WorldWideScience

Sample records for based x-ray tomography

  1. Cone-beam x-ray luminescence computed tomography based on x-ray absorption dosage

    Science.gov (United States)

    Liu, Tianshuai; Rong, Junyan; Gao, Peng; Zhang, Wenli; Liu, Wenlei; Zhang, Yuanke; Lu, Hongbing

    2018-02-01

    With the advances of x-ray excitable nanophosphors, x-ray luminescence computed tomography (XLCT) has become a promising hybrid imaging modality. In particular, a cone-beam XLCT (CB-XLCT) system has demonstrated its potential in in vivo imaging with the advantage of fast imaging speed over other XLCT systems. Currently, the imaging models of most XLCT systems assume that nanophosphors emit light based on the intensity distribution of x-ray within the object, not completely reflecting the nature of the x-ray excitation process. To improve the imaging quality of CB-XLCT, an imaging model that adopts an excitation model of nanophosphors based on x-ray absorption dosage is proposed in this study. To solve the ill-posed inverse problem, a reconstruction algorithm that combines the adaptive Tikhonov regularization method with the imaging model is implemented for CB-XLCT reconstruction. Numerical simulations and phantom experiments indicate that compared with the traditional forward model based on x-ray intensity, the proposed dose-based model could improve the image quality of CB-XLCT significantly in terms of target shape, localization accuracy, and image contrast. In addition, the proposed model behaves better in distinguishing closer targets, demonstrating its advantage in improving spatial resolution.

  2. X-Ray Computed Tomography of Tranquility Base Moon Rock

    Science.gov (United States)

    Jones, Justin S.; Garvin, Jim; Viens, Mike; Kent, Ryan; Munoz, Bruno

    2016-01-01

    X-ray Computed Tomography (CT) was used for the first time on the Apollo 11 Lunar Sample number 10057.30, which had been previously maintained by the White House, then transferred back to NASA under the care of Goddard Space Flight Center. Results from this analysis show detailed images of the internal structure of the moon rock, including vesicles (pores), crystal needles, and crystal bundles. These crystals, possibly the common mineral ilmenite, are found in abundance and with random orientation. Future work, in particular a greater understanding of these crystals and their formation, may lead to a more in-depth understanding of the lunar surface evolution and mineral content.

  3. X-ray-based attenuation correction for positron emission tomography/computed tomography scanners.

    Science.gov (United States)

    Kinahan, Paul E; Hasegawa, Bruce H; Beyer, Thomas

    2003-07-01

    A synergy of positron emission tomography (PET)/computed tomography (CT) scanners is the use of the CT data for x-ray-based attenuation correction of the PET emission data. Current methods of measuring transmission use positron sources, gamma-ray sources, or x-ray sources. Each of the types of transmission scans involves different trade-offs of noise versus bias, with positron transmission scans having the highest noise but lowest bias, whereas x-ray scans have negligible noise but the potential for increased quantitative errors. The use of x-ray-based attenuation correction, however, has other advantages, including a lack of bias introduced from post-injection transmission scanning, which is an important practical consideration for clinical scanners, as well as reduced scan times. The sensitivity of x-ray-based attenuation correction to artifacts and quantitative errors depends on the method of translating the CT image from the effective x-ray energy of approximately 70 keV to attenuation coefficients at the PET energy of 511 keV. These translation methods are usually based on segmentation and/or scaling techniques. Errors in the PET emission image arise from positional mismatches caused by patient motion or respiration differences between the PET and CT scans; incorrect calculation of attenuation coefficients for CT contrast agents or metallic implants; or keeping the patient's arms in the field of view, which leads to truncation and/or beam-hardening (or x-ray scatter) artifacts. Proper interpretation of PET emission images corrected for attenuation by using the CT image relies on an understanding of the potential artifacts. In cases where an artifact or bias is suspected, careful inspection of all three available images (CT and PET emission with and without attenuation correction) is recommended. Copyright 2003 Elsevier Inc. All rights reserved.

  4. A nanotube-based field emission x-ray source for microcomputed tomography

    International Nuclear Information System (INIS)

    Zhang, J.; Cheng, Y.; Lee, Y.Z.; Gao, B.; Qiu, Q.; Lin, W.L.; Lalush, D.; Lu, J.P.; Zhou, O.

    2005-01-01

    Microcomputed tomography (micro-CT) is a noninvasive imaging tool commonly used to probe the internal structures of small animals for biomedical research and for the inspection of microelectronics. Here we report the development of a micro-CT scanner with a carbon nanotube- (CNT-) based microfocus x-ray source. The performance of the CNT x-ray source and the imaging capability of the micro-CT scanner were characterized

  5. Hafnium-Based Contrast Agents for X-ray Computed Tomography.

    Science.gov (United States)

    Berger, Markus; Bauser, Marcus; Frenzel, Thomas; Hilger, Christoph Stephan; Jost, Gregor; Lauria, Silvia; Morgenstern, Bernd; Neis, Christian; Pietsch, Hubertus; Sülzle, Detlev; Hegetschweiler, Kaspar

    2017-05-15

    Heavy-metal-based contrast agents (CAs) offer enhanced X-ray absorption for X-ray computed tomography (CT) compared to the currently used iodinated CAs. We report the discovery of new lanthanide and hafnium azainositol complexes and their optimization with respect to high water solubility and stability. Our efforts culminated in the synthesis of BAY-576, an uncharged hafnium complex with 3:2 stoichiometry and broken complex symmetry. The superior properties of this asymmetrically substituted hafnium CA were demonstrated by a CT angiography study in rabbits that revealed excellent signal contrast enhancement.

  6. Three Dimensional Digital Sieving of Asphalt Mixture Based on X-ray Computed Tomography

    OpenAIRE

    Chichun Hu; Jiexian Ma; M. Emin Kutay

    2017-01-01

    In order to perform three-dimensional digital sieving based on X-ray computed tomography images, the definition of digital sieve size (DSS) was proposed, which was defined as the minimum length of the minimum bounding squares of all possible orthographic projections of an aggregate. The corresponding program was developed to reconstruct aggregate structure and to obtain DSS. Laboratory experiments consisting of epoxy-filled aggregate specimens were conducted to investigate the difference betw...

  7. Cone Beam X-ray Luminescence Computed Tomography Based on Bayesian Method.

    Science.gov (United States)

    Zhang, Guanglei; Liu, Fei; Liu, Jie; Luo, Jianwen; Xie, Yaoqin; Bai, Jing; Xing, Lei

    2017-01-01

    X-ray luminescence computed tomography (XLCT), which aims to achieve molecular and functional imaging by X-rays, has recently been proposed as a new imaging modality. Combining the principles of X-ray excitation of luminescence-based probes and optical signal detection, XLCT naturally fuses functional and anatomical images and provides complementary information for a wide range of applications in biomedical research. In order to improve the data acquisition efficiency of previously developed narrow-beam XLCT, a cone beam XLCT (CB-XLCT) mode is adopted here to take advantage of the useful geometric features of cone beam excitation. Practically, a major hurdle in using cone beam X-ray for XLCT is that the inverse problem here is seriously ill-conditioned, hindering us to achieve good image quality. In this paper, we propose a novel Bayesian method to tackle the bottleneck in CB-XLCT reconstruction. The method utilizes a local regularization strategy based on Gaussian Markov random field to mitigate the ill-conditioness of CB-XLCT. An alternating optimization scheme is then used to automatically calculate all the unknown hyperparameters while an iterative coordinate descent algorithm is adopted to reconstruct the image with a voxel-based closed-form solution. Results of numerical simulations and mouse experiments show that the self-adaptive Bayesian method significantly improves the CB-XLCT image quality as compared with conventional methods.

  8. Grating-based X-ray Dark-field Computed Tomography of Living Mice.

    Science.gov (United States)

    Velroyen, A; Yaroshenko, A; Hahn, D; Fehringer, A; Tapfer, A; Müller, M; Noël, P B; Pauwels, B; Sasov, A; Yildirim, A Ö; Eickelberg, O; Hellbach, K; Auweter, S D; Meinel, F G; Reiser, M F; Bech, M; Pfeiffer, F

    2015-10-01

    Changes in x-ray attenuating tissue caused by lung disorders like emphysema or fibrosis are subtle and thus only resolved by high-resolution computed tomography (CT). The structural reorganization, however, is of strong influence for lung function. Dark-field CT (DFCT), based on small-angle scattering of x-rays, reveals such structural changes even at resolutions coarser than the pulmonary network and thus provides access to their anatomical distribution. In this proof-of-concept study we present x-ray in vivo DFCTs of lungs of a healthy, an emphysematous and a fibrotic mouse. The tomographies show excellent depiction of the distribution of structural - and thus indirectly functional - changes in lung parenchyma, on single-modality slices in dark field as well as on multimodal fusion images. Therefore, we anticipate numerous applications of DFCT in diagnostic lung imaging. We introduce a scatter-based Hounsfield Unit (sHU) scale to facilitate comparability of scans. In this newly defined sHU scale, the pathophysiological changes by emphysema and fibrosis cause a shift towards lower numbers, compared to healthy lung tissue.

  9. Model-based image reconstruction in X-ray computed tomography

    NARCIS (Netherlands)

    Zbijewski, Wojciech Bartosz

    2006-01-01

    The thesis investigates the applications of iterative, statistical reconstruction (SR) algorithms in X-ray Computed Tomography. Emphasis is put on various aspects of system modeling in statistical reconstruction. Fundamental issues such as effects of object discretization and algorithm

  10. Sensitivity of photon-counting based K-edge imaging in X-ray computed tomography.

    Science.gov (United States)

    Roessl, Ewald; Brendel, Bernhard; Engel, Klaus-Jürgen; Schlomka, Jens-Peter; Thran, Axel; Proksa, Roland

    2011-09-01

    The feasibility of K-edge imaging using energy-resolved, photon-counting transmission measurements in X-ray computed tomography (CT) has been demonstrated by simulations and experiments. The method is based on probing the discontinuities of the attenuation coefficient of heavy elements above and below the K-edge energy by using energy-sensitive, photon counting X-ray detectors. In this paper, we investigate the dependence of the sensitivity of K-edge imaging on the atomic number Z of the contrast material, on the object diameter D , on the spectral response of the X-ray detector and on the X-ray tube voltage. We assume a photon-counting detector equipped with six adjustable energy thresholds. Physical effects leading to a degradation of the energy resolution of the detector are taken into account using the concept of a spectral response function R(E,U) for which we assume four different models. As a validation of our analytical considerations and in order to investigate the influence of elliptically shaped phantoms, we provide CT simulations of an anthropomorphic Forbild-Abdomen phantom containing a gold-contrast agent. The dependence on the values of the energy thresholds is taken into account by optimizing the achievable signal-to-noise ratios (SNR) with respect to the threshold values. We find that for a given X-ray spectrum and object size the SNR in the heavy element's basis material image peaks for a certain atomic number Z. The dependence of the SNR in the high- Z basis-material image on the object diameter is the natural, exponential decrease with particularly deteriorating effects in the case where the attenuation from the object itself causes a total signal loss below the K-edge. The influence of the energy-response of the detector is very important. We observed that the optimal SNR values obtained with an ideal detector and with a CdTe pixel detector whose response, showing significant tailing, has been determined at a synchrotron differ by factors of

  11. Noise texture and signal detectability in propagation-based x-ray phase-contrast tomography

    International Nuclear Information System (INIS)

    Chou, Cheng-Ying; Anastasio, Mark A.

    2010-01-01

    Purpose: X-ray phase-contrast tomography (PCT) is a rapidly emerging imaging modality for reconstructing estimates of an object's three-dimensional x-ray refractive index distribution. Unlike conventional x-ray computed tomography methods, the statistical properties of the reconstructed images in PCT remain unexplored. The purpose of this work is to quantitatively investigate noise propagation in PCT image reconstruction. Methods: The authors derived explicit expressions for the autocovariance of the reconstructed absorption and refractive index images to characterize noise texture and understand how the noise properties are influenced by the imaging geometry. Concepts from statistical detection theory were employed to understand how the imaging geometry-dependent statistical properties affect the signal detection performance in a signal-known-exactly/background-known-exactly task. Results: The analytical formulas for the phase and absorption autocovariance functions were implemented numerically and compared to the corresponding empirical values, and excellent agreement was found. They observed that the reconstructed refractive images are highly spatially correlated, while the absorption images are not. The numerical results confirm that the strength of the covariance is scaled by the detector spacing. Signal detection studies were conducted, employing a numerical observer. The detection performance was found to monotonically increase as the detector-plane spacing was increased. Conclusions: The authors have conducted the first quantitative investigation of noise propagation in PCT image reconstruction. The reconstructed refractive images were found to be highly spatially correlated, while absorption images were not. This is due to the presence of a Fourier space singularity in the reconstruction formula for the refraction images. The statistical analysis may facilitate the use of task-based image quality measures to further develop and optimize this emerging

  12. Noise texture and signal detectability in propagation-based x-ray phase-contrast tomography

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Cheng-Ying; Anastasio, Mark A. [Department of Bio-Industrial Mechatronics Engineering, National Taiwan University, 1, Section 4, Roosevelt Road, Taipei, Taiwan 106, Taiwan (China); Department of Biomedical Engineering, Medical Imaging Research Center, Illinois Institute of Technology, 3440 S. Dearborn Street, E1-116, Chicago, Illinois 60616 (United States)

    2010-01-15

    Purpose: X-ray phase-contrast tomography (PCT) is a rapidly emerging imaging modality for reconstructing estimates of an object's three-dimensional x-ray refractive index distribution. Unlike conventional x-ray computed tomography methods, the statistical properties of the reconstructed images in PCT remain unexplored. The purpose of this work is to quantitatively investigate noise propagation in PCT image reconstruction. Methods: The authors derived explicit expressions for the autocovariance of the reconstructed absorption and refractive index images to characterize noise texture and understand how the noise properties are influenced by the imaging geometry. Concepts from statistical detection theory were employed to understand how the imaging geometry-dependent statistical properties affect the signal detection performance in a signal-known-exactly/background-known-exactly task. Results: The analytical formulas for the phase and absorption autocovariance functions were implemented numerically and compared to the corresponding empirical values, and excellent agreement was found. They observed that the reconstructed refractive images are highly spatially correlated, while the absorption images are not. The numerical results confirm that the strength of the covariance is scaled by the detector spacing. Signal detection studies were conducted, employing a numerical observer. The detection performance was found to monotonically increase as the detector-plane spacing was increased. Conclusions: The authors have conducted the first quantitative investigation of noise propagation in PCT image reconstruction. The reconstructed refractive images were found to be highly spatially correlated, while absorption images were not. This is due to the presence of a Fourier space singularity in the reconstruction formula for the refraction images. The statistical analysis may facilitate the use of task-based image quality measures to further develop and optimize this emerging

  13. Film-based X-ray tomography combined with digital image processing: investigation of an ancient pattern-welded sword

    International Nuclear Information System (INIS)

    Lindegaard-Andersen, A.; Vedel, T.; Jeppesen, L.; Gottlieb, B.

    1988-01-01

    Film-based X-ray tomography and digital image processing have been used to investigate an inhomogeneous object of non-circular cross-section. The feasibility of using digital image processing to compensate for the poor contrast resolution inherent in film-based tomography has been demonstrated. (author)

  14. Contextual Multivariate Segmentation of Pork Tissue from Grating-Based Multimodal X-Ray Tomography

    DEFF Research Database (Denmark)

    Einarsdottir, Hildur; Nielsen, Mikkel S.; Ersbøll, Bjarne Kjær

    2013-01-01

    have made novel X-ray image modalities available, where the refraction and scattering of X-rays is obtained simultaneously with the absorption properties, providing enhanced contrast for soft biological tissues. This paper demonstrates how data obtained from grating-based imaging can be segmented...

  15. Breast tumor segmentation in high resolution x-ray phase contrast analyzer based computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Brun, E., E-mail: emmanuel.brun@esrf.fr [European Synchrotron Radiation Facility (ESRF), Grenoble 380000, France and Department of Physics, Ludwig-Maximilians University, Garching 85748 (Germany); Grandl, S.; Sztrókay-Gaul, A.; Gasilov, S. [Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, 81377 Munich (Germany); Barbone, G. [Department of Physics, Harvard University, Cambridge, Massachusetts 02138 (United States); Mittone, A.; Coan, P. [Department of Physics, Ludwig-Maximilians University, Garching 85748, Germany and Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, 81377 Munich (Germany); Bravin, A. [European Synchrotron Radiation Facility (ESRF), Grenoble 380000 (France)

    2014-11-01

    Purpose: Phase contrast computed tomography has emerged as an imaging method, which is able to outperform present day clinical mammography in breast tumor visualization while maintaining an equivalent average dose. To this day, no segmentation technique takes into account the specificity of the phase contrast signal. In this study, the authors propose a new mathematical framework for human-guided breast tumor segmentation. This method has been applied to high-resolution images of excised human organs, each of several gigabytes. Methods: The authors present a segmentation procedure based on the viscous watershed transform and demonstrate the efficacy of this method on analyzer based phase contrast images. The segmentation of tumors inside two full human breasts is then shown as an example of this procedure’s possible applications. Results: A correct and precise identification of the tumor boundaries was obtained and confirmed by manual contouring performed independently by four experienced radiologists. Conclusions: The authors demonstrate that applying the watershed viscous transform allows them to perform the segmentation of tumors in high-resolution x-ray analyzer based phase contrast breast computed tomography images. Combining the additional information provided by the segmentation procedure with the already high definition of morphological details and tissue boundaries offered by phase contrast imaging techniques, will represent a valuable multistep procedure to be used in future medical diagnostic applications.

