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Chalmers MC, Kitchen MJ, Uesugi K, Falzon G, Quin P, Pavlov KM. Tomographic reconstruction using tilted Laue analyser-based X-ray phase-contrast imaging. JOURNAL OF SYNCHROTRON RADIATION 2021; 28:283-291. [PMID: 33399579 DOI: 10.1107/s1600577520013995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 10/20/2020] [Indexed: 06/12/2023]
Abstract
Analyser-based phase-contrast imaging (ABPCI) is a highly sensitive phase-contrast imaging method that produces high-contrast images of weakly absorbing materials. However, it is only sensitive to phase gradient components lying in the diffraction plane of the analyser crystal [i.e. in one dimension (1-D)]. In order to accurately account for and measure phase effects produced by the wavefield-sample interaction, ABPCI and other 1-D phase-sensitive methods must achieve 2-D phase gradient sensitivity. An inclined geometry method was applied to a Laue geometry setup for X-ray ABPCI through rotation of the detector and object about the optical axis. This allowed this traditionally 1-D phase-sensitive phase-contrast method to possess 2-D phase gradient sensitivity. Tomographic datasets were acquired over 360° of a multi-material phantom with the detector and sample tilted by 8°. The real and imaginary parts of the refractive index were reconstructed for the phantom.
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Affiliation(s)
- M C Chalmers
- University of Canterbury, 20 Kirkwood Avenue, Upper Riccarton, Christchurch 8041, New Zealand
| | - M J Kitchen
- Monash University, Wellington Road, Clayton, VIC 3800, Australia
| | - K Uesugi
- Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - G Falzon
- College of Science and Engineering, Flinders University, Adelaide, South Australia 5001, Australia
| | - P Quin
- University of New England, Armidale, NSW 2351, Australia
| | - K M Pavlov
- University of Canterbury, 20 Kirkwood Avenue, Upper Riccarton, Christchurch 8041, New Zealand
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2
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Schaff F, Morgan KS, Pollock JA, Croton LCP, Hooper SB, Kitchen MJ. Material Decomposition Using Spectral Propagation-Based Phase-Contrast X-Ray Imaging. IEEE TRANSACTIONS ON MEDICAL IMAGING 2020; 39:3891-3899. [PMID: 32746132 DOI: 10.1109/tmi.2020.3006815] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Material decomposition in X-ray imaging uses the energy-dependence of attenuation to digitally decompose an object into specific constituent materials, generally at the cost of enhanced image noise. Propagation-based X-ray phase-contrast imaging is a developing technique that can be used to reduce image noise, in particular from weakly attenuating objects. In this paper, we combine spectral phase-contrast imaging with material decomposition to both better visualize weakly attenuating features and separate them from overlying objects in radiography. We derive an algorithm that performs both tasks simultaneously and verify it against numerical simulations and experimental measurements of ideal two-component samples composed of pure aluminum and poly(methyl methacrylate). Additionally, we showcase first imaging results of a rabbit kitten's lung. The attenuation signal of a thorax, in particular, is dominated by the strongly attenuating bones of the ribcage. Combined with the weak soft tissue signal, this makes it difficult to visualize the fine anatomical structures across the whole lung. In all cases, clean material decomposition was achieved, without residual phase-contrast effects, from which we generate an un-obstructed image of the lung, free of bones. Spectral propagation-based phase-contrast imaging has the potential to be a valuable tool, not only in future lung research, but also in other systems for which phase-contrast imaging in combination with material decomposition proves to be advantageous.
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3
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Li HT, Schaff F, Croton LCP, Morgan KS, Kitchen MJ. Quantitative material decomposition using linear iterative near-field phase retrieval dual-energy x-ray imaging. Phys Med Biol 2020; 65:185014. [PMID: 32946429 DOI: 10.1088/1361-6560/ab9558] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
This paper expands the linear iterative near-field phase retrieval (LIPR) formalism to achieve quantitative material thickness decomposition. Propagation-based phase contrast x-ray imaging with subsequent phase retrieval has been shown to improve the signal-to-noise ratio (SNR) by factors of up to hundreds compared to conventional x-ray imaging. This is a key step in biomedical imaging, where radiation exposure must be kept low without compromising the SNR. However, for a satisfactory phase retrieval from a single measurement, assumptions must be made about the object investigated. To avoid such assumptions, we use two measurements collected at the same propagation distance but at different x-ray energies. Phase retrieval is then performed by incorporating the Alvarez-Macovski (AM) model, which models the x-ray interactions as being comprised of distinct photoelectric and Compton scattering components. We present the first application of dual-energy phase retrieval with the AM model to monochromatic experimental x-ray projections at two different energies for obtaining split x-ray interactions. Our phase retrieval method allows us to separate the object investigated into the projected thicknesses of two known materials. Our phase retrieval output leads to no visible loss in spatial resolution while the SNR improves by factors of 2 to 10. This corresponds to a possible x-ray dose reduction by a factor of 4 to 100, under the Poisson noise assumption.
