title: Iterative dual energy material decomposition from spatial mismatched raw data sets.
abstract: Today's clinical dual energy computed tomography (DECT) scanners generally measure different rays for different energy spectra and acquire spatial mismatched raw data sets. The deficits in clinical DECT technologies suggest that mainly image based material decomposition methods are in use nowadays. However, the image based material decomposition is an approximate technique, and beam hardening artifacts remain in decomposition results. A recently developed image based iterative method for material decomposition from inconsistent rays (MDIR) can achieve much better image quality than the conventional image based methods. Inspired by the MDIR method, this paper proposes an iterative method to indirectly perform raw data based DECT even with completely mismatched raw data sets. The iterative process is initialized by density images that were obtained from an image based material decomposition. Then the density images are iteratively corrected by comparing the estimated polychromatic projections and the measured polychromatic projections. Only three iterations of the method are sufficient to greatly improve the qualitative and quantitative information in material density images. Compared with the MDIR method, the proposed method needs not to perform additional water precorrection. The advantages of the method are verified with numerical experiments from inconsistent noise free and noisy raw data.
authors.affiliation: The CT laboratory, School of Mathematical Sciences, Capital Normal University, Beijing, China Beijing Center for Mathematics and Information Interdisciplinary Sciences, Beijing, China.
authors.forename: Xing
authors.initials: X
authors.lastname: Zhao
authors.affiliation: School of Software, Beijing Institute of Technology, Beijing, China.
authors.forename: Jing-Jing
authors.initials: JJ
authors.lastname: Hu
authors.affiliation: The CT laboratory, School of Mathematical Sciences, Capital Normal University, Beijing, China Beijing Center for Mathematics and Information Interdisciplinary Sciences, Beijing, China.
authors.forename: Yun-Song
authors.initials: YS
authors.lastname: Zhao
authors.affiliation: The CT laboratory, School of Mathematical Sciences, Capital Normal University, Beijing, China Beijing Center for Mathematics and Information Interdisciplinary Sciences, Beijing, China.
authors.forename: Hui-Tao
authors.initials: HT
authors.lastname: Zhang
authors.affiliation: The CT laboratory, School of Mathematical Sciences, Capital Normal University, Beijing, China Beijing Center for Mathematics and Information Interdisciplinary Sciences, Beijing, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
mesh_terms: D000465:Algorithms; D001842:Bone and Bones / Q000000981:diagnostic imaging; D002138:Calibration; D003198:Computer Simulation; D006257:Head / Q000000981:diagnostic imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008954:Models, Biological; D008962:Models, Theoretical; D019047:Phantoms, Imaging; D013902:Radiography, Thoracic; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: Dual energy computed tomography; basis material decomposition; calibration; iterative algorithm