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Sunaguchi N, Huang Z, Shimao D, Ichihara S, Nishimura R, Iwakoshi A, Yuasa T, Ando M. Crystal optics simulations for delineation of the three-dimensional cellular nuclear distribution using analyzer-based refraction-contrast computed tomography. Sci Rep 2022; 12:19595. [PMID: 36380223 PMCID: PMC9666655 DOI: 10.1038/s41598-022-24249-8] [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: 05/21/2022] [Accepted: 11/11/2022] [Indexed: 11/16/2022] Open
Abstract
Refraction-contrast computed tomography (RCT) using a refractive angle analyzer of Si perfect crystal can reconstruct the three-dimensional structure of biological soft tissue with contrast comparable to that of stained two-dimensional pathological images. However, the blurring of X-ray beam by the analyzer has prevented improvement of the spatial resolution of RCT, and the currently possible observation of tissue structure at a scale of approximately 20 µm provides only limited medical information. As in pathology, to differentiate between benign and malignant forms of cancer, it is necessary to observe the distribution of the cell nucleus, which is approximately 5-10 µm in diameter. In this study, based on the X-ray dynamical diffraction theory using the Takagi-Taupin equation, which calculates the propagation of X-ray energy in crystals, an analyzer crystal optical system depicting the distribution of cell nuclei was investigated by RCT imaging simulation experiments in terms of the thickness of the Laue-case analyzer, the camera pixel size and the difference in spatial resolution between the Bragg-case and Laue-case analyzers.
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Affiliation(s)
- Naoki Sunaguchi
- grid.27476.300000 0001 0943 978XDepartment of Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Zhuoran Huang
- grid.27476.300000 0001 0943 978XDepartment of Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Daisuke Shimao
- grid.444700.30000 0001 2176 3638Department of Radiological Technology, Hokkaido University of Science, Sapporo, Japan
| | - Shu Ichihara
- grid.410840.90000 0004 0378 7902Department of Pathology, Clinical Research Center, Nagoya Medical Center, Nagoya, Japan
| | - Rieko Nishimura
- grid.410840.90000 0004 0378 7902Department of Pathology, Clinical Research Center, Nagoya Medical Center, Nagoya, Japan
| | - Akari Iwakoshi
- grid.410840.90000 0004 0378 7902Department of Pathology, Clinical Research Center, Nagoya Medical Center, Nagoya, Japan
| | - Tetsuya Yuasa
- grid.268394.20000 0001 0674 7277Graduate School of Engineering and Science, Yamagata University, Yonezawa, Japan
| | - Masami Ando
- grid.410794.f0000 0001 2155 959XHigh Energy Accelerator Research Organization, Tsukuba, Japan
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Wesemann L, Rickett J, Song J, Lou J, Hinde E, Davis TJ, Roberts A. Nanophotonics enhanced coverslip for phase imaging in biology. LIGHT, SCIENCE & APPLICATIONS 2021; 10:98. [PMID: 33966035 PMCID: PMC8106685 DOI: 10.1038/s41377-021-00540-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 04/01/2021] [Accepted: 04/19/2021] [Indexed: 05/31/2023]
Abstract
The ability to visualise transparent objects such as live cells is central to understanding biological processes. Here we experimentally demonstrate a novel nanostructured coverslip that converts phase information to high-contrast intensity images. This compact device enables real-time, all-optical generation of pseudo three-dimensional images of phase objects on transmission. We show that by placing unstained human cancer cells on the device, the internal structure within the cells can be clearly seen. Our research demonstrates the significant potential of nanophotonic devices for integration into compact imaging and medical diagnostic devices. The nanophotonics enhanced coverslip (NEC) enables ultra-compact phase imaging of samples placed directly on top of the device. Visualisation of artificial phase objects and unstained biological cells is demonstrated.
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Affiliation(s)
- Lukas Wesemann
- School of Physics, University of Melbourne, Melbourne, VIC, 3010, Australia.
- ARC Centre of Excellence for Transformative Meta-Optical Systems, School of Physics, University of Melbourne, Melbourne, VIC, 3010, Australia.
| | - Jon Rickett
- School of Physics, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Jingchao Song
- School of Physics, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Jieqiong Lou
- School of Physics, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Elizabeth Hinde
- School of Physics, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Timothy J Davis
- School of Physics, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Ann Roberts
- School of Physics, University of Melbourne, Melbourne, VIC, 3010, Australia.
- ARC Centre of Excellence for Transformative Meta-Optical Systems, School of Physics, University of Melbourne, Melbourne, VIC, 3010, Australia.
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Krivonosov YS, Asadchikov VE, Buzmakov AV. Phase-Contrast Imaging in a Polychromatic X-ray Beam at a Laboratory Source. CRYSTALLOGR REP+ 2020. [DOI: 10.1134/s1063774520040136] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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4
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Rauch T, Rieger J, Pelzer G, Horn F, Erber R, Wunderle M, Emons J, Nabieva N, Fuhrich N, Michel T, Hartmann A, Fasching PA, Anton G. Discrimination analysis of breast calcifications using x-ray dark-field radiography. Med Phys 2020; 47:1813-1826. [PMID: 31977070 DOI: 10.1002/mp.14043] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 11/27/2019] [Accepted: 12/24/2019] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND X-ray dark-field radiography could enhance mammography by providing more information on imaged tissue and microcalcifications. The dark field signal is a measure of small angle scattering and can thus provide additional information on the imaged materials. This information can be useful for material distinction of calcifications and the diagnosis of breast cancer by classifying benign and malign association of these calcifications. METHODS For this study, institutional review board approval was obtained. We present the evaluation of images acquired with interferometric grating-based x-ray imaging of 323 microcalcifications (166 malign and 157 benign associated) in freshly dissected breast tissue and compare the results to the information extracted in follow-up pathological evaluation. The number of imaged calcifications is sufficiently higher than in similar previous studies. Fourteen calcification properties were extracted from the digital images and used as predictors in three different models common in discrimination analysis namely a simple threshold model, a naive Bayes model and a linear regression model, which classify the calcifications as associated with a benign or suspicious finding. Three of these fourteen predictors have been newly defined in this work and are independent from the tissue background surrounding the microcalcifications. Using these predictors no background correction is needed, as in previous works in this field. The new predictors are the length of the first and second principle component of the absorption and dark-field data, as well as the angle between the first principle component and the dark-field axis. We called these predictors data length, data width, and data orientation. RESULTS In fourfold cross-validation malignancy of the imaged tissue was predicted. Models that take only classical absorption predictors into account reached a sensitivity of 53.3% at a specificity of 81.1%. For a combination of predictors that also include dark field information, a sensitivity of 63.2% and specificity of 80.8% were obtained. The included dark field information consisted of the newly introduced parameters, data orientation and data width. CONCLUSIONS While remaining at a similar specificity, the sensitivity, with which a trained model was able to distinguish malign from benign associated calcifications, was increased by 10% on including dark-field information. This suggests grating-based x-ray imaging as a promising clinical imaging method in the field of mammography.
