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Rix KR, Dreier T, Shen T, Bech M. Super-resolution x-ray phase-contrast and dark-field imaging with a single 2D grating and electromagnetic source stepping. Phys Med Biol 2019; 64:165009. [PMID: 31284279 DOI: 10.1088/1361-6560/ab2ff5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Here we report a method for increased resolution of single exposure three modality x-ray images using super-resolution. The three x-ray image modalities are absorption-, differential phase-contrast-, and dark-field-images. To create super-resolution, a non-mechanically movable micro-focus x-ray source is used. A series of almost identical x-ray projection images is obtained while the point source is translated in a two-dimensional grid pattern. The three image modalities are extracted from fourier space using spatial harmonic analysis, also known as the single-shot method. Using super-resolution on the low-resolution series of the three modalities separately results in high-resolution images for the modalities. This approach allows to compensate for the inherent loss in resolution caused by the single-shot method without increasing the need for stability or algorithms accounting for possible motion.
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Affiliation(s)
- Kristian R Rix
- University of Copenhagen, Niels Bohr Institute, x-ray and Neutron Science, 2100 Copenhagen, Denmark. These authors contributed equally
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2
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Wu Z, Gao K, Wang Z, Wei C, Wali F, Zan G, Wei W, Zhu P, Tian Y. Direct information retrieval after 3D reconstruction in grating-based X-ray phase-contrast computed tomography. JOURNAL OF SYNCHROTRON RADIATION 2018; 25:1222-1228. [PMID: 29979185 PMCID: PMC6038613 DOI: 10.1107/s1600577518008019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 05/30/2018] [Indexed: 06/08/2023]
Abstract
Grating-based X-ray differential phase-contrast imaging has attracted a great amount of attention and has been considered as a potential imaging method in clinical medicine because of its compatibility with the traditional X-ray tube source and the possibility of a large field of view. Moreover, phase-contrast computed tomography provides three-dimensional phase-contrast visualization. Generally, two-dimensional information retrieval performed on every projection is required prior to three-dimensional reconstruction in phase-contrast computed tomography. In this paper, a three-dimensional information retrieval method to separate absorption and phase information directly from two reconstructed images is derived. Theoretical derivations together with numerical simulations have been performed to confirm the feasibility and veracity of the proposed method. The advantages and limitations compared with the reverse projection method are also discussed. Owing to the reduced data size and the absence of a logarithm operation, the computational time for information retrieval is shortened by the proposed method. In addition, the hybrid three-dimensional images of absorption and phase information were reconstructed using an absorption reconstruction algorithm, hence the existing data pre-processing methods and iterative reconstruction algorithms in absorption reconstruction may be utilized in phase reconstruction immediately.
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Affiliation(s)
- Zhao Wu
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, People’s Republic of China
| | - Kun Gao
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, People’s Republic of China
| | - Zhili Wang
- School of Electronic Science and Applied Physics, Hefei University of Technology, Hefei, Anhui 230009, People’s Republic of China
| | - Chenxi Wei
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, People’s Republic of China
| | - Faiz Wali
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, People’s Republic of China
| | - Guibin Zan
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, People’s Republic of China
| | - Wenbin Wei
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, People’s Republic of China
| | - Peiping Zhu
- Institute of High-Energy Physics, Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
| | - Yangchao Tian
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, People’s Republic of China
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3
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Zamir A, Hagen C, Diemoz PC, Endrizzi M, Vittoria F, Chen Y, Anastasio MA, Olivo A. Recent advances in edge illumination x-ray phase-contrast tomography. J Med Imaging (Bellingham) 2017; 4:040901. [PMID: 29057286 PMCID: PMC5641577 DOI: 10.1117/1.jmi.4.4.040901] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 09/21/2017] [Indexed: 11/14/2022] Open
Abstract
Edge illumination (EI) is an x-ray phase-contrast imaging technique, exploiting sensitivity to x-ray refraction to visualize features, which are often not detected by conventional absorption-based radiography. The method does not require a high degree of spatial coherence and is achromatic and, therefore, can be implemented with both synchrotron radiation and commercial x-ray tubes. Using different retrieval algorithms, information about an object's attenuation, refraction, and scattering properties can be obtained. In recent years, a theoretical framework has been developed that enables EI computed tomography (CT) and, hence, three-dimensional imaging. This review provides a summary of these advances, covering the development of different image acquisition schemes, retrieval approaches, and applications. These developments constitute an integral part in the transformation of EI CT into a widely spread imaging tool for use in a range of fields.