  16. Breast tumor segmentation in high resolution x-ray phase contrast analyzer based computed tomography.

    Science.gov (United States)

    Brun, E; Grandl, S; Sztrókay-Gaul, A; Barbone, G; Mittone, A; Gasilov, S; Bravin, A; Coan, P

    2014-11-01

    Phase contrast computed tomography has emerged as an imaging method, which is able to outperform present day clinical mammography in breast tumor visualization while maintaining an equivalent average dose. To this day, no segmentation technique takes into account the specificity of the phase contrast signal. In this study, the authors propose a new mathematical framework for human-guided breast tumor segmentation. This method has been applied to high-resolution images of excised human organs, each of several gigabytes. The authors present a segmentation procedure based on the viscous watershed transform and demonstrate the efficacy of this method on analyzer based phase contrast images. The segmentation of tumors inside two full human breasts is then shown as an example of this procedure's possible applications. A correct and precise identification of the tumor boundaries was obtained and confirmed by manual contouring performed independently by four experienced radiologists. The authors demonstrate that applying the watershed viscous transform allows them to perform the segmentation of tumors in high-resolution x-ray analyzer based phase contrast breast computed tomography images. Combining the additional information provided by the segmentation procedure with the already high definition of morphological details and tissue boundaries offered by phase contrast imaging techniques, will represent a valuable multistep procedure to be used in future medical diagnostic applications.

  17. X-ray microtome by fluorescence tomography

    CERN Document Server

    Simionovici, A S; Guenzler, F; Schrör, C; Snigirev, A; Snigireva, I; Tümmler, J; Weitkamp, T

    2001-01-01

    The X-ray fluorescence microtomography method is presented, which is capable of virtually slicing samples to obtain cross-sections of their inner structure. High precision experimental results of fluo-tomography in 'pencil-beam' geometry with up to 1.2 mu m resolution are described. Image reconstructions are based on either a simplified algebraic reconstruction method (ART) or the filtered back-projection method (FBP). Phantoms of inhomogeneous test objects as well as biological samples are successfully analyzed.

  18. X-ray computed tomography

    International Nuclear Information System (INIS)

    Kalender, Willi A

    2006-01-01

    X-ray computed tomography (CT), introduced into clinical practice in 1972, was the first of the modern slice-imaging modalities. To reconstruct images mathematically from measured data and to display and to archive them in digital form was a novelty then and is commonplace today. CT has shown a steady upward trend with respect to technology, performance and clinical use independent of predictions and expert assessments which forecast in the 1980s that it would be completely replaced by magnetic resonance imaging. CT not only survived but exhibited a true renaissance due to the introduction of spiral scanning which meant the transition from slice-by-slice imaging to true volume imaging. Complemented by the introduction of array detector technology in the 1990s, CT today allows imaging of whole organs or the whole body in 5 to 20 s with sub-millimetre isotropic resolution. This review of CT will proceed in chronological order focussing on technology, image quality and clinical applications. In its final part it will also briefly allude to novel uses of CT such as dual-source CT, C-arm flat-panel-detector CT and micro-CT. At present CT possibly exhibits a higher innovation rate than ever before. In consequence the topical and most recent developments will receive the greatest attention. (review)

  19. Review of X-ray Tomography and X-ray Fluorescence Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Shear, Trevor A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-03-16

    This literature review will focus on both laboratory and synchrotron based X-ray tomography of materials and highlight the inner workings of these instruments. X-ray fluorescence spectroscopy will also be reviewed and applications of the tandem use of these techniques will be explored. The real world application of these techniques during the internship will also be discussed.

  20. Three Dimensional Digital Sieving of Asphalt Mixture Based on X-ray Computed Tomography

    Directory of Open Access Journals (Sweden)

    Chichun Hu

    2017-07-01

    Full Text Available In order to perform three-dimensional digital sieving based on X-ray computed tomography images, the definition of digital sieve size (DSS was proposed, which was defined as the minimum length of the minimum bounding squares of all possible orthographic projections of an aggregate. The corresponding program was developed to reconstruct aggregate structure and to obtain DSS. Laboratory experiments consisting of epoxy-filled aggregate specimens were conducted to investigate the difference between mechanical sieve analysis and the digital sieving technique. It was suggested that concave surface of aggregate was the possible reason for the disparity between DSS and mechanical sieve size. A comparison between DSS and equivalent diameter was also performed. Moreover, the digital sieving technique was adopted to evaluate the gradation of stone mastic asphalt mixtures. The results showed that the closest proximity of the laboratory gradation curve was achieved by calibrated DSS, among gradation curves based on calibrated DSS, un-calibrated DSS and equivalent diameter.

  1. Quantitative cone beam X-ray luminescence tomography/X-ray computed tomography imaging

    International Nuclear Information System (INIS)

    Chen, Dongmei; Zhu, Shouping; Chen, Xueli; Chao, Tiantian; Cao, Xu; Zhao, Fengjun; Huang, Liyu; Liang, Jimin

    2014-01-01

    X-ray luminescence tomography (XLT) is an imaging technology based on X-ray-excitable materials. The main purpose of this paper is to obtain quantitative luminescence concentration using the structural information of the X-ray computed tomography (XCT) in the hybrid cone beam XLT/XCT system. A multi-wavelength luminescence cone beam XLT method with the structural a priori information is presented to relieve the severe ill-posedness problem in the cone beam XLT. The nanophosphors and phantom experiments were undertaken to access the linear relationship of the system response. Then, an in vivo mouse experiment was conducted. The in vivo experimental results show that the recovered concentration error as low as 6.67% with the location error of 0.85 mm can be achieved. The results demonstrate that the proposed method can accurately recover the nanophosphor inclusion and realize the quantitative imaging

  2. Information-theoretic discrepancy based iterative reconstructions (IDIR) for polychromatic x-ray tomography

    International Nuclear Information System (INIS)

    Jang, Kwang Eun; Lee, Jongha; Sung, Younghun; Lee, SeongDeok

    2013-01-01

    Purpose: X-ray photons generated from a typical x-ray source for clinical applications exhibit a broad range of wavelengths, and the interactions between individual particles and biological substances depend on particles' energy levels. Most existing reconstruction methods for transmission tomography, however, neglect this polychromatic nature of measurements and rely on the monochromatic approximation. In this study, we developed a new family of iterative methods that incorporates the exact polychromatic model into tomographic image recovery, which improves the accuracy and quality of reconstruction.Methods: The generalized information-theoretic discrepancy (GID) was employed as a new metric for quantifying the distance between the measured and synthetic data. By using special features of the GID, the objective function for polychromatic reconstruction which contains a double integral over the wavelength and the trajectory of incident x-rays was simplified to a paraboloidal form without using the monochromatic approximation. More specifically, the original GID was replaced with a surrogate function with two auxiliary, energy-dependent variables. Subsequently, the alternating minimization technique was applied to solve the double minimization problem. Based on the optimization transfer principle, the objective function was further simplified to the paraboloidal equation, which leads to a closed-form update formula. Numerical experiments on the beam-hardening correction and material-selective reconstruction were conducted to compare and assess the performance of conventional methods and the proposed algorithms.Results: The authors found that the GID determines the distance between its two arguments in a flexible manner. In this study, three groups of GIDs with distinct data representations were considered. The authors demonstrated that one type of GIDs that comprises “raw” data can be viewed as an extension of existing statistical reconstructions; under a

  3. Limited-angle tomography for analyzer-based phase-contrast x-ray imaging

    International Nuclear Information System (INIS)

    Majidi, Keivan; Wernick, Miles N; Brankov, Jovan G; Li, Jun; Muehleman, Carol

    2014-01-01

    Multiple-image radiography (MIR) is an analyzer-based phase-contrast x-ray imaging method, which is emerging as a potential alternative to conventional radiography. MIR simultaneously generates three planar parametric images containing information about scattering, refraction and attenuation properties of the object. The MIR planar images are linear tomographic projections of the corresponding object properties, which allows reconstruction of volumetric images using computed tomography (CT) methods. However, when acquiring a full range of linear projections around the tissue of interest is not feasible or the scanning time is limited, limited-angle tomography techniques can be used to reconstruct these volumetric images near the central plane, which is the plane that contains the pivot point of the tomographic movement. In this work, we use computer simulations to explore the applicability of limited-angle tomography to MIR. We also investigate the accuracy of reconstructions as a function of number of tomographic angles for a fixed total radiation exposure. We use this function to find an optimal range of angles over which data should be acquired for limited-angle tomography MIR (LAT-MIR). Next, we apply the LAT-MIR technique to experimentally acquired MIR projections obtained in a cadaveric human thumb study. We compare the reconstructed slices near the central plane to the same slices reconstructed by CT-MIR using the full angular view around the object. Finally, we perform a task-based evaluation of LAT-MIR performance for different numbers of angular views, and use template matching to detect cartilage in the refraction image near the central plane. We use the signal-to-noise ratio of this test as the detectability metric to investigate an optimum range of tomographic angles for detecting soft tissues in LAT-MIR. Both results show that there is an optimum range of angular view for data acquisition where LAT-MIR yields the best performance, comparable to CT

  4. Limited-angle tomography for analyzer-based phase-contrast x-ray imaging

    Science.gov (United States)

    Majidi, Keivan; Wernick, Miles N.; Li, Jun; Muehleman, Carol; Brankov, Jovan G.

    2014-07-01

    Multiple-image radiography (MIR) is an analyzer-based phase-contrast x-ray imaging method, which is emerging as a potential alternative to conventional radiography. MIR simultaneously generates three planar parametric images containing information about scattering, refraction and attenuation properties of the object. The MIR planar images are linear tomographic projections of the corresponding object properties, which allows reconstruction of volumetric images using computed tomography (CT) methods. However, when acquiring a full range of linear projections around the tissue of interest is not feasible or the scanning time is limited, limited-angle tomography techniques can be used to reconstruct these volumetric images near the central plane, which is the plane that contains the pivot point of the tomographic movement. In this work, we use computer simulations to explore the applicability of limited-angle tomography to MIR. We also investigate the accuracy of reconstructions as a function of number of tomographic angles for a fixed total radiation exposure. We use this function to find an optimal range of angles over which data should be acquired for limited-angle tomography MIR (LAT-MIR). Next, we apply the LAT-MIR technique to experimentally acquired MIR projections obtained in a cadaveric human thumb study. We compare the reconstructed slices near the central plane to the same slices reconstructed by CT-MIR using the full angular view around the object. Finally, we perform a task-based evaluation of LAT-MIR performance for different numbers of angular views, and use template matching to detect cartilage in the refraction image near the central plane. We use the signal-to-noise ratio of this test as the detectability metric to investigate an optimum range of tomographic angles for detecting soft tissues in LAT-MIR. Both results show that there is an optimum range of angular view for data acquisition where LAT-MIR yields the best performance, comparable to CT

  5. Quantitative Analysis of Micro-Structure in Meat Emulsions from Grating-Based Multimodal X-Ray Tomography

    DEFF Research Database (Denmark)

    Einarsdottir, Hildur; Nielsen, Mikkel Schou; Miklos, Rikke

    2013-01-01

    Using novel X-ray techniques, based on grating-interferometry, new imaging modalities can be obtained simultaneously with absorption computed tomography (CT). These modalities, called phase contrast and dark field imaging, measure the electron density and the diffusion length of the sample....... Enhanced contrast capabilities of this X-ray technique makes studies on materials with similar attenuation properties possible. In this paper the focus is set on processing grating-based X-ray tomograms of meat emulsions to quantitatively measure micro-structural changes due to heat treatment. The emulsion...... samples were imaged both in a raw and cooked state. Additionally, different fat types were used in the emulsions in order to compare micro-structural differences when either pork fat or sunflower oil was used. From the reconstructed tomograms the different ingredients in the emulsions were segmented using...

  6. Grating-based X-ray tomography of 3D food structures

    DEFF Research Database (Denmark)

    Miklos, Rikke; Nielsen, Mikkel Schou; Einarsdottir, Hildur

    2016-01-01

    A novel grating based X-ray phase-contrast tomographic method has been used to study how partly substitution of meat proteins with two different types of soy proteins affect the structure of the formed protein gel in meat emulsions. The measurements were performed at the Swiss synchrotron radiati...

  7. Image-based metal artifact reduction in x-ray computed tomography utilizing local anatomical similarity

    Science.gov (United States)

    Dong, Xue; Yang, Xiaofeng; Rosenfield, Jonathan; Elder, Eric; Dhabaan, Anees

    2017-03-01

    X-ray computed tomography (CT) is widely used in radiation therapy treatment planning in recent years. However, metal implants such as dental fillings and hip prostheses can cause severe bright and dark streaking artifacts in reconstructed CT images. These artifacts decrease image contrast and degrade HU accuracy, leading to inaccuracies in target delineation and dose calculation. In this work, a metal artifact reduction method is proposed based on the intrinsic anatomical similarity between neighboring CT slices. Neighboring CT slices from the same patient exhibit similar anatomical features. Exploiting this anatomical similarity, a gamma map is calculated as a weighted summation of relative HU error and distance error for each pixel in an artifact-corrupted CT image relative to a neighboring, artifactfree image. The minimum value in the gamma map for each pixel is used to identify an appropriate pixel from the artifact-free CT slice to replace the corresponding artifact-corrupted pixel. With the proposed method, the mean CT HU error was reduced from 360 HU and 460 HU to 24 HU and 34 HU on head and pelvis CT images, respectively. Dose calculation accuracy also improved, as the dose difference was reduced from greater than 20% to less than 4%. Using 3%/3mm criteria, the gamma analysis failure rate was reduced from 23.25% to 0.02%. An image-based metal artifact reduction method is proposed that replaces corrupted image pixels with pixels from neighboring CT slices free of metal artifacts. This method is shown to be capable of suppressing streaking artifacts, thereby improving HU and dose calculation accuracy.

  8. Cone Beam X-Ray Luminescence Tomography Imaging Based on KA-FEM Method for Small Animals.

    Science.gov (United States)

    Chen, Dongmei; Meng, Fanzhen; Zhao, Fengjun; Xu, Cao

    2016-01-01

    Cone beam X-ray luminescence tomography can realize fast X-ray luminescence tomography imaging with relatively low scanning time compared with narrow beam X-ray luminescence tomography. However, cone beam X-ray luminescence tomography suffers from an ill-posed reconstruction problem. First, the feasibility of experiments with different penetration and multispectra in small animal has been tested using nanophosphor material. Then, the hybrid reconstruction algorithm with KA-FEM method has been applied in cone beam X-ray luminescence tomography for small animals to overcome the ill-posed reconstruction problem, whose advantage and property have been demonstrated in fluorescence tomography imaging. The in vivo mouse experiment proved the feasibility of the proposed method.

  9. Pollen structure visualization using high-resolution laboratory-based hard X-ray tomography.

    Science.gov (United States)

    Li, Qiong; Gluch, Jürgen; Krüger, Peter; Gall, Martin; Neinhuis, Christoph; Zschech, Ehrenfried

    2016-10-14

    A laboratory-based X-ray microscope is used to investigate the 3D structure of unstained whole pollen grains. For the first time, high-resolution laboratory-based hard X-ray microscopy is applied to study pollen grains. Based on the efficient acquisition of statistically relevant information-rich images using Zernike phase contrast, both surface- and internal structures of pine pollen - including exine, intine and cellular structures - are clearly visualized. The specific volumes of these structures are calculated from the tomographic data. The systematic three-dimensional study of pollen grains provides morphological and structural information about taxonomic characters that are essential in palynology. Such studies have a direct impact on disciplines such as forestry, agriculture, horticulture, plant breeding and biodiversity. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Energy-angle correlation correction algorithm for monochromatic computed tomography based on Thomson scattering X-ray source

    Science.gov (United States)

    Chi, Zhijun; Du, Yingchao; Huang, Wenhui; Tang, Chuanxiang

    2017-12-01

    The necessity for compact and relatively low cost x-ray sources with monochromaticity, continuous tunability of x-ray energy, high spatial coherence, straightforward polarization control, and high brightness has led to the rapid development of Thomson scattering x-ray sources. To meet the requirement of in-situ monochromatic computed tomography (CT) for large-scale and/or high-attenuation materials based on this type of x-ray source, there is an increasing demand for effective algorithms to correct the energy-angle correlation. In this paper, we take advantage of the parametrization of the x-ray attenuation coefficient to resolve this problem. The linear attenuation coefficient of a material can be decomposed into a linear combination of the energy-dependent photoelectric and Compton cross-sections in the keV energy regime without K-edge discontinuities, and the line integrals of the decomposition coefficients of the above two parts can be determined by performing two spectrally different measurements. After that, the line integral of the linear attenuation coefficient of an imaging object at a certain interested energy can be derived through the above parametrization formula, and monochromatic CT can be reconstructed at this energy using traditional reconstruction methods, e.g., filtered back projection or algebraic reconstruction technique. Not only can monochromatic CT be realized, but also the distributions of the effective atomic number and electron density of the imaging object can be retrieved at the expense of dual-energy CT scan. Simulation results validate our proposal and will be shown in this paper. Our results will further expand the scope of application for Thomson scattering x-ray sources.

  11. Feature-based analysis for quality assessment of x-ray computed tomography measurements

    International Nuclear Information System (INIS)

    Nardelli, Vitor C; Arenhart, Francisco A; Donatelli, Gustavo D; Porath, Maurício C; Niggemann, Christian; Schmitt, Robert

    2012-01-01

    This paper presents an approach to assess the quality of the data extracted with computed tomography (CT) measuring systems to perform geometrical evaluations. The approach consists in analyzing the error features introduced by the CT measuring system during the extraction operation. The analysis of the features is performed qualitatively (using graphical analysis tools) and/or quantitatively (by means of the root-mean-square deviation parameter of the error features). The approach was used to analyze four sets of measurements performed with an industrial x-ray cone beam CT measuring system. Three test parts were used in the experiments: a high accuracy manufacturing multi-wave standard, a calibrated step cylinder and a calibrated production part. The results demonstrate the usefulness of the approach to gain knowledge on CT measuring processes and improve the quality of CT geometrical evaluations. Advantages and limitations of the approach are discussed. (paper)

  12. The color of X-rays: Spectral X-ray computed tomography using energy sensitive pixel detectors

    NARCIS (Netherlands)

    Schioppa, E.J.