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Affiliation(s)
- Thomas Rauch
- Erlangen Centre for Astroparticle Physics (ECAP), Friedrich-Alexander-University Erlangen-Nuremberg, Erwin-Rommel-Str. 1, D-91058, Erlangen, Germany
| | - Jens Rieger
- Erlangen Centre for Astroparticle Physics (ECAP), Friedrich-Alexander-University Erlangen-Nuremberg, Erwin-Rommel-Str. 1, D-91058, Erlangen, Germany
| | - Georg Pelzer
- Erlangen Centre for Astroparticle Physics (ECAP), Friedrich-Alexander-University Erlangen-Nuremberg, Erwin-Rommel-Str. 1, D-91058, Erlangen, Germany
| | - Florian Horn
- Erlangen Centre for Astroparticle Physics (ECAP), Friedrich-Alexander-University Erlangen-Nuremberg, Erwin-Rommel-Str. 1, D-91058, Erlangen, Germany
| | - Ramona Erber
- Institute of Pathology, Comprehensive Cancer Center Erlangen-EMN, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Marius Wunderle
- Department of Gynecology and Obstetrics, Comprehensive Cancer Center Erlangen-EMN, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Julius Emons
- Department of Gynecology and Obstetrics, Comprehensive Cancer Center Erlangen-EMN, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Naiba Nabieva
- Department of Gynecology and Obstetrics, Comprehensive Cancer Center Erlangen-EMN, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Nicole Fuhrich
- Institute of Pathology, Comprehensive Cancer Center Erlangen-EMN, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Thilo Michel
- Erlangen Centre for Astroparticle Physics (ECAP), Friedrich-Alexander-University Erlangen-Nuremberg, Erwin-Rommel-Str. 1, D-91058, Erlangen, Germany
| | - Arndt Hartmann
- Institute of Pathology, Comprehensive Cancer Center Erlangen-EMN, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Peter A Fasching
- Department of Gynecology and Obstetrics, Comprehensive Cancer Center Erlangen-EMN, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Gisela Anton
- Erlangen Centre for Astroparticle Physics (ECAP), Friedrich-Alexander-University Erlangen-Nuremberg, Erwin-Rommel-Str. 1, D-91058, Erlangen, Germany
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Davis TJ, Eftekhari F, Gómez DE, Roberts A. Metasurfaces with Asymmetric Optical Transfer Functions for Optical Signal Processing. PHYSICAL REVIEW LETTERS 2019; 123:013901. [PMID: 31386393 DOI: 10.1103/physrevlett.123.013901] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Indexed: 05/22/2023]
Abstract
Metasurface thin films created from arrays of structured optical elements have been shown to perform spatial filtering of optical signals. To extend their usefulness it is important that the symmetry of their response with changes to the in-plane wave vector k_{p}→-k_{p} can be tailored or even dynamically tuned. In this Letter we use a general theory of metasurfaces constructed from nondiffracting arrays of coupled metal particles to derive the optical transfer function and identify the physical properties essential for asymmetry. We validate our theory experimentally showing how the asymmetric response of a two-dimensional (planar) metasurface can be optically tuned. Our results set the direction for future developments of metasurfaces for optical signal processing.
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Affiliation(s)
- T J Davis
- 1School of Physics, University of Melbourne, Victoria 3010, Australia
| | - F Eftekhari
- 2Melbourne Centre for Nanofabrication, 151 Wellington Road Clayton, Victoria 3168, Australia
| | - D E Gómez
- 2Melbourne Centre for Nanofabrication, 151 Wellington Road Clayton, Victoria 3168, Australia
- 3School of Science, RMIT University, Melbourne, Victoria, 3000, Australia
| | - A Roberts
- 1School of Physics, University of Melbourne, Victoria 3010, Australia
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Preliminary research on body composition measurement using X-ray phase contrast imaging. Phys Med 2018; 52:1-8. [PMID: 30139597 DOI: 10.1016/j.ejmp.2018.06.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 05/21/2018] [Accepted: 06/09/2018] [Indexed: 11/23/2022] Open
Abstract
Body composition measurement is of cardinal significance for medical and clinical applications. Currently, the dual-energy X-ray absorptiometry (DEXA) technique is widely applied for this measurement. In this study, we present a novel measurement method using the absorption and phase information obtained simultaneously from the X-ray grating-based interferometer (XGI). Rather than requiring two projection data sets with different X-ray energy spectra, with the proposed method, both the areal densities of the bone and the surrounding soft tissue can be acquired utilizing one projection data set. By using a human body phantom constructed to validate the proposed method, experimental results have shown that the compositions can be calculated with an improved accuracy comparing to the dual energy method, especially for the soft tissue measurement. Since the proposed method can be easily implemented on current XGI setup, it will greatly extend the applications of the XGI, and meanwhile has the potential to be an alternative to DEXA for human body composition measurement.