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Affiliation(s)
- Anna Zamir
- University College London, Department of Medical Physics and Biomedical Engineering, London, United Kingdom
| | - Charlotte Hagen
- University College London, Department of Medical Physics and Biomedical Engineering, London, United Kingdom
| | - Paul C Diemoz
- University College London, Department of Medical Physics and Biomedical Engineering, London, United Kingdom
| | - Marco Endrizzi
- University College London, Department of Medical Physics and Biomedical Engineering, London, United Kingdom
| | - Fabio Vittoria
- University College London, Department of Medical Physics and Biomedical Engineering, London, United Kingdom
| | - Yujia Chen
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri, United States
| | - Mark A Anastasio
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri, United States
| | - Alessandro Olivo
- University College London, Department of Medical Physics and Biomedical Engineering, London, United Kingdom
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4
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Ritter A, Anton G, Weber T. Simultaneous Maximum-Likelihood Reconstruction of Absorption Coefficient, Refractive Index and Dark-Field Scattering Coefficient in X-Ray Talbot-Lau Tomography. PLoS One 2016; 11:e0163016. [PMID: 27695126 PMCID: PMC5047447 DOI: 10.1371/journal.pone.0163016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 09/01/2016] [Indexed: 11/20/2022] Open
Abstract
A maximum-likelihood reconstruction technique for X-ray Talbot-Lau tomography is presented. This technique allows the iterative simultaneous reconstruction of discrete distributions of absorption coefficient, refractive index and a dark-field scattering coefficient. This technique avoids prior phase retrieval in the tomographic projection images and thus in principle allows reconstruction from tomographic data with less than three phase steps per projection. A numerical phantom is defined which is used to evaluate convergence of the technique with regard to photon statistics and with regard to the number of projection angles and phase steps used. It is shown that the use of a random phase sampling pattern allows the reconstruction even for the extreme case of only one single phase step per projection. The technique is successfully applied to measured tomographic data of a mouse. In future, this reconstruction technique might also be used to implement enhanced imaging models for X-ray Talbot-Lau tomography. These enhancements might be suited to correct for example beam hardening and dispersion artifacts and improve overall image quality of X-ray Talbot-Lau tomography.
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Affiliation(s)
- André Ritter
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen Centre for Astroparticle Physics (ECAP), Erwin-Rommel-Str. 1, 91052 Erlangen, Germany
- * E-mail:
| | - Gisela Anton
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen Centre for Astroparticle Physics (ECAP), Erwin-Rommel-Str. 1, 91052 Erlangen, Germany
| | - Thomas Weber
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen Centre for Astroparticle Physics (ECAP), Erwin-Rommel-Str. 1, 91052 Erlangen, Germany
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Marschner M, Willner M, Potdevin G, Fehringer A, Noël PB, Pfeiffer F, Herzen J. Helical X-ray phase-contrast computed tomography without phase stepping. Sci Rep 2016; 6:23953. [PMID: 27052368 PMCID: PMC4823776 DOI: 10.1038/srep23953] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 03/17/2016] [Indexed: 01/15/2023] Open
Abstract
X-ray phase-contrast computed tomography (PCCT) using grating interferometry provides enhanced soft-tissue contrast. The possibility to use standard polychromatic laboratory sources enables an implementation into a clinical setting. Thus, PCCT has gained significant attention in recent years. However, phase-contrast CT scans still require significantly increased measurement times in comparison to conventional attenuation-based CT imaging. This is mainly due to a time-consuming stepping of a grating, which is necessary for an accurate retrieval of the phase information. In this paper, we demonstrate a novel scan technique, which directly allows the determination of the phase signal without a phase-stepping procedure. The presented work is based on moiré fringe scanning, which allows fast data acquisition in radiographic applications such as mammography or in-line product analysis. Here, we demonstrate its extension to tomography enabling a continuous helical sample rotation as routinely performed in clinical CT systems. Compared to standard phase-stepping techniques, the proposed helical fringe-scanning procedure enables faster measurements, an extended field of view and relaxes the stability requirements of the system, since the gratings remain stationary. Finally, our approach exceeds previously introduced methods by not relying on spatial interpolation to acquire the phase-contrast signal.