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Affiliation(s)
- Heyang Thomas Li
- School of Physics and Astronomy, Monash University, Clayton, VIC 3800, Australia. School of Mathematics and Statistics, College of Engineering, University of Canterbury, Ilam, Christchurch, 8041, New Zealand
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4
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Kitchen MJ, Buckley GA, Kerr LT, Lee KL, Uesugi K, Yagi N, Hooper SB. Emphysema quantified: mapping regional airway dimensions using 2D phase contrast X-ray imaging. BIOMEDICAL OPTICS EXPRESS 2020; 11:4176-4190. [PMID: 32923035 PMCID: PMC7449757 DOI: 10.1364/boe.390587] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 05/29/2020] [Accepted: 06/02/2020] [Indexed: 06/11/2023]
Abstract
We have developed an analyser-based phase contrast X-ray imaging technique to measure the mean length scale of pores or particles that cannot be resolved directly by the system. By combining attenuation, phase and ultra-small angle X-ray scattering information, the technique was capable of measuring differences in airway dimension between lungs of healthy mice and those with mild and severe emphysema. Our measurements of airway dimensions from 2D images showed a 1:1 relationship to the actual airway dimensions measured using micro-CT. Using 80 images, the sensitivity and specificity were measured to be 0.80 and 0.89, respectively, with the area under the ROC curve close to ideal at 0.96. Reducing the number of images to 11 slightly decreased the sensitivity to 0.75 and the ROC curve area to 0.90, whilst the specificity remained high at 0.89.
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Affiliation(s)
- Marcus J. Kitchen
- School of Physics and Astronomy, Monash
University, Clayton, Victoria, 3800, Australia
| | - Genevieve A. Buckley
- School of Physics and Astronomy, Monash
University, Clayton, Victoria, 3800, Australia
| | | | - Katie L. Lee
- School of Physics and Astronomy, Monash
University, Clayton, Victoria, 3800, Australia
| | - Kentaro Uesugi
- The Ritchie Centre, MIMR-PHI Institute of
Medical Research and the Department of Obstetrics and Gynaecology,
Monash University, Clayton, Victoria, 3168, Australia
| | - Naoto Yagi
- The Ritchie Centre, MIMR-PHI Institute of
Medical Research and the Department of Obstetrics and Gynaecology,
Monash University, Clayton, Victoria, 3168, Australia
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5
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Groenendijk CF, Schaff F, Croton LCP, Kitchen MJ, Morgan KS. Material decomposition from a single x-ray projection via single-grid phase contrast imaging. OPTICS LETTERS 2020; 45:4076-4079. [PMID: 32667358 DOI: 10.1364/ol.389770] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 06/18/2020] [Indexed: 06/11/2023]
Abstract
This study describes a new approach for material decomposition in x-ray imaging, utilizing phase contrast both to increase sensitivity to weakly attenuating samples and to act as a complementary measurement to attenuation, therefore allowing two overlaid materials to be separated. The measurements are captured using the single-exposure, single-grid x-ray phase contrast imaging technique, with a novel correction that aims to remove propagation-based phase effects seen at sharp edges in the attenuation image. The use of a single-exposure technique means that images can be collected in a high-speed sequence. Results are shown for both a known two-material sample and for a biological specimen.
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6
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Exploring potential of different X-ray imaging methods for early-stage lung cancer detection. RADIATION DETECTION TECHNOLOGY AND METHODS 2020. [DOI: 10.1007/s41605-020-00173-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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7
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Leong AFT, Asare E, Rex R, Xiao XH, Ramesh KT, Hufnagel TC. Determination of size distributions of non-spherical pores or particles from single x-ray phase contrast images. OPTICS EXPRESS 2019; 27:17322-17347. [PMID: 31252944 DOI: 10.1364/oe.27.017322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 04/25/2019] [Indexed: 06/09/2023]
Abstract
Although x-ray tomography is commonly used to characterize the three-dimensional structure of materials, sometimes this is impractical due either to limited time for data collection (such as in rapidly-evolving systems) or the need to limit the radiation exposure of the sample. In such situations, it is desirable to extract as much information as possible from a more limited data set. In this paper, we describe how to extract the size distribution of non-spherical pores (or, equivalently, particles) from single x-ray phase contrast imaging (XPCI). Because the pores overlap in projection, interpreting the images and extracting quantitative information about the size distribution is non-trivial. In this paper we extend a previously-developed Fourier-based framework for interpreting the speckle pattern of XPCI images from materials with spherical pores to the more challenging case of non-spherical pores. We develop an analytical expression for the XPCI image from a distribution of randomly-oriented ellipsoidal pores, and show that we can use this expression to extract quantitative information about the size distribution from single images. We discuss three approaches to evaluating this expression, corresponding to different assumptions about the nature of the size distribution, and validate our results with simulated XPCI images and experimental data from Berea sandstone.
