title: Physico-mathematical considerations on x-ray computed tomography based on diffraction enhanced imaging.
abstract: We consider x-ray computed tomography (CT) technique based on refractive effects, which has advantages for delineating biological weakly-absorbing soft-tissues over the conventional absorption-contrast CT (computed tomography) because of the use of phase sensitive detection. The refraction-based CT described here detects the angular deviation of the beam, refracted by a sample, from the incident beam in a cross-sectional plane of interest, based on the diffraction enhanced imaging (DEI) method using the Bragg-case analyzing crystal, which is arranged behind the sample on a positioning device for collecting projection data from various directions. The set of angular deviation data from various directions, which corresponds to the projection data in the conventional absorption-contrast CT, are used for reconstruction of the refractive-index gradient vector field. So far, some groups have proposed the distinct DEI-based CT protocols. We theoretically summarize and compare the algorithms from the viewpoint of geometrical optics.
authors.affiliation: Yamagata University, Yonezawa, 992-8510 Japan. yuasa@eat72.yz.yamagata-u.ac.jp
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Yuasa
authors.forename: Anton
authors.initials: A
authors.lastname: Maksimenko
authors.forename: Eiko
authors.initials: E
authors.lastname: Hashimoto
authors.forename: Takao
authors.initials: T
authors.lastname: Akatsuka
authors.forename: Masami
authors.initials: M
authors.lastname: Ando
mesh_terms: D000465:Algorithms; D008962:Models, Theoretical; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*