Phase Contrast Imaging with Coded Apertures Using Laboratory-Based X-ray Sources

Ignatyev, Konstantin; Munro, Peter; Speller, RD; Olivo, Alessandro; McNulty, Ian; Eyberger, Catherine; Lai, Barry

doi:10.1063/1.3625352

Cited by 2 publications

(4 citation statements)

References 11 publications

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“…Edge-illumination XPCi produces differential phase contrast profiles through integration (at the pixel level) of partial free-space propagation profiles, in themselves proportional to the second derivative of the phase shift Speller 2008, Munro et al 2012b). The final result practically matches the signal that is obtained in analyser based imaging (Davis et al 1995, Ingal and Beliaevskaya 1995, Chapman et al 1997: this was already recognized in the original edge-illumination paper (Olivo et al 2001), and was more recently formally demonstrated (Munro et al 2013). Due to this corpus of previous literature, and in the interest of brevity as required by a note, formal equations expressing the x-ray intensity detected at N2 the pixel level will not be repeated here-explicit expressions can be found in Munro et al 2010, 2012a, Diemoz et al 2013.…”

Section: Introductionsupporting

confidence: 77%

“…Most importantly, the detector output (e.g. outside the sample) is in itself a measure of the pre-sample mask position: this can be used in a feedback mechanism that tracks the pre-sample mask position and keeps the system dynamically aligned, as discussed in Ignatyev et al (2013).…”

Section: Resultsmentioning

confidence: 99%

“…The pre-sample mask has the same design demagnified by a factor 1.25 to account for the beam divergence-source-to-sample and sample-to-detector distances were 1.6 and 0.4 m respectively in this case. Both masks are mounted on a stack of Newport translators and Kohzu cradles which allows the alignment of each aperture with a pixel column in the detector (Ignatyev et al 2013). Images were obtained at '50% illumination' (Olivo and Speller 2007b), which means that the two masks were misaligned by half an aperture size along x (see figure 1(b)).…”

Section: Methodsmentioning

confidence: 99%

“…At the same time, it is admittedly a limiting approach, as it prevents the application of promising algorithms like, for example, the one recently introduced by Köhler et al (2011), as they require the prior separation of phase and absorption signals. Phase retrieval methods are a relatively recent development for our method (Munro et al 2012a(Munro et al , 2013, and more research in this direction will be undertaken in the next stages of this preliminary study.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Proof-of-concept demonstration of edge-illumination x-ray phase contrast imaging combined with tomosynthesis

Szafraniec¹,

Millard²,

Ignatyev³

et al. 2014

Phys. Med. Biol.

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In this note we present the first proof-of-concept results on the potential effectiveness of the edge-illumination x-ray phase contrast method (in its 'coded-aperture' based lab implementation) combined with tomosynthesis. We believe that, albeit admittedly preliminary (e.g. we only present phantom work), these results deserve early publication in a note primarily for four reasons. First, we fully modelled the imaging acquisition method, and validated the simulation directly with experimental results. This shows that the implementation of the method in the new geometry is understood, and thus that it will be possible to use the model to simulate more complex scenarios in the future. Secondly, we show that a strong phase contrast signal is preserved in the reconstructed tomosynthesis slices: this was a concern, as the high spatial frequency nature of the signal makes it sensitive to any filtration-related procedure. Third, we show that, despite the non-optimized nature of the imaging prototype used, we can perform a full angular scan at acceptable dose levels and with exposure times not excessively distant from what is required by clinical practice. Finally, we discuss how the proposed phase contrast method, unlike other approaches apart from free-space propagation (which however requires a smaller focal spot, thus reducing the flux and increasing exposure times), can be easily implemented in a tomosynthesis geometry suitable for clinical use. In summary, we find that these technical results indicate a high potential for the combination of the two methods. Combining slice separation with detail enhancement provided by phase effects would substantially increase the detectability of small lesions and/or calcifications, which we aim to demonstrate in the next steps of this study.

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Section: Introductionsupporting

confidence: 77%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Proof-of-concept demonstration of edge-illumination x-ray phase contrast imaging combined with tomosynthesis

Szafraniec¹,

Millard²,

Ignatyev³

et al. 2014

Phys. Med. Biol.

View full text Add to dashboard Cite

show abstract

Simulations and experimental demonstrations of encoding for X-ray coherent scattering

et al. 2017

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Diffraction data may be measured using approaches that lead to ambiguity in the interpretation of scattering distributions. Thus, the encoding and decoding of coherent scattering distributions have been considered with a view to enabling unequivocal data interpretation. Two encoding regimes are considered, where encoding occurs between the X-ray source and sample, and where the encoder is placed between the sample and detector. In the first case, the successful recovery of diffraction data formed from the interrogation of powder samples with annular incident beams is presented using a coded aperture approach. In the second regime, encoding of Debye cones is shown to enable recovery of the sample position relative to the detector. The errors associated with both regimes are considered and the advantages of combining the two discussed.

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Phase Contrast Imaging with Coded Apertures Using Laboratory-Based X-ray Sources

Cited by 2 publications

References 11 publications

Proof-of-concept demonstration of edge-illumination x-ray phase contrast imaging combined with tomosynthesis

Proof-of-concept demonstration of edge-illumination x-ray phase contrast imaging combined with tomosynthesis

Simulations and experimental demonstrations of encoding for X-ray coherent scattering

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