    2014-01-01

    Energy sensitive X-ray imaging detectors are produced by connecting a semiconductor sensor to a spectroscopic pixel readout chip. In this thesis, the applicability of such detectors to X-ray Computed Tomography (CT) is studied. A prototype Medipix based silicon detector is calibrated using X-ray

  13. A compressed sensing based reconstruction algorithm for synchrotron source propagation-based X-ray phase contrast computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Melli, Seyed Ali, E-mail: sem649@mail.usask.ca [Department of Electrical and Computer Engineering, University of Saskatchewan, Saskatoon, SK (Canada); Wahid, Khan A. [Department of Electrical and Computer Engineering, University of Saskatchewan, Saskatoon, SK (Canada); Babyn, Paul [Department of Medical Imaging, University of Saskatchewan, Saskatoon, SK (Canada); Montgomery, James [College of Medicine, University of Saskatchewan, Saskatoon, SK (Canada); Snead, Elisabeth [Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK (Canada); El-Gayed, Ali [College of Medicine, University of Saskatchewan, Saskatoon, SK (Canada); Pettitt, Murray; Wolkowski, Bailey [College of Agriculture and Bioresources, University of Saskatchewan, Saskatoon, SK (Canada); Wesolowski, Michal [Department of Medical Imaging, University of Saskatchewan, Saskatoon, SK (Canada)

    2016-01-11

    Synchrotron source propagation-based X-ray phase contrast computed tomography is increasingly used in pre-clinical imaging. However, it typically requires a large number of projections, and subsequently a large radiation dose, to produce high quality images. To improve the applicability of this imaging technique, reconstruction algorithms that can reduce the radiation dose and acquisition time without degrading image quality are needed. The proposed research focused on using a novel combination of Douglas–Rachford splitting and randomized Kaczmarz algorithms to solve large-scale total variation based optimization in a compressed sensing framework to reconstruct 2D images from a reduced number of projections. Visual assessment and quantitative performance evaluations of a synthetic abdomen phantom and real reconstructed image of an ex-vivo slice of canine prostate tissue demonstrate that the proposed algorithm is competitive in reconstruction process compared with other well-known algorithms. An additional potential benefit of reducing the number of projections would be reduction of time for motion artifact to occur if the sample moves during image acquisition. Use of this reconstruction algorithm to reduce the required number of projections in synchrotron source propagation-based X-ray phase contrast computed tomography is an effective form of dose reduction that may pave the way for imaging of in-vivo samples.

  14. Radiomics-based differentiation of lung disease models generated by polluted air based on X-ray computed tomography data.

    Science.gov (United States)

    Szigeti, Krisztián; Szabó, Tibor; Korom, Csaba; Czibak, Ilona; Horváth, Ildikó; Veres, Dániel S; Gyöngyi, Zoltán; Karlinger, Kinga; Bergmann, Ralf; Pócsik, Márta; Budán, Ferenc; Máthé, Domokos

    2016-02-11

    Lung diseases (resulting from air pollution) require a widely accessible method for risk estimation and early diagnosis to ensure proper and responsive treatment. Radiomics-based fractal dimension analysis of X-ray computed tomography attenuation patterns in chest voxels of mice exposed to different air polluting agents was performed to model early stages of disease and establish differential diagnosis. To model different types of air pollution, BALBc/ByJ mouse groups were exposed to cigarette smoke combined with ozone, sulphur dioxide gas and a control group was established. Two weeks after exposure, the frequency distributions of image voxel attenuation data were evaluated. Specific cut-off ranges were defined to group voxels by attenuation. Cut-off ranges were binarized and their spatial pattern was associated with calculated fractal dimension, then abstracted by the fractal dimension -- cut-off range mathematical function. Nonparametric Kruskal-Wallis (KW) and Mann-Whitney post hoc (MWph) tests were used. Each cut-off range versus fractal dimension function plot was found to contain two distinctive Gaussian curves. The ratios of the Gaussian curve parameters are considerably significant and are statistically distinguishable within the three exposure groups. A new radiomics evaluation method was established based on analysis of the fractal dimension of chest X-ray computed tomography data segments. The specific attenuation patterns calculated utilizing our method may diagnose and monitor certain lung diseases, such as chronic obstructive pulmonary disease (COPD), asthma, tuberculosis or lung carcinomas.

  15. Lab-based x-ray tomography of a cochlear implant using energy discriminating detectors for metal artefact reduction

    Science.gov (United States)

    Yokhana, Viona S. K.; Arhatari, Benedicta D.; Gureyev, Timur E.; Abbey, Brian

    2018-01-01

    X-ray computed tomography (XCT) is an important clinical diagnostic tool which is also used in a range of biological imaging applications in research. The increasing prevalence of metallic implants in medical and dental radiography and tomography has driven the demand for new approaches to solving the issue of metal artefacts in XCT. Metal artefacts occur when a highly absorbing material is imaged which is in boundary contact with one or more weakly absorbing components, such as soft-tissue. The resulting `streaking' in the reconstructed images creates significant challenges for X-ray analysis due to the non-linear dependence on the absorption properties of the sample. In this paper we introduce a new approach to removing metal artefacts which exploits the capabilities of the recently available, photon-counting PiXirad detector. Our approach works for standard lab-based polychromatic X-ray tubes and does not rely on any postprocessing of the data. The method is demonstrated using both simulated data from a test phantom and experimental data collected from a cochlear implant. The results show that by combining the individual images, which are simultaneously generated for each different energy threshold, artefact -free segmentation of the implant from the surrounding biological tissue is achieved.

  16. Physics of x-ray computed tomography

    International Nuclear Information System (INIS)

    Akutagawa, W.M.; Huth, G.C.

    1976-01-01

    Sections are included on theoretical limits of x-ray computed tomography and the relationship of these limits to human organ imaging and specific disease diagnosis; potential of x-ray computed tomography in detection of small calcified particles in early breast cancer detection; early lung cancer measurement and detection; advanced materials for ionizing radiation detection; positron system with circular ring transaxial tomographic camera; contrast mechanism of transmission scanner and algorithms; and status of design on a 200 keV scanning proton microprobe

  17. A simulation-based study on the influence of beam hardening in X-ray computed tomography for dimensional metrology.

    Science.gov (United States)

    Lifton, Joseph J; Malcolm, Andrew A; McBride, John W

    2015-01-01

    X-ray computed tomography (CT) is a radiographic scanning technique for visualising cross-sectional images of an object non-destructively. From these cross-sectional images it is possible to evaluate internal dimensional features of a workpiece which may otherwise be inaccessible to tactile and optical instruments. Beam hardening is a physical process that degrades the quality of CT images and has previously been suggested to influence dimensional measurements. Using a validated simulation tool, the influence of spectrum pre-filtration and beam hardening correction are evaluated for internal and external dimensional measurements. Beam hardening is shown to influence internal and external dimensions in opposition, and to have a greater influence on outer dimensions compared to inner dimensions. The results suggest the combination of spectrum pre-filtration and a local gradient-based surface determination method are able to greatly reduce the influence of beam hardening in X-ray CT for dimensional metrology.

  18. X-ray Compton line scan tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kupsch, Andreas; Lange, Axel; Jaenisch, Gerd-Ruediger [Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin (Germany). Fachgruppe 8.5 - Mikro-ZfP; Hentschel, Manfred P. [Technische Univ. Berlin (Germany); Kardjilov, Nikolay; Markoetter, Henning; Hilger, Andre; Manke, Ingo [Helmholtz-Zentrum Berlin (HZB) (Germany); Toetzke, Christian [Potsdam Univ. (Germany)

    2015-07-01

    The potentials of incoherent X-ray scattering (Compton) computed tomography (CT) are investigated. The imaging of materials of very different atomic number or density at once is generally a perpetual challenge for X-ray tomography or radiography. In a basic laboratory set-up for simultaneous perpendicular Compton scattering and direct beam attenuation tomography are conducted by single channel photon counting line scans. This results in asymmetric distortions of the projection profiles of the scattering CT data set. In a first approach, corrections of Compton scattering data by taking advantage of rotational symmetry yield tomograms without major geometric artefacts. A cylindrical sample composed of PE, PA, PVC, glass and wood demonstrates similar Compton contrast for all the substances, while the conventional absorption tomogram only reveals the two high order materials. Comparison to neutron tomography reveals astonishing similarities except for the glass component (without hydrogen). Therefore, Compton CT offers the potential to replace neutron tomography, which requires much more efforts.

  19. X-ray Computed Tomography.

    Science.gov (United States)

    Michael, Greg

    2001-01-01

    Describes computed tomography (CT), a medical imaging technique that produces images of transaxial planes through the human body. A CT image is reconstructed mathematically from a large number of one-dimensional projections of a plane. The technique is used in radiological examinations and radiotherapy treatment planning. (Author/MM)

  20. 4D nano-tomography of electrochemical energy devices using lab-based X-ray imaging

    Energy Technology Data Exchange (ETDEWEB)

    Heenan, T. M. M.; Finegan, D. P.; Tjaden, B.; Lu, X.; Iacoviello, F.; Millichamp, J.; Brett, D. J. L.; Shearing, P. R.

    2018-05-01

    Electrochemical energy devices offer a variety of alternate means for low-carbon, multi-scale energy conversion and storage. Reactions in these devices are supported by electrodes with characteristically complex microstructures. To meet the increasing capacity and lifetime demands across a range of applications, it is essential to understand microstructural evolutions at a cell and electrode level which are thought to be critical aspects influencing material and device lifetime and performance. X-ray computed tomography (CT) has become a highly employed method for non-destructive characterisation of such microstructures with high spatial resolution. However, sub-micron resolutions present significant challenges for sample preparation and handling particularly in 4D studies, (three spatial dimensions plus time). Here, microstructural information is collected from the same region of interest within two electrode materials: a solid oxide fuel cell and the positive electrode from a lithium-ion battery. Using a lab-based X-ray instrument, tomograms with sub-micron resolutions were obtained between thermal cycling. The intricate microstructural evolutions captured within these two materials provide model examples of 4D X-ray nano-CT capabilities in tracking challenging degradation mechanisms. This technique is valuable in the advancement of electrochemical research as well as broader applications for materials characterisation.

  1. Radiomics-based differentiation of lung disease models generated by polluted air based on X-ray computed tomography data

    International Nuclear Information System (INIS)

    Szigeti, Krisztián; Szabó, Tibor; Korom, Csaba; Czibak, Ilona; Horváth, Ildikó; Veres, Dániel S.; Gyöngyi, Zoltán; Karlinger, Kinga; Bergmann, Ralf; Pócsik, Márta; Budán, Ferenc; Máthé, Domokos

    2016-01-01

    Lung diseases (resulting from air pollution) require a widely accessible method for risk estimation and early diagnosis to ensure proper and responsive treatment. Radiomics-based fractal dimension analysis of X-ray computed tomography attenuation patterns in chest voxels of mice exposed to different air polluting agents was performed to model early stages of disease and establish differential diagnosis. To model different types of air pollution, BALBc/ByJ mouse groups were exposed to cigarette smoke combined with ozone, sulphur dioxide gas and a control group was established. Two weeks after exposure, the frequency distributions of image voxel attenuation data were evaluated. Specific cut-off ranges were defined to group voxels by attenuation. Cut-off ranges were binarized and their spatial pattern was associated with calculated fractal dimension, then abstracted by the fractal dimension -- cut-off range mathematical function. Nonparametric Kruskal-Wallis (KW) and Mann–Whitney post hoc (MWph) tests were used. Each cut-off range versus fractal dimension function plot was found to contain two distinctive Gaussian curves. The ratios of the Gaussian curve parameters are considerably significant and are statistically distinguishable within the three exposure groups. A new radiomics evaluation method was established based on analysis of the fractal dimension of chest X-ray computed tomography data segments. The specific attenuation patterns calculated utilizing our method may diagnose and monitor certain lung diseases, such as chronic obstructive pulmonary disease (COPD), asthma, tuberculosis or lung carcinomas. The online version of this article (doi:10.1186/s12880-016-0118-z) contains supplementary material, which is available to authorized users

  2. Photons-based medical imaging - Radiology, X-ray tomography, gamma and positrons tomography, optical imaging; Imagerie medicale a base de photons - Radiologie, tomographie X, tomographie gamma et positons, imagerie optique

    Energy Technology Data Exchange (ETDEWEB)

    Fanet, H.; Dinten, J.M.; Moy, J.P.; Rinkel, J. [CEA Leti, Grenoble (France); Buvat, I. [IMNC - CNRS, Orsay (France); Da Silva, A. [Institut Fresnel, Marseille (France); Douek, P.; Peyrin, F. [INSA Lyon, Lyon Univ. (France); Frija, G. [Hopital Europeen George Pompidou, Paris (France); Trebossen, R. [CEA-Service hospitalier Frederic Joliot, Orsay (France)

    2010-07-01

    This book describes the different principles used in medical imaging. The detection aspects, the processing electronics and algorithms are detailed for the different techniques. This first tome analyses the photons-based techniques (X-rays, gamma rays and visible light). Content: 1 - physical background: radiation-matter interaction, consequences on detection and medical imaging; 2 - detectors for medical imaging; 3 - processing of numerical radiography images for quantization; 4 - X-ray tomography; 5 - positrons emission tomography: principles and applications; 6 - mono-photonic imaging; 7 - optical imaging; Index. (J.S.)

  3. Using high resolution X-ray computed tomography to create an image based model of a lymph node.

    Science.gov (United States)

    Cooper, L J; Zeller-Plumhoff, B; Clough, G F; Ganapathisubramani, B; Roose, T

    2018-07-14

    Lymph nodes are an important part of the immune system. They filter the lymphatic fluid as it is transported from the tissues before being returned to the blood stream. The fluid flow through the nodes influences the behaviour of the immune cells that gather within the nodes and the structure of the node itself. Measuring the fluid flow in lymph nodes experimentally is challenging due to their small size and fragility. In this paper, we present high resolution X-ray computed tomography images of a murine lymph node. The impact of the resulting visualized structures on fluid transport are investigated using an image based model. The high contrast between different structures within the lymph node provided by phase contrast X-ray computed tomography reconstruction results in images that, when related to the permeability of the lymph node tissue, suggest an increased fluid velocity through the interstitial channels in the lymph node tissue. Fluid taking a direct path from the afferent to the efferent lymphatic vessel, through the centre of the node, moved faster than the fluid that flowed around the periphery of the lymph node. This is a possible mechanism for particles being moved into the cortex. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. Quantification of root water uptake in soil using X-ray computed tomography and image-based modelling.

    Science.gov (United States)

    Daly, Keith R; Tracy, Saoirse R; Crout, Neil M J; Mairhofer, Stefan; Pridmore, Tony P; Mooney, Sacha J; Roose, Tiina

    2018-01-01

    Spatially averaged models of root-soil interactions are often used to calculate plant water uptake. Using a combination of X-ray computed tomography (CT) and image-based modelling, we tested the accuracy of this spatial averaging by directly calculating plant water uptake for young wheat plants in two soil types. The root system was imaged using X-ray CT at 2, 4, 6, 8 and 12 d after transplanting. The roots were segmented using semi-automated root tracking for speed and reproducibility. The segmented geometries were converted to a mesh suitable for the numerical solution of Richards' equation. Richards' equation was parameterized using existing pore scale studies of soil hydraulic properties in the rhizosphere of wheat plants. Image-based modelling allows the spatial distribution of water around the root to be visualized and the fluxes into the root to be calculated. By comparing the results obtained through image-based modelling to spatially averaged models, the impact of root architecture and geometry in water uptake was quantified. We observed that the spatially averaged models performed well in comparison to the image-based models with <2% difference in uptake. However, the spatial averaging loses important information regarding the spatial distribution of water near the root system. © 2017 John Wiley & Sons Ltd.

  5. Determination of the metal distribution in tooth fillings in real teeth based on element sensitive X-ray tomography

    International Nuclear Information System (INIS)

    Masschaele, B.; Mondelaers, W.; Cauwels, P.; Jolie, J.; Baechler, S.; Materna, T.

    2000-01-01

    Since a couple of centuries people are using metal tooth-fillings in order to protect their teeth. In the beginning of the 19th century the amalgam or silver fillings were introduced for to first time. Nowadays, dentists mostly use amalgam. These fillings are a mixture of silver, tin and mercury. The mercury which is abundant, about 50%, is dangerous for any living organism. Mercury has a particular affinity for the brain tissue but is also accumulated in the liver, kidneys, lungs, gastrointestinal track and jawbone. Mercury Basely crosses the placenta and is gathered in the heart, pituitary gland and liver of the fetus. It is been proven that the mercury vaporises and enter enters the body via the lungs. Since a couple of years we apply the element sensitive X-ray tomography technique on heavy elements like uranium or lead. By scanning teeth using photons having two different energies, one just below and one just above the K-edge of the element under investigation, the tomography becomes element sensitive. The experiment has been done at the ESRF, beam line ID15A, with a very intense tunable monochromatic high energy X-ray beam. We made tomographies of different teeth with 20 μm image resolution. The slices were 20 μm apart. The results after reconstruction are three dimensional mercury maps which can tell us something about the possibility of mercury diffusion into the roots of the tooth. From there the mercury could enter the blood stream and end up in the organs. (author)

  6. Myoanatomy of the velvet worm leg revealed by laboratory-based nanofocus X-ray source tomography.

    Science.gov (United States)

    Müller, Mark; de Sena Oliveira, Ivo; Allner, Sebastian; Ferstl, Simone; Bidola, Pidassa; Mechlem, Korbinian; Fehringer, Andreas; Hehn, Lorenz; Dierolf, Martin; Achterhold, Klaus; Gleich, Bernhard; Hammel, Jörg U; Jahn, Henry; Mayer, Georg; Pfeiffer, Franz

    2017-11-21

    X-ray computed tomography (CT) is a powerful noninvasive technique for investigating the inner structure of objects and organisms. However, the resolution of laboratory CT systems is typically limited to the micrometer range. In this paper, we present a table-top nanoCT system in conjunction with standard processing tools that is able to routinely reach resolutions down to 100 nm without using X-ray optics. We demonstrate its potential for biological investigations by imaging a walking appendage of Euperipatoides rowelli , a representative of Onychophora-an invertebrate group pivotal for understanding animal evolution. Comparative analyses proved that the nanoCT can depict the external morphology of the limb with an image quality similar to scanning electron microscopy, while simultaneously visualizing internal muscular structures at higher resolutions than confocal laser scanning microscopy. The obtained nanoCT data revealed hitherto unknown aspects of the onychophoran limb musculature, enabling the 3D reconstruction of individual muscle fibers, which was previously impossible using any laboratory-based imaging technique.

