title: Large-angle x-ray scatter in Talbot-Lau interferometry for breast imaging.
abstract: Monte Carlo simulations were used to investigate large-angle x-ray scatter at design energy of 25 keV during small field of view (9.6 cm × 5 cm) differential phase contrast imaging of the breast using Talbot-Lau interferometry. Homogenous, adipose and fibroglandular breasts of uniform thickness ranging from 2 to 8 cm encompassing the field of view were modeled. Theoretically determined transmission efficiencies of the gratings were used to validate the Monte Carlo simulations, followed by simulations to determine the x-ray scatter reaching the detector. The recorded x-ray scatter was classified into x-ray photons that underwent at least one Compton interaction (incoherent scatter) and Rayleigh interaction alone (coherent scatter) for further analysis. Monte Carlo based estimates of transmission efficiencies showed good correspondence [Formula: see text] with theoretical estimates. Scatter-to-primary ratio increased with increasing breast thickness, ranging from 0.11 to 0.22 for 2-8 cm thick adipose breasts and from 0.12 to 0.28 for 2-8 cm thick fibroglandular breasts. The analyzer grating reduced incoherent scatter by ~18% for 2 cm thick adipose breast and by ~35% for 8 cm thick fibroglandular breast. Coherent scatter was the dominant contributor to the total scatter. Coherent-to-incoherent scatter ratio ranged from 2.2 to 3.1 for 2-8 cm thick adipose breasts and from 2.7 to 3.4 for 2-8 cm thick fibroglandular breasts.
authors.affiliation: Department of Radiology, University of Massachusetts Medical School, Worcester, MA 01655, USA.
authors.forename: Srinivasan
authors.initials: S
authors.lastname: Vedantham
authors.forename: Linxi
authors.initials: L
authors.lastname: Shi
authors.forename: Andrew
authors.initials: A
authors.lastname: Karellas
mesh_terms: D005260:Female; D006801:Humans; D007368:Interferometry / Q000379:methods; D008327:Mammography / Q000379:methods*; D008962:Models, Theoretical; D017785:Photons; D014961:X-Ray Diffraction