Analysis Of Flat Fields In Edge Illumination Phase Contrast Imaging

Huyge, Ben; Sanctorum, Jonathan; Six, Nathanaël; Beenhouwer, Jan De; Sijbers, Jan

doi:10.1109/isbi48211.2021.9433849

Cited by 4 publications

(9 citation statements)

References 12 publications

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“…Compared to the projection approximation, the virtual grating model clearly provides an approximation that lies much closer to the full MC grating model. This is explained by shadowing effects [41] that increase towards the detector edges, which are taken into account in our model, but not by the projection approximation. This shadowing effect is also known as angular filtration.…”

Section: Discussionmentioning

confidence: 93%

“…In the proposed approach, the grating bars are essentially modelled as purely absorbing 3D objects, where the absorption is calculated from attenuation coefficients through the Lambert-Beer law. Whereas this is obviously an approximation compared to a full MC grating bar model that includes explicit scattering events and refraction [40,41], it provides a higher level of simulation detail than the oftenused projection approximation (i.e. infinitely flat gratings).…”

Section: Discussionmentioning

confidence: 99%

“…(2) modelling the grating as a volume with bars extending along the direction of the optical axis (3D) [21,22,40,41], or (3) simulation frameworks where the effect of the grating is accounted for implicitly, without introducing the gratings as components in the simulation [16,33,31]. Two-dimensional (flat) grating models are common in, but not restricted to, wave-optics simulations and involve either an idealised binary representation of the grating [18,26,27,44] or application of a complex transmission function (projection approximation) [23,14,15,25,24,32,20].…”

Section: Simulation Models For Gratingsmentioning

confidence: 99%

“…X-rays can, for example, intersect the grating bars under an angle, impacting the effective distance traveled through the material. To incorporate these effects, grating bars are modelled as full 3D objects [21,22,40,41]. Three-dimensional MC models of membranes have been used for simulating speckle-based imaging as well [45].…”

Section: Simulation Models For Gratingsmentioning

confidence: 99%

“…Hence, geometrical optics can be used to describe image formation and phase shifts are modelled as refraction effects [38,39]. As interference modeling is no longer required, the simulation can be performed entirely in GATE, as demonstrated in earlier work [40,41].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Virtual grating approach for Monte Carlo simulations of edge illumination-based x-ray phase contrast imaging

Sanctorum¹,

Sijbers²,

Beenhouwer³

2022

Preprint

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The design of new x-ray phase contrast imaging setups often relies on Monte Carlo simulations for prospective parameter studies. Monte Carlo simulations are known to be accurate but time consuming, leading to long simulation times, especially when many parameter variations are required. This is certainly the case for imaging methods relying on absorbing masks or gratings, with various tunable properties, such as pitch, aperture size, and thickness. In this work, we present the virtual grating approach to overcome this limitation. By replacing the gratings in the simulation with virtual gratings, the parameters of the gratings can be changed after the simulation, thereby significantly reducing the overall simulation time. The method is validated by comparison to explicit grating simulations, followed by representative demonstration cases.

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Section: Discussionmentioning

confidence: 93%

Section: Discussionmentioning

confidence: 99%

Section: Simulation Models For Gratingsmentioning

confidence: 99%

Section: Simulation Models For Gratingsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Virtual grating approach for Monte Carlo simulations of edge illumination-based x-ray phase contrast imaging

Sanctorum¹,

Sijbers²,

Beenhouwer³

2022

Preprint

Self Cite

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PEPI Lab: a flexible compact multi-modal setup for X-ray phase-contrast and spectral imaging

Brombal

Arfelli

Menk

et al. 2023

Sci Rep

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This paper presents a new flexible compact multi-modal imaging setup referred to as PEPI (Photon-counting Edge-illumination Phase-contrast imaging) Lab, which is based on the edge-illumination (EI) technique and a chromatic detector. The system enables both X-ray phase-contrast (XPCI) and spectral (XSI) imaging of samples on the centimeter scale. This work conceptually follows all the stages in its realization, from the design to the first imaging results. The setup can be operated in four different modes, i.e. photon-counting/conventional, spectral, double-mask EI, and single-mask EI, whereby the switch to any modality is fast, software controlled, and does not require any hardware modification or lengthy re-alignment procedures. The system specifications, ranging from the X-ray tube features to the mask material and aspect ratio, have been quantitatively studied and optimized through a dedicated Geant4 simulation platform, guiding the choice of the instrumentation. The realization of the imaging setup, both in terms of hardware and control software, is detailed and discussed with a focus on practical/experimental aspects. Flexibility and compactness (66 cm source-to-detector distance in EI) are ensured by dedicated motion stages, whereas spectral capabilities are enabled by the Pixirad-1/Pixie-III detector in combination with a tungsten anode X-ray source operating in the range 40–100 kVp. The stability of the system, when operated in EI, has been verified, and drifts leading to mask misalignment of less than 1 $$\upmu$$ μ m have been measured over a period of 54 h. The first imaging results, one for each modality, demonstrate that the system fulfills its design requirements. Specifically, XSI tomographic images of an iodine-based phantom demonstrate the system’s quantitativeness and sensibility to concentrations in the order of a few mg/ml. Planar XPCI images of a carpenter bee specimen, both in single and double-mask modes, demonstrate that refraction sensitivity (below 0.6 $$\upmu$$ μ rad in double-mask mode) is comparable with other XPCI systems based on microfocus sources. Phase CT capabilities have also been tested on a dedicated plastic phantom, where the phase channel yielded a 15-fold higher signal-to-noise ratio with respect to attenuation.

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Alternative grating designs for cone-beam edge illumination x-ray phase contrast imaging

Vanthienen¹,

Sanctorum²,

Huyge³

et al. 2022

Developments in X-Ray Tomography XIV

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Edge illumination X-ray phase contrast imaging is a method which relies on two gratings to obtain attenuation, phase and dark field contrast. Current gratings consist of periodic apertures in a high-absorbing flat plate. While edge illumination was originally designed for parallel-beam imaging, it also works with cone-beam sources when the opening angle is sufficiently low. With higher opening angles, however, current gratings cause a shadow which results in a decreased intensity. In this paper, three alternative grating geometries are studied with Monte-Carlo simulations and their performance is evaluated in terms of shadowing. Results show that the alternative grating geometries significantly reduce shadowing in cone-beam based edge illumination.

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Analysis Of Flat Fields In Edge Illumination Phase Contrast Imaging

Cited by 4 publications

References 12 publications

Virtual grating approach for Monte Carlo simulations of edge illumination-based x-ray phase contrast imaging

Virtual grating approach for Monte Carlo simulations of edge illumination-based x-ray phase contrast imaging

PEPI Lab: a flexible compact multi-modal setup for X-ray phase-contrast and spectral imaging

Alternative grating designs for cone-beam edge illumination x-ray phase contrast imaging

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