A comprehensive model for x-ray projection imaging system efficiency and image quality characterization in the presence of scattered radiation.

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State: Public
Version: author
Serval ID
serval:BIB_961FF162EA76
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
A comprehensive model for x-ray projection imaging system efficiency and image quality characterization in the presence of scattered radiation.
Journal
Physics in medicine and biology
Author(s)
Monnin P., Verdun F.R., Bosmans H., Pérez S.R., Marshall N.W.
ISSN
1361-6560 (Electronic)
ISSN-L
0031-9155
Publication state
Published
Issued date
23/06/2017
Peer-reviewed
Oui
Volume
62
Number
14
Pages
5691-5722
Language
english
Notes
Publication types: Journal Article
Publication Status: epublish
Abstract
This work proposes a method for assessing the detective quantum efficiency (DQE) of radiographic imaging systems that include both the x-ray detector and the antiscatter device. Cascaded linear analysis of the antiscatter device efficiency (DQEASD) with the x-ray detector DQE is used to develop a metric of system efficiency (DQEsys); the new metric is then related to the existing system efficiency parameters of effective DQE (eDQE) and generalized DQE (gDQE). The effect of scatter on signal transfer was modelled through its point spread function (PSF), leading to an x-ray beam transfer function (BTF) that multiplies with the classical presampling modulation transfer function (MTF) to give the system MTF. Expressions are then derived for the influence of scattered radiation on signal-difference to noise ratio (SDNR) and contrast-detail (c-d) detectability. The DQEsys metric was tested using two digital mammography systems, for eight x-ray beams (four with and four without scatter), matched in terms of effective energy. The model was validated through measurements of contrast, SDNR and MTF for poly(methyl)methacrylate thicknesses covering the range of scatter fractions expected in mammography. The metric also successfully predicted changes in c-d detectability for different scatter conditions. Scatter fractions for the four beams with scatter were established with the beam stop method using an extrapolation function derived from the scatter PSF, and validated through Monte Carlo (MC) simulations. Low-frequency drop of the MTF from scatter was compared to both theory and MC calculations. DQEsys successfully quantified the influence of the grid on SDNR and accurately gave the break-even object thickness at which system efficiency was improved by the grid. The DQEsys metric is proposed as an extension of current detector characterization methods to include a performance evaluation in the presence of scattered radiation, with an antiscatter device in place.

Keywords
Models, Theoretical, Monte Carlo Method, Phantoms, Imaging, Radiographic Image Enhancement, Radiography/methods, Scattering, Radiation, Signal-To-Noise Ratio
Pubmed
Web of science
Open Access
Yes
Create date
04/09/2017 16:33
Last modification date
20/08/2019 14:58
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