  7. Soft x-ray tomography on TFTR

    International Nuclear Information System (INIS)

    Kuo-Petravic, G.

    1988-12-01

    The tomographic method used for deriving soft x-ray local emissivities on TFTR, using one horizontal array of 60 soft x-ray detectors, is described. This method, which is based on inversion of Fourier components and subsequent reconstruction, has been applied to the study of a sawtooth crash. A flattening in the soft x-ray profile, which we interpret as an m = 1 island, is clearly visible during the precursor phase and its location and width correlate well with those from electron temperature profiles reconstructed from electron cyclotron emission measurement. The limitations of the Fourier method, due notably to the aperiodic nature of the signals in the fast crash phase and the difficulty of obtaining accurately the higher Fourier harmonics, are discussed. 9 refs., 13 figs

  8. A simple fracture energy prediction method for fiber network based on its morphological features extracted by X-ray tomography

    International Nuclear Information System (INIS)

    Huang, Xiang; Wang, Qinghui; Zhou, Wei; Li, Jingrong

    2013-01-01

    The fracture behavior of a novel porous metal fiber sintered sheet (PMFSS) was predicted using a semi-empirical method combining the knowledge of its morphological characteristics and micro-mechanical responses. The morphological characteristics were systematically summarized based on the analysis of the topologically identical skeleton representation extracted from the X-ray tomography images. The analytical model firstly proposed by Tan et al. [1] was further modified according to the experimental observations from both tensile tests of single fibers and sintered fiber sheets, which built the coupling of single fiber segment and fiber network in terms of fracture energy using a simple prediction method. The efficacy of the prediction model was verified by comparing the predicted results to the experimental measurements. The prediction error that arose at high porosity was analyzed through fiber orientation distribution. Moreover, the tensile fracture process evolving from single fiber segments at micro-scale to the global mechanical performance was investigated

  9. Contribution to industrial X-ray tomography

    International Nuclear Information System (INIS)

    Huet, J.; Thomas, G.

    1983-06-01

    Based on the previous experience on medical scanner, a prototype of industrial X-Ray scanner has been studied and realized by the CEA. This apparatus uses a 420 kVolts generator as a beam source. The results obtained are shown. The characteristics of a flexible and polyvalent system well adapted to industrial testing are defined [fr

  10. Laboratory soft x-ray microscopy and tomography

    International Nuclear Information System (INIS)

    Bertilson, Michael

    2011-01-01

    Soft x-ray microscopy in the water-window (λ = 2.28 nm - 4.36 nm) is based on zone-plate optics and allows high-resolution imaging of, e.g., cells and soils in their natural or near-natural environment. Three-dimensional imaging is provided via tomographic techniques, soft x-ray cryo tomography. However, soft x-ray microscopes with such capabilities have been based on large-scale synchrotron x-ray facilities, thereby limiting their accessibility for a wider scientific community. This Thesis describes the development of the Stockholm laboratory soft x-ray microscope to three-dimensional cryo tomography and to new optics-based contrast mechanisms. The microscope relies on a methanol or nitrogen liquid-jet laser-plasma source, normal-incidence multilayer or zone-plate condenser optics, in-house fabricated zone-plate objectives, and allows operation at two wavelengths in the water-window, λ = 2.48 nm and λ = 2.48 nm. With the implementation of a new state-of-the-art normal-incidence multilayer condenser for operation at λ = 2.48 nm and a tiltable cryogenic sample stage the microscope now allows imaging of dry, wet or cryo-fixed samples. This arrangement was used for the first demonstration of laboratory soft x-ray cryo microscopy and tomography. The performance of the microscope has been demonstrated in a number of experiments described in this Thesis, including, tomographic imaging with a resolution of 140 nm, cryo microscopy and tomography of various cells and parasites, and for studies of aqueous soils and clays. The Thesis also describes the development and implementation of single-element differential-interference and Zernike phase-contrast zone-plate objectives. The enhanced contrast provided by these optics reduce exposure times or lowers the dose in samples and are of major importance for harder x-ray microscopy. The implementation of a high-resolution 50 nm compound zone-plate objective for sub-25-nm resolution imaging is also described. All experiments

  11. Ross filter pairs for metal artefact reduction in x-ray tomography: a case study based on imaging and segmentation of metallic implants

    Science.gov (United States)

    Arhatari, Benedicta D.; Abbey, Brian

    2018-01-01

    Ross filter pairs have recently been demonstrated as a highly effective means of producing quasi-monoenergetic beams from polychromatic X-ray sources. They have found applications in both X-ray spectroscopy and for elemental separation in X-ray computed tomography (XCT). Here we explore whether they could be applied to the problem of metal artefact reduction (MAR) for applications in medical imaging. Metal artefacts are a common problem in X-ray imaging of metal implants embedded in bone and soft tissue. A number of data post-processing approaches to MAR have been proposed in the literature, however these can be time-consuming and sometimes have limited efficacy. Here we describe and demonstrate an alternative approach based on beam conditioning using Ross filter pairs. This approach obviates the need for any complex post-processing of the data and enables MAR and segmentation from the surrounding tissue by exploiting the absorption edge contrast of the implant.

  12. [Treatment choice in dacryostenosis based on single-photon emission computed tomography and X-ray computed tomography findings].

    Science.gov (United States)

    At'kova, E L; Yartsev, V D; Tomashevskiy, I O; Krakhovetskiy, N N

    2016-01-01

    To develop surgical indications in dacryostenosis within the vertical portion of lacrimal pathways that would consider findings of single-photon emission computed tomography (SPECT) combined with X-ray computed tomography (CT). A total of 96 patients with isolated vertical-portion dacryostenosis (127 cases) were enrolled. The examination included collecting Munk's scores for epiphora, optical coherence tomography of the lower tear meniscus, lacrimal scintigraphy, and SPECT/CT. Group 1 (40 cases) was composed of patients with lacrimal obstruction on CT, group 2 (87 cases) - of those whose lacrimal pathways proved passable. There were also 3 patients (4 cases) from group 1, whose lacrimal pathways, despite being blocked on CT, were still passable on SPECT. Surgeries performed in group 1 were endoscopic endonasal dacryocystorhinostomy (DCR) (36 cases) and pathways recanalization with bicanalicular intubation and balloon dacryoplasty (DCP) (4 cases). In group 2, all patients (87 cases) underwent recanalization with bicanalicular intubation (supplemented with balloon DCP in 32 cases). Surgical results were evaluated 8-12 months after the treatment. In group 2, particular attention was paid to the concordance in locations of dacryostenosis provided by CT and SPECT scans. Favorable outcomes of endoscopic endonasal DCR were obtained in as many as 32 cases from group 1 (88.9%), while in 4 cases (12.1%) the condition relapsed. Of those patients whose stenosis was not complete on SPECT, 3 cases (75.0%) improved, 1 (25.0%) - relapsed. In group 2, favorable outcomes were obtained in 65 cases (74.7%), relapses were 22 (25.3%). A high concordance in stenosis locations by CT and SPECT was noted in 60 cases of those who improved (92.3%) and 3 cases of those who relapsed (13.6%). The value of information provided by SPECT/CT has proved high in patients with nasolacrimal duct stenosis or obstruction. A combined scan allows to establish causal relationships between anatomical changes

  13. X-ray tomography on TCV

    International Nuclear Information System (INIS)

    Anton, M.; Weisen, H.; Dutch, M.J.; Buhlmann, F.; Chavan, R.; Marletaz, B.; Marmillod, P.; Paris, P.

    1996-04-01

    The TCV Tokamak offers an outstanding variability of the plasma shape. Using X-ray tomography, the shape of the inner flux surfaces of a poloidal cross section of the plasma can be reconstructed, including fast variations due to MHD activity. The hardware as well as the software of the 200 channel system developed for TCV is described. A new, 'dynamical' calibration is used. The actual plasma temperature and some global profile parameters serve to determine the spectrum-dependent efficiency of the photodiodes. Compared to a 'static' calibration with constant calibration factors, an enhanced quality of the reconstructed images is observed. The tomographic inversion is performed using a variety of methods such as Maximum Entropy, linear Regularisation and a new method making use of the Fisher information of the emissivity distribution. The merits of the different algorithms which have been implemented as MATLAB functions are compared. The tomographic inversion results are analysed with the help of the biorthogonal decomposition, allowing e.g. identification of MHD modes without using any a priori information on the poloidal mode structure. Recent results on the dependence of sawtooth activity on the plasma triangularity are presented to demonstrate the performance of the soft X-ray tomography system. (author) 14 figs., 2 tabs., 26 refs

  14. Ex-situ X-ray computed tomography data for a non-crimp fabric based glass fibre composite under fatigue loading

    DEFF Research Database (Denmark)

    Jespersen, Kristine Munk; Mikkelsen, Lars Pilgaard

    2017-01-01

    The data published with this article are high resolution X-ray computed tomography (CT) data obtained during an ex-situ fatigue test of a coupon test specimen made from a non-crimp fabric based glass fibre composite similar to those used for wind turbine blades. The fatigue test was interrupted...

  15. EOL3 M0 X-ray Tomography Test Results

    CERN Document Server

    Avramidou, R; Bozhko, N; Borisov, A; Goriatchev, V; Goriatchev, S; Gushin, V; Fakhroutdinov, R; Kojine, A; Kononov, A; Larionov, A; Salomatin, Yu I; Schuh, S; Sedykh, Yu; Tchougouev, A

    2001-01-01

    Results of X-ray tomography test of EOL3 module 0 chamber is presented in the note. Peculiarities of the X-ray tomography of the chamber are discussed. Comparison of the tomography results with predictions of the production site measurements is made.

  16. Assessment of skull base involvement in nasopharyngeal carcinoma: comparisons of single-photon emission tomography with planar bone scintigraphy and X-ray computed tomography

    International Nuclear Information System (INIS)

    Lee Chianghsuan; Wang Peiwen; Chen Hueyong; Lui Chunchung; Su Chihying

    1995-01-01

    The diagnostic contribution of single-photon emission tomography (SPET) to the detection of bone lesions of the skull base was explored in 200 patients with nasopharyngeal carcinoma (NPC). Comparison of SPET with planar bone scintigraphy showed that SPET improved the contrast and better defined the lesions in 107 out of the 200 patients. Comparison of SPET with X-ray computed tomography (CT) showed that SPET did not miss the lesions detected by CT while CT missed 49% of the lesions detected by SPET. The only false-positive lesion with SPET was detected in the mastoid bone. SPET detected skull base lesions in all of the 35 patients with cranial nerve involvement, while CT missed eight and planar bone scintigraphy missed four. The findings suggest that SPET should be included in the routine check-up examinations of patients with NPC. (orig.)

  17. Initial evaluation of image performance of a 3-D x-ray system: phantom-based comparison of 3-D tomography with conventional computed tomography.

    Science.gov (United States)

    Benz, Robyn Melanie; Garcia, Meritxell Alzamora; Amsler, Felix; Voigt, Johannes; Fieselmann, Andreas; Falkowski, Anna Lucja; Stieltjes, Bram; Hirschmann, Anna

    2018-01-01

    Phantom-based initial performance assessment of a prototype three-dimensional (3-D) x-ray system and comparison of 3-D tomography with computed tomography (CT) were proposed. A 3-D image quality phantom was scanned with a prototype version of 3-D cone-beam CT imaging implemented on a twin robotic x-ray system using three trajectories (163 deg = table, 188 deg = upright, and 200 deg = side), six tube voltages (60, 70, 81, 90, 100, and 121 kV), and four detector doses (0.348, 0.696, 1.740, and [Formula: see text]). CT was obtained with a clinical protocol. Spatial resolution (line pairs/cm) and soft-tissue-contrast resolution were assessed by two independent readers. Radiation dose was assessed. Descriptive and analysis of variance (ANOVA) ([Formula: see text]) were performed. With 3-D tomography, a maximum of 16 lp/cm was visible and best soft-tissue-contrast resolution was 2 mm at 30 Hounsfield units (HU) for 160 projections. With CT, 10 lp/cm was visible and soft-tissue-contrast resolution was 4 mm at 20 HU. The upright trajectory yielded significantly better spatial resolution and soft tissue contrast, and the side trajectory yielded significantly higher soft tissue contrast than the table trajectory ([Formula: see text]). Radiation dose was higher in 3-D tomography (45 to 704 mGycm) than CT (44 mGycm). Three-dimensional tomography renders overall equal or higher spatial resolution and comparable soft tissue contrast to CT for medium- and high-dose protocols in the side and upright trajectories, but with higher radiation doses.

  18. Analytical device for X-ray tomography by transmission

    International Nuclear Information System (INIS)

    Allemand, Robert.

    1975-01-01

    The invention concerns an analytical system for X ray tomography by transmission. The principle of these appliances is based on measuring the absorption of an X ray beam in terms of the density of the tissue being examined. In the apparatus marketed by E.M.I. (Electric and Musical Industries Ltd) of Great Britain, one hundred absorption determinations are performed during a scan lasting around one second; with this apparatus the number of scans is 180. In order to extend this examination to organs other than the brain, it is necessary to use shorter examination times. To do so, the detection cells employed are ionization chambers and they are associated with instrumentation for determining the charge collected in each chamber over a given time under the effect of the X rays which have passed through the organ being examined [fr

  19. Quantitative x-ray dark-field computed tomography

    International Nuclear Information System (INIS)

    Bech, M; Pfeiffer, F; Bunk, O; Donath, T; David, C; Feidenhans'l, R

    2010-01-01

    The basic principles of x-ray image formation in radiology have remained essentially unchanged since Roentgen first discovered x-rays over a hundred years ago. The conventional approach relies on x-ray attenuation as the sole source of contrast and draws exclusively on ray or geometrical optics to describe and interpret image formation. Phase-contrast or coherent scatter imaging techniques, which can be understood using wave optics rather than ray optics, offer ways to augment or complement the conventional approach by incorporating the wave-optical interaction of x-rays with the specimen. With a recently developed approach based on x-ray optical gratings, advanced phase-contrast and dark-field scatter imaging modalities are now in reach for routine medical imaging and non-destructive testing applications. To quantitatively assess the new potential of particularly the grating-based dark-field imaging modality, we here introduce a mathematical formalism together with a material-dependent parameter, the so-called linear diffusion coefficient and show that this description can yield quantitative dark-field computed tomography (QDFCT) images of experimental test phantoms.

  20. Molecular Imaging of Cancer Using X-ray Computed Tomography with Protease Targeted Iodinated Activity-Based Probes.

    Science.gov (United States)

    Gaikwad, Hanmant K; Tsvirkun, Darya; Ben-Nun, Yael; Merquiol, Emmanuelle; Popovtzer, Rachela; Blum, Galia

    2018-03-14

    X-ray computed tomography (CT) is a robust, precise, fast, and reliable imaging method that enables excellent spatial resolution and quantification of contrast agents throughout the body. However, CT is largely inadequate for molecular imaging applications due mainly to its low contrast sensitivity that forces the use of large concentrations of contrast agents for detection. To overcome this limitation, we generated a new class of iodinated nanoscale activity-based probes (IN-ABPs) that sufficiently accumulates at the target site by covalently binding cysteine cathepsins that are exceptionally highly expressed in cancer. The IN-ABPs are comprised of a short targeting peptide selective to specific cathepsins, an electrophilic moiety that allows activity-dependent covalent binding, and tags containing dendrimers with up to 48 iodine atoms. IN-ABPs selectively bind and inhibit activity of recombinant and intracellular cathepsin B, L, and S. We compared the in vivo kinetics, biodistribution, and tumor accumulation of IN-ABPs bearing 18 and 48 iodine atoms each, and their control counterparts lacking the targeting moiety. Here we show that although both IN-ABPs bind specifically to cathepsins within the tumor and produce detectable CT contrast, the 48-iodine bearing IN-ABP was found to be optimal with signals over 2.1-fold higher than its nontargeted counterpart. In conclusion, this study shows the synthetic feasibility and potential utility of IN-ABPs as potent contrast agents that enable molecular imaging of tumors using CT.

  1. Preclinical validation of automated dual-energy X-ray absorptiometry and computed tomography-based body composition measurements

    International Nuclear Information System (INIS)

    DEVRIESE, Joke; Pottel, Hans; BEELS, Laurence; VAN DE WIELE, Christophe; MAES, Alex; GHEYSENS, Olivier

    2016-01-01

    The aim of this study was to determine and validate a set of Hounsfield unit (HU) ranges to segment computed tomography (CT) images into tissue types and to test the validity of dual-energy X-ray absorptiometry (DXA) tissue segmentation on pure, unmixed porcine tissues. This preclinical prospective study was approved by the local ethical committee. Different quantities of porcine bone tissue (BT), lean tissue (LT) and adipose tissue (AT) were scanned using DXA and CT. Tissue type segmentation in DXA was performed via the standard clinical protocol and in CT through different sets of HU ranges. Percent coefficients of variation (%CV) were used to assess precision while % differences of observed masses were tested against zero using the Wilcoxon signed-rank Test. Total mass DXA measurements differ little but significantly (P=0.016) from true mass, while total mass CT measurements based on literature values show non-significant (P=0.69) differences of 1.7% and 2.0%. BT mass estimates with DXA differed more from true mass (median -78.2 to -75.8%) than other tissue types (median -11.3 to -8.1%). Tissue mass estimates with CT and literature HU ranges showed small differences from true mass for every tissue type (median -10.4 to 8.8%). The most suited method for automated tissue segmentation is CT and can become a valuable tool in quantitative nuclear medicine.