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8
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Braig E, Böhm J, Dierolf M, Jud C, Günther B, Mechlem K, Allner S, Sellerer T, Achterhold K, Gleich B, Noël P, Pfeiffer D, Rummeny E, Herzen J, Pfeiffer F. Direct quantitative material decomposition employing grating-based X-ray phase-contrast CT. Sci Rep 2018; 8:16394. [PMID: 30401876 PMCID: PMC6219573 DOI: 10.1038/s41598-018-34809-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 10/24/2018] [Indexed: 11/09/2022] Open
Abstract
Dual-energy CT has opened up a new level of quantitative X-ray imaging for many diagnostic applications. The energy dependence of the X-ray attenuation is the key to quantitative material decomposition of the volume under investigation. This material decomposition allows the calculation of virtual native images in contrast enhanced angiography, virtual monoenergetic images for beam-hardening artifact reduction and quantitative material maps, among others. These visualizations have been proven beneficial for various diagnostic questions. Here, we demonstrate a new method of 'virtual dual-energy CT' employing grating-based phase-contrast for quantitative material decomposition. Analogue to the measurement at two different energies, the applied phase-contrast measurement approach yields dual information in form of a phase-shift and an attenuation image. Based on these two image channels, all known dual-energy applications can be demonstrated with our technique. While still in a preclinical state, the method features the important advantages of direct access to the electron density via the phase image, simultaneous availability of the conventional attenuation image at the full energy spectrum and therefore inherently registered image channels. The transfer of this signal extraction approach to phase-contrast data multiplies the diagnostic information gained within a single CT acquisition. The method is demonstrated with a phantom consisting of exemplary solid and fluid materials as well as a chicken heart with an iodine filled tube simulating a vessel. For this first demonstration all measurements have been conducted at a compact laser-undulator synchrotron X-ray source with a tunable X-ray energy and a narrow spectral bandwidth, to validate the quantitativeness of the processing approach.
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Affiliation(s)
- Eva Braig
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748, Garching, Germany.
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, 81675, München, Germany.
| | - Jessica Böhm
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748, Garching, Germany
| | - Martin Dierolf
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748, Garching, Germany
| | - Christoph Jud
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748, Garching, Germany
| | - Benedikt Günther
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748, Garching, Germany
- Max-Planck-Institute of Quantum Optics, Hans-Kopfermann-Straße 1, 85748, Garching, Germany
| | - Korbinian Mechlem
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748, Garching, Germany
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, 81675, München, Germany
| | - Sebastian Allner
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748, Garching, Germany
| | - Thorsten Sellerer
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748, Garching, Germany
| | - Klaus Achterhold
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748, Garching, Germany
| | - Bernhard Gleich
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748, Garching, Germany
| | - Peter Noël
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, 81675, München, Germany
| | - Daniela Pfeiffer
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, 81675, München, Germany
| | - Ernst Rummeny
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, 81675, München, Germany
| | - Julia Herzen
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748, Garching, Germany
| | - Franz Pfeiffer
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748, Garching, Germany
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, 81675, München, Germany
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9
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Aulakh GK, Mann A, Belev G, Wiebe S, Kuebler WM, Singh B, Chapman D. Multiple image x-radiography for functional lung imaging. Phys Med Biol 2017; 63:015009. [PMID: 29116051 DOI: 10.1088/1361-6560/aa9904] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Detection and visualization of lung tissue structures is impaired by predominance of air. However, by using synchrotron x-rays, refraction of x-rays at the interface of tissue and air can be utilized to generate contrast which may in turn enable quantification of lung optical properties. We utilized multiple image radiography, a variant of diffraction enhanced imaging, at the Canadian light source to quantify changes in unique x-ray optical properties of lungs, namely attenuation, refraction and ultra small-angle scatter (USAXS or width) contrast ratios as a function of lung orientation in free-breathing or respiratory-gated mice before and after intra-nasal bacterial endotoxin (lipopolysaccharide) instillation. The lung ultra small-angle scatter and attenuation contrast ratios were significantly higher 9 h post lipopolysaccharide instillation compared to saline treatment whereas the refraction contrast decreased in magnitude. In ventilated mice, end-expiratory pressures result in an increase in ultra small-angle scatter contrast ratio when compared to end-inspiratory pressures. There were no detectable changes in lung attenuation or refraction contrast ratio with change in lung pressure alone. In effect, multiple image radiography can be applied towards following optical properties of lung air-tissue barrier over time during pathologies such as acute lung injury.
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Affiliation(s)
- G K Aulakh
- Small Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada
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10
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Werdiger F, Kitchen MJ, Paganin DM. Generalised Cornu spirals: an experimental study using hard x-rays. OPTICS EXPRESS 2016; 24:10620-10634. [PMID: 27409884 DOI: 10.1364/oe.24.010620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The Cornu spiral is a graphical aid that has been used historically to evaluate Fresnel integrals. It is also the Argand-plane mapping of a monochromatic complex scalar plane wave diffracted by a hard edge. We have successfully reconstructed a Cornu spiral due to diffraction of hard x-rays from a piece of Kapton tape. Additionally, we have explored the generalisation of the Cornu spiral by observing the Argand-plane mapping of complex scalar electromagnetic fields diffracted by a cylinder and a sphere embedded within a cylinder.