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Affiliation(s)
- M Marschner
- Lehrstuhl für Biomedizinische Physik, Physik-Department &Institut für Medizintechnik, Technische Universität München, 85748 Garching, Germany
| | - M Willner
- Lehrstuhl für Biomedizinische Physik, Physik-Department &Institut für Medizintechnik, Technische Universität München, 85748 Garching, Germany
| | - G Potdevin
- Lehrstuhl für Biomedizinische Physik, Physik-Department &Institut für Medizintechnik, Technische Universität München, 85748 Garching, Germany
| | - A Fehringer
- Lehrstuhl für Biomedizinische Physik, Physik-Department &Institut für Medizintechnik, Technische Universität München, 85748 Garching, Germany
| | - P B Noël
- Lehrstuhl für Biomedizinische Physik, Physik-Department &Institut für Medizintechnik, Technische Universität München, 85748 Garching, Germany.,Institut für diagnostische und interventionelle Radiologie, Klinikum rechts der Isar, Technische Universität München, 81675 München, Germany
| | - F Pfeiffer
- Lehrstuhl für Biomedizinische Physik, Physik-Department &Institut für Medizintechnik, Technische Universität München, 85748 Garching, Germany.,Institut für diagnostische und interventionelle Radiologie, Klinikum rechts der Isar, Technische Universität München, 81675 München, Germany
| | - J Herzen
- Lehrstuhl für Biomedizinische Physik, Physik-Department &Institut für Medizintechnik, Technische Universität München, 85748 Garching, Germany
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6
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Li P, Zhang K, Bao Y, Ren Y, Ju Z, Wang Y, He Q, Zhu Z, Huang W, Yuan Q, Zhu P. Angular signal radiography. OPTICS EXPRESS 2016; 24:5829-5845. [PMID: 27136780 DOI: 10.1364/oe.24.005829] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Microscopy techniques using visible photons, x-rays, neutrons, and electrons have made remarkable impact in many scientific disciplines. The microscopic data can often be expressed as the convolution of the spatial distribution of certain properties of the specimens and the inherent response function of the imaging system. The x-ray grating interferometer (XGI), which is sensitive to the deviation angle of the incoming x-rays, has attracted significant attention in the past years due to its capability in achieving x-ray phase contrast imaging with low brilliance source. However, the comprehensive and analytical theoretical framework is yet to be presented. Herein, we propose a theoretical framework termed angular signal radiography (ASR) to describe the imaging process of the XGI system in a classical, comprehensive and analytical manner. We demonstrated, by means of theoretical deduction and synchrotron based experiments, that the spatial distribution of specimens' physical properties, including absorption, refraction and scattering, can be extracted by ASR in XGI. Implementation of ASR in XGI offers advantages such as simplified phase retrieval algorithm, reduced overall radiation dose, and improved image acquisition speed. These advantages, as well as the limitations of the proposed method, are systematically investigated in this paper.
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7
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Mittone A, Gasilov S, Brun E, Bravin A, Coan P. A single-image method for x-ray refractive index CT. Phys Med Biol 2015; 60:3433-40. [PMID: 25856228 DOI: 10.1088/0031-9155/60/9/3433] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
X-ray refraction-based computer tomography imaging is a well-established method for nondestructive investigations of various objects. In order to perform the 3D reconstruction of the index of refraction, two or more raw computed tomography phase-contrast images are usually acquired and combined to retrieve the refraction map (i.e. differential phase) signal within the sample. We suggest an approximate method to extract the refraction signal, which uses a single raw phase-contrast image. This method, here applied to analyzer-based phase-contrast imaging, is employed to retrieve the index of refraction map of a biological sample. The achieved accuracy in distinguishing the different tissues is comparable with the non-approximated approach. The suggested procedure can be used for precise refraction computer tomography with the advantage of a reduction of at least a factor of two of both the acquisition time and the dose delivered to the sample with respect to any of the other algorithms in the literature.