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Vignero J, Marshall NW, Bliznakova K, Bosmans H. A hybrid simulation framework for computer simulation and modelling studies of grating-based x-ray phase-contrast images. ACTA ACUST UNITED AC 2018; 63:14NT03. [DOI: 10.1088/1361-6560/aaceb8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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8
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X-Ray Phase-Contrast Technology in Breast Imaging: Principles, Options, and Clinical Application. AJR Am J Roentgenol 2018; 211:133-145. [DOI: 10.2214/ajr.17.19179] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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Abstract
Advances in cardiovascular computed tomography (CT) have resulted in an excellent ability to exclude coronary heart disease (CHD). Anatomical information, functional information, and spectral information can already be obtained with current CT technologies. Moreover, novel developments such as targeted nanoparticle contrast agents, photon-counting CT, and phase contrast CT will further enhance the diagnostic value of cardiovascular CT. This review provides an overview of current state of the art and future cardiovascular CT imaging.
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Izadifar Z, Belev G, Izadifar M, Izadifar Z, Chapman D. Visualization of ultrasound induced cavitation bubbles using the synchrotron x-ray Analyzer Based Imaging technique. Phys Med Biol 2014; 59:7541-55. [DOI: 10.1088/0031-9155/59/23/7541] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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11
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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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12
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Hetterich H, Willner M, Fill S, Herzen J, Bamberg F, Hipp A, Schüller U, Adam-Neumair S, Wirth S, Reiser M, Pfeiffer F, Saam T. Phase-contrast CT: qualitative and quantitative evaluation of atherosclerotic carotid artery plaque. Radiology 2014; 271:870-8. [PMID: 24588675 DOI: 10.1148/radiol.14131554] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To evaluate the potential of phase-contrast computed tomography (CT) for atherosclerotic plaque imaging in human carotid arteries in an experimental ex vivo study. MATERIALS AND METHODS The study was approved by the institutional review board, and informed consent was obtained from the patients' relatives. Seven postmortem human carotid artery specimens were imaged at a laboratory setup by using a conventional x-ray tube and grating interferometer. After histologic processing, phase-contrast imaging and histopathologic data were matched. Characteristics of the necrotic core (NC) covered by a fibrous cap (FC), intraplaque hemorrhage (IPH), and calcifications (CAs) were established, and sensitivity, specificity, and accuracy of phase-contrast CT for plaque detection and the potential for accurate quantification were assessed. The Cohen κ and Pearson correlation coefficient R were used to determine the agreement between phase-contrast imaging and histopathologic findings for plaque characterization and correlation of quantitative plaque measurements, respectively. A difference with a P value of less than .05 was considered significant. RESULTS Characteristic criteria were found in all analyzed plaque components. Applying these criteria, phase-contrast CT had a good sensitivity for the detection of the FC and NC, IPH, and CAs (all, >80%) and excellent specificity and accuracy (all, >90%), with good interreader agreement (κ ≥ 0.72, P < .0001). There were excellent correlations for quantitative measurements of FC, NC, and CAs between phase-contrast imaging and histopathologic findings (R ≥ 0.92). Interreader reproducibility was excellent, with an intraclass correlation coefficient of 0.98 or higher for all measurements. CONCLUSION The results of this study indicate that ex vivo phase-contrast CT can help identify and quantify atherosclerotic plaque components, with excellent correlation to histopathologic findings. Although not yet applicable in vivo, phase-contrast CT may become a valuable tool to monitor atherosclerotic disease process noninvasively.
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Affiliation(s)
- Holger Hetterich
- From the Institute of Clinical Radiology (H.H., S.F., F.B., S.A., S.W., M.R., T.S.), Center for Neuropathology (U.S.), and Institute of Anatomy (S.A.), Ludwig-Maximilians-University Hospital, Pettenkoferstrasse 8a, 80336 Munich, Germany; {Department of Physics and Institute for Technical Medicine}, Technische Universität München, Garching, Germany (M.W., J.H., A.H., F.P.); and Institute of Materials Research, Helmholtz-Zentrum, Geesthacht, Germany (J.H.)
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Wu Z, Wang Z, Gao K, Zhang K, Ge X, Wang D, Wang S, Chen J, Pan Z, Zhu P, Wu Z. A generalized reverse projection method for fan beam geometry under partially coherent illumination. Radiat Phys Chem Oxf Engl 1993 2014. [DOI: 10.1016/j.radphyschem.2013.01.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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14
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Izadifar Z, Chapman LD, Chen X. Computed Tomography Diffraction-Enhanced Imaging forIn SituVisualization of Tissue Scaffolds Implanted in Cartilage. Tissue Eng Part C Methods 2014; 20:140-8. [DOI: 10.1089/ten.tec.2013.0138] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Zohreh Izadifar
- Division of Biomedical Engineering, University of Saskatchewan, Saskatoon, Canada
| | - Leroy Dean Chapman
- Division of Biomedical Engineering, University of Saskatchewan, Saskatoon, Canada
- Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, Canada
- Biomedical Imaging and Therapy (BMIT) Beamline, Canadian Light Source (CLS), Saskatoon, Canada
| | - Xiongbiao Chen
- Division of Biomedical Engineering, University of Saskatchewan, Saskatoon, Canada
- Department of Mechanical Engineering, University of Saskatchewan, Saskatoon, Canada
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15
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Herzen J, Willner MS, Fingerle AA, Noël PB, Köhler T, Drecoll E, Rummeny EJ, Pfeiffer F. Imaging liver lesions using grating-based phase-contrast computed tomography with bi-lateral filter post-processing. PLoS One 2014; 9:e83369. [PMID: 24465378 PMCID: PMC3894935 DOI: 10.1371/journal.pone.0083369] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2013] [Accepted: 11/02/2013] [Indexed: 12/21/2022] Open
Abstract
X-ray phase-contrast imaging shows improved soft-tissue contrast compared to standard absorption-based X-ray imaging. Especially the grating-based method seems to be one promising candidate for clinical implementation due to its extendibility to standard laboratory X-ray sources. Therefore the purpose of our study was to evaluate the potential of grating-based phase-contrast computed tomography in combination with a novel bi-lateral denoising method for imaging of focal liver lesions in an ex vivo feasibility study. Our study shows that grating-based phase-contrast CT (PCCT) significantly increases the soft-tissue contrast in the ex vivo liver specimens. Combining the information of both signals – absorption and phase-contrast – the bi-lateral filtering leads to an improvement of lesion detectability and higher contrast-to-noise ratios. The normal and the pathological tissue can be clearly delineated and even internal structures of the pathological tissue can be visualized, being invisible in the absorption-based CT alone. Histopathology confirmed the presence of the corresponding findings in the analyzed tissue. The results give strong evidence for a sufficiently high contrast for different liver lesions using non-contrast-enhanced PCCT. Thus, ex vivo imaging of liver lesions is possible with a polychromatic X-ray source and at a spatial resolution of ∼100 µm. The post-processing with the novel bi-lateral denoising method improves the image quality by combining the information from the absorption and the phase-contrast images.