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11
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Garrett J, Ge Y, Li K, Chen GH. Correction of data truncation artifacts in differential phase contrast (DPC) tomosynthesis imaging. Phys Med Biol 2015; 60:7713-28. [DOI: 10.1088/0031-9155/60/19/7713] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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12
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Leong AF, Buckley GA, Paganin DM, Hooper SB, Wallace MJ, Kitchen MJ. Real-time measurement of alveolar size and population using phase contrast x-ray imaging. BIOMEDICAL OPTICS EXPRESS 2014; 5:4024-38. [PMID: 25426328 PMCID: PMC4242036 DOI: 10.1364/boe.5.004024] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 10/16/2014] [Accepted: 10/18/2014] [Indexed: 05/09/2023]
Abstract
Herein a propagation-based phase contrast x-ray imaging technique for measuring particle size and number is presented. This is achieved with an algorithm that utilizes the Fourier space signature of the speckle pattern associated with the images of particles. We validate this algorithm using soda-lime glass particles, demonstrating its effectiveness on random and non-randomly packed particles. This technique is then applied to characterise lung alveoli, which are difficult to measure dynamically in vivo with current imaging modalities due to inadequate temporal resolution and/or depth of penetration and field-of-view. We obtain an important result in that our algorithm is able to measure changes in alveolar size on the micron scale during ventilation and shows the presence of alveolar recruitment/de-recruitment in newborn rabbit kittens. This technique will be useful for ventilation management and lung diagnostic procedures.
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Affiliation(s)
| | | | | | - Stuart B. Hooper
- The Ritchie Centre MIMR-PHI Institute of Medical Research and the Department of Obstetrics and Gynaecology, Monash University, Vic 3168,
Australia
| | - Megan J. Wallace
- The Ritchie Centre MIMR-PHI Institute of Medical Research and the Department of Obstetrics and Gynaecology, Monash University, Vic 3168,
Australia
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13
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Zhou W, Majidi K, Brankov JG. Analyzer-based phase-contrast imaging system using a micro focus X-ray source. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:085114. [PMID: 25173319 PMCID: PMC4141915 DOI: 10.1063/1.4890281] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 07/02/2014] [Indexed: 06/03/2023]
Abstract
Here we describe a new in-laboratory analyzer based phase contrast-imaging (ABI) instrument using a conventional X-ray tube source (CXS) aimed at bio-medical imaging applications. Phase contrast-imaging allows visualization of soft tissue details usually obscured in conventional X-ray imaging. The ABI system design and major features are described in detail. The key advantage of the presented system, over the few existing CXS ABI systems, is that it does not require high precision components, i.e., CXS, X-ray detector, and electro-mechanical components. To overcome a main problem introduced by these components, identified as temperature stability, the system components are kept at a constant temperature inside of three enclosures, thus minimizing the electrical and mechanical thermal drifts. This is achieved by using thermoelectric (Peltier) cooling/heating modules that are easy to control precisely. For CXS we utilized a microfocus X-ray source with tungsten (W) anode material. In addition the proposed system eliminates tungsten's multiple spectral lines by selecting monochromator crystal size appropriately therefore eliminating need for the costly mismatched, two-crystal monochromator. The system imaging was fine-tuned for tungsten Kα1 line with the energy of 59.3 keV since it has been shown to be of great clinical significance by a number of researchers at synchrotron facilities. In this way a laboratory system that can be used for evaluating and quantifying tissue properties, initially explored at synchrotron facilities, would be of great interest to a larger research community. To demonstrate the imaging capability of our instrument we use a chicken thigh tissue sample.
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Affiliation(s)
- Wei Zhou
- BME Department, Illinois Institute of Technology, Chicago, Illinois 60616, USA
| | - Keivan Majidi
- ECE Department, Illinois Institute of Technology, Chicago, Illinois 60616, USA
| | - Jovan G Brankov
- ECE Department, Illinois Institute of Technology, Chicago, Illinois 60616, USA
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14
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Umetani K, Kondoh T. Phase contrast portal imaging using synchrotron radiation. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:073704. [PMID: 25085143 DOI: 10.1063/1.4885755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Microbeam radiation therapy is an experimental form of radiation treatment with great potential to improve the treatment of many types of cancer. We applied a synchrotron radiation phase contrast technique to portal imaging to improve targeting accuracy for microbeam radiation therapy in experiments using small animals. An X-ray imaging detector was installed 6.0 m downstream from an object to produce a high-contrast edge enhancement effect in propagation-based phase contrast imaging. Images of a mouse head sample were obtained using therapeutic white synchrotron radiation with a mean beam energy of 130 keV. Compared to conventional portal images, remarkably clear images of bones surrounding the cerebrum were acquired in an air environment for positioning brain lesions with respect to the skull structure without confusion with overlapping surface structures.