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Affiliation(s)
- A Mittone
- Department of Physics, Ludwig Maximilian University, 85748 Garching, Germany. Department of Clinical Radiology, Ludwig Maximilian University, Munich 81377, Germany. European Synchrotron Radiation Facility (ESRF), Grenoble 38043, France
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8
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Velroyen A, Bech M, Zanette I, Schwarz J, Rack A, Tympner C, Herrler T, Staab-Weijnitz C, Braunagel M, Reiser M, Bamberg F, Pfeiffer F, Notohamiprodjo M. X-ray phase-contrast tomography of renal ischemia-reperfusion damage. PLoS One 2014; 9:e109562. [PMID: 25299243 PMCID: PMC4192129 DOI: 10.1371/journal.pone.0109562] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 09/02/2014] [Indexed: 01/28/2023] Open
Abstract
Purpose The aim of the study was to investigate microstructural changes occurring in unilateral renal ischemia-reperfusion injury in a murine animal model using synchrotron radiation. Material and Methods The effects of renal ischemia-reperfusion were investigated in a murine animal model of unilateral ischemia. Kidney samples were harvested on day 18. Grating-Based Phase-Contrast Imaging (GB-PCI) of the paraffin-embedded kidney samples was performed at a Synchrotron Radiation Facility (beam energy of 19 keV). To obtain phase information, a two-grating Talbot interferometer was used applying the phase stepping technique. The imaging system provided an effective pixel size of 7.5 µm. The resulting attenuation and differential phase projections were tomographically reconstructed using filtered back-projection. Semi-automated segmentation and volumetry and correlation to histopathology were performed. Results GB-PCI provided good discrimination of the cortex, outer and inner medulla in non-ischemic control kidneys. Post-ischemic kidneys showed a reduced compartmental differentiation, particularly of the outer stripe of the outer medulla, which could not be differentiated from the inner stripe. Compared to the contralateral kidney, after ischemia a volume loss was detected, while the inner medulla mainly retained its volume (ratio 0.94). Post-ischemic kidneys exhibited severe tissue damage as evidenced by tubular atrophy and dilatation, moderate inflammatory infiltration, loss of brush borders and tubular protein cylinders. Conclusion In conclusion GB-PCI with synchrotron radiation allows for non-destructive microstructural assessment of parenchymal kidney disease and vessel architecture. If translation to lab-based approaches generates sufficient density resolution, and with a time-optimized image analysis protocol, GB-PCI may ultimately serve as a non-invasive, non-enhanced alternative for imaging of pathological changes of the kidney.
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Affiliation(s)
- Astrid Velroyen
- Chair of Biomedical Physics, Department of Physics (E17), Munich, Bavaria, Germany
| | - Martin Bech
- Chair of Biomedical Physics, Department of Physics (E17), Munich, Bavaria, Germany
- Medical Radiation Physics, Lund University, Lund, Sweden
| | - Irene Zanette
- Chair of Biomedical Physics, Department of Physics (E17), Munich, Bavaria, Germany
| | - Jolanda Schwarz
- Chair of Biomedical Physics, Department of Physics (E17), Munich, Bavaria, Germany
| | - Alexander Rack
- European Synchrotron Radiation Facility, Grenoble, France
| | - Christiane Tympner
- Institute of Pathology, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Tanja Herrler
- Department of General, Trauma, Hand, and Plastic Surgery, Ludwig-Maximilians-University Hospital Munich, Munich, Germany
| | - Claudia Staab-Weijnitz
- Institute for Clinical Radiology, University Hospitals Munich, Munich, Germany
- Comprehensive Pneumology Center, University Hospital, Ludwig-Maximilians-University and Helmholtz Zentrum Munich, Munich, Germany
| | - Margarita Braunagel
- Institute for Clinical Radiology, University Hospitals Munich, Munich, Germany
| | - Maximilian Reiser
- Institute for Clinical Radiology, University Hospitals Munich, Munich, Germany
| | - Fabian Bamberg
- Institute for Clinical Radiology, University Hospitals Munich, Munich, Germany
- Department of Radiology, University Hospital Tuebingen, Tuebingen, Germany
| | - Franz Pfeiffer
- Chair of Biomedical Physics, Department of Physics (E17), Munich, Bavaria, Germany
| | - Mike Notohamiprodjo
- Institute for Clinical Radiology, University Hospitals Munich, Munich, Germany
- Department of Radiology, University Hospital Tuebingen, Tuebingen, Germany
- * E-mail:
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9