  2. Fluorescent scanning x-ray tomography with synchrotron radiation

    Science.gov (United States)

    Takeda, Tohoru; Maeda, Toshikazu; Yuasa, Tetsuya; Akatsuka, Takao; Ito, Tatsuo; Kishi, Kenichi; Wu, Jin; Kazama, Masahiro; Hyodo, Kazuyuki; Itai, Yuji

    1995-02-01

    Fluorescent scanning (FS) x-ray tomography was developed to detect nonradioactive tracer materials (iodine and gadolinium) in a living object. FS x-ray tomography consists of a silicon (111) channel cut monochromator, an x-ray shutter, an x-ray slit system and a collimator for detection, a scanning table for the target organ, and an x-ray detector with pure germanium. The minimal detectable dose of iodine in this experiment was 100 ng in a volume of 2 mm3 and a linear relationship was shown between the photon counts of a fluorescent x ray and the concentration of iodine contrast material. A FS x-ray tomographic image was clearly obtained with a phantom.

  3. The color of X-rays Spectral X-ray computed tomography using energy sensitive pixel detectors

    CERN Document Server

    Schioppa, Enrico Junior

    Energy sensitive X-ray imaging detectors are produced by connecting a semiconductor sensor to a spectroscopic pixel readout chip. In this thesis, the applicability of such detectors to X-ray Computed Tomography (CT) is studied. A prototype Medipix based silicon detector is calibrated using X-ray fluorescence. The charge transport properties of the sensor are characterized using a high energy beam of charged particles at the Super Proton Synchrotron (SPS) at the European Center for Nuclear Research (CERN). Monochromatic X-rays at the European Synchrotron Radiation Facility (ESRF) are used to determined the energy response function. These data are used to implement a physics-based CT projection operator that accounts for the transmission of the source spectrum through the sample and detector effects. Based on this projection operator, an iterative spectral CT reconstruction algorithm is developed by extending an Ordered Subset Expectation Maximization (OSEM) method. Subsequently, a maximum likelihood based algo...

  4. Rapid data processing for ultrafast X-ray computed tomography using scalable and modular CUDA based pipelines

    Science.gov (United States)

    Frust, Tobias; Wagner, Michael; Stephan, Jan; Juckeland, Guido; Bieberle, André

    2017-10-01

    Ultrafast X-ray tomography is an advanced imaging technique for the study of dynamic processes basing on the principles of electron beam scanning. A typical application case for this technique is e.g. the study of multiphase flows, that is, flows of mixtures of substances such as gas-liquidflows in pipelines or chemical reactors. At Helmholtz-Zentrum Dresden-Rossendorf (HZDR) a number of such tomography scanners are operated. Currently, there are two main points limiting their application in some fields. First, after each CT scan sequence the data of the radiation detector must be downloaded from the scanner to a data processing machine. Second, the current data processing is comparably time-consuming compared to the CT scan sequence interval. To enable online observations or use this technique to control actuators in real-time, a modular and scalable data processing tool has been developed, consisting of user-definable stages working independently together in a so called data processing pipeline, that keeps up with the CT scanner's maximal frame rate of up to 8 kHz. The newly developed data processing stages are freely programmable and combinable. In order to achieve the highest processing performance all relevant data processing steps, which are required for a standard slice image reconstruction, were individually implemented in separate stages using Graphics Processing Units (GPUs) and NVIDIA's CUDA programming language. Data processing performance tests on different high-end GPUs (Tesla K20c, GeForce GTX 1080, Tesla P100) showed excellent performance. Program Files doi:http://dx.doi.org/10.17632/65sx747rvm.1 Licensing provisions: LGPLv3 Programming language: C++/CUDA Supplementary material: Test data set, used for the performance analysis. Nature of problem: Ultrafast computed tomography is performed with a scan rate of up to 8 kHz. To obtain cross-sectional images from projection data computer-based image reconstruction algorithms must be applied. The

  5. Effects of X-Ray Dose On Rhizosphere Studies Using X-Ray Computed Tomography

    Science.gov (United States)

    Zappala, Susan; Helliwell, Jonathan R.; Tracy, Saoirse R.; Mairhofer, Stefan; Sturrock, Craig J.; Pridmore, Tony; Bennett, Malcolm; Mooney, Sacha J.

    2013-01-01

    X-ray Computed Tomography (CT) is a non-destructive imaging technique originally designed for diagnostic medicine, which was adopted for rhizosphere and soil science applications in the early 1980s. X-ray CT enables researchers to simultaneously visualise and quantify the heterogeneous soil matrix of mineral grains, organic matter, air-filled pores and water-filled pores. Additionally, X-ray CT allows visualisation of plant roots in situ without the need for traditional invasive methods such as root washing. However, one routinely unreported aspect of X-ray CT is the potential effect of X-ray dose on the soil-borne microorganisms and plants in rhizosphere investigations. Here we aimed to i) highlight the need for more consistent reporting of X-ray CT parameters for dose to sample, ii) to provide an overview of previously reported impacts of X-rays on soil microorganisms and plant roots and iii) present new data investigating the response of plant roots and microbial communities to X-ray exposure. Fewer than 5% of the 126 publications included in the literature review contained sufficient information to calculate dose and only 2.4% of the publications explicitly state an estimate of dose received by each sample. We conducted a study involving rice roots growing in soil, observing no significant difference between the numbers of root tips, root volume and total root length in scanned versus unscanned samples. In parallel, a soil microbe experiment scanning samples over a total of 24 weeks observed no significant difference between the scanned and unscanned microbial biomass values. We conclude from the literature review and our own experiments that X-ray CT does not impact plant growth or soil microbial populations when employing a low level of dose (<30 Gy). However, the call for higher throughput X-ray CT means that doses that biological samples receive are likely to increase and thus should be closely monitored. PMID:23840640

  6. Systematic Errors in Dimensional X-ray Computed Tomography

    DEFF Research Database (Denmark)

    that it is possible to compensate them. In dimensional X-ray computed tomography (CT), many physical quantities influence the final result. However, it is important to know which factors in CT measurements potentially lead to systematic errors. In this talk, typical error sources in dimensional X-ray CT are discussed...

  7. X-ray Computed Tomography of Ultralightweight Metals

    National Research Council Canada - National Science Library

    Winter, John

    2001-01-01

    .... To date, the imaging capabilities of x-ray computed tomography have not been generally employed to nondestructively examine the internal structure of the products formed by these various processes...

  8. X-ray Computed Tomography Image Quality Indicator (IQI) Development

    Data.gov (United States)

    National Aeronautics and Space Administration — Phase one of the program is to identify suitable x-ray Computed Tomography (CT) Image Quality Indicator (IQI) design(s) that can be used to adequately capture CT...

  9. Principle and realization of segmenting contour series algorithm in reverse engineering based on X-ray computerized tomography

    International Nuclear Information System (INIS)

    Wang Yanfang; Liu Li; Yan Yonglian; Shan Baoci; Tang Xiaowei

    2007-01-01

    A new algorithm of segmenting contour series of images is presented, which can achieve three dimension reconstruction with parametric recognition in Reverse Engineering based on X-ray CT. First, in order to get the nested relationship between contours, a method of a certain angle ray is used. Second, for realizing the contour location in one slice, another approach is presented to generate the contour tree by scanning the relevant vector only once. Last, a judge algorithm is put forward to accomplish the contour match between slices by adopting the qualitative and quantitative properties. The example shows that this algorithm can segment contour series of CT parts rapidly and precisely. (authors)

  10. Synchrotron-radiation-based X-ray micro-computed tomography reveals dental bur debris under dental composite restorations.

    Science.gov (United States)

    Hedayat, Assem; Nagy, Nicole; Packota, Garnet; Monteith, Judy; Allen, Darcy; Wysokinski, Tomasz; Zhu, Ning

    2016-05-01

    Dental burs are used extensively in dentistry to mechanically prepare tooth structures for restorations (fillings), yet little has been reported on the bur debris left behind in the teeth, and whether it poses potential health risks to patients. Here it is aimed to image dental bur debris under dental fillings, and allude to the potential health hazards that can be caused by this debris when left in direct contact with the biological surroundings, specifically when the debris is made of a non-biocompatible material. Non-destructive micro-computed tomography using the BioMedical Imaging & Therapy facility 05ID-2 beamline at the Canadian Light Source was pursued at 50 keV and at a pixel size of 4 µm to image dental bur fragments under a composite resin dental filling. The bur's cutting edges that produced the fragment were also chemically analyzed. The technique revealed dental bur fragments of different sizes in different locations on the floor of the prepared surface of the teeth and under the filling, which places them in direct contact with the dentinal tubules and the dentinal fluid circulating within them. Dispersive X-ray spectroscopy elemental analysis of the dental bur edges revealed that the fragments are made of tungsten carbide-cobalt, which is bio-incompatible.

  11. The effects of gas diffusion layers structure on water transportation using X-ray computed tomography based Lattice Boltzmann method

    Science.gov (United States)

    Jinuntuya, Fontip; Whiteley, Michael; Chen, Rui; Fly, Ashley

    2018-02-01

    The Gas Diffusion Layer (GDL) of a Polymer Electrolyte Membrane Fuel Cell (PEMFC) plays a crucial role in overall cell performance. It is responsible for the dissemination of reactant gasses from the gas supply channels to the reactant sites at the Catalyst Layer (CL), and the adequate removal of product water from reactant sites back to the gas channels. Existing research into water transport in GDLs has been simplified to 2D estimations of GDL structures or use virtual stochastic models. This work uses X-ray computed tomography (XCT) to reconstruct three types of GDL in a model. These models are then analysed via Lattice Boltzmann methods to understand the water transport behaviours under differing contact angles and pressure differences. In this study, the three GDL samples were tested over the contact angles of 60°, 80°, 90°, 100°, 120° and 140° under applied pressure differences of 5 kPa, 10 kPa and 15 kPa. By varying the contact angle and pressure difference, it was found that the transition between stable displacement and capillary fingering is not a gradual process. Hydrophilic contact angles in the region of 60°<θ < 90° showed stable displacement properties, whereas contact angles in the region of 100°<θ < 140° displayed capillary fingering characteristics.

  12. Revising the lower statistical limit of x-ray grating-based phase-contrast computed tomography.

    Science.gov (United States)

    Marschner, Mathias; Birnbacher, Lorenz; Willner, Marian; Chabior, Michael; Herzen, Julia; Noël, Peter B; Pfeiffer, Franz

    2017-01-01

    Phase-contrast x-ray computed tomography (PCCT) is currently investigated as an interesting extension of conventional CT, providing high soft-tissue contrast even if examining weakly absorbing specimen. Until now, the potential for dose reduction was thought to be limited compared to attenuation CT, since meaningful phase retrieval fails for scans with very low photon counts when using the conventional phase retrieval method via phase stepping. In this work, we examine the statistical behaviour of the reverse projection method, an alternative phase retrieval approach and compare the results to the conventional phase retrieval technique. We investigate the noise levels in the projections as well as the image quality and quantitative accuracy of the reconstructed tomographic volumes. The results of our study show that this method performs better in a low-dose scenario than the conventional phase retrieval approach, resulting in lower noise levels, enhanced image quality and more accurate quantitative values. Overall, we demonstrate that the lower statistical limit of the phase stepping procedure as proposed by recent literature does not apply to this alternative phase retrieval technique. However, further development is necessary to overcome experimental challenges posed by this method which would enable mainstream or even clinical application of PCCT.

  13. Method for spatially modulating X-ray pulses using MEMS-based X-ray optics

    Science.gov (United States)

    Lopez, Daniel; Shenoy, Gopal; Wang, Jin; Walko, Donald A.; Jung, Il-Woong; Mukhopadhyay, Deepkishore

    2015-03-10

    A method and apparatus are provided for spatially modulating X-rays or X-ray pulses using microelectromechanical systems (MEMS) based X-ray optics. A torsionally-oscillating MEMS micromirror and a method of leveraging the grazing-angle reflection property are provided to modulate X-ray pulses with a high-degree of controllability.

  14. X-ray computer tomography in geotechnics

    Czech Academy of Sciences Publication Activity Database

    Blaheta, Radim; Kohut, Roman; Kolcun, Alexej; Souček, Kamil; Staš, Lubomír

    2011-01-01

    Roč. 21, č. 3 (2011), s. 12-12 ISSN 1213-3825. [Defektoskopie 2011 - Mezinárodní konference /41./. 09.07.2011-11.11.2011, Ostrava] R&D Projects: GA ČR GA105/09/1830 Grant - others:GA MŠk(CZ) ED2.1.00/03/0082 Institutional research plan: CEZ:AV0Z30860518 Source of funding: O - operačné programy Keywords : X-ray CT * geocomposite * FEM * homogenization Subject RIV: JQ - Machines ; Tools

  15. Development and prospects of X-ray computerized tomography. I

    International Nuclear Information System (INIS)

    Dobes, V.

    1985-01-01

    The history and developmental trends are described of X-ray computerized tomography (CT) as are its applications in clinical practise. Suitable criteria and economic aspects are proposed for the choice of CT systems. The types are listed and described of X-ray CT systems, including brain, whole-body, mobile and special systems. A table is given showing available specifications (types of detectors, X-ray source, resolution, configuration, scan angles, scan fields, image reconstruction, etc.) for machines by different companies. (M.D.)

  16. X-ray computed tomography using curvelet sparse regularization.

    Science.gov (United States)

    Wieczorek, Matthias; Frikel, Jürgen; Vogel, Jakob; Eggl, Elena; Kopp, Felix; Noël, Peter B; Pfeiffer, Franz; Demaret, Laurent; Lasser, Tobias

    2015-04-01

    Reconstruction of x-ray computed tomography (CT) data remains a mathematically challenging problem in medical imaging. Complementing the standard analytical reconstruction methods, sparse regularization is growing in importance, as it allows inclusion of prior knowledge. The paper presents a method for sparse regularization based on the curvelet frame for the application to iterative reconstruction in x-ray computed tomography. In this work, the authors present an iterative reconstruction approach based on the alternating direction method of multipliers using curvelet sparse regularization. Evaluation of the method is performed on a specifically crafted numerical phantom dataset to highlight the method's strengths. Additional evaluation is performed on two real datasets from commercial scanners with different noise characteristics, a clinical bone sample acquired in a micro-CT and a human abdomen scanned in a diagnostic CT. The results clearly illustrate that curvelet sparse regularization has characteristic strengths. In particular, it improves the restoration and resolution of highly directional, high contrast features with smooth contrast variations. The authors also compare this approach to the popular technique of total variation and to traditional filtered backprojection. The authors conclude that curvelet sparse regularization is able to improve reconstruction quality by reducing noise while preserving highly directional features.

  17. Towards adaptive, streaming analysis of x-ray tomography data

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Mathew; Kleese van Dam, Kerstin; Marshall, Matthew J.; Kuprat, Andrew P.; Carson, James P.; Lansing, Carina S.; Guillen, Zoe C.; Miller, Erin A.; Lanekoff, Ingela; Laskin, Julia

    2015-03-04

    Temporal and spatial resolution of chemical imaging methodologies such as x-ray tomography are rapidly increasing, leading to more complex experimental procedures and fast growing data volumes. Automated analysis pipelines and big data analytics are becoming essential to effectively evaluate the results of such experiments. Offering those data techniques in an adaptive, streaming environment can further substantially improve the scientific discovery process, by enabling experimental control and steering based on the evaluation of emerging phenomena as they are observed by the experiment. Pacific Northwest National Laboratory (PNNL)’ Chemical Imaging Initiative (CII - http://imaging.pnnl.gov/ ) has worked since 2011 towards developing a framework that allows users to rapidly compose and customize high throughput experimental analysis pipelines for multiple instrument types. The framework, named ‘Rapid Experimental Analysis’ (REXAN) Framework [1], is based on the idea of reusable component libraries and utilizes the PNNL developed collaborative data management and analysis environment ‘Velo’, to provide a user friendly analysis and data management environment for experimental facilities. This article will, discuss the capabilities established for X-Ray tomography, discuss lessons learned, and provide an overview of our more recent work in the Analysis in Motion Initiative (AIM - http://aim.pnnl.gov/ ) at PNNL to provide REXAN capabilities in a streaming environment.

  18. Polarized X-ray excitation for scatter reduction in X-ray fluorescence computed tomography.

    Science.gov (United States)

    Vernekohl, Don; Tzoumas, Stratis; Zhao, Wei; Xing, Lei

    2018-05-25

    X-ray fluorescence computer tomography (XFCT) is a new molecular imaging modality which uses X-ray excitation to stimulate the emission of fluorescent photons in high atomic number contrast agents. Scatter contamination is one of the main challenges in XFCT imaging which limits the molecular sensitivity. When polarized X-rays are used, it is possible to reduce the scatter contamination significantly by placing detectors perpendicular to the polarization direction. This study quantifies scatter contamination for polarized and unpolarized X-ray excitation and determines the advantages of scatter reduction. The amount of scatter in preclinical XFCT is quantified in Monte Carlo simulations. The fluorescent X-rays are emitted isotropically, while scattered X-rays propagate in polarization direction. The magnitude of scatter contamination is studied in XFCT simulations of a mouse phantom. In this study, the contrast agent gold is examined as an example but a scatter reduction from polarized excitation is also expected for other elements. The scatter reduction capability is examined for different polarization intensities with a monoenergetic X-ray excitation energy of 82 keV. The study evaluates two different geometrical shapes of CZT detectors which are modeled with an energy resolution of 1 keV FWHM at an X-ray energy of 80 keV. Benefits of a detector placement perpendicular to the polarization direction are shown in iterative and analytic image reconstruction including scatter correction. The contrast to noise ratio (CNR) and the normalized mean square error (NMSE) are analyzed and compared for the reconstructed images. A substantial scatter reduction for common detector sizes was achieved for 100% and 80% linear polarization while lower polarization intensities provide a decreased scatter reduction. By placing the detector perpendicular to the polarization direction, a scatter reduction by factor up to 5.5 can be achieved for common detector sizes. The image

  19. Phase-contrast x-ray computed tomography for biological imaging

    Science.gov (United States)

    Momose, Atsushi; Takeda, Tohoru; Itai, Yuji

    1997-10-01

    We have shown so far that 3D structures in biological sot tissues such as cancer can be revealed by phase-contrast x- ray computed tomography using an x-ray interferometer. As a next step, we aim at applications of this technique to in vivo observation, including radiographic applications. For this purpose, the size of view field is desired to be more than a few centimeters. Therefore, a larger x-ray interferometer should be used with x-rays of higher energy. We have evaluated the optimal x-ray energy from an aspect of does as a function of sample size. Moreover, desired spatial resolution to an image sensor is discussed as functions of x-ray energy and sample size, basing on a requirement in the analysis of interference fringes.

  20. Dynamic X-ray computed tomography

    International Nuclear Information System (INIS)

    Grangeat, P.

    2003-01-01

    Paper Dynamic computed tomography (CT) imaging aims at reconstructing image sequences where the dynamic nature of the living human body is of primary interest. Main concerned applications are image-guided interventional procedures, functional studies and cardiac imaging. The introduction of ultra-fast rotating gantries along with multi-row detectors and in near future area detectors allows a huge progress toward the imaging of moving organs with low-contrast resolution. This paper gives an overview of the different concepts used in dynamic CT. A new reconstruction algorithm based on a voxel-specific dynamic evolution compensation is also presented. It provides four-dimensional image sequences with accurate spatio-temporal information, where each frame is reconstructed using a long-scan acquisition mode on several half-turns. In the same time, this technique permits to reduce the dose delivered per rotation while keeping the same signal to noise ratio for every frame using an adaptive motion-compensated temporal averaging. Results are illustrated on simulated data. (authors)

  1. High-speed X-ray phase tomography with Talbot interferometer and fringe scanning method

    International Nuclear Information System (INIS)

    Kibayashi, Shunsuke; Harasse, Sébastien; Yashiro, Wataru; Momose, Atsushi

    2012-01-01

    High-speed X-ray phase tomography based on the Fourier-transform method has been demonstrated with an X-ray Talbot interferometer using white synchrotron radiation. We report the experimental results of high-speed X-ray phase tomography with fringe-scanning method instead of Fourier-transform method to improve spatial resolution without a considerable increase of scan time. To apply fringe-scanning method to high speed tomography, we tested a scan that is a synchronous combination of one-way continuous movements of the sample rotation and the grating displacement. When this scanning method was combined with X-ray phase tomography, we were able to obtain a scan time of 5 s. A comparison of the image quality derived with the conventional approach and with the proposed approach using the fringe-scanning method showed that the latter had better spatial resolution.

  2. Multi-scale X-ray computed tomography to detect and localize metal-based nanomaterials in lung tissues of in vivo exposed mice.

    Science.gov (United States)

    Chaurand, Perrine; Liu, Wei; Borschneck, Daniel; Levard, Clément; Auffan, Mélanie; Paul, Emmanuel; Collin, Blanche; Kieffer, Isabelle; Lanone, Sophie; Rose, Jérôme; Perrin, Jeanne

    2018-03-13

    In this methodological study, we demonstrated the relevance of 3D imaging performed at various scales for the ex vivo detection and location of cerium oxide nanomaterials (CeO 2 -NMs) in mouse lung. X-ray micro-computed tomography (micro-CT) with a voxel size from 14 µm to 1 µm (micro-CT) was combined with X-ray nano-computed tomography with a voxel size of 63 nm (nano-CT). An optimized protocol was proposed to facilitate the sample preparation, to minimize the experimental artifacts and to optimize the contrast of soft tissues exposed to metal-based nanomaterials (NMs). 3D imaging of the NMs biodistribution in lung tissues was consolidated by combining a vast variety of techniques in a correlative approach: histological observations, 2D chemical mapping and speciation analysis were performed for an unambiguous detection of NMs. This original methodological approach was developed following a worst-case scenario of exposure, i.e. high dose of exposure with administration via intra-tracheal instillation. Results highlighted both (i) the non-uniform distribution of CeO 2 -NMs within the entire lung lobe (using large field-of-view micro-CT) and (ii) the detection of CeO 2 -NMs down to the individual cell scale, e.g. macrophage scale (using nano-CT with a voxel size of 63 nm).

  3. 21 CFR 892.1750 - Computed tomography x-ray system.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Computed tomography x-ray system. 892.1750 Section... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1750 Computed tomography x-ray system. (a) Identification. A computed tomography x-ray system is a diagnostic x-ray system intended to...

  4. Radiation dosimetry of computed tomography x-ray scanners

    International Nuclear Information System (INIS)

    Poletti, J.L.; Williamson, B.D.P.; Le Heron, J.C.

    1983-01-01

    This report describes the development and application of the methods employed in National Radiation Laboratory (NRL) surveys of computed tomography x-ray scanners (CT scanners). It includes descriptions of the phantoms and equipment used, discussion of the various dose parameters measured, the principles of the various dosimetry systems employed and some indication of the doses to occupationally exposed personnel

  5. Introduction to the foundations of X-ray computed tomography

    International Nuclear Information System (INIS)

    Herman, G.T.

    1979-01-01

    The author gives a brief survey of a small fraction of the existing literature on the foundations of X-ray computed tomography. While the selection is biased by the interests of the author, taken in conjunction with the other articles in this book, it should provide the means for getting acquainted with this very active field of applicable research. (Auth.)

  6. Comparison of algebraic and analytical approaches to the formulation of the statistical model-based reconstruction problem for X-ray computed tomography.

    Science.gov (United States)

    Cierniak, Robert; Lorent, Anna

    2016-09-01

    The main aim of this paper is to investigate properties of our originally formulated statistical model-based iterative approach applied to the image reconstruction from projections problem which are related to its conditioning, and, in this manner, to prove a superiority of this approach over ones recently used by other authors. The reconstruction algorithm based on this conception uses a maximum likelihood estimation with an objective adjusted to the probability distribution of measured signals obtained from an X-ray computed tomography system with parallel beam geometry. The analysis and experimental results presented here show that our analytical approach outperforms the referential algebraic methodology which is explored widely in the literature and exploited in various commercial implementations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. X-ray-induced acoustic computed tomography of concrete infrastructure

    Science.gov (United States)

    Tang, Shanshan; Ramseyer, Chris; Samant, Pratik; Xiang, Liangzhong

    2018-02-01

    X-ray-induced Acoustic Computed Tomography (XACT) takes advantage of both X-ray absorption contrast and high ultrasonic resolution in a single imaging modality by making use of the thermoacoustic effect. In XACT, X-ray absorption by defects and other structures in concrete create thermally induced pressure jumps that launch ultrasonic waves, which are then received by acoustic detectors to form images. In this research, XACT imaging was used to non-destructively test and identify defects in concrete. For concrete structures, we conclude that XACT imaging allows multiscale imaging at depths ranging from centimeters to meters, with spatial resolutions from sub-millimeter to centimeters. XACT imaging also holds promise for single-side testing of concrete infrastructure and provides an optimal solution for nondestructive inspection of existing bridges, pavement, nuclear power plants, and other concrete infrastructure.

  8. X-ray luminescence computed tomography imaging via multiple intensity weighted narrow beam irradiation

    Science.gov (United States)

    Feng, Bo; Gao, Feng; Zhao, Huijuan; Zhang, Limin; Li, Jiao; Zhou, Zhongxing

    2018-02-01

    The purpose of this work is to introduce and study a novel x-ray beam irradiation pattern for X-ray Luminescence Computed Tomography (XLCT), termed multiple intensity-weighted narrow-beam irradiation. The proposed XLCT imaging method is studied through simulations of x-ray and diffuse lights propagation. The emitted optical photons from X-ray excitable nanophosphors were collected by optical fiber bundles from the right-side surface of the phantom. The implementation of image reconstruction is based on the simulated measurements from 6 or 12 angular projections in terms of 3 or 5 x-ray beams scanning mode. The proposed XLCT imaging method is compared against the constant intensity weighted narrow-beam XLCT. From the reconstructed XLCT images, we found that the Dice similarity and quantitative ratio of targets have a certain degree of improvement. The results demonstrated that the proposed method can offer simultaneously high image quality and fast image acquisition.

  9. Computed tomography for light materials using a monochromatic X-ray beam produced by parametric X-ray radiation

    Energy Technology Data Exchange (ETDEWEB)

    Hayakawa, Y., E-mail: yahayak@lebra.nihon-u.ac.jp [Laboratory for Electron Beam Research and Application, Nihon University, Narashinodai 7-24-1, Funabashi 274-8501 (Japan); Hayakawa, K.; Inagaki, M. [Laboratory for Electron Beam Research and Application, Nihon University, Narashinodai 7-24-1, Funabashi 274-8501 (Japan); Kaneda, T. [Nihon University School of Dentistry at Matsudo, Sakaecho-Nishi 2-870-1, Matsudo 271-8587 (Japan); Nakao, K.; Nogami, K. [Laboratory for Electron Beam Research and Application, Nihon University, Narashinodai 7-24-1, Funabashi 274-8501 (Japan); Sakae, T. [Nihon University School of Dentistry at Matsudo, Sakaecho-Nishi 2-870-1, Matsudo 271-8587 (Japan); Sakai, T.; Sato, I. [Laboratory for Electron Beam Research and Application, Nihon University, Narashinodai 7-24-1, Funabashi 274-8501 (Japan); Takahashi, Y. [Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Oho, Tsukuba 305-8501 (Japan); Tanaka, T. [Laboratory for Electron Beam Research and Application, Nihon University, Narashinodai 7-24-1, Funabashi 274-8501 (Japan)

    2013-08-15

    Computed tomography (CT) for light materials such as soft biological tissues was performed using a monochromatic X-ray beam provided by a parametric X-ray radiation (PXR) source at the Laboratory for Electron Beam Research and Application (LEBRA) of Nihon University. Using a high-efficiency flat panel detector (FPD), each projection image for CT was taken with exposure times of 5 or 10 s, and 60–360 projection images in each run were obtained with total measurement time of 5 min to 1 h. CT images were obtained from the projection images using the conventional calculation method. The typical tomograms obtained had sharp outlines, which are likely attributable to the propagation-based phase contrast.

  10. Noninvasive 3D Structural Analysis of Arthropod by Synchrotron X-Ray Phase Contrast Tomography

    International Nuclear Information System (INIS)

    Yao, S.; Zong, Y.; Fan, J.; Sun, Z.; Jiang, H.

    2015-01-01

    X-ray imaging techniques significantly advanced our understanding of materials and biology, among which phase contrast X-ray microscopy has obvious advantages in imaging biological specimens which have low contrast by conventional absorption contrast microscopy. In this paper, three-dimensional microstructure of arthropod with high contrast has been demonstrated by synchrotron X-ray in-line phase contrast tomography. The external morphology and internal structures of an earthworm were analyzed based upon tomographic reconstructions with and without phase retrieval. We also identified and characterized various fine structural details such as the musculature system, the digestive system, the nervous system, and the circulatory system. This work exhibited the high efficiency, high precision, and wide potential applications of synchrotron X-ray phase contrast tomography in nondestructive investigation of low-density materials and biology.

  11. X-ray radiography and tomography applied to material testing

    International Nuclear Information System (INIS)

    Rechapt, Jean de.

    1982-11-01

    X-ray radiography and tomography are compared to detect a defect in an object. These image acquisition processes are first modelled by a convolution system. For a fixed contrast defect and a given X ray dose, the process providing the best signal-to-noise ratio is given by calculation. Then a system for pattern recognition is given: for identifying a defect, the related signs from binary images are sorted according to their size. The improvement in the detection performance of the device, for an adapted filtration of the images obtained, is assessed. The whole of the preceding results is validated on images synthesized on a computer, selecting between tomography and radiography, the technique making it possible to ensure the detectability of a defect with a minimal dose of X photons [fr

  12. Quantitative X-ray dark-field and phase tomography using single directional speckle scanning technique

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hongchang, E-mail: hongchang.wang@diamond.ac.uk; Kashyap, Yogesh; Sawhney, Kawal [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom)

    2016-03-21

    X-ray dark-field contrast tomography can provide important supplementary information inside a sample to the conventional absorption tomography. Recently, the X-ray speckle based technique has been proposed to provide qualitative two-dimensional dark-field imaging with a simple experimental arrangement. In this letter, we deduce a relationship between the second moment of scattering angle distribution and cross-correlation degradation of speckle and establish a quantitative basis of X-ray dark-field tomography using single directional speckle scanning technique. In addition, the phase contrast images can be simultaneously retrieved permitting tomographic reconstruction, which yields enhanced contrast in weakly absorbing materials. Such complementary tomography technique can allow systematic investigation of complex samples containing both soft and hard materials.

  13. Quality control of aluminium casting: X ray radiography or tomography?

    International Nuclear Information System (INIS)

    Munier, B.; Tamziti, J.; Grignard, A.; Peix, G.; Kaftandjian, V.

    2007-01-01

    Full text of publication follows: X ray radiography has been for years a well known method commonly used for controlling parts either on line or off line. The purpose is to detect internal defects or to achieve reverse engineering on the parts. More recently two-dimensional or three-dimensional Computed Tomography has been introduced and provides key advantages over standard X ray radiography, such as dimensional measurement of complex objects with hidden structures and 3D defect localisation. However, from the user point of view, despite the clear advantages of tomography, the time consuming drawback is predominant, and thus, it is worth assessing the added value of tomography with respect to several radioscopic images. It is clear that there is no unique response to that question. If unacceptable defects are already detected in one radioscopic image, then the sample can be rejected and 3D tomography is useless. On another hand, 3D tomography cannot be replaced if internal structures such as holes must be measured with accuracy. The paper will present a comparison between radiography and tomography for controlling parts in the aluminium casting industry. Advantages and drawbacks of both methods will be reviewed. Performance features in both cases will be assessed in this specific industrial case by estimating the defect detection efficiency and image quality parameters. (authors)

  14. Grating-based X-ray phase-contrast tomography of atherosclerotic plaque at high photon energies

    Energy Technology Data Exchange (ETDEWEB)

    Hetterich, Holger; Fill, Sandra [Klinikum der Ludwig-Maximilians-Univ., Muenchen (Germany). Inst. fuer Klinische Radiologie; Herzen, Julia [Technische Univ. Muenchen, Garching (Germany). Physik-Dept. und Inst. fuer Medizintechnik; Helmholtz-Zentrum Geesthacht, Geesthacht (Germany). Zentrum fuer Materialforschung] [and others

    2013-10-01

    Background: Tissue characterization of atherosclerosis by absorption-based imaging methods is limited due to low soft-tissue contrast. Grating-based phase-contrast computed tomography (PC-CT) may become an alternative for plaque assessment if the phase signal can be retrieved at clinically applicable photon energies. The aims of this feasibility study were (i) to characterize arterial vessels at low and high photon energies, (ii) to extract qualitative features and (iii) quantitative phase-contrast Hounsfield units (HU-phase) of plaque components at 53 keV using histopathology as gold standard. Materials and methods: Five human carotid artery specimens underwent grating-based PC-CT using synchrotron radiation of either 23 keV or 53 keV and histological work-up. Specimens without advanced atherosclerosis were used to extract signal criteria of vessel layers. Diseased specimens were screened for important plaque components including fibrous tissue (FT), lipid (LIP), necrotic core (NEC), intraplaque hemorrhage (IPH), inflammatory cell infiltration (INF) and calcifications (CA). Qualitative features as well as quantitative HU-phase were analyzed. Results: Thirty-three regions in 6 corresponding PC-CT scans and histology sections were identified. Healthy samples had the same signal characteristics at 23 keV and 53 keV with bright tunica intima and adventitia and dark media. Plaque components showed differences in signal intensity and texture at 53 keV. Quantitative analysis demonstrated the highest HU-phase of soft plaque in dense FT. Less organized LIP, NEC and INF were associated with lower HU-phase values. The highest HU-phase were measured in CA. Conclusion: PC-CT of atherosclerosis is feasible at high, clinically relevant photon energies and provides detailed information about plaque structure including features of high risk vulnerable plaques. (orig.)

  15. Visualizing and Quantifying Bioaccessible Pores in Field-Aged Petroleum Hydrocarbon-Contaminated Clay Soils Using Synchrotron-based X-ray Computed Tomography

    Science.gov (United States)

    Chang, W.; Kim, J.; Zhu, N.; McBeth, J. M.

