title: Study of OSEM with different subsets in grating-based X-ray differential phase-contrast imaging.
abstract: Impressive developments in X-ray imaging are associated with X-ray phase contrast computed tomography based on grating interferometry, a technique that provides increased contrast compared with conventional absorption-based imaging. A new "single-step" method capable of separating phase information from other contributions has been recently proposed. This approach not only simplifies data-acquisition procedures, but, compared with the existing phase step approach, significantly reduces the dose delivered to a sample. However, the image reconstruction procedure is more demanding than for traditional methods and new algorithms have to be developed to take advantage of the "single-step" method. In the work discussed in this paper, a fast iterative image reconstruction method named OSEM (ordered subsets expectation maximization) was applied to experimental data to evaluate its performance and range of applicability. The OSEM algorithm with different subsets was also characterized by comparison of reconstruction image quality and convergence speed. Computer simulations and experimental results confirm the reliability of this new algorithm for phase-contrast computed tomography applications. Compared with the traditional filtered back projection algorithm, in particular in the presence of a noisy acquisition, it furnishes better images at a higher spatial resolution and with lower noise. We emphasize that the method is highly compatible with future X-ray phase contrast imaging clinical applications.
authors.affiliation: Institute of High-Energy Physics, Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Zhang
authors.forename: Youli
authors.initials: Y
authors.lastname: Hong
authors.forename: Peiping
authors.initials: P
authors.lastname: Zhu
authors.forename: Qingxi
authors.initials: Q
authors.lastname: Yuan
authors.forename: Wanxia
authors.initials: W
authors.lastname: Huang
authors.forename: Zhili
authors.initials: Z
authors.lastname: Wang
authors.forename: Shengqi
authors.initials: S
authors.lastname: Chu
authors.forename: Samuel A
authors.initials: SA
authors.lastname: McDonald
authors.forename: Federica
authors.initials: F
authors.lastname: Marone
authors.forename: Marco
authors.initials: M
authors.lastname: Stampanoni
authors.forename: Ziyu
authors.initials: Z
authors.lastname: Wu
mesh_terms: D000465:Algorithms; D000818:Animals; D001921:Brain / Q000000981:diagnostic imaging*; D003198:Computer Simulation; D021621:Imaging, Three-Dimensional / Q000379:methods*; D010363:Pattern Recognition, Automated; D051381:Rats; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed