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Li Z, An K, Yu H, Luo F, Pan J, Wang S, Zhang J, Wu W, Chang D. Spectrum learning for super-resolution tomographic reconstruction. Phys Med Biol 2024; 69:085018. [PMID: 38373346 DOI: 10.1088/1361-6560/ad2a94] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 02/19/2024] [Indexed: 02/21/2024]
Abstract
Objective. Computed Tomography (CT) has been widely used in industrial high-resolution non-destructive testing. However, it is difficult to obtain high-resolution images for large-scale objects due to their physical limitations. The objective is to develop an improved super-resolution technique that preserves small structures and details while efficiently capturing high-frequency information.Approach. The study proposes a new deep learning based method called spectrum learning (SPEAR) network for CT images super-resolution. This approach leverages both global information in the image domain and high-frequency information in the frequency domain. The SPEAR network is designed to reconstruct high-resolution images from low-resolution inputs by considering not only the main body of the images but also the small structures and other details. The symmetric property of the spectrum is exploited to reduce weight parameters in the frequency domain. Additionally, a spectrum loss is introduced to enforce the preservation of both high-frequency components and global information.Main results. The network is trained using pairs of low-resolution and high-resolution CT images, and it is fine-tuned using additional low-dose and normal-dose CT image pairs. The experimental results demonstrate that the proposed SPEAR network outperforms state-of-the-art networks in terms of image reconstruction quality. The approach successfully preserves high-frequency information and small structures, leading to better results compared to existing methods. The network's ability to generate high-resolution images from low-resolution inputs, even in cases of low-dose CT images, showcases its effectiveness in maintaining image quality.Significance. The proposed SPEAR network's ability to simultaneously capture global information and high-frequency details addresses the limitations of existing methods, resulting in more accurate and informative image reconstructions. This advancement can have substantial implications for various industries and medical diagnoses relying on accurate imaging.
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Affiliation(s)
- Zirong Li
- The School of Biomedical Engineering, Shenzhen Campus of Sun Yat-sen University, Guangdong, People's Republic of China
| | - Kang An
- The Key Laboratory of Optoelectronic Technology and Systems, ICT Research Center, Ministry of Education, Chongqing University, Chongqing, People's Republic of China
| | - Hengyong Yu
- The Department of Electrical and Computer Engineering, University of Massachusetts Lowell, Lowell, MA, United States of America
| | - Fulin Luo
- The College of Computer Science, Chongqing University, Chongqing, People's Republic of China
| | - Jiayi Pan
- The School of Biomedical Engineering, Shenzhen Campus of Sun Yat-sen University, Guangdong, People's Republic of China
| | - Shaoyu Wang
- The Henan Key Laboratory of Imaging and Intelligent Processing, PLA Strategic Support Force Information Engineering University, Zhengzhou, People's Republic of China
| | - Jianjia Zhang
- The School of Biomedical Engineering, Shenzhen Campus of Sun Yat-sen University, Guangdong, People's Republic of China
| | - Weiwen Wu
- The School of Biomedical Engineering, Shenzhen Campus of Sun Yat-sen University, Guangdong, People's Republic of China
- The Henan Key Laboratory of Imaging and Intelligent Processing, PLA Strategic Support Force Information Engineering University, Zhengzhou, People's Republic of China
| | - Dingyue Chang
- The China Academy of Engineering Physics, Institute of Materials, Mianyang 621700, People's Republic of China
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Dierks H, Stjärneblad P, Wallentin J. A versatile laboratory setup for high resolution X-ray phase contrast tomography and scintillator characterization. JOURNAL OF X-RAY SCIENCE AND TECHNOLOGY 2023; 31:1-12. [PMID: 36404526 PMCID: PMC9912733 DOI: 10.3233/xst-221294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 10/11/2022] [Accepted: 10/30/2022] [Indexed: 06/16/2023]
Abstract
BACKGROUND X-ray micro-tomography (μCT) is a powerful non-destructive 3D imaging method applied in many scientific fields. In combination with propagation-based phase-contrast, the method is suitable for samples with low absorption contrast. Phase contrast tomography has become available in the lab with the ongoing development of micro-focused tube sources, but it requires sensitive and high-resolution X-ray detectors. The development of novel scintillation detectors, particularly for microscopy, requires more flexibility than available in commercial tomography systems. OBJECTIVE We aim to develop a compact, flexible, and versatile μCT laboratory setup that combines absorption and phase contrast imaging as well as the option to use it for scintillator characterization. Here, we present details on the design and implementation of the setup. METHODS We used the setup for μCT in absorption and propagation-based phase-contrast mode, as well as to study a perovskite scintillator. RESULTS We show the 2D and 3D performance in absorption and phase contrast mode, as well as how the setup can be used for testing new scintillator materials in a realistic imaging environment. A spatial resolution of around 1.3μm is measured in 2D and 3D. CONCLUSIONS The setup meets the needs for common absorption μCT applications and offers increased contrast in phase contrast mode. The availability of a versatile laboratory μCT setup allows not only for easy access to tomographic measurements, but also enables a prompt monitoring and feedback beneficial for advances in scintillator fabrication.