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Hagen CK, Diemoz PC, Endrizzi M, Rigon L, Dreossi D, Arfelli F, Lopez FCM, Longo R, Olivo A. Theory and preliminary experimental verification of quantitative edge illumination x-ray phase contrast tomography. OPTICS EXPRESS 2014; 22:7989-8000. [PMID: 24718174 DOI: 10.1364/oe.22.007989] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
X-ray phase contrast imaging (XPCi) methods are sensitive to phase in addition to attenuation effects and, therefore, can achieve improved image contrast for weakly attenuating materials, such as often encountered in biomedical applications. Several XPCi methods exist, most of which have already been implemented in computed tomographic (CT) modality, thus allowing volumetric imaging. The Edge Illumination (EI) XPCi method had, until now, not been implemented as a CT modality. This article provides indications that quantitative 3D maps of an object's phase and attenuation can be reconstructed from EI XPCi measurements. Moreover, a theory for the reconstruction of combined phase and attenuation maps is presented. Both reconstruction strategies find applications in tissue characterisation and the identification of faint, weakly attenuating details. Experimental results for wires of known materials and for a biological object validate the theory and confirm the superiority of the phase over conventional, attenuation-based image contrast.
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Diemoz PC, Endrizzi M, Bravin A, Robinson IK, Olivo A. Sensitivity of edge illumination X-ray phase-contrast imaging. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2014; 372:20130128. [PMID: 24470420 PMCID: PMC3900038 DOI: 10.1098/rsta.2013.0128] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Recently, we developed a theoretical model that can predict the signal-to-noise ratio for edge-like features in phase-contrast images. This model was then applied for the estimation of the sensitivity of three different X-ray phase-contrast techniques: propagation-based imaging, analyser-based imaging and grating interferometry. We show here how the same formalism can be used also in the case of the edge illumination (EI) technique, providing results that are consistent with those of a recently developed method for the estimation of noise in the retrieved refraction image. The new model is then applied to calculate, in the case of a given synchrotron radiation set-up, the optimum positions of the pre-sample aperture and detector edge to maximize the sensitivity. Finally, an example of the extremely high angular resolution achievable with the EI technique is presented.
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Affiliation(s)
- P. C. Diemoz
- Department of Medical Physics and Bioengineering, University College London, London WC1E 6BT, UK
- Research Complex at Harwell, Harwell Oxford Campus, Didcot OX11 0FA, UK
- e-mail:
| | - M. Endrizzi
- Department of Medical Physics and Bioengineering, University College London, London WC1E 6BT, UK
| | - A. Bravin
- European Synchrotron Radiation Facility, Grenoble 38043, France
| | - I. K. Robinson
- Research Complex at Harwell, Harwell Oxford Campus, Didcot OX11 0FA, UK
- London Centre for Nanotechnology, London WC1H 0AH, UK
| | - A. Olivo
- Department of Medical Physics and Bioengineering, University College London, London WC1E 6BT, UK
- Research Complex at Harwell, Harwell Oxford Campus, Didcot OX11 0FA, UK
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11
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Saam T, Herzen J, Hetterich H, Fill S, Willner M, Stockmar M, Achterhold K, Zanette I, Weitkamp T, Schüller U, Auweter S, Adam-Neumair S, Nikolaou K, Reiser MF, Pfeiffer F, Bamberg F. Translation of atherosclerotic plaque phase-contrast CT imaging from synchrotron radiation to a conventional lab-based X-ray source. PLoS One 2013; 8:e73513. [PMID: 24039969 PMCID: PMC3767700 DOI: 10.1371/journal.pone.0073513] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 07/21/2013] [Indexed: 11/26/2022] Open
Abstract
Objectives Phase-contrast imaging is a novel X-ray based technique that provides enhanced soft tissue contrast. The aim of this study was to evaluate the feasibility of visualizing human carotid arteries by grating-based phase-contrast tomography (PC-CT) at two different experimental set-ups: (i) applying synchrotron radiation and (ii) using a conventional X-ray tube. Materials and Methods Five ex-vivo carotid artery specimens were examined with PC-CT either at the European Synchrotron Radiation Facility using a monochromatic X-ray beam (2 specimens; 23 keV; pixel size 5.4 µm), or at a laboratory set-up on a conventional X-ray tube (3 specimens; 35-40 kVp; 70 mA; pixel size 100 µm). Tomographic images were reconstructed and compared to histopathology. Two independent readers determined vessel dimensions and one reader determined signal-to-noise ratios (SNR) between PC-CT and absorption