Monochromatic Propagation-Based Phase-Contrast Microscale Computed-Tomography System with a Rotating-Anode Source

Brombal, Luca; Kallon, Gibril K.; Jiang, Jingying; Savvidis, Savvas; Coppi, Paolo De; Urbani, Luca; Forty, Ellen; Chambers, Rachel C.; Longo, Renata; Olivo, Alessandro; Endrizzi, Marco

doi:10.1103/physrevapplied.11.034004

Cited by 24 publications

(24 citation statements)

References 35 publications

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“…Recently, transferring the PBCT method onto laboratory X-ray sources, such as microfocus X-ray sources, has been an active area of research. Compared with the SR source, the laboratory X-ray sources typically have lower photon flux [9,41], which results in longer scan times for collecting data (typically a few hours). For laboratory X-ray source-based PBCT technology, few-projection PBCT reconstruction algorithms will also be highly desirable, and they have great potential to make both fresh and chemically unfixed biological tissues available for this technology [4].…”

Section: Discussionmentioning

confidence: 99%

“…Over the past two decades, a variety of PCI techniques have been developed to transform phase shifts into measurable intensity variations on the detector, such as crystal interferometry imaging, analyzer-based imaging, propagation-based X-ray phase-contrast imaging (PBI), edge-illumination imaging and grating-based imaging. Among the abovementioned techniques, PBI is the simplest to implement in reality because it only requires that the incident X-ray beams are sufficiently spatially coherent, and the sample-todetector distance (SDD) can be adjusted, and no additional optical elements or multiexposures are needed [9]. In general, by extending PBI to CT (PBCT), PBCT can be used for high-resolution 3D visualization of the internal detailed structures in weakly absorbing objects.…”

Section: Introductionmentioning

confidence: 99%

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Three-dimensional visualization of microvasculature from few-projection data using a novel CT reconstruction algorithm for propagation-based X-ray phase-contrast imaging

Zhao

et al. 2019

Biomed. Opt. Express

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Propagation-based X-ray phase-contrast imaging (PBI) is a powerful nondestructive imaging technique that can reveal the internal detailed structures in weakly absorbing samples. Extending PBI to CT (PBCT) enables high-resolution and high-contrast 3D visualization of microvasculature, which can be used for the understanding, diagnosis and therapy of diseases involving vasculopathy, such as cardiovascular disease, stroke and tumor. However, the long scan time for PBCT impedes its wider use in biomedical and preclinical microvascular studies. To address this issue, a novel CT reconstruction algorithm for PBCT is presented that aims at shortening the scan time for microvascular samples by reducing the number of projections while maintaining the high quality of reconstructed images. The proposed algorithm combines the filtered backprojection method into the iterative reconstruction framework, and a weighted guided image filtering approach (WGIF) is utilized to optimize the intermediate reconstructed images. Notably, the homogeneity assumption on the microvasculature sample is adopted as prior knowledge, and therefore, a prior image of microvasculature structures can be acquired by a k-means clustering approach. Then, the prior image is used as the guided image in the WGIF procedure to effectively suppress streaking artifacts and preserve microvasculature structures. To evaluate the effectiveness and capability of the proposed algorithm, simulation experiments on 3D microvasculature numerical phantom and real experiments with CT reconstruction on the microvasculature sample are performed. The results demonstrate that the proposed algorithm can, under noise-free and noisy conditions, significantly reduce the artifacts and effectively preserve the microvasculature structures on the reconstructed images and thus enables it to be used for clear and accurate 3D visualization of microvasculature from few-projection data. Therefore, for 3D visualization of microvasculature, the proposed algorithm can be considered an effective approach for reducing the scan time required by PBCT.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Three-dimensional visualization of microvasculature from few-projection data using a novel CT reconstruction algorithm for propagation-based X-ray phase-contrast imaging

Zhao

et al. 2019

Biomed. Opt. Express

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“…For coherent, mono‐chromatic radiation and single‐material sample, the parameters in Equation () are uniquely defined. However, for partially coherent, broad‐spectrum laboratory setup the parameters in the denominator in front of the quadratic frequency term are typically lumped into a single coefficient that is determined empirically 7,25,26 . Empirical determination of the coefficient is also done if the Paganin retrieval is applied in the above form for multi‐material samples, which is often the case in practice.…”

Section: Methodsmentioning

confidence: 99%

Optimizing and applying high‐resolution, in‐line laboratory phase‐contrast X‐ray imaging for low‐density material samples