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Affiliation(s)
- Hanna Dierks
- Lund University, Synchrotron Radiation Research and NanoLund, Lund, Sweden
| | - Philip Stjärneblad
- Lund University, Synchrotron Radiation Research and NanoLund, Lund, Sweden
| | - Jesper Wallentin
- Lund University, Synchrotron Radiation Research and NanoLund, Lund, Sweden
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Lioliou G, Roche i Morgó O, Marathe S, Wanelik K, Cipiccia S, Olivo A, Hagen CK. Cycloidal-spiral sampling for three-modal x-ray CT flyscans with two-dimensional phase sensitivity. Sci Rep 2022; 12:21336. [PMID: 36494470 PMCID: PMC9734192 DOI: 10.1038/s41598-022-25999-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 12/07/2022] [Indexed: 12/13/2022] Open
Abstract
We present a flyscan compatible acquisition scheme for three-modal X-Ray Computed Tomography (CT) with two-dimensional phase sensitivity. Our approach is demonstrated using a "beam tracking" setup, through which a sample's attenuation, phase (refraction) and scattering properties can be measured from a single frame, providing three complementary contrast channels. Up to now, such setups required the sample to be stepped at each rotation angle to sample signals at an adequate rate, to prevent resolution losses, anisotropic resolution, and under-sampling artefacts. However, the need for stepping necessitated a step-and-shoot implementation, which is affected by motors' overheads and increases the total scan time. By contrast, our proposed scheme, by which continuous horizontal and vertical translations of the sample are integrated with its rotation (leading to a "cycloidal-spiral" trajectory), is fully compatible with continuous scanning (flyscans). This leads to greatly reduced scan times while largely preserving image quality and isotropic resolution.
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Affiliation(s)
- G. Lioliou
- grid.83440.3b0000000121901201Department of Medical Physics and Biomedical Engineering, University College London, Malet Place, London, WC1E 6BT UK
| | - O. Roche i Morgó
- grid.83440.3b0000000121901201Department of Medical Physics and Biomedical Engineering, University College London, Malet Place, London, WC1E 6BT UK
| | - S. Marathe
- grid.18785.330000 0004 1764 0696Diamond Light Source, Harwell Science and Innovation Campus, Fermi Avenue, Didcot, OX11 0DE UK
| | - K. Wanelik
- grid.18785.330000 0004 1764 0696Diamond Light Source, Harwell Science and Innovation Campus, Fermi Avenue, Didcot, OX11 0DE UK
| | - S. Cipiccia
- grid.83440.3b0000000121901201Department of Medical Physics and Biomedical Engineering, University College London, Malet Place, London, WC1E 6BT UK
| | - A. Olivo
- grid.83440.3b0000000121901201Department of Medical Physics and Biomedical Engineering, University College London, Malet Place, London, WC1E 6BT UK
| | - C. K. Hagen
- grid.83440.3b0000000121901201Department of Medical Physics and Biomedical Engineering, University College London, Malet Place, London, WC1E 6BT UK
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Roche i Morgó O, Aleksejev J, Astolfo A, Savvidis S, Gerli MFM, Cipiccia S, Olivo A, Hagen CK. Utility of knife-edge position tracking in cycloidal computed tomography. OPTICS EXPRESS 2022; 30:43209-43222. [PMID: 36523024 PMCID: PMC9765405 DOI: 10.1364/oe.470798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 10/03/2022] [Accepted: 10/03/2022] [Indexed: 06/17/2023]
Abstract
Cycloidal computed tomography provides high-resolution images within relatively short scan times by combining beam modulation with dedicated under-sampling. However, implementing the technique relies on accurate knowledge of the sample's motion, particularly in the case of continuous scans, which is often unavailable due to hardware or software limitations. We have developed an easy-to-implement position tracking technique using a sharp edge, which can provide reliable information about the trajectory of the sample and thus improve the reconstruction process. Furthermore, this approach also enables the development of other innovative sampling schemes, which may otherwise be difficult to implement.
