Development of simulations for a mesh-based x-ray phase imaging system

Hassan, Laila; Pyakurel, Uttam; Sun, Weiyuan; MacDonald, Carolyn A.; Petruccelli, Jonathan C.

doi:10.1117/12.2558926

Cited by 5 publications

(6 citation statements)

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“…where y I is proportional to the visibility of the horizontally oriented mesh wires with the object in place relative to the visibility of the mesh-only image, such that a value of Similarly, the horizontal DPC and DF images are obtained from the windowed Fourier transform of the first order harmonic in the horizontal direction. 6,19 The dark field signal SDF was taken as the difference between the value in the thickest part of the object and the background…”

Section: Methodsmentioning

confidence: 99%

Dark field signal maximization in mesh-based x-ray imaging

Pyakurel

MacDonald

Petruccelli

2023

Computational Imaging VII

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Small angle x-ray scatter from microstructure too small to resolve in conventional imaging can provide an additional "dark field" signal that is complementary to attenuation and phase. Unfortunately, the low spatial coherence of clinical sources reduces dark field contrast. Focusing polycapillary optics are employed to allow for the use of high-power primary sources by increasing the phase signal after the focus. The method for this system is to structure the beam with a low-cost wire mesh that further relaxes the coherence requirement on the source. However, the coarseness of the mesh reduces the strength of the dark field signal compared with grating-based techniques, so optimization of the signal is important.

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Section: Methodsmentioning

confidence: 99%

Dark field signal maximization in mesh-based x-ray imaging

Pyakurel

MacDonald

Petruccelli

2023

Computational Imaging VII

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“…Similarly, the horizontal DF images are obtained from the windowed fast Fourier transform of the first order harmonic in the horizontal direction. 19 To implement CT, an image of the mesh is first acquired to compute the mesh harmonics, and then an object is placed on a rotation stage immediately after the mesh. Projection images of the object are acquired at fixed angles as the object is rotated through 180° in 1° increments and then each is processed to retrieve a transmission image, x and y derivatives of the phase, and DF images due to fine sample structure in the x and y directions.…”

Section: Figure 1 Mesh-based Phase Imaging Systemmentioning

confidence: 99%

Initial investigation of mesh-based x-ray phase tomography

Allahyani

Pyakurel

Redgate

et al. 2023

Computational Imaging VII

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X-ray phase and dark field imaging offer two additional channels of information to enhance image contrast as well as providing information on material micro-texture that is unavailable to conventional x-ray imaging. These signals are commonly acquired by using multiple precisely aligned, fine-pitched gratings to both pattern the beam and to detect subtle shifts and blurring in this pattern. We instead use a single, low-cost, easily-aligned, coarse-pitched mesh to produce a pattern that is imaged directly to produce phase and dark field computed tomography (CT) images. We demonstrate phase and CT reconstructions using our system for a variety of phantoms.

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“…The mesh distortion can be modeled, for small ray deflection, using the transport of the intensity equation (TIE) and equation (8). The approximate forward model [30][31][32][33][34] for mesh-based x-ray phase-contrast imaging can be written as…”

Section: Fourier-based Differential Phase Contrast Imagingmentioning

confidence: 99%

Grating-free quantitative phase retrieval for x-ray phase-contrast imaging with conventional sources

Sun¹,

Pyakurel²,

MacDonald³

et al. 2022

Biomed. Phys. Eng. Express

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X-ray phase-contrast imaging can display subtle differences in low-density materials (e.g. soft tissues) more readily than conventional x-ray imaging. However, producing x-ray phase images requires significant spatial coherence of the beam which in turn requires highly specialized sources such as synchrotrons, small and low power microfocus sources, or complex procedures, such as multiple exposures with several carefully stepped precision gratings. To find appropriate approaches for producing x-ray phase-contrast imaging in a clinically meaningful way, we employed a grating-free method that utilized a low-cost, coarse wire mesh and simple processing. This method relaxes the spatial coherence constraint and allows quantitative phase retrieval for not only monochromatic but also polychromatic beams. We also combined the mesh-based system with polycapillary optics to significantly improve the accuracy of quantitative phase retrieval.

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Development of simulations for a mesh-based x-ray phase imaging system

Cited by 5 publications

References 0 publications

Dark field signal maximization in mesh-based x-ray imaging

Dark field signal maximization in mesh-based x-ray imaging

Initial investigation of mesh-based x-ray phase tomography

Grating-free quantitative phase retrieval for x-ray phase-contrast imaging with conventional sources

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