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Affiliation(s)
- K Umetani
- Japan Synchrotron Radiation Research Institute, SPring-8, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - T Kondoh
- Kobe University Graduate School of Medicine, Kusunoki-cho, Chuo-ku, Kobe-shi, Hyogo 650-0017, Japan
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15
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Majidi K, Li J, Muehleman C, Brankov JG. Noise and analyzer-crystal angular position analysis for analyzer-based phase-contrast imaging. Phys Med Biol 2014; 59:1877-97. [PMID: 24651402 DOI: 10.1088/0031-9155/59/8/1877] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The analyzer-based phase-contrast x-ray imaging (ABI) method is emerging as a potential alternative to conventional radiography. Like many of the modern imaging techniques, ABI is a computed imaging method (meaning that images are calculated from raw data). ABI can simultaneously generate a number of planar parametric images containing information about absorption, refraction, and scattering properties of an object. These images are estimated from raw data acquired by measuring (sampling) the angular intensity profile of the x-ray beam passed through the object at different angular positions of the analyzer crystal. The noise in the estimated ABI parametric images depends upon imaging conditions like the source intensity (flux), measurements angular positions, object properties, and the estimation method. In this paper, we use the Cramér-Rao lower bound (CRLB) to quantify the noise properties in parametric images and to investigate the effect of source intensity, different analyzer-crystal angular positions and object properties on this bound, assuming a fixed radiation dose delivered to an object. The CRLB is the minimum bound for the variance of an unbiased estimator and defines the best noise performance that one can obtain regardless of which estimation method is used to estimate ABI parametric images. The main result of this paper is that the variance (hence the noise) in parametric images is directly proportional to the source intensity and only a limited number of analyzer-crystal angular measurements (eleven for uniform and three for optimal non-uniform) are required to get the best parametric images. The following angular measurements only spread the total dose to the measurements without improving or worsening CRLB, but the added measurements may improve parametric images by reducing estimation bias. Next, using CRLB we evaluate the multiple-image radiography, diffraction enhanced imaging and scatter diffraction enhanced imaging estimation techniques, though the proposed methodology can be used to evaluate any other ABI parametric image estimation technique.
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Affiliation(s)
- Keivan Majidi
- Department of Electrical and Computer Engineering, Illinois Institute of Technology, Chicago, IL 60616, USA
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16
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Wilkins SW, Nesterets YI, Gureyev TE, Mayo SC, Pogany A, Stevenson AW. On the evolution and relative merits of hard X-ray phase-contrast imaging methods. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2014; 372:20130021. [PMID: 24470408 DOI: 10.1098/rsta.2013.0021] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
This review provides a brief overview, albeit from a somewhat personal perspective, of the evolution and key features of various hard X-ray phase-contrast imaging (PCI) methods of current interest in connection with translation to a wide range of imaging applications. Although such methods have already found wide-ranging applications using synchrotron sources, application to dynamic studies in a laboratory/clinical context, for example for in vivo imaging, has been slow due to the current limitations in the brilliance of compact laboratory sources and the availability of suitable high-performance X-ray detectors. On the theoretical side, promising new PCI methods are evolving which can record both components of the phase gradient in a single exposure and which can accept a relatively large spectral bandpass. In order to help to identify the most promising paths forward, we make some suggestions as to how the various PCI methods might be compared for performance with a particular view to identifying those which are the most efficient, given the fact that source performance is currently a key limiting factor on the improved performance and applicability of PCI systems, especially in the context of dynamic sample studies. The rapid ongoing development of both suitable improved sources and detectors gives strong encouragement to the view that hard X-ray PCI methods are poised for improved performance and an even wider range of applications in the near future.
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Affiliation(s)
- S W Wilkins
- CSIRO Materials Science and Engineering, PB33, Clayton South, Victoria 3169, Australia
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17
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Meinel FG, Schwab F, Yaroshenko A, Velroyen A, Bech M, Hellbach K, Fuchs J, Stiewe T, Yildirim AÖ, Bamberg F, Reiser MF, Pfeiffer F, Nikolaou K. Lung tumors on multimodal radiographs derived from grating-based X-ray imaging--a feasibility study. Phys Med 2013; 30:352-7. [PMID: 24316287 DOI: 10.1016/j.ejmp.2013.11.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 11/13/2013] [Accepted: 11/14/2013] [Indexed: 02/01/2023] Open
Abstract
PURPOSE The purpose of this study was to assess whether grating-based X-ray imaging may have a role in imaging of pulmonary nodules on radiographs. MATERIALS AND METHODS A mouse lung containing multiple lung tumors was imaged using a small-animal scanner with a conventional X-ray source and a grating interferometer for phase-contrast imaging. We qualitatively compared the signal characteristics of lung nodules on transmission, dark-field and phase-contrast images. Furthermore, we quantitatively compared signal characteristics of lung tumors and the adjacent lung tissue and calculated the corresponding contrast-to-noise ratios. RESULTS Of the 5 tumors visualized on the transmission image, 3/5 tumors were clearly visualized and 1 tumor was faintly visualized in the dark-field image as areas of decreased small angle scattering. In the phase-contrast images, 3/5 tumors were clearly visualized, while the remaining 2 tumors were faintly visualized by the phase-shift occurring at their edges. No additional tumors were visualized in either the dark-field or phase-contrast images. Compared to the adjacent lung tissue, lung tumors were characterized by a significant decrease in transmission signal (median 0.86 vs. 0.91, p = 0.04) and increase in dark-field signal (median 0.71 vs. 0.65, p = 0.04). Median contrast-to-noise ratios for the visualization of lung nodules were 4.4 for transmission images and 1.7 for dark-field images (p = 0.04). CONCLUSION Lung nodules can be visualized on all three radiograph modalities derived from grating-based X-ray imaging. However, our initial data suggest that grating-based multimodal X-ray imaging does not increase the sensitivity of chest radiographs for the detection of lung nodules.
