-FDK算法进行重建的分区短扫描FDK重建算法。理论分析及试验仿真表明,该方法虽然计算复杂度有所增加,但充分利用了锥束CT投影数据,较大地增大了重建区域,完全重建区域高度达到扫描高度的1-sin2δ倍(δ为射线源半张角),且重建精度和图像质量与FDK算法相当。
The data loss and cone-beam angle artifacts increase with cone angle in circular trajectory cone-beam computed tomography (CT). This limits the reconstruction coverage and image quality of the FDK (Feldkamp-Davis-Kress) algorithm. This paper analyzed the data completeness of the short scan FDK (SS-FDK) algorithm and presented a segmentation short scan FDK reconstruction algorithm. In the algorithm, the reconstruction slice was adaptively divided into several sub-regions according to the slice height and then the SS-FDK algorithm was used to reconstruct each sub-region. Theoretical analyses and simulations show that, although the reconstruction complexity is increased, the reconstruction region height is enlarged to 1 -- sin^2δ times of the scan height (δ, half fan angle of the source), and the image quality and accuracy is at least comparable to that of the FDK algorithm.
出处
《清华大学学报(自然科学版)》
EI
CAS
CSCD
北大核心
2009年第6期860-863,867,共5页
Journal of Tsinghua University(Science and Technology)
关键词
锥束CT
数据完整性
重建区域
FDK算法
cone-beam computed tomography (CT)
data completeness
reconstruction region
FDK algorithm