Quantitative X-ray phase-contrast computed tomography at 82 keV

Willner, Marian; Bech, Martin; Herzen, Julia; Zanette, Irène; Hahn, D; Kenntner, J.; Mohr, J.; Rack, Alexander; Weitkamp, Timm; Pfeiffer, Franz

doi:10.1364/oe.21.004155

Cited by 59 publications

(65 citation statements)

References 31 publications

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“…the electron density) is represented in both contrast modalities. However, the experimental setup has been successfully designed to provide enhanced, in the form of higher contrast-to-noise ratios, phase-contrast images as compared to the attenuation-contrast results, hereby confirming the experimental findings from the monochromatic case by Willner et al [5]. This contrast gain depends strongly on the specific grating interferometer and its optical parameters.…”

Section: Discussionsupporting

confidence: 83%

“…The more the attenuation process results from the Compton effect, the more the attenuation-based image is proportional to the electron density, as is also the case in the phase contrast. No additional information on the material composition can be gained if attenuation is mostly attributed to Compton scattering [5]. Thus, for all low-Z materials we expect similar contrast differences for attenuation and phase contrast images at high X-ray energies.…”

Section: Contrast Dependence / Formationmentioning

confidence: 90%

“…At 45 keV mean X-ray energy, the attenuation contrast is a result of both effects. Therefore, attenuation-and phase-contrast images provide complementary information and materials can be more easily distinguished as seen in the monochromatic case [5].…”

Section: Contrast Dependence / Formationmentioning

confidence: 99%

“…When larger samples are of interest, asymmetric rotation axis position can be used [4] which works well only with parallel beam reconstruction and at the expense of increased measurement time. Grating interferometry at high energy using synchrotron sources have been already demonstrated [5]. However, access to them is limited and the operation of the interferometer is less challenging with the monochromatic radiation.…”

Section: Introductionmentioning

confidence: 99%

“…We further investigate to which extent the complementarity of phase and attenuation contrast presented at low X-ray energy for low-Z materials [9] is still retained since it is lost with higher energies for low-Z materials [5].…”

Section: Introductionmentioning

confidence: 99%

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Quantitative imaging using high-energy X-ray phase-contrast CT with a 70 kVp polychromatic X-ray spectrum

Sarapata¹,

Willner²,

Walter³

et al. 2015

Opt. Express

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Abstract:Imaging of large and dense objects with grating-based X-ray phase-contrast computed tomography requires high X-ray photon energy and large fields of view. It has become increasingly possible due to the improvements in the grating manufacturing processes. Using a high-energy X-ray phase-contrast CT setup with a large (10 cm in diameter) analyzer grating and operated at an acceleration tube voltage of 70 kVp, we investigate the complementarity of both attenuation and phase contrast modalities with materials of various atomic numbers (Z). We confirm experimentally that for low-Z materials, phase contrast yields no additional information content over attenuation images, yet it provides increased contrast-to-noise ratios (CNRs). The complementarity of both signals can be seen again with increasing Z of the materials and a more comprehensive material characterization is thus possible. Imaging of a part of a human cervical spine with intervertebral discs surrounded by bones and various soft tissue types showcases the benefit of high-energy X-ray phase-contrast system. Phase-contrast reconstruction reveals the internal structure of the discs and makes the boundary between the disc annulus and nucleus pulposus visible. Despite the fact that it still remains challenging to develop a high-energy grating interferometer with a broad polychromatic source with satisfactory optical performance, improved image quality for phase contrast as compared to attenuation contrast can be obtained and new exciting applications foreseen. gratings for x-ray phase contrast imaging," AIP Conf.

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Section: Discussionsupporting

confidence: 83%

Section: Contrast Dependence / Formationmentioning

confidence: 90%

Section: Contrast Dependence / Formationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Quantitative imaging using high-energy X-ray phase-contrast CT with a 70 kVp polychromatic X-ray spectrum

Sarapata¹,

Willner²,

Walter³

et al. 2015

Opt. Express

Self Cite

View full text Add to dashboard Cite

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Technical Note: Single‐shot phase retrieval method for synchrotron‐based high‐energy x‐ray grating interferometry

et al. 2019

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Purpose X‐ray grating interferometry (XGI) provides substantially increased contrast over conventional absorption‐based imaging methods and therefore shows great potential for future biomedical applications. In this work, we propose a single‐shot phase retrieval method for synchrotron‐based high‐energy x‐ray grating interferometry. Contrary to existing retrieval methods, the presented novel approach enables direct retrieval of the object's phase map quantitatively from a single projection image, thus significantly simplifying the experimental procedure and reducing data acquisition times. Methods The phase retrieval method is analytically derived, based on the phase‐attenuation duality of soft tissues when being imaged with high‐energy x rays. The sensitivity of the retrieved phase map, quantified by the standard deviation, is evaluated as a function of the photon number. Numerical experiments are performed to validate the proposed method and provide some quantitative insight. Results The numerical results show that the method can provide high‐quality phase images, where the well‐known streak artifacts are significantly suppressed. Moreover, the retrieved phase maps confirm that the method is highly stable with respect to statistical noise. Conclusions Thanks to simplified experimental procedure and reduced acquisition time and dose deposition to the sample, we believe that this new method can find its potential in biomedical imaging and in vivo studies. Future work will focus on the adaptation of the method to polychromatic x ray from tube source and to computed tomography.

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Electrical conductivity and mechanical properties, free volume, and γ‐ray transmission of ethylene propylene diene monomer/butadiene rubber composites

Hamed

Taha

Alaa³

2019

Polymer Composites

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Mechanism of electrical conductivity (σ), mechanical properties, and γ‐ray transmission properties of ethylene propylene diene monomer (EPDM)/butadiene rubber (BR) composites have been investigated from the viewpoint of free volume (ie, open hole size). The EPDM/BR composites (100/0, 70/30, 50/50, 30/70, and 0/100) loaded with 50 phr carbon black as a reinforcing filler and irradiated with different doses (10, 30, 50, 70, and 100 kGy). The ortho‐positronium lifetime (o‐Ps) for all the composites is measured using the positron annihilation lifetime (PAL) spectroscopy. Linear attenuation coefficients are measured for unirradiated composite at 59.5 keV using 241Am γ‐source. Scan electron microscope, electrical conductivity, stress‐strain, and hardness tests are investigated for all the composites before irradiation at room temperature (25°C). The results show a good linear correlation between the open hole size evaluated by PAL spectroscopy and all of the measured properties. These correlations confirmed the important role played by the free volume (ie, is governed by the open hole size) in all of the electrical conductivity, mechanical, and transmission properties in the composite. The results status that, the composite sample EPDM/BR (0/100) may be used as a radiation resistant material or as a radiation protector for tools in high‐level radiation areas.

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Quantitative X-ray phase-contrast computed tomography at 82 keV

Cited by 59 publications

References 31 publications

Quantitative imaging using high-energy X-ray phase-contrast CT with a 70 kVp polychromatic X-ray spectrum

Quantitative imaging using high-energy X-ray phase-contrast CT with a 70 kVp polychromatic X-ray spectrum

Technical Note: Single‐shot phase retrieval method for synchrotron‐based high‐energy x‐ray grating interferometry

Electrical conductivity and mechanical properties, free volume, and γ‐ray transmission of ethylene propylene diene monomer/butadiene rubber composites

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