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Affiliation(s)
- Felix G Meinel
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Marchioninistr. 15, 81377 München, Germany.
| | - Felix Schwab
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Marchioninistr. 15, 81377 München, Germany
| | - Andre Yaroshenko
- Department of Physics and Institute of Medical Engineering, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany
| | - Astrid Velroyen
- Department of Physics and Institute of Medical Engineering, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany
| | - Martin Bech
- Department of Physics and Institute of Medical Engineering, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany; Medical Radiation Physics, Lund University, 22185 Lund, Sweden
| | - Katharina Hellbach
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Marchioninistr. 15, 81377 München, Germany
| | - Jeanette Fuchs
- Molecular Oncology Unit, Philipps-University Marburg, D-35032 Marburg, Germany
| | - Thorsten Stiewe
- Molecular Oncology Unit, Philipps-University Marburg, D-35032 Marburg, Germany
| | - Ali Ö Yildirim
- Comprehensive Pneumology Center, Institute of Lung Biology and Disease, Helmholtz Zentrum Munich, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany
| | - Fabian Bamberg
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Marchioninistr. 15, 81377 München, Germany
| | - Maximilian F Reiser
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Marchioninistr. 15, 81377 München, Germany
| | - Franz Pfeiffer
- Department of Physics and Institute of Medical Engineering, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany
| | - Konstantin Nikolaou
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Marchioninistr. 15, 81377 München, Germany
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18
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Leong AFT, Paganin DM, Hooper SB, Siew ML, Kitchen MJ. Measurement of absolute regional lung air volumes from near-field x-ray speckles. OPTICS EXPRESS 2013; 21:27905-23. [PMID: 24514306 DOI: 10.1364/oe.21.027905] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Propagation-based phase contrast x-ray (PBX) imaging yields high contrast images of the lung where airways that overlap in projection coherently scatter the x-rays, giving rise to a speckled intensity due to interference effects. Our previous works have shown that total and regional changes in lung air volumes can be accurately measured from two-dimensional (2D) absorption or phase contrast images when the subject is immersed in a water-filled container. In this paper we demonstrate how the phase contrast speckle patterns can be used to directly measure absolute regional lung air volumes from 2D PBX images without the need for a water-filled container. We justify this technique analytically and via simulation using the transport-of-intensity equation and calibrate the technique using our existing methods for measuring lung air volume. Finally, we show the full capabilities of this technique for measuring regional differences in lung aeration.
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Leong AFT, Fouras A, Islam MS, Wallace MJ, Hooper SB, Kitchen MJ. High spatiotemporal resolution measurement of regional lung air volumes from 2D phase contrast x-ray images. Med Phys 2013; 40:041909. [PMID: 23556903 DOI: 10.1118/1.4794926] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Described herein is a new technique for measuring regional lung air volumes from two-dimensional propagation-based phase contrast x-ray (PBI) images at very high spatial and temporal resolution. Phase contrast dramatically increases lung visibility and the outlined volumetric reconstruction technique quantifies dynamic changes in respiratory function. These methods can be used for assessing pulmonary disease and injury and for optimizing mechanical ventilation techniques for preterm infants using animal models. METHODS The volumetric reconstruction combines the algorithms of temporal subtraction and single image phase retrieval (SIPR) to isolate the image of the lungs from the thoracic cage in order to measure regional lung air volumes. The SIPR algorithm was used to recover the change in projected thickness of the lungs on a pixel-by-pixel basis (pixel dimensions ≈ 16.2 μm). The technique has been validated using numerical simulation and compared results of measuring regional lung air volumes with and without the use of temporal subtraction for removing the thoracic cage. To test this approach, a series of PBI images of newborn rabbit pups mechanically ventilated at different frequencies was employed. RESULTS Regional lung air volumes measured from PBI images of newborn rabbit pups showed on average an improvement of at least 20% in 16% of pixels within the lungs in comparison to that measured without the use of temporal subtraction. The majority of pixels that showed an improvement was found to be in regions occupied by bone. Applying the volumetric technique to sequences of PBI images of newborn rabbit pups, it is shown that lung aeration at birth can be highly heterogeneous. CONCLUSIONS This paper presents an image segmentation technique based on temporal subtraction that has successfully been used to isolate the lungs from PBI chest images, allowing the change in lung air volume to be measured over regions as small as the pixel size. Using this technique, it is possible to measure changes in regional lung volume at high spatial and temporal resolution during breathing at much lower x-ray dose than would be required using computed tomography.
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20
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Wu Y, Xiao S, Lu J, Liu L, Yang Q, Huang X. Research on a logarithmically bent Laue crystal analyzer for X-ray monochromatic backlight imaging. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2013; 84:073507. [PMID: 23902063 DOI: 10.1063/1.4815549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
A new logarithmically bent Laue imaging crystal analyzer (LBLICA) was proposed to obtain the monochromatic image of plasmas and exhibited a great potential for application in the Inertial Confinement Fusion experiment over a large field of view (FOV) and with a high spatial resolution. The imaging geometry of the LBLICA has been discussed. According to the Bragg condition and the equation of the logarithmic spiral, the key image parameters of the crystal analyzer, including the system magnification, the spatial resolution, and the FOV, have been analyzed theoretically. An experiment has been performed with a Cu target X-ray tube as a backlighter to backlight a mesh grid consisting of 50-μm Cu wires, and the monochromatic image of the grid has been obtained with a spatial resolution of approximately 30 μm.