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Affiliation(s)
- Oriol Roche i Morgó
- Dept. of Medical Physics and Biomedical Engineering, University College London, WC1E 6BT, UK
| | - Jure Aleksejev
- Dept. of Medical Physics and Biomedical Engineering, University College London, WC1E 6BT, UK
| | - Alberto Astolfo
- Dept. of Medical Physics and Biomedical Engineering, University College London, WC1E 6BT, UK
| | - Savvas Savvidis
- Dept. of Medical Physics and Biomedical Engineering, University College London, WC1E 6BT, UK
| | - Mattia FM Gerli
- UCL Divison of Surgery and Interventional Science, University College London, Rowland Hill Street, London, NW3 2P, UK
| | - Silvia Cipiccia
- Dept. of Medical Physics and Biomedical Engineering, University College London, WC1E 6BT, UK
| | - Alessandro Olivo
- Dept. of Medical Physics and Biomedical Engineering, University College London, WC1E 6BT, UK
| | - Charlotte K. Hagen
- Dept. of Medical Physics and Biomedical Engineering, University College London, WC1E 6BT, UK
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Gustschin A, Riedel M, Taphorn K, Petrich C, Gottwald W, Noichl W, Busse M, Francis SE, Beckmann F, Hammel JU, Moosmann J, Thibault P, Herzen J. High-resolution and sensitivity bi-directional x-ray phase contrast imaging using 2D Talbot array illuminators. OPTICA 2021; 8:1588-1595. [PMID: 37829605 PMCID: PMC10567101 DOI: 10.1364/optica.441004] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 11/01/2021] [Accepted: 11/01/2021] [Indexed: 10/14/2023]
Abstract
Two-dimensional (2D) Talbot array illuminators (TAIs) were designed, fabricated, and evaluated for high-resolution high-contrast x-ray phase imaging of soft tissue at 10-20 keV. The TAIs create intensity modulations with a high compression ratio on the micrometer scale at short propagation distances. Their performance was compared with various other wavefront markers in terms of period, visibility, flux efficiency, and flexibility to be adapted for limited beam coherence and detector resolution. Differential x-ray phase contrast and dark-field imaging were demonstrated with a one-dimensional, linear phase stepping approach yielding 2D phase sensitivity using unified modulated pattern analysis (UMPA) for phase retrieval. The method was employed for x-ray phase computed tomography reaching a resolution of 3 µm on an unstained murine artery. It opens new possibilities for three-dimensional, non-destructive, and quantitative imaging of soft matter such as virtual histology. The phase modulators can also be used for various other x-ray applications such as dynamic phase imaging, super-resolution structured illumination microscopy, or wavefront sensing.
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Affiliation(s)
- Alex Gustschin
- Department of Physics and Munich School of Bioengineering, Technical University of Munich, 85748, Garching, Germany
| | - Mirko Riedel
- Department of Physics and Munich School of Bioengineering, Technical University of Munich, 85748, Garching, Germany
- Institute of Materials Physics, Helmholtz-Zentrum Hereon, Max-Planck-Str. 1, 21502 Geesthacht, Germany
| | - Kirsten Taphorn
- Department of Physics and Munich School of Bioengineering, Technical University of Munich, 85748, Garching, Germany
| | - Christian Petrich
- Department of Physics and Munich School of Bioengineering, Technical University of Munich, 85748, Garching, Germany
| | - Wolfgang Gottwald
- Department of Physics and Munich School of Bioengineering, Technical University of Munich, 85748, Garching, Germany
| | - Wolfgang Noichl
- Department of Physics and Munich School of Bioengineering, Technical University of Munich, 85748, Garching, Germany
| | - Madleen Busse
- Department of Physics and Munich School of Bioengineering, Technical University of Munich, 85748, Garching, Germany
| | - Sheila E. Francis
- Department of Infection, Immunity and Cardiovascular Disease, Medical School, University of Sheffield S10 2RX, UK
| | - Felix Beckmann
- Institute of Materials Physics, Helmholtz-Zentrum Hereon, Max-Planck-Str. 1, 21502 Geesthacht, Germany
| | - Jörg U. Hammel
- Institute of Materials Physics, Helmholtz-Zentrum Hereon, Max-Planck-Str. 1, 21502 Geesthacht, Germany
| | - Julian Moosmann
- Institute of Materials Physics, Helmholtz-Zentrum Hereon, Max-Planck-Str. 1, 21502 Geesthacht, Germany
| | - Pierre Thibault
- Department of Physics, University of Trieste, Trieste 34217, Italy
| | - Julia Herzen
- Department of Physics and Munich School of Bioengineering, Technical University of Munich, 85748, Garching, Germany
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Qiao Z, Shi X, Wojcik M, Assoufid L. High-Resolution Scanning Coded-Mask-Based X-ray Multi-Contrast Imaging and Tomography. J Imaging 2021; 7:jimaging7120249. [PMID: 34940716 PMCID: PMC8705295 DOI: 10.3390/jimaging7120249] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 11/19/2021] [Accepted: 11/20/2021] [Indexed: 11/16/2022] Open
Abstract
Near-field X-ray speckle tracking has been used in phase-contrast imaging and tomography as an emerging technique, providing higher contrast images than traditional absorption radiography. Most reported methods use sandpaper or membrane filters as speckle generators and digital image cross-correlation for phase reconstruction, which has either limited resolution or requires a large number of position scanning steps. Recently, we have proposed a novel coded-mask-based multi-contrast imaging (CMMI) technique for single-shot measurement with superior performance in efficiency and resolution compared with other single-shot methods. We present here a scanning CMMI method for the ultimate imaging resolution and phase sensitivity by using a coded mask as a high-contrast speckle generator, the flexible scanning mode, the adaption of advanced maximum-likelihood optimization to scanning data, and the multi-resolution analysis. Scanning CMMI can outperform other speckle-based imaging methods, such as X-ray speckle vector tracking, providing higher quality absorption, phase, and dark-field images with fewer scanning steps. Scanning CMMI is also successfully demonstrated in multi-contrast tomography, showing great potentials in high-resolution full-field imaging applications, such as in vivo biomedical imaging.