    2015-12-01

    Microbial hydrocarbon degradation is environmentally significant and applicable to contaminated site remediation practices only when hydrocarbons (substrates) are physically bioaccessible to bacteria in soil matrices. Powerful X-rays are produced by synchrotron radiation, allowing for bioaccessible pores in soil (larger than 4 microns), where bacteria can be accommodated, colonize and remain active, can be visualized at a much higher resolution. This study visualized and quantified such bioaccessible pores in intact field-aged, oil-contaminated unsaturated soil fractions, and examined the relationship between the abundance of bioaccessible pores and hydrocarbon biodegradation. Using synchrotron-based X-ray Computed Tomography (CT) at the Canadian Light Source, a large dataset of soil particle characteristics, such as pore volumes, surface areas, number of pores and pore size distribution, was generated. Duplicate samples of five different soil fractions with different soil aggregate sizes and water contents (13, 18 and 25%) were examined. The method for calculating the number and distribution of bioaccessible pores using CT images was validated using the known porosity of Ottawa sand. This study indicated that the distribution of bioaccessible pore sizes in soil fractions are very closely related to microbial enhancement. A follow-up aerobic biodegradation experiment for the soils at 17 °C (average site temperature) over 90 days confirmed that a notable decrease in hydrocarbon concentrations occurred in soils fractions with abundant bioaccessible pores and with a larger number of pores between 10 and 100 μm. The hydrocarbon degradation in bioactive soil fractions was extended to relatively high-molecular-weight hydrocarbons (C16-C34). This study provides quantitative information about how internal soil pore characteristics can influence bioremediation performance.

  16. Dynamic angle selection in X-ray computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Dabravolski, Andrei, E-mail: andrei.dabravolski@uantwerpen.be [iMinds-Vision Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk (Belgium); Batenburg, Kees Joost, E-mail: joost.batenburg@uantwerpen.be [iMinds-Vision Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk (Belgium); Centrum Wiskunde and Informatica (CWI), Science Park 123, 1098 XG Amsterdam (Netherlands); Sijbers, Jan, E-mail: jan.sijbers@uantwerpen.be [iMinds-Vision Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk (Belgium)

    2014-04-01

    Highlights: • We propose the dynamic angle selection algorithm for CT scanning. • The approach is based on the concept of information gain over a set of solutions. • Projection angles are selected based on the already available projection data. • The approach can lead to more accurate results from fewer projections. - Abstract: In X-ray tomography, a number of radiographs (projections) are recorded from which a tomogram is then reconstructed. Conventionally, these projections are acquired equiangularly, resulting in an unbiased sampling of the Radon space. However, especially in case when only a limited number of projections can be acquired, the selection of the angles has a large impact on the quality of the reconstructed image. In this paper, a dynamic algorithm is proposed, in which new projection angles are selected by maximizing the information gain about the object, given the set of possible new angles. Experiments show that this approach can select projection angles for which the accuracy of the reconstructed image is significantly higher compared to the standard angle selections schemes.

  17. Dynamic angle selection in X-ray computed tomography

    International Nuclear Information System (INIS)

    Dabravolski, Andrei; Batenburg, Kees Joost; Sijbers, Jan

    2014-01-01

    Highlights: • We propose the dynamic angle selection algorithm for CT scanning. • The approach is based on the concept of information gain over a set of solutions. • Projection angles are selected based on the already available projection data. • The approach can lead to more accurate results from fewer projections. - Abstract: In X-ray tomography, a number of radiographs (projections) are recorded from which a tomogram is then reconstructed. Conventionally, these projections are acquired equiangularly, resulting in an unbiased sampling of the Radon space. However, especially in case when only a limited number of projections can be acquired, the selection of the angles has a large impact on the quality of the reconstructed image. In this paper, a dynamic algorithm is proposed, in which new projection angles are selected by maximizing the information gain about the object, given the set of possible new angles. Experiments show that this approach can select projection angles for which the accuracy of the reconstructed image is significantly higher compared to the standard angle selections schemes

  18. Non-destructive analysis of micro texture and grain boundary character from X-ray diffraction contrast tomography

    DEFF Research Database (Denmark)

    King, A.; Herbig, M.; Ludwig, W.

    2010-01-01

    Recent advances in synchrotron based X-ray imaging and diffraction techniques offer interesting new possibilities for mapping 3D grain shapes and crystallographic orientations in different classes of polycrystalline materials. X-ray diffraction contrast tomography (DCT) is a monochromatic beam...... imaging technique combining the principles of X-ray micro-tomography and three-dimensional X-ray diffraction microscopy (3DXRD). DCT provides simultaneous access to 3D grain shape, crystallographic orientation and attenuation coefficient distribution at the micrometer length scale. The microtexture...

  19. Soft x-ray tomography on the Alcator C tokamak

    International Nuclear Information System (INIS)

    Camacho, J.F.

    1985-06-01

    A soft x-ray tomography experiment has been performed on the Alcator C tokamak. An 80-chord array of detectors consisting of miniature PIN photodiodes was used to obtain tomographic reconstructions of the soft x-ray emissivity function's poloidal cross-section. The detectors are located around the periphery of the plasma at one toroidal location (top and bottom ports) and are capable of yielding useful information over a wide range of plasma operating parameters and conditions. The reconstruction algorithm employed makes no assumption whatsoever about plasma rotation, position, or symmetry. Its performance was tested, and it was found to work well and to be fairly insensitive to estimated levels of random and systematic errors in the data

  20. Variation in the human ribs geometrical properties and mechanical response based on X-ray computed tomography images resolution.

    Science.gov (United States)

    Perz, Rafał; Toczyski, Jacek; Subit, Damien

    2015-01-01

    Computational models of the human body are commonly used for injury prediction in automobile safety research. To create these models, the geometry of the human body is typically obtained from segmentation of medical images such as computed tomography (CT) images that have a resolution between 0.2 and 1mm/pixel. While the accuracy of the geometrical and structural information obtained from these images depend greatly on their resolution, the effect of image resolution on the estimation of the ribs geometrical properties has yet to be established. To do so, each of the thirty-four sections of ribs obtained from a Post Mortem Human Surrogate (PMHS) was imaged using three different CT modalities: standard clinical CT (clinCT), high resolution clinical CT (HRclinCT), and microCT. The images were processed to estimate the rib cross-section geometry and mechanical properties, and the results were compared to those obtained from the microCT images by computing the 'deviation factor', a metric that quantifies the relative difference between results obtained from clinCT and HRclinCT to those obtained from microCT. Overall, clinCT images gave a deviation greater than 100%, and were therefore deemed inadequate for the purpose of this study. HRclinCT overestimated the rib cross-sectional area by 7.6%, the moments of inertia by about 50%, and the cortical shell area by 40.2%, while underestimating the trabecular area by 14.7%. Next, a parametric analysis was performed to quantify how the variations in the estimate of the geometrical properties affected the rib predicted mechanical response under antero-posterior loading. A variation of up to 45% for the predicted peak force and up to 50% for the predicted stiffness was observed. These results provide a quantitative estimate of the sensitivity of the response of the FE model to the resolution of the images used to generate it. They also suggest that a correction factor could be derived from the comparison between microCT and

  1. Computed tomography of x-ray index of refraction using the diffraction enhanced imaging method

    International Nuclear Information System (INIS)

    Dilmanian, F.A.; Ren, B.; Wu, X.Y.; Orion, I.; Zhong, Z.; Thomlinson, W.C.; Chapman, L.D.

    2000-01-01

    Diffraction enhanced imaging (DEI) is a new, synchrotron-based, x-ray radiography method that uses monochromatic, fan-shaped beams, with an analyser crystal positioned between the subject and the detector. The analyser allows the detection of only those x-rays transmitted by the subject that fall into the acceptance angle (central part of the rocking curve) of the monochromator/analyser system. As shown by Chapman et al , in addition to the x-ray attenuation, the method provides information on the out-of-plane angular deviation of x-rays. New images result in which the image contrast depends on the x-ray index of refraction and on the yield of small-angle scattering, respectively. We implemented DEI in the tomography mode at the National Synchrotron Light Source using 22 keV x-rays, and imaged a cylindrical acrylic phantom that included oil-filled, slanted channels. The resulting 'refraction CT image' shows the pure image of the out-of-plane gradient of the x-ray index of refraction. No image artefacts were present, indicating that the CT projection data were a consistent set. The 'refraction CT image' signal is linear with the gradient of the refractive index, and its value is equal to that expected. The method, at the energy used or higher, has the potential for use in clinical radiography and in industry. (author)

  2. Quasimonochromatic x-ray computed tomography by the balanced filter method using a conventional x-ray source

    International Nuclear Information System (INIS)

    Saito, Masatoshi

    2004-01-01

    A quasimonochromatic x-ray computed tomography (CT) system utilizing balanced filters has recently been developed for acquiring quantitative CT images. This system consisted of basic components such as a conventional x-ray generator for radiography, a stage for mounting and rotating objects, and an x-ray line sensor camera. Metallic sheets of Er and Yb were used as the balanced filters for obtaining quasimonochromatic incident x rays that include the characteristic lines of the W Kα doublet from a tungsten target. The mean energy and energy width of the quasimonochromatic x rays were determined to be 59.0 and 1.9 keV, respectively, from x-ray spectroscopic measurements using a high-purity Ge detector. The usefulness of the present x-ray CT system was demonstrated by obtaining spatial distributions of the linear attenuation coefficients of three selected samples--a 20 cm diameter cylindrical water phantom, a 3.5 cm diameter aluminum rod, and a human head phantom. The results clearly indicate that this apparatus is surprisingly effective for estimating the distribution of the linear attenuation coefficients without any correction of the beam-hardening effect. Thus, implementing the balanced filter method on an x-ray CT scanner has promise in producing highly quantitative CT images

  3. Three-Dimensional Imaging and Numerical Reconstruction of Graphite/Epoxy Composite Microstructure Based on Ultra-High Resolution X-Ray Computed Tomography

    Science.gov (United States)

    Czabaj, M. W.; Riccio, M. L.; Whitacre, W. W.

    2014-01-01

    A combined experimental and computational study aimed at high-resolution 3D imaging, visualization, and numerical reconstruction of fiber-reinforced polymer microstructures at the fiber length scale is presented. To this end, a sample of graphite/epoxy composite was imaged at sub-micron resolution using a 3D X-ray computed tomography microscope. Next, a novel segmentation algorithm was developed, based on concepts adopted from computer vision and multi-target tracking, to detect and estimate, with high accuracy, the position of individual fibers in a volume of the imaged composite. In the current implementation, the segmentation algorithm was based on Global Nearest Neighbor data-association architecture, a Kalman filter estimator, and several novel algorithms for virtualfiber stitching, smoothing, and overlap removal. The segmentation algorithm was used on a sub-volume of the imaged composite, detecting 508 individual fibers. The segmentation data were qualitatively compared to the tomographic data, demonstrating high accuracy of the numerical reconstruction. Moreover, the data were used to quantify a) the relative distribution of individual-fiber cross sections within the imaged sub-volume, and b) the local fiber misorientation relative to the global fiber axis. Finally, the segmentation data were converted using commercially available finite element (FE) software to generate a detailed FE mesh of the composite volume. The methodology described herein demonstrates the feasibility of realizing an FE-based, virtual-testing framework for graphite/fiber composites at the constituent level.

  4. Improving material identification by combining x-ray and neutron tomography

    Science.gov (United States)

    LaManna, Jacob M.; Hussey, Daniel S.; Baltic, Eli; Jacobson, David L.

    2017-09-01

    X-rays and neutrons provide complementary non-destructive probes for the analysis of structure and chemical composition of materials. Contrast differences between the modes arise due to the differences in interaction with matter. Due to the high sensitivity to hydrogen, neutrons excel at separating liquid water or hydrogenous phases from the underlying structure while X-rays resolve the solid structure. Many samples of interest, such as fluid flow in porous materials or curing concrete, are stochastic or slowly changing with time which makes analysis of sequential imaging with X-rays and neutrons difficult as the sample may change between scans. To alleviate this issue, NIST has developed a system for simultaneous X-ray and neutron tomography by orienting a 90 keVpeak micro-focus X-ray tube orthogonally to a thermal neutron beam. This system allows for non-destructive, multimodal tomography of dynamic or stochastic samples while penetrating through sample environment equipment such as pressure and flow vessels. Current efforts are underway to develop methods for 2D histogram based segmentation of reconstructed volumes. By leveraging the contrast differences between X-rays and neutrons, greater histogram peak separation can occur in 2D vs 1D enabling improved material identification.

  5. Material Characterization and Geometric Segmentation of a Composite Structure Using Microfocus X-Ray Computed Tomography Image-Based Finite Element Modeling

    Science.gov (United States)

    Abdul-Aziz, Ali; Roth, D. J.; Cotton, R.; Studor, George F.; Christiansen, Eric; Young, P. C.

    2011-01-01

    This study utilizes microfocus x-ray computed tomography (CT) slice sets to model and characterize the damage locations and sizes in thermal protection system materials that underwent impact testing. ScanIP/FE software is used to visualize and process the slice sets, followed by mesh generation on the segmented volumetric rendering. Then, the local stress fields around several of the damaged regions are calculated for realistic mission profiles that subject the sample to extreme temperature and other severe environmental conditions. The resulting stress fields are used to quantify damage severity and make an assessment as to whether damage that did not penetrate to the base material can still result in catastrophic failure of the structure. It is expected that this study will demonstrate that finite element modeling based on an accurate three-dimensional rendered model from a series of CT slices is an essential tool to quantify the internal macroscopic defects and damage of a complex system made out of thermal protection material. Results obtained showing details of segmented images; three-dimensional volume-rendered models, finite element meshes generated, and the resulting thermomechanical stress state due to impact loading for the material are presented and discussed. Further, this study is conducted to exhibit certain high-caliber capabilities that the nondestructive evaluation (NDE) group at NASA Glenn Research Center can offer to assist in assessing the structural durability of such highly specialized materials so improvements in their performance and capacities to handle harsh operating conditions can be made.

  6. Design, development and integration of a large scale multiple source X-ray computed tomography system

    International Nuclear Information System (INIS)

    Malcolm, Andrew A.; Liu, Tong; Ng, Ivan Kee Beng; Teng, Wei Yuen; Yap, Tsi Tung; Wan, Siew Ping; Kong, Chun Jeng

    2013-01-01

    X-ray Computed Tomography (CT) allows visualisation of the physical structures in the interior of an object without physically opening or cutting it. This technology supports a wide range of applications in the non-destructive testing, failure analysis or performance evaluation of industrial products and components. Of the numerous factors that influence the performance characteristics of an X-ray CT system the energy level in the X-ray spectrum to be used is one of the most significant. The ability of the X-ray beam to penetrate a given thickness of a specific material is directly related to the maximum available energy level in the beam. Higher energy levels allow penetration of thicker components made of more dense materials. In response to local industry demand and in support of on-going research activity in the area of 3D X-ray imaging for industrial inspection the Singapore Institute of Manufacturing Technology (SIMTech) engaged in the design, development and integration of large scale multiple source X-ray computed tomography system based on X-ray sources operating at higher energies than previously available in the Institute. The system consists of a large area direct digital X-ray detector (410 x 410 mm), a multiple-axis manipulator system, a 225 kV open tube microfocus X-ray source and a 450 kV closed tube millifocus X-ray source. The 225 kV X-ray source can be operated in either transmission or reflection mode. The body of the 6-axis manipulator system is fabricated from heavy-duty steel onto which high precision linear and rotary motors have been mounted in order to achieve high accuracy, stability and repeatability. A source-detector distance of up to 2.5 m can be achieved. The system is controlled by a proprietary X-ray CT operating system developed by SIMTech. The system currently can accommodate samples up to 0.5 x 0.5 x 0.5 m in size with weight up to 50 kg. These specifications will be increased to 1.0 x 1.0 x 1.0 m and 100 kg in future

  7. X-ray micro-modulated luminescence tomography (XMLT)

    Science.gov (United States)

    Cong, Wenxiang; Liu, Fenglin; Wang, Chao; Wang, Ge

    2014-01-01

    Imaging depth of optical microscopy has been fundamentally limited to millimeter or sub-millimeter due to strong scattering of light in a biological sample. X-ray microscopy can resolve spatial details of few microns deep inside a sample but contrast resolution is inadequate to depict heterogeneous features at cellular or sub-cellular levels. To enhance and enrich biological contrast at large imaging depth, various nanoparticles are introduced and become essential to basic research and molecular medicine. Nanoparticles can be functionalized as imaging probes, similar to fluorescent and bioluminescent proteins. LiGa5O8:Cr3+ nanoparticles were recently synthesized to facilitate luminescence energy storage with x-ray pre-excitation and subsequently stimulated luminescence emission by visible/near-infrared (NIR) light. In this paper, we propose an x-ray micro-modulated luminescence tomography (XMLT, or MLT to be more general) approach to quantify a nanophosphor distribution in a thick biological sample with high resolution. Our numerical simulation studies demonstrate the feasibility of the proposed approach. PMID:24663898

  8. Multi-Mounted X-Ray Computed Tomography.

    Science.gov (United States)

    Fu, Jian; Liu, Zhenzhong; Wang, Jingzheng

    2016-01-01

    Most existing X-ray computed tomography (CT) techniques work in single-mounted mode and need to scan the inspected objects one by one. It is time-consuming and not acceptable for the inspection in a large scale. In this paper, we report a multi-mounted CT method and its first engineering implementation. It consists of a multi-mounted scanning geometry and the corresponding algebraic iterative reconstruction algorithm. This approach permits the CT rotation scanning of multiple objects simultaneously without the increase of penetration thickness and the signal crosstalk. Compared with the conventional single-mounted methods, it has the potential to improve the imaging efficiency and suppress the artifacts from the beam hardening and the scatter. This work comprises a numerical study of the method and its experimental verification using a dataset measured with a developed multi-mounted X-ray CT prototype system. We believe that this technique is of particular interest for pushing the engineering applications of X-ray CT.

  9. Diagnostic perspectives of mobile x-ray computerized tomography

    International Nuclear Information System (INIS)

    Portnoj, L.M.; Dibirov, M.P.; Denisova, L.B.

    1992-01-01

    Mobile x-ray computerized tomography (CT) and an organization and methodological scheme of its application were assessed. CT is realized in special hospitals of large regions, where the patients with the optimal indications for CT are assembled. Over 15000 examinations were carried out with the use of the suggested CT program over 4 years, that resulted in detection of 1295 brain tumors, 804 cases with neoplastic involvement of the abdominal cavity and the retroperitoneal space. Wide application of mobile CT devices according to the program will help to decide the problem of unavailability of such examinations. One mobile device may replace 3 permanent CT devices

  10. Principles of image reconstruction in X-ray computer tomography

    International Nuclear Information System (INIS)

    Schwierz, G.; Haerer, W.; Ruehrnschopf, E.P.