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Affiliation(s)
- Yufen Wu
- Key Laboratory of Optoelectronic Technology and System of the Ministry of Education, College of Optoelectronic Engineering, Chongqing University, Chongqing 400030, China.
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21
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Garson A, Izaguirre E, Price S, Anastasio M. Characterization of speckle in lung images acquired with a benchtop in-line x-ray phase-contrast system. Phys Med Biol 2013; 58:4237-53. [PMID: 23719476 PMCID: PMC4031689 DOI: 10.1088/0031-9155/58/12/4237] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We investigate the manifestation of speckle in propagation-based x-ray phase-contrast imaging of mouse lungs in situ by use of a benchtop imager. The key contributions of the work are the demonstration that lung speckle can be observed by use of a benchtop imaging system employing a polychromatic tube-source and a systematic experimental investigation of how the texture of the speckle pattern depends on the parameters of the imaging system. Our analyses consists of image texture characterization based on the statistical properties of pixel intensity values.
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Affiliation(s)
- A.B. Garson
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130
| | - E.W. Izaguirre
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130
- Washington University School of Medicine, St. Louis, MO 63110
- Nuclear Science and Engineering Institute. University of Missouri, Columbia, MO, 65211
| | - S.G. Price
- Washington University School of Medicine, St. Louis, MO 63110
- Nuclear Science and Engineering Institute. University of Missouri, Columbia, MO, 65211
| | - M.A. Anastasio
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130
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22
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Li K, Zambelli J, Bevins N, Ge Y, Chen GH. Spatial resolution characterization of differential phase contrast CT systems via modulation transfer function (MTF) measurements. Phys Med Biol 2013; 58:4119-35. [PMID: 23685949 DOI: 10.1088/0031-9155/58/12/4119] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
By adding a Talbot-Lau interferometer to a conventional x-ray absorption computed tomography (CT) imaging system, both differential phase contrast (DPC) signal and absorption contrast signal can be simultaneously measured from the same set of CT measurements. The imaging performance of such multi-contrast x-ray CT imaging systems can be characterized with standard metrics such as noise variance, noise power spectrum, contrast-to-noise ratio, modulation transfer function (MTF), and task-based detectability index. Among these metrics, the measurement of the MTF can be challenging in DPC-CT systems due to several confounding factors such as phase wrapping and the difficulty of using fine wires as probes. To address these technical challenges, this paper discusses a viable and reliable method to experimentally measure the MTF of DPC-CT. It has been found that the spatial resolution of DPC-CT is degraded, when compared to that of the corresponding absorption CT, due to the presence of a source grating G0 in the Talbot-Lau interferometer. An effective MTF was introduced and experimentally estimated to describe the impact of the Talbot-Lau interferometer on the system MTF.
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Affiliation(s)
- Ke Li
- Department of Medical Physics, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, WI 53705, USA
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23
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Bravin A, Coan P, Suortti P. X-ray phase-contrast imaging: from pre-clinical applications towards clinics. Phys Med Biol 2012; 58:R1-35. [PMID: 23220766 DOI: 10.1088/0031-9155/58/1/r1] [Citation(s) in RCA: 379] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Phase-contrast x-ray imaging (PCI) is an innovative method that is sensitive to the refraction of the x-rays in matter. PCI is particularly adapted to visualize weakly absorbing details like those often encountered in biology and medicine. In past years, PCI has become one of the most used imaging methods in laboratory and preclinical studies: its unique characteristics allow high contrast 3D visualization of thick and complex samples even at high spatial resolution. Applications have covered a wide range of pathologies and organs, and are more and more often performed in vivo. Several techniques are now available to exploit and visualize the phase-contrast: propagation- and analyzer-based, crystal and grating interferometry and non-interferometric methods like the coded aperture. In this review, covering the last five years, we will give an overview of the main theoretical and experimental developments and of the important steps performed towards the clinical implementation of PCI.
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Affiliation(s)
- Alberto Bravin
- European Synchrotron Radiation Facility, 6 rue Horowitz, 38043 Grenoble Cedex, France.
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24
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Diemoz PC, Bravin A, Langer M, Coan P. Analytical and experimental determination of signal-to-noise ratio and figure of merit in three phase-contrast imaging techniques. OPTICS EXPRESS 2012; 20:27670-90. [PMID: 23262715 DOI: 10.1364/oe.20.027670] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We present a theoretical and experimental comparison of three X-ray phase-contrast techniques: propagation-based imaging, analyzer-based imaging and grating interferometry. The signal-to-noise ratio and the figure of merit are quantitatively compared for the three techniques on the same phantoms and using the same X-ray source and detector. Principal dependencies of the signal upon the numerous acquisition parameters, the spatial resolution and X-ray energy are discussed in detail. The sensitivity of each technique, in terms of the smallest detectable phase shift, is also evaluated.