images. Results In total, 51 sections were included in the analysis. Images from both set-ups provided sufficient contrast to differentiate individual vessel layers. All PCI-based measurements strongly predicted but significantly overestimated lumen, intima and vessel wall area for both the synchrotron and the laboratory-based measurements as compared with histology (all p<0.001 with slope >0.53 per mm2, 95%-CI: 0.35 to 0.70). Although synchrotron-based images were characterized by higher SNRs than laboratory-based images; both PC-CT set-ups had superior SNRs compared to corresponding conventional absorption-based images (p<0.001). Inter-reader reproducibility was excellent (ICCs >0.98 and >0.84 for synchrotron and for laboratory-based measurements; respectively). Conclusion Experimental PC-CT of carotid specimens is feasible with both synchrotron and conventional X-ray sources, producing high-resolution images suitable for vessel characterization and atherosclerosis research.
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Affiliation(s)
- Tobias Saam
- Institute of Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany
- * E-mail:
| | - Julia Herzen
- Chair of Biomedical Physics, Technical University of Munich, Munich, Germany
- Institute of Materials Research, Helmholtz-Zentrum Geesthacht, Geesthacht, Germany
| | - Holger Hetterich
- Institute of Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany
| | - Sandra Fill
- Institute of Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany
| | - Marian Willner
- Chair of Biomedical Physics, Technical University of Munich, Munich, Germany
| | - Marco Stockmar
- Chair of Biomedical Physics, Technical University of Munich, Munich, Germany
| | - Klaus Achterhold
- Chair of Biomedical Physics, Technical University of Munich, Munich, Germany
| | - Irene Zanette
- European Synchrotron Radiation Facility (ESRF), Grenoble, France
| | | | - Ulrich Schüller
- Center for Neuropathology, Ludwig-Maximilians-University Hospital, Munich, Germany
| | - Sigrid Auweter
- Institute of Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany
| | | | - Konstantin Nikolaou
- Institute of Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany
| | - Maximilian F. Reiser
- Institute of Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany
| | - Franz Pfeiffer
- Chair of Biomedical Physics, Technical University of Munich, Munich, Germany
| | - Fabian Bamberg
- Institute of Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany
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12
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Pelliccia D, Rigon L, Arfelli F, Menk RH, Bukreeva I, Cedola A. A three-image algorithm for hard x-ray grating interferometry. OPTICS EXPRESS 2013; 21:19401-19411. [PMID: 23938856 DOI: 10.1364/oe.21.019401] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
A three-image method to extract absorption, refraction and scattering information for hard x-ray grating interferometry is presented. The method comprises a post-processing approach alternative to the conventional phase stepping procedure and is inspired by a similar three-image technique developed for analyzer-based x-ray imaging. Results obtained with this algorithm are quantitatively comparable with phase-stepping. This method can be further extended to samples with negligible scattering, where only two images are needed to separate absorption and refraction signal. Thanks to the limited number of images required, this technique is a viable route to bio-compatible imaging with x-ray grating interferometer. In addition our method elucidates and strengthens the formal and practical analogies between grating interferometry and the (non-interferometric) diffraction enhanced imaging technique.
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13
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Munro PRT, Hagen CK, Szafraniec MB, Olivo A. A simplified approach to quantitative coded aperture X-ray phase imaging. OPTICS EXPRESS 2013; 21:11187-201. [PMID: 23669976 DOI: 10.1364/oe.21.011187] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We recently demonstrated how quantitative X-ray phase contrast imaging may be performed with laboratory sources using the coded aperture technique. This technique required the knowledge of system parameters such as, for example, the source focal spot size and distances between elements of the imaging system. The method also assumes that the absorbing regions of the apertures are perfectly absorbing. In this paper we demonstrate how quantitative imaging can be performed without knowledge of individual system parameters and with partially absorbing apertures. We also show that this method is analogous to that employed in analyser based imaging which uses the rocking curve of an analyser crystal.