    1978-01-01

    The presented geometrical interpretation elucidates the convergence behavior of the classical iteration technique in X-ray computer tomography. The filter techniques nowadays used in preference are derived from a concept of linear system theory which excels due to its particular clarity. The one-dimensional form of the filtering is of decisive importance for immediate image reproduction as realized by both Siemens systems, the SIRETOM 2000 head scanner and the SOMATOM whole-body machine, as such unique to date for whole-body machines. The equivalence of discrete and continuous filtering when dealing with frequency-band-limited projections is proved. (orig.) [de

  11. Three dimensional subsurface elemental identification of minerals using confocal micro-X-ray fluorescence and micro-X-ray computed tomography

    International Nuclear Information System (INIS)

    Cordes, Nikolaus L.; Seshadri, Srivatsan; Havrilla, George J.; Yuan, Xiaoli; Feser, Michael; Patterson, Brian M.

    2015-01-01

    Current non-destructive elemental characterization methods, such as scanning electron microscopy-based energy dispersive spectroscopy (SEM–EDS) and micro-X-ray fluorescence spectroscopy (MXRF), are limited to either elemental identification at the surface (SEM–EDS) or suffer from an inability to discriminate between surface or depth information (MXRF). Thus, a non-destructive elemental characterization of individual embedded particles beneath the surface is impossible with either of these techniques. This limitation can be overcome by using laboratory-based 3D confocal micro-X-ray fluorescence spectroscopy (confocal MXRF). This technique utilizes focusing optics on the X-ray source and detector which allows for spatial discrimination in all three dimensions. However, the voxel-by-voxel serial acquisition of a 3D elemental scan can be very time-intensive (~ 1 to 4 weeks) if it is necessary to locate individual embedded particles of interest. As an example, if each point takes a 5 s measurement time, a small volume of 50 × 50 × 50 pixels leads to an acquisition time of approximately 174 h, not including sample stage movement time. Initially screening the samples for particles of interest using micro-X-ray computed tomography (micro-CT) can significantly reduce the time required to spatially locate these particles. Once located, these individual particles can be elementally characterized with confocal MXRF. Herein, we report the elemental identification of high atomic number surface and subsurface particles embedded in a mineralogical matrix by coupling micro-CT and confocal MXRF. Synergistically, these two X-ray based techniques first rapidly locate and then elementally identify individual subsurface particles. - Highlights: • Coupling of confocal X-ray fluorescence spectroscopy and X-ray computed tomography • Qualitative elemental identification of surface and subsurface mineral particles • Non-destructive particle size measurements • Utilization of

  12. Three dimensional subsurface elemental identification of minerals using confocal micro-X-ray fluorescence and micro-X-ray computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Cordes, Nikolaus L., E-mail: ncordes@lanl.gov [Polymers and Coatings Group, Material Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Seshadri, Srivatsan, E-mail: srivatsan.seshadri@zeiss.com [Carl Zeiss X-ray Microscopy, Inc., Pleasanton, CA 94588 (United States); Havrilla, George J. [Chemical Diagnostics and Engineering, Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Yuan, Xiaoli [Julius Kruttschnitt Mineral Research Centre, University of Queensland, Indooroopilly, Brisbane, QLD 4068 (Australia); Feser, Michael [Carl Zeiss X-ray Microscopy, Inc., Pleasanton, CA 94588 (United States); Patterson, Brian M. [Polymers and Coatings Group, Material Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2015-01-01

    Current non-destructive elemental characterization methods, such as scanning electron microscopy-based energy dispersive spectroscopy (SEM–EDS) and micro-X-ray fluorescence spectroscopy (MXRF), are limited to either elemental identification at the surface (SEM–EDS) or suffer from an inability to discriminate between surface or depth information (MXRF). Thus, a non-destructive elemental characterization of individual embedded particles beneath the surface is impossible with either of these techniques. This limitation can be overcome by using laboratory-based 3D confocal micro-X-ray fluorescence spectroscopy (confocal MXRF). This technique utilizes focusing optics on the X-ray source and detector which allows for spatial discrimination in all three dimensions. However, the voxel-by-voxel serial acquisition of a 3D elemental scan can be very time-intensive (~ 1 to 4 weeks) if it is necessary to locate individual embedded particles of interest. As an example, if each point takes a 5 s measurement time, a small volume of 50 × 50 × 50 pixels leads to an acquisition time of approximately 174 h, not including sample stage movement time. Initially screening the samples for particles of interest using micro-X-ray computed tomography (micro-CT) can significantly reduce the time required to spatially locate these particles. Once located, these individual particles can be elementally characterized with confocal MXRF. Herein, we report the elemental identification of high atomic number surface and subsurface particles embedded in a mineralogical matrix by coupling micro-CT and confocal MXRF. Synergistically, these two X-ray based techniques first rapidly locate and then elementally identify individual subsurface particles. - Highlights: • Coupling of confocal X-ray fluorescence spectroscopy and X-ray computed tomography • Qualitative elemental identification of surface and subsurface mineral particles • Non-destructive particle size measurements • Utilization of

  13. Studying fatigue damage evolution in uni-directional composites using x-ray computed tomography

    DEFF Research Database (Denmark)

    Mikkelsen, Lars Pilgaard

    , it will be possible to lower the costs of energy for wind energy based electricity. In the present work, a lab-source x-ray computed tomography equipment (Zeiss Xradia 520 Versa) has been used in connection with ex-situ fatigue testing of uni-directional composites in order to identify fibre failure during...... comparable x-ray studies) have been used in order to ensure a representative test volume during the ex-situ fatigue testing. Using the ability of the x-ray computed tomography to zoom into regions of interest, non-destructive, the fatigue damage evolution in a repeating ex-situ fatigue loaded test sample has...... improving the fatigue resistance of non-crimp fabric used in the wind turbine industry can be made....

  14. 3D chemical imaging in the laboratory by hyperspectral X-ray computed tomography

    Science.gov (United States)

    Egan, C. K.; Jacques, S. D. M.; Wilson, M. D.; Veale, M. C.; Seller, P.; Beale, A. M.; Pattrick, R. A. D.; Withers, P. J.; Cernik, R. J.

    2015-01-01

    We report the development of laboratory based hyperspectral X-ray computed tomography which allows the internal elemental chemistry of an object to be reconstructed and visualised in three dimensions. The method employs a spectroscopic X-ray imaging detector with sufficient energy resolution to distinguish individual elemental absorption edges. Elemental distributions can then be made by K-edge subtraction, or alternatively by voxel-wise spectral fitting to give relative atomic concentrations. We demonstrate its application to two material systems: studying the distribution of catalyst material on porous substrates for industrial scale chemical processing; and mapping of minerals and inclusion phases inside a mineralised ore sample. The method makes use of a standard laboratory X-ray source with measurement times similar to that required for conventional computed tomography. PMID:26514938

  15. Comparison of Combined X-Ray Radiography and Magnetic Resonance (XMR) Imaging-Versus Computed Tomography-Based Dosimetry for the Evaluation of Permanent Prostate Brachytherapy Implants

    International Nuclear Information System (INIS)

    Acher, Peter; Rhode, Kawal; Morris, Stephen; Gaya, Andrew; Miquel, Marc; Popert, Rick; Tham, Ivan; Nichol, Janette; McLeish, Kate; Deehan, Charles; Dasgupta, Prokar; Beaney, Ronald; Keevil, Stephen F.

    2008-01-01

    Purpose: To present a method for the dosimetric analysis of permanent prostate brachytherapy implants using a combination of stereoscopic X-ray radiography and magnetic resonance (MR) imaging (XMR) in an XMR facility, and to compare the clinical results between XMR- and computed tomography (CT)-based dosimetry. Methods and Materials: Patients who had received nonstranded iodine-125 permanent prostate brachytherapy implants underwent XMR and CT imaging 4 weeks later. Four observers outlined the prostate gland on both sets of images. Dose-volume histograms (DVHs) were derived, and agreement was compared among the observers and between the modalities. Results: A total of 30 patients were evaluated. Inherent XMR registration based on prior calibration and optical tracking required a further automatic seed registration step that revealed a median root mean square registration error of 4.2 mm (range, 1.6-11.4). The observers agreed significantly more closely on prostate base and apex positions as well as outlining contours on the MR images than on those from CT. Coefficients of variation were significantly higher for observed prostate volumes, D90, and V100 parameters on CT-based dosimetry as opposed to XMR. The XMR-based dosimetry showed little agreement with that from CT for all observers, with D90 95% limits of agreement ranges of 65, 118, 79, and 73 Gy for Observers 1, 2, 3, and 4, respectively. Conclusions: The study results showed that XMR-based dosimetry offers an alternative to other imaging modalities and registration methods with the advantages of MR-based prostate delineation and confident three-dimensional reconstruction of the implant. The XMR-derived dose-volume histograms differ from the CT-derived values and demonstrate less interobserver variability

  16. Neutron and X-ray Tomography (NeXT) system for simultaneous, dual modality tomography

    Science.gov (United States)

    LaManna, J. M.; Hussey, D. S.; Baltic, E.; Jacobson, D. L.

    2017-11-01

    Dual mode tomography using neutrons and X-rays offers the potential of improved estimation of the composition of a sample from the complementary interaction of the two probes with the sample. We have developed a simultaneous neutron and 90 keV X-ray tomography system that is well suited to the study of porous media systems such as fuel cells, concrete, unconventional reservoir geologies, limestones, and other geological media. We present the characteristic performance of both the neutron and X-ray modalities. We illustrate the use of the simultaneous acquisition through improved phase identification in a concrete core.

  17. Introduction to 2D and 3D tomographic methods based on straight line propagation: X-ray, emission and ultrasonic tomography

    International Nuclear Information System (INIS)

    Peyrin, F.; Magnin, I.; Garnero, L.

    1996-01-01

    This paper presents the basic principles of computerized tomography (CT), and its evolution towards three dimensional (3D) imaging. Since the modeling of CT reconstruction relies on the Radon transform, its definition and major properties are first recalled. After a brief summary on conventional 2D methods, we present the imaging principles for two modalities appropriated to this modeling: X-Ray and emission tomography. We describe the evolution of the instrumentation for these two techniques, and emphasize the approximations introduced by a modeling using the Radon transform taking into account the physics of the problem. We also describe the principles of ultrasonic tomography systems, and their major differences with the two previous techniques. At last, we formulate the general problematic of 3D image reconstruction from 2D projections. We consider four classes of reconstruction methods corresponding to the classification to the classification chosen for the synthetic presentation of methods, accompanying this paper. (authors)

  18. Three-dimensional reciprocal space x-ray coherent scattering tomography of two-dimensional object.

    Science.gov (United States)

    Zhu, Zheyuan; Pang, Shuo

    2018-04-01

    X-ray coherent scattering tomography is a powerful tool in discriminating biological tissues and bio-compatible materials. Conventional x-ray scattering tomography framework can only resolve isotropic scattering profile under the assumption that the material is amorphous or in powder form, which is not true especially for biological samples with orientation-dependent structure. Previous tomography schemes based on x-ray coherent scattering failed to preserve the scattering pattern from samples with preferred orientations, or required elaborated data acquisition scheme, which could limit its application in practical settings. Here, we demonstrate a simple imaging modality to preserve the anisotropic scattering signal in three-dimensional reciprocal (momentum transfer) space of a two-dimensional sample layer. By incorporating detector movement along the direction of x-ray beam, combined with a tomographic data acquisition scheme, we match the five dimensions of the measurements with the five dimensions (three in momentum transfer domain, and two in spatial domain) of the object. We employed a collimated pencil beam of a table-top copper-anode x-ray tube, along with a panel detector to investigate the feasibility of our method. We have demonstrated x-ray coherent scattering tomographic imaging at a spatial resolution ~2 mm and momentum transfer resolution 0.01 Å -1 for the rotation-invariant scattering direction. For any arbitrary, non-rotation-invariant direction, the same spatial and momentum transfer resolution can be achieved based on the spatial information from the rotation-invariant direction. The reconstructed scattering profile of each pixel from the experiment is consistent with the x-ray diffraction profile of each material. The three-dimensional scattering pattern recovered from the measurement reveals the partially ordered molecular structure of Teflon wrap in our sample. We extend the applicability of conventional x-ray coherent scattering tomography to

  19. A review of X-ray computed axial tomography

    International Nuclear Information System (INIS)

    Schmidt, M.

    1989-01-01

    A review of Computed axial tomography (CAT) scanning literature outlining the theoretical and practical aspects of this technique with application in both medical diagnosis and industrial non-destructive inspection (NDI) is presented. Practical aspects of CAT scanning discussed include : radiation sources, currently available spatial and contrast resolution limits and the evolution of the computerized tomography (CT) system. It was found that monochromatic gamma rays are preferred to X-rays, especially for very high density materials, and that in medical CAT scanning, the special resolution is only, 0.5 mm while spatial resolutions of less than 50μm have been achieved in NDI. An increased number of scientific and industrial applications are anticipated (e.g. for studying sintering reactions), as the capital cost of CAT scanning decreased. 13 refs., 9 figs., 2 tabs

  20. X-ray coherent scattering tomography of textured material (Conference Presentation)

    Science.gov (United States)

    Zhu, Zheyuan; Pang, Shuo

    2017-05-01

    Small-angle X-ray scattering (SAXS) measures the signature of angular-dependent coherently scattered X-rays, which contains richer information in material composition and structure compared to conventional absorption-based computed tomography. SAXS image reconstruction method of a 2 or 3 dimensional object based on computed tomography, termed as coherent scattering computed tomography (CSCT), enables the detection of spatially-resolved, material-specific isotropic scattering signature inside an extended object, and provides improved contrast for medical diagnosis, security screening, and material characterization applications. However, traditional CSCT methods assumes materials are fine powders or amorphous, and possess isotropic scattering profiles, which is not generally true for all materials. Anisotropic scatters cannot be captured using conventional CSCT method and result in reconstruction errors. To obtain correct information from the sample, we designed new imaging strategy which incorporates extra degree of detector motion into X-ray scattering tomography for the detection of anisotropic scattered photons from a series of two-dimensional intensity measurements. Using a table-top, narrow-band X-ray source and a panel detector, we demonstrate the anisotropic scattering profile captured from an extended object and the reconstruction of a three-dimensional object. For materials possessing a well-organized crystalline structure with certain symmetry, the scatter texture is more predictable. We will also discuss the compressive schemes and implementation of data acquisition to improve the collection efficiency and accelerate the imaging process.

  1. SU-C-206-03: Metal Artifact Reduction in X-Ray Computed Tomography Based On Local Anatomical Similarity

    International Nuclear Information System (INIS)

    Dong, X; Yang, X; Rosenfield, J; Elder, E; Dhabaan, A

    2016-01-01

    Purpose: Metal implants such as orthopedic hardware and dental fillings cause severe bright and dark streaking in reconstructed CT images. These artifacts decrease image contrast and degrade HU accuracy, leading to inaccuracies in target delineation and dose calculation. Additionally, such artifacts negatively impact patient set-up in image guided radiation therapy (IGRT). In this work, we propose a novel method for metal artifact reduction which utilizes the anatomical similarity between neighboring CT slices. Methods: Neighboring CT slices show similar anatomy. Based on this anatomical similarity, the proposed method replaces corrupted CT pixels with pixels from adjacent, artifact-free slices. A gamma map, which is the weighted summation of relative HU error and distance error, is calculated for each pixel in the artifact-corrupted CT image. The minimum value in each pixel’s gamma map is used to identify a pixel from the adjacent CT slice to replace the corresponding artifact-corrupted pixel. This replacement only occurs if the minimum value in a particular pixel’s gamma map is larger than a threshold. The proposed method was evaluated with clinical images. Results: Highly attenuating dental fillings and hip implants cause severe streaking artifacts on CT images. The proposed method eliminates the dark and bright streaking and improves the implant delineation and visibility. In particular, the image non-uniformity in the central region of interest was reduced from 1.88 and 1.01 to 0.28 and 0.35, respectively. Further, the mean CT HU error was reduced from 328 HU and 460 HU to 60 HU and 36 HU, respectively. Conclusions: The proposed metal artifact reduction method replaces corrupted image pixels with pixels from neighboring slices that are free of metal artifacts. This method proved capable of suppressing streaking artifacts, improving HU accuracy and image detectability.

  2. A density-based segmentation for 3D images, an application for X-ray micro-tomography

    International Nuclear Information System (INIS)

    Tran, Thanh N.; Nguyen, Thanh T.; Willemsz, Tofan A.; Kessel, Gijs van; Frijlink, Henderik W.; Voort Maarschalk, Kees van der

    2012-01-01

    Highlights: ► We revised the DBSCAN algorithm for segmentation and clustering of large 3D image dataset and classified multivariate image. ► The algorithm takes into account the coordinate system of the image data to improve the computational performance. ► The algorithm solved the instability problem in boundaries detection of the original DBSCAN. ► The segmentation results were successfully validated with synthetic 3D image and 3D XMT image of a pharmaceutical powder. - Abstract: Density-based spatial clustering of applications with noise (DBSCAN) is an unsupervised classification algorithm which has been widely used in many areas with its simplicity and its ability to deal with hidden clusters of different sizes and shapes and with noise. However, the computational issue of the distance table and the non-stability in detecting the boundaries of adjacent clusters limit the application of the original algorithm to large datasets such as images. In this paper, the DBSCAN algorithm was revised and improved for image clustering and segmentation. The proposed clustering algorithm presents two major advantages over the original one. Firstly, the revised DBSCAN algorithm made it applicable for large 3D image dataset (often with millions of pixels) by using the coordinate