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Affiliation(s)
- P C Diemoz
- Faculty of Physics, Ludwig-Maximilians-Universität München, 85748 Garching, Germany
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25
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Carnibella RP, Fouras A, Kitchen MJ. Single-exposure dual-energy-subtraction X-ray imaging using a synchrotron source. JOURNAL OF SYNCHROTRON RADIATION 2012; 19:954-959. [PMID: 23093755 DOI: 10.1107/s0909049512033900] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Accepted: 07/29/2012] [Indexed: 06/01/2023]
Abstract
Projection radiography of the chest has long been plagued by the presence of bony anatomy obscuring visibility of the lungs and heart. Dual-energy subtraction is a well known method for differentiating bone and soft tissue, but existing techniques are not ideally suited to dynamic imaging. Herein a new technique to address this problem is presented. The harmonic content of a monochromated X-ray beam is exploited, and two in-line detectors are used to perform single-exposure dual-energy imaging. Images of a phantom demonstrate the ability to both separate and quantitatively measure the thickness of constituent materials, whilst images of a mouse thorax demonstrate the ability to separate bone and soft tissue in a biological specimen. The technique is expected to improve the performance of dynamic lung imaging.
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Affiliation(s)
- R P Carnibella
- Division of Biological Engineering, Monash University, Clayton, Victoria 3800, Australia.
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26
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Emphysema diagnosis using X-ray dark-field imaging at a laser-driven compact synchrotron light source. Proc Natl Acad Sci U S A 2012; 109:17880-5. [PMID: 23074250 DOI: 10.1073/pnas.1206684109] [Citation(s) in RCA: 140] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
In early stages of various pulmonary diseases, such as emphysema and fibrosis, the change in X-ray attenuation is not detectable with absorption-based radiography. To monitor the morphological changes that the alveoli network undergoes in the progression of these diseases, we propose using the dark-field signal, which is related to small-angle scattering in the sample. Combined with the absorption-based image, the dark-field signal enables better discrimination between healthy and emphysematous lung tissue in a mouse model. All measurements have been performed at 36 keV using a monochromatic laser-driven miniature synchrotron X-ray source (Compact Light Source). In this paper we present grating-based dark-field images of emphysematous vs. healthy lung tissue, where the strong dependence of the dark-field signal on mean alveolar size leads to improved diagnosis of emphysema in lung radiographs.
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27
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Appel A, Anastasio MA, Brey EM. Potential for imaging engineered tissues with X-ray phase contrast. TISSUE ENGINEERING. PART B, REVIEWS 2011; 17:321-30. [PMID: 21682604 PMCID: PMC3179620 DOI: 10.1089/ten.teb.2011.0230] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Accepted: 06/15/2011] [Indexed: 11/12/2022]
Abstract
As the field of tissue engineering advances, it is crucial to develop imaging methods capable of providing detailed three-dimensional information on tissue structure. X-ray imaging techniques based on phase-contrast (PC) have great potential for a number of biomedical applications due to their ability to provide information about soft tissue structure without exogenous contrast agents. X-ray PC techniques retain the excellent spatial resolution, tissue penetration, and calcified tissue contrast of conventional X-ray techniques while providing drastically improved imaging of soft tissue and biomaterials. This suggests that X-ray PC techniques are very promising for evaluation of engineered tissues. In this review, four different implementations of X-ray PC imaging are described and applications to tissues of relevance to tissue engineering reviewed. In addition, recent applications of X-ray PC to the evaluation of biomaterial scaffolds and engineered tissues are presented and areas for further development and application of these techniques are discussed. Imaging techniques based on X-ray PC have significant potential for improving our ability to image and characterize engineered tissues, and their continued development and optimization could have significant impact on the field of tissue engineering.
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Affiliation(s)
- Alyssa Appel
- Department of Biomedical Engineering and Pritzker Institute of Biomedical Science and Engineering, Illinois Institute of Technology, Chicago, Illinois
- Research Service, Hines Veterans Administration Hospital, Hines, Illinois
| | - Mark A. Anastasio
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri
| | - Eric M. Brey
- Department of Biomedical Engineering and Pritzker Institute of Biomedical Science and Engineering, Illinois Institute of Technology, Chicago, Illinois
- Research Service, Hines Veterans Administration Hospital, Hines, Illinois
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Hooper SB, Kitchen MJ, Fouras A, Wallace MJ, Dubsky S, Siu KKW, Siew ML, Yagi N, Uesugi K, Lewis RA. Combined Lung Imaging and Respiratory Physiology Research at SPring-8. ACTA ACUST UNITED AC 2011. [DOI: 10.1080/08940886.2011.567164] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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29
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Dicken A, Rogers K, Evans P, Chan JW, Rogers J, Godber S. Combined X-ray diffraction and kinetic depth effect imaging. OPTICS EXPRESS 2011; 19:6406-6413. [PMID: 21451668 DOI: 10.1364/oe.19.006406] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In this preliminary study we present a depth resolved transmission image sequence of an object combined with the materials discriminating ability of angular dispersive X-ray diffraction. Volumes within the object giving rise to diffraction patterns matched to a library of specific materials have been encoded visually within the images. The intensity of these highlighted areas has been weighted based on the certainty of the match. Both the theory and experimental proof of principle have been demonstrated. Considerations pertaining to a "scaled up" version of this technique are also discussed.
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Affiliation(s)
- Anthony Dicken
- Cranfield Forensic Institute, Cranfield University, Shrivenham, Swindon, UK.
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