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Affiliation(s)
- Peter R T Munro
- Optical + Biomedical Engineering Laboratory, School of Electrical, Electronic and Computer Engineering, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia.
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14
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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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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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16
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Sztrókay A, Diemoz PC, Schlossbauer T, Brun E, Bamberg F, Mayr D, Reiser MF, Bravin A, Coan P. High-resolution breast tomography at high energy: a feasibility study of phase contrast imaging on a whole breast. Phys Med Biol 2012; 57:2931-42. [PMID: 22516937 DOI: 10.1088/0031-9155/57/10/2931] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Previous studies on phase contrast imaging (PCI) mammography have demonstrated an enhancement of breast morphology and cancerous tissue visualization compared to conventional imaging. We show here the first results of the PCI analyser-based imaging (ABI) in computed tomography (CT) mode on whole and large (>12 cm) tumour-bearing breast tissues. We demonstrate in this work the capability of the technique of working at high x-ray energies and producing high-contrast images of large and complex specimens. One entire breast of an 80-year-old woman with invasive ductal cancer was imaged using ABI-CT with monochromatic 70 keV x-rays and an area detector of 92×92 µm² pixel size. Sagittal slices were reconstructed from the acquired data, and compared to corresponding histological sections. Comparison with conventional absorption-based CT was also performed. Five blinded radiologists quantitatively evaluated the visual aspects of the ABI-CT images with respect to sharpness, soft tissue contrast, tissue boundaries and the discrimination of different structures/tissues. ABI-CT excellently depicted the entire 3D architecture of the breast volume by providing high-resolution and high-contrast images of the normal and cancerous breast tissues. These results are an important step in the evolution of PCI-CT towards its clinical implementation.
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Affiliation(s)
- A Sztrókay
- Institute of Clinical Radiology, Ludwig-Maximilians University, Munich, Germany
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Olivo A, Diemoz PC, Bravin A. Amplification of the phase contrast signal at very high x-ray energies. OPTICS LETTERS 2012; 37:915-7. [PMID: 22378437 DOI: 10.1364/ol.37.000915] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
X-ray phase contrast imaging is increasingly being used in several fields, both at synchrotron facilities and with laboratory sources, due to its increased sensitivity compared to conventional x-ray methods. One important problem is the development of methods to make it suitable for use at very high x-ray energies, needed in many applications. We show how the edge illumination concept, which stands at the basis of the coded-aperture method, allows achieving hyperintense phase signals at energies close to 100 keV, by showing images of both weak phase objects and highly absorbing fossils with a high iron content.
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Affiliation(s)
- Alessandro Olivo
- Department of Medical Physics and Bioengineering, UCL, London WC1E 6BT, UK.
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Diemoz PC, Bravin A, Coan P. Theoretical comparison of three X-ray phase-contrast imaging techniques: propagation-based imaging, analyzer-based imaging and grating interferometry. OPTICS EXPRESS 2012; 20:2789-805. [PMID: 22330515 DOI: 10.1364/oe.20.002789] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Various X-ray phase-contrast imaging techniques have been developed and applied over the last twenty years in different domains, such as material sciences, biology and medicine. However, no comprehensive inter-comparison exists in the literature. We present here a theoretical study that compares three among the most used techniques: propagation-based imaging (PBI), analyzer-based imaging (ABI) and grating interferometry (GI). These techniques are evaluated in terms of signal-to-noise ratio, figure of merit and spatial resolution. Both area and edge signals are considered. Dependences upon the object properties (absorption, phase shift) and the experimental acquisition parameters (energy, system point-spread function etc.) are derived and discussed. The results obtained from this analysis can be used as the reference for determining the most suitable technique for a given application.
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Affiliation(s)
- P C Diemoz
- Faculty of Physics, Ludwig-Maximilians-University Munchen, 85748 Garching, Germany.
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