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Affiliation(s)
- Julia Herzen
- Institute of Materials Science, Helmholtz-Zentrum Geesthacht, Geesthacht, Germany
- Physics Department & Institute of Medical Engineering, Technische Universität München, Garching, Germany
- * E-mail:
| | - Marian S. Willner
- Physics Department & Institute of Medical Engineering, Technische Universität München, Garching, Germany
| | | | - Peter B. Noël
- Department of Radiology, Technische Universität München, Munich, Germany
| | - Thomas Köhler
- Philips Technologie GmbH, Innovative Technologies, Research Laboratories, Hamburg, Germany
| | - Enken Drecoll
- Institute of Pathology, Technische Universität München, Munich, Germany
| | - Ernst J. Rummeny
- Department of Radiology, Technische Universität München, Munich, Germany
| | - Franz Pfeiffer
- Physics Department & Institute of Medical Engineering, Technische Universität München, Garching, Germany
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17
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Hammonds JC, Price RR, Pickens DR, Donnelly EF. In-line phase shift tomosynthesis. Med Phys 2013; 40:081911. [PMID: 23927325 DOI: 10.1118/1.4813295] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The purpose of this work is to (1) demonstrate laboratory measurements of phase shift images derived from in-line phase-contrast radiographs using the attenuation-partition based algorithm (APBA) of Yan et al. [Opt. Express 18(15), 16074-16089 (2010)], (2) verify that the APBA reconstructed images obey the linearity principle, and (3) reconstruct tomosynthesis phase shift images from a collection of angularly sampled planar phase shift images. METHODS An unmodified, commercially available cabinet x-ray system (Faxitron LX-60) was used in this experiment. This system contains a tungsten anode x-ray tube with a nominal focal spot size of 10 μm. The digital detector uses CsI∕CMOS with a pixel size of 50×50 μm. The phantoms used consisted of one acrylic plate, two polystyrene plates, and a habanero pepper. Tomosynthesis images were reconstructed from 51 images acquired over a ±25° arc. All phase shift images were reconstructed using the APBA. RESULTS Image contrast derived from the planar phase shift image of an acrylic plate of uniform thickness exceeded the contrast of the traditional attenuation image by an approximate factor of two. Comparison of the planar phase shift images from a single, uniform thickness polystyrene plate with two polystyrene plates demonstrated an approximate linearity of the estimated phase shift with plate thickness (-1600 rad vs -2970 rad). Tomographic phase shift images of the habanero pepper exhibited acceptable spatial resolution and contrast comparable to the corresponding attenuation image. CONCLUSIONS This work demonstrated the feasibility of laboratory-based phase shift tomosynthesis and suggests that phase shift imaging could potentially provide a new imaging biomarker. Further investigation will be needed to determine if phase shift contrast will be able to provide new tissue contrast information or improved clinical performance.
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Affiliation(s)
- Jeffrey C Hammonds
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA.
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18
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Rutishauser S, Rack A, Weitkamp T, Kayser Y, David C, Macrander AT. Heat bump on a monochromator crystal measured with X-ray grating interferometry. JOURNAL OF SYNCHROTRON RADIATION 2013; 20:300-305. [PMID: 23412487 DOI: 10.1107/s0909049513001817] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Accepted: 01/18/2013] [Indexed: 06/01/2023]
Abstract
Deformation of the first crystal of an X-ray monochromator under the heat load of a high-power beam, commonly referred to as `heat bump', is a challenge frequently faced at synchrotron beamlines. Here, quantitative measurements of the deformations of an externally water-cooled silicon (111) double-crystal monochromator tuned to a photon energy of 17.6 keV are reported. These measurements were made using two-dimensional hard X-ray grating interferometry, a technique that enables in situ at-wavelength wavefront investigations with high angular sensitivity. The observed crystal deformations were of the order of 100 nm in the meridional and 5 nm in the sagittal direction, which lead to wavefront slope errors of up to 4 µrad in the meridional and a few hundred nanoradians in the sagittal direction.