Zboray

2021

Journal of Microscopy

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In‐line, or propagation‐based phase‐contrast X‐ray imaging (PBI) is an attractive alternative to the attenuation‐based modality for low‐density, soft samples showing low attenuation contrast. With the growing availability of micro‐ and nano‐focus X‐ray tubes, the method is increasingly applied in the laboratory. Here, we discuss the technique and demonstrate its advantages for selected low‐density, low attenuation material samples using a lab‐based micro‐ and nano‐computed tomography systems Easytom XL Ultra, providing micron and sub‐micron range resolution PBI images. We demonstrate a multi‐step optimization of the lab‐based PBI technique on our scanner that includes choosing the optimal detector‐source hardware combination available in the setup, then optimizing the imaging geometry and finally the phase retrieval process through a parametric study. We point out and elaborate on the effect of noise correlation and texturing due to phase retrieval. We demonstrate the overall benefits of using the phase image and the phase retrieval for the selected samples such as improved image quality, increased contrast‐to‐noise ratio while only marginally influencing the spatial resolution. The improvement in image quality also enables further image processing steps for detailed structural analysis of the samples, which would be much more complicated if not impossible based on the transmission image.

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“…More recently, this has been overcome by several XPCi techniques based on conventional sources or by new source technologies. [10][11][12][13][14] Many laboratories that are currently developing phase detection techniques rely on optical elements (absorption or phase gratings). These approaches represent the most attractive solution toward commercially available XPCi scanners to serve the preclinical and medical communities.…”

Section: Introductionmentioning

confidence: 99%

“…Historically, the limited accessibility of synchrotron sources has limited the widespread use of XPCi. More recently, this has been overcome by several XPCi techniques based on conventional sources or by new source technologies 10–14 . Many laboratories that are currently developing phase detection techniques rely on optical elements (absorption or phase gratings).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of a compact multicontrast and multiresolution X‐ray phase contrast edge illumination system for small animal imaging

et al. 2020

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Purpose In this work the performance of a compact multiresolution and multicontrast x‐ray phase system based on edge illumination is investigated. It has been designed for small animal imaging and with a limited footprint for ease of deployment in laboratories. Methods The presented edge illumination system is based on a compact microfocus tungsten x‐ray source combined with a flat panel detector. The source has a maximum output of 10 W when the minimum spot size of about 15 μm is used. The system has an overall length of 70 cm. A new double sample mask design, obtained by arranging both skipped and nonskipped configurations on the same structure, provides dual resolution capability. To test the system, we carried out computed tomography (CT) scans of a plastic phantom with different source settings using both single‐image and multi‐image acquisition schemes at different spatial resolutions. In addition, CT scans of an ex‐vivo mouse specimen were acquired at the best identified working conditions to demonstrate the application of the presented system to small animal imaging. Results We found this system delivers good image quality, allowing for an efficient material separation and improving detail visibility in small animals thanks to the higher signal‐to‐noise ratio (SNR) of phase contrast with respect to conventional attenuation contrast. The system offers high versatility in terms of spatial resolution thanks to the double sample mask design integrated into a single scanner. The availability of both multi‐ and single‐image acquisition schemes coupled with their dedicated retrieval algorithms, allows different working modes which can be selected based on user preference. Multi‐image acquisition provides quantitative separation of the real and imaginary part of the refractive index, however, it requires a long scanning time. On the other hand, the single image approach delivers the best material separation and image quality at all the investigated source settings with a shorter scanning time but at the cost of quantitativeness. Finally, we also observed that the single image approach combined with a high‐power x‐ray source may result in a fast acquisition protocol compatible with in‐vivo imaging.

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Monochromatic Propagation-Based Phase-Contrast Microscale Computed-Tomography System with a Rotating-Anode Source

Cited by 24 publications

References 35 publications

Three-dimensional visualization of microvasculature from few-projection data using a novel CT reconstruction algorithm for propagation-based X-ray phase-contrast imaging

Three-dimensional visualization of microvasculature from few-projection data using a novel CT reconstruction algorithm for propagation-based X-ray phase-contrast imaging

Optimizing and applying high‐resolution, in‐line laboratory phase‐contrast X‐ray imaging for low‐density material samples

Evaluation of a compact multicontrast and multiresolution X‐ray phase contrast edge illumination system for small animal imaging

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