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Olivo A. Edge-illumination x-ray phase-contrast imaging. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:363002. [PMID: 34167096 PMCID: PMC8276004 DOI: 10.1088/1361-648x/ac0e6e] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 06/07/2021] [Accepted: 06/24/2021] [Indexed: 05/08/2023]
Abstract
Although early demonstration dates back to the mid-sixties, x-ray phase-contrast imaging (XPCI) became hugely popular in the mid-90s, thanks to the advent of 3rd generation synchrotron facilities. Its ability to reveal object features that had so far been considered invisible to x-rays immediately suggested great potential for applications across the life and the physical sciences, and an increasing number of groups worldwide started experimenting with it. At that time, it looked like a synchrotron facility was strictly necessary to perform XPCI with some degree of efficiency-the only alternative being micro-focal sources, the limited flux of which imposed excessively long exposure times. However, new approaches emerged in the mid-00s that overcame this limitation, and allowed XPCI implementations with conventional, non-micro-focal x-ray sources. One of these approaches showing particular promise for 'real-world' applications is edge-illumination XPCI: this article describes the key steps in its evolution in the context of contemporary developments in XPCI research, and presents its current state-of-the-art, especially in terms of transition towards practical applications.
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Affiliation(s)
- Alessandro Olivo
- Department of Medical Physics and Biomedical Engineering, UCL, London, United Kingdom
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Dreier T, Peruzzi N, Lundström U, Bech M. Improved resolution in x-ray tomography by super-resolution. APPLIED OPTICS 2021; 60:5783-5794. [PMID: 34263797 DOI: 10.1364/ao.427934] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 05/28/2021] [Indexed: 06/13/2023]
Abstract
In this paper, super-resolution imaging is described and evaluated for x-ray tomography and is compared with standard tomography and upscaling during reconstruction. Blurring is minimized due to the negligible point spread of photon counting detectors and an electromagnetically movable micro-focus x-ray spot. Scans are acquired in high and low magnification geometry, where the latter is used to minimize penumbral blurring from the x-ray source. Sharpness and level of detail can be significantly increased in reconstructed slices to the point where the source size becomes the limiting factor. The achieved resolution of the different methods is quantified and compared using biological samples via the edge spread function, modulation transfer function, and Fourier ring correlation.
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Vila-Comamala J, Romano L, Jefimovs K, Dejea H, Bonnin A, Cook AC, Planinc I, Cikes M, Wang Z, Stampanoni M. High sensitivity X-ray phase contrast imaging by laboratory grating-based interferometry at high Talbot order geometry. OPTICS EXPRESS 2021; 29:2049-2064. [PMID: 33726406 DOI: 10.1364/oe.414174] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 12/24/2020] [Indexed: 06/12/2023]
Abstract
X-ray phase contrast imaging is a powerful analysis technique for materials science and biomedicine. Here, we report on laboratory grating-based X-ray interferometry employing a microfocus X-ray source and a high Talbot order (35th) asymmetric geometry to achieve high angular sensitivity and high spatial resolution X-ray phase contrast imaging in a compact system (total length <1 m). The detection of very small refractive angles (∼50 nrad) at an interferometer design energy of 19 keV was enabled by combining small period X-ray gratings (1.0, 1.5 and 3.0 µm) and a single-photon counting X-ray detector (75 µm pixel size). The performance of the X-ray interferometer was fully characterized in terms of angular sensitivity and spatial resolution. Finally, the potential of laboratory X-ray phase contrast for biomedical imaging is demonstrated by obtaining high resolution X-ray phase tomographies of a mouse embryo embedded in solid paraffin and a formalin-fixed full-thickness sample of human left ventricle in water with a spatial resolution of 21.5 µm.
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