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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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Zhu N, Chapman D, Cooper D, Schreyer DJ, Chen X. X-ray diffraction enhanced imaging as a novel method to visualize low-density scaffolds in soft tissue engineering. Tissue Eng Part C Methods 2011; 17:1071-80. [PMID: 21870940 DOI: 10.1089/ten.tec.2011.0102] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Scaffold visualization is challenging yet essential to the success of various tissue engineering applications. The aim of this study was to explore the potential of X-ray diffraction enhanced imaging (DEI) as a novel method for the visualization of low density engineered scaffolds in soft tissue. Imaging of the scaffolds made from poly(L-lactide) (PLLA) and chitosan was conducted using synchrotron radiation-based radiography, in-line phase-contrast imaging (in-line PCI), and DEI techniques as well as laboratory-based radiography. Scaffolds were visualized in air, water, and rat muscle tissue. Compared with the images from X-ray radiography and in-line PCI techniques, DEI images more clearly show the structure of the low density scaffold in air and have enhanced image contrast. DEI was the only technique able to visualize scaffolds embedded in unstained muscle tissue; this method could also define the microstructure of muscle tissue in the boundary areas. At a photon energy of 20 KeV, DEI had the capacity to image PLLA/chitosan scaffolds in soft tissue with a sample thickness of up to 4 cm. The DEI technique can be applied at high X-ray energies, thus facilitating lower in vivo radiation doses to tissues during imaging as compared to conventional radiography.
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Affiliation(s)
- Ning Zhu
- Division of Biomedical Engineering, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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21
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Hammonds JC, Price RR, Donnelly EF, Pickens DR. Phase-contrast digital tomosynthesis. Med Phys 2011; 38:2353-8. [PMID: 21776769 DOI: 10.1118/1.3574871] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
PURPOSE Phase-contrast (PC) edge enhancement occurs at the boundary between different tissues and is an interference effect that results from the differential phase-shifts that the x-rays acquire while traversing the two tissues. While observable in planar phase-contrast radiographs, the impact of digital tomosynthesis on this edge enhancement effect has not been previously reported. The purpose of this work is to demonstrate: (1) that phase-contrast digital tomosynthesis (PC-DTS) is possible with a conventional x-ray source, (2) that the reconstructed tomosynthesis images demonstrate and retain edge enhancement as compared to planar phase-contrast radiographs and (3) tomosynthesis improves object contrast by reducing the effects of superimposed structures. METHODS An unmodified, commercially available cabinet x-ray system (Faxitron LX-60) was used. The system contains a tungsten anode x-ray tube that was operated at 24 kVp and 3 mAs for each PC radiographic image taken, with a nominal focal spot size of 0.010 mm. The digital detector uses CsI/CMOS with a pixel size of 0.054 mm x 0.054 mm. Objects to be imaged were attached to a computer-controlled rotating motor and are rotated +/- 25 degrees about a central position in one degree increments. At each increment, three phase-contrast radiographs are taken and then averaged to reduce the effect of noise. These planar images are then used to reconstruct a series of 56 longitudinal tomographic images with an image offset increment of about 0.7 mm. RESULTS Tomographic z-plane resolution was measured to be approximately 4 mm. When compared to planar PC images, the tomosynthesis images were shown to retain the PC boundary edge enhancement in addition to an improvement in object contrast. CONCLUSIONS Our work demonstrates that PC digital tomosynthesis retains the edge-enhancement observed in planar PC radiograph and further improves soft-tissue conspicuity by reducing the effects of superimposed tissue structure.
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Affiliation(s)
- Jeffrey C Hammonds
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA.
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22
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Chen GH, Bevins N, Zambelli J, Qi Z. Small-angle scattering computed tomography (SAS-CT) using a Talbot-Lau interferometerand a rotating anode x-ray tube:theory and experiments. OPTICS EXPRESS 2010; 18:12960-70. [PMID: 20588425 PMCID: PMC3746741 DOI: 10.1364/oe.18.012960] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
X-ray differential phase contrast imaging methods, including projection imaging and the corresponding computed tomography (CT), have been implemented using a Talbot interferometer and either a synchrotron beam line or a low brilliance x-ray source generated by a stationary-anode x-ray tube. From small-angle scattering events which occur as an x-ray propagates through a medium, a signal intensity loss can be recorded and analyzed for an understanding of the micro-structures in an image object. This has been demonstrated using a Talbot-Lau interferometer and a stationary-anode x-ray tube. In this paper, theoretical principles and an experimental implementation of the corresponding CT imaging method are presented. First, a line integral is derived from analyzing the cross section of the small-angle scattering events. This method is referred to as small-angle scattering computed tomography (SAS-CT). Next, a Talbot-Lau interferometer and a rotating-anode x-ray tube were used to implement SAS-CT. A physical phantom and human breast tissue sample were used to demonstrate the reconstructed SAS-CT image volumes.
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Affiliation(s)
- Guang-Hong Chen
- Department of Medical Physics, University of Wisconsin-Madison, WI 53705, USA.
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23
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Connor DM, Hallen HD, Lalush DS, Sumner DR, Zhong Z. Comparison of diffraction-enhanced computed tomography and monochromatic synchrotron radiation computed tomography of human trabecular bone. Phys Med Biol 2009; 54:6123-33. [PMID: 19779219 DOI: 10.1088/0031-9155/54/20/006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Diffraction-enhanced imaging (DEI) is an x-ray-based medical imaging modality that, when used in tomography mode (DECT), can generate a three-dimensional map of both the apparent absorption coefficient and the out-of-plane gradient of the index of refraction of the sample. DECT is known to have contrast gains over monochromatic synchrotron radiation CT (SRCT) for soft tissue structures. The goal of this experiment was to compare contrast-to-noise ratio (CNR) and resolution in images of human trabecular bone acquired using SRCT with images acquired using DECT. All images were acquired at the National Synchrotron Light Source (Upton, NY, USA) at beamline X15 A at an x-ray energy of 40 keV and the silicon [3 3 3] reflection. SRCT, apparent absorption DECT and refraction DECT slice images of the trabecular bone were created. The apparent absorption DECT images have significantly higher spatial resolution and CNR than the corresponding SRCT images. Thus, DECT will prove to be a useful tool for imaging applications in which high contrast and high spatial resolution are required for both soft tissue features and bone.
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Affiliation(s)
- D M Connor
- Department of Biomedical Engineering, Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, 4030 Bondurant Hall, CB 7000, Chapel Hill, NC 27599, USA.
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24
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Meng F, Liu H, Wu X. Feasibility study of the iterative x-ray phase retrieval algorithm. APPLIED OPTICS 2009; 48:91-98. [PMID: 19107177 DOI: 10.1364/ao.48.000091] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
An iterative phase retrieval algorithm was previously investigated for in-line x-ray phase imaging. Through detailed theoretical analysis and computer simulations, we now discuss the limitations, robustness, and efficiency of the algorithm. The iterative algorithm was proved robust against imaging noise but sensitive to the variations of several system parameters. It is also efficient in terms of calculation time. It was shown that the algorithm can be applied to phase retrieval based on one phase-contrast image and one attenuation image, or two phase-contrast images; in both cases, the two images can be obtained either by one detector in two exposures, or by two detectors in only one exposure as in the dual-detector scheme.
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Affiliation(s)
- Fanbo Meng
- Center for Bioengineering and School of Electrical and Computer Engineering, University of Oklahoma, Norman, Oklahoma 73019, USA
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25
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Coan P, Mollenhauer J, Wagner A, Muehleman C, Bravin A. Analyzer-based imaging technique in tomography of cartilage and metal implants: a study at the ESRF. Eur J Radiol 2008; 68:S41-8. [PMID: 18584983 DOI: 10.1016/j.ejrad.2008.04.036] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2008] [Accepted: 04/25/2008] [Indexed: 11/19/2022]
Abstract
Monitoring the progression of osteoarthritis (OA) and the effects of therapy during clinical trials is still a challenge for present clinical imaging techniques since they present intrinsic limitations and can be sensitive only in case of advanced OA stages. In very severe cases, partial or complete joint replacement surgery is the only solution for reducing pain and restoring the joint functions. Poor imaging quality in practically all medical imaging technologies with respect to joint surfaces and to metal implant imaging calls for the development of new techniques that are sensitive to stages preceding the point of irreversible damage of the cartilage tissue. In this scenario, X-ray phase contrast modalities could play an important role since they can provide improved contrast compared to conventional absorption radiography, with a similar or even reduced tissue radiation dose. In this study, the analyzer-based imaging (ABI), a technique sensitive to the X-ray refraction and permitting a high scatter rejection, has been successfully applied in vitro on excised human synovial joints and sheep implants. Pathological and healthy joints as well as metal implants have been imaged in projection and computed tomography ABI mode at high resolution and clinically compatible doses (<10 mGy). Volume rendering and segmentation permitted visualization of the cartilage from volumetric CT-scans. The results demonstrate that ABI can provide an unequivocal non-invasive diagnosis of the state of disease of the joint and be considered a new tool in orthopaedic research.
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Affiliation(s)
- Paola Coan
- European Synchrotron Radiation Facility (ESRF), 6 rue Jules Horowitz, BP220, 38043 Grenoble, France.
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26
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Abstract
In this report we clarify two aspects for in-line phase-sensitive x-ray imaging, which includes phase-contrast imaging and phase imaging. First, we point out that there is confusion in the literature about the lateral coherence length, which is widely adopted as the coherence criteria for implementing phase-sensitive imaging. The confusion exaggerates the coherence requirement for clinical implementation of in-line phase-sensitive imaging. Instead we show that the ratio of the phase-space shearing length to lateral coherence length is a good measure for gauging the partial coherence realized in a specific image setting. Second, based on the general intensity equation for in-line phase-sensitive imaging, we discuss the differences between the phase-contrast imaging and phase imaging in terms of the physics mechanism, image acquisition approaches, computation algorithm development, and the potentials for tissue quantitative characterization.
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Affiliation(s)
- Xizeng Wu
- Department of Radiology, University of Alabama at Birmingham, Birmingham, Alabama 35233, USA.
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27
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Donnelly EF, Lewis KG, Wolske KM, Pickens DR, Price RR. Characterization of the phase-contrast radiography edge-enhancement effect in a cabinet x-ray system. Phys Med Biol 2005; 51:21-30. [PMID: 16357428 DOI: 10.1088/0031-9155/51/1/002] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The purpose of this study was to demonstrate that a commercially available cabinet x-ray system is capable of phase-contrast radiography (PC-R) and to evaluate the effect of different system parameters on the degree of edge enhancement. An acrylic plastic edge phantom was imaged at different tube potentials (25-60 kV) and in different geometries (variable object-to-detector distances, R(2), at a constant source-to-detector distance, R(1) + R(2)). In addition, the effect of noise on the perceived edge enhancement was studied as a function of exposure time. Our results show that a modest degree of phase contrast can be achieved in an unmodified cabinet x-ray system. In addition, the particular system evaluated allowed low-noise PC-R images to be obtained with short (6 s or less) exposures. These results suggest that with appropriate geometric choices PC-R is already available to a wide range of research scientists for use in both small-animal and human-specimen experiments.
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Affiliation(s)
- Edwin F Donnelly
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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28
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Yuasa T, Sugiyama H, Zhong Z, Maksimenko A, Dilmanian FA, Akatsuka T, Ando M. High-pass-filtered diffraction microtomography by coherent hard x rays for cell imaging: theoretical and numerical studies of the imaging and reconstruction principles. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2005; 22:2622-34. [PMID: 16396022 DOI: 10.1364/josaa.22.002622] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
This paper presents theoretical and numerical studies of diffraction tomography using hard x rays, from the viewpoint of imaging and reconstruction methods for cell imaging. The proposed system employs a single-perfect-crystal analyzer in symmetric Laue-case transmission geometry to efficiently detect the higher spatial frequency components of an object's refractive-index distribution, and to effectively suppress interference between the unperturbated wave field and the wave field diffracted by the object. This system features acquisition of a single projection by a single exposure using a simple geometry and aggressive use of diffracted x rays. We present the physical description of the imaging method using the Fourier diffraction theorem derived from the Born approximation. First, we demonstrate that the reconstruction leads to the phase-retrieval problem. We then describe a reconstruction algorithm based on the classical Gerchberg-Saxton-Fienup algorithm. Finally, we show the efficacy of this system by computer simulation. Our simulation demonstrates that the imaging system delineates microstructure 3.5 microm in diameter in a phase object 400 microm in diameter.
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Affiliation(s)
- Tetsuya Yuasa
- Department of Bio-System Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan.
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29
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Briedis D, Siu KKW, Paganin DM, Pavlov KM, Lewis RA. Analyser-based mammography using single-image reconstruction. Phys Med Biol 2005; 50:3599-611. [PMID: 16030385 DOI: 10.1088/0031-9155/50/15/008] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We implement an algorithm that is able to decode a single analyser-based x-ray phase-contrast image of a sample, converting it into an equivalent conventional absorption-contrast radiograph. The algorithm assumes the projection approximation for x-ray propagation in a single-material object embedded in a substrate of approximately uniform thickness. Unlike the phase-contrast images, which have both directional bias and a bias towards edges present in the sample, the reconstructed images are directly interpretable in terms of the projected absorption coefficient of the sample. The technique was applied to a Leeds TOR[MAM] phantom, which is designed to test mammogram quality by the inclusion of simulated microcalcifications, filaments and circular discs. This phantom was imaged at varying doses using three modalities: analyser-based synchrotron phase-contrast images converted to equivalent absorption radiographs using our algorithm, slot-scanned synchrotron imaging and imaging using a conventional mammography unit. Features in the resulting images were then assigned a quality score by volunteers. The single-image reconstruction method achieved higher scores at equivalent and lower doses than the conventional mammography images, but no improvement of visualization of the simulated microcalcifications, and some degradation in image quality at reduced doses for filament features.
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30
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Donnelly EF, Price RR, Pickens DR. Quantification of the effect of system and object parameters on edge enhancement in phase-contrast radiography. Med Phys 2004; 30:2888-96. [PMID: 14655935 DOI: 10.1118/1.1617430] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The purpose of this study was to evaluate the effects of system parameters (focal spot size, tube voltage, geometry, detector resolution, and image noise) and object characteristics (edge gradient/ shape, composition, thickness, and overlying attenuating material) upon the edge enhancement effect in phase-contrast radiography. Each variable of interest was adjusted and images of a 3 mm lucite phantom were obtained with the other variables remaining constant. A microfocus x-ray source coupled to a CCD camera with an intensifying screen was used to acquire the digital images. Two parameters of image analysis were used to quantify the effects. The edge enhancement index (EEI) was used to measure the absolute degree of edge enhancement, while the edge enhancement to noise ratio (EE/N) was used to measure the conspicuity of the edge enhancement relative to image noise. Little effect on EEI was seen from tube voltage, object thickness, overlying attenuating material, while focal spot size and system geometry demonstrated measurable effects upon the degree of edge enhancement. It was also shown that while the edge enhancement effect over straight edges is highly dependent upon how the edge aligns with the x-ray beam, rounded edges, which better model biological objects, do not suffer from this dependence and the EEI reaches its maximal level at any alignment. Decreasing detector resolution diminished the EEI slightly, but even with pixel sizes of 0.360 x 0.360 mm edge enhancement effects were readily visible. The effect of image noise on EE/N was evaluated using different exposure times showing an expected improvement with longer exposure time with EE/N approaching a plateau at 5 min. Many of the parameters that will go into the design of a future PC-R imaging system have been quantified in terms of their effect on the degree of edge enhancement in the acquired image. These results, taken together, indicate that either a specimen or even clinical breast imaging system could be created with currently available technology. The major limitation to a clinical system would be the low x-ray flux from the microfocal x-ray source.
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Affiliation(s)
- Edwin F Donnelly
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2675, USA.
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31
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Donnelly EF, Price RR, Pickens DR. Dual focal-spot imaging for phase extraction in phase-contrast radiography. Med Phys 2003; 30:2292-6. [PMID: 14528949 DOI: 10.1118/1.1598672] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The purpose of this study was to evaluate dual focal spot imaging as a method for extracting the phase component from a phase-contrast radiography image. All measurements were performed using a microfocus tungsten-target x-ray tube with an adjustable focal-spot size (0.01 mm to 0.045 mm). For each object, high-resolution digital radiographs were obtained with two different focal spot sizes to produce matched image pairs in which all other geometric variables as well as total exposure and tube kVp were held constant. For each image pair, a phase extraction was performed using pixel-wise division. The phase-extracted image resulted in an image similar to the standard image processing tool commonly referred to as "unsharp masking" but with the additional edge-enhancement produced by phase-contrast effects. The phase-extracted image illustrates the differences between the two images whose imaging parameters differ only in focal spot size. The resulting image shows effects from both phase contrast as well as geometric unsharpness. In weakly attenuating materials the phase-contrast effect predominates, while in strongly attenuating materials the phase effects are so small that they are not detectable. The phase-extracted image in the strongly attenuating object reflects differences in geometric unsharpness. The degree of phase extraction depends strongly on the size of the smallest focal spot used. This technique of dual-focal spot phase-contrast radiography provides a simple technique for phase-component (edge) extraction in phase-contrast radiography. In strongly attenuating materials the phase-component is overwhelmed by differences in geometric unsharpness. In these cases the technique provides a form of unsharp masking which also accentuates the edges. Thus, the two effects are complimentary and may be useful in the detection of small objects.
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Affiliation(s)
- Edwin F Donnelly
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA.
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32
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Donnelly EF, Price RR. Quantification of the effect of kvp on edge-enhancement index in phase-contrast radiography. Med Phys 2002; 29:999-1002. [PMID: 12094995 DOI: 10.1118/1.1477416] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
This study was performed to measure the dependence of edge-enhancement in polychromatic phase-contrast radiography on x-ray tube operating voltage. Measurements of edge enhancement were made at tube voltages from 40 to 86 kVp using a tungsten anode x-ray tube with a nominal focal spot size of 100 micrometers. A relatively weak attenuating, sharp edge consisting of a thin lucite sheet (3 mm) in air was imaged utilizing phase-contrast radiography (PC-R). PC-R images were acquired at different radiographic techniques in which x-ray tube voltage was varied from 40 to 86 kVp. The image receptor was a single emulsion x-ray mammography cassette. Optical density profiles across the edge of the object were obtained using a film digitizer and edge-enhancement indices were calculated. Increasing kVp resulted in a gradual decrease of the edge-enhancement index. Even at the highest kVp (86), however, important edge-enhancement effects were evident. While there is some degradation in the edge-enhancement effect of phase-contrast radiography at higher kVps, the decrease from 40 to 86 kVp is relatively small (11%). Our results suggest that further investigation into the role of phase-contrast imaging at higher kVp values for the purpose of patient dose reduction while still realizing the advantage of phase-contrast effects for improved soft-tissue detectability is warranted.
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Affiliation(s)
- Edwin F Donnelly
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA.
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33
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Kaulich B, Wilhein T, Di FE, Romanato F, Altissimo M, Cabrini S, Fayard B, Susini J. Differential interference contrast x-ray microscopy with twin zone plates. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2002; 19:797-806. [PMID: 11934173 DOI: 10.1364/josaa.19.000797] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
X-ray imaging in differential interference contrast (DIC) with submicrometer optical resolution was performed by using a twin zone plate (TZP) setup generating focal spots closely spaced within the TZP spatial resolution of 160 nm. Optical path differences introduced by the sample are recorded by a CCD camera in a standard full-field imaging and by an aperture photodiode in a standard scanning transmission x-ray microscope. Applying this x-ray DIC technique, we demonstrate for both the full-field imaging and scanning x-ray microscope methods a drastic increase in image contrast (approximately 20x) for a low-absorbing specimen, similar to the Nomarski DIC method for visible-light microscopy.
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Affiliation(s)
- Burkhard Kaulich
- X-Ray Microscopy Section, ELETTRA-Sincrotrone Trieste, Basovizzo-Trieste, Italy.
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34
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Noninterferometric phase determination. ACTA ACUST UNITED AC 2001. [DOI: 10.1016/s1076-5670(01)80104-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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36
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Allman BE, McMahon PJ, Tiller JB, Nugent KA, Paganin D, Barty A. Noninterferometric quantitative phase imaging with soft x rays. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2000; 17:1732-1743. [PMID: 11028521 DOI: 10.1364/josaa.17.001732] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We demonstrate quantitative noninterferometric x-ray phase-amplitude measurement. We present results from two experimental geometries. The first geometry uses x rays diverging from a point source to produce high-resolution holograms of submicrometer-sized objects. The measured phase of the projected image agrees with the geometrically determined phase to within +/-7%. The second geometry uses a direct imaging microscope setup that allows the formation of a magnified image with a zone-plate lens. Here a direct measure of the object phase is made and agrees with that of the magnified object to better than +/-10%. In both cases the accuracy of the phase is limited by the pixel resolution.
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Affiliation(s)
- B E Allman
- School of Physics, University of Melbourne, Victoria, Australia.
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37
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Pisano ED, Johnston RE, Chapman D, Geradts J, Iacocca MV, Livasy CA, Washburn DB, Sayers DE, Zhong Z, Kiss MZ, Thomlinson WC. Human breast cancer specimens: diffraction-enhanced imaging with histologic correlation--improved conspicuity of lesion detail compared with digital radiography. Radiology 2000; 214:895-901. [PMID: 10715065 DOI: 10.1148/radiology.214.3.r00mr26895] [Citation(s) in RCA: 152] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Seven breast cancer specimens were examined with diffraction-enhanced imaging at 18 keV with a silicon crystal with use of the silicon 333 reflection in Bragg mode. Images were compared with digital radiographs of the specimen, and regions of increased detail were identified. Six of the seven cases (86%) showed enhanced visibility of surface spiculation that correlated with histopathologic information, including extension of tumor into surrounding tissue.
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Affiliation(s)
- E D Pisano
- Department of Radiology, UNC-Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill 27599-7510, USA.
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Chapman D, Thomlinson W, Johnston RE, Washburn D, Pisano E, Gmür N, Zhong Z, Menk R, Arfelli F, Sayers D. Diffraction enhanced x-ray imaging. Phys Med Biol 1997; 42:2015-25. [PMID: 9394394 DOI: 10.1088/0031-9155/42/11/001] [Citation(s) in RCA: 448] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Diffraction enhanced imaging is a new x-ray radiographic imaging modality using monochromatic x-rays from a synchrotron which produces images of thick absorbing objects that are almost completely free of scatter. They show dramatically improved contrast over standard imaging applied to the same phantom. The contrast is based not only on attenuation but also the refraction and diffraction properties of the sample. This imaging method may improve image quality for medical applications, industrial radiography for non-destructive testing and x-ray computed tomography.
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Affiliation(s)
- D Chapman
- CSRRI, Illinois Institute of Technology, Chicago 60616, USA.
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40
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Wave-optical description of X-ray phase contrast images of weakly absorbing non-crystalline objects. ACTA ACUST UNITED AC 1997. [DOI: 10.1007/bf03041011] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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41
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Nugent KA, Gureyev TE, Cookson DJ, Paganin D, Barnea Z. Quantitative Phase Imaging Using Hard X Rays. PHYSICAL REVIEW LETTERS 1996; 77:2961-2964. [PMID: 10062096 DOI: 10.1103/physrevlett.77.2961] [Citation(s) in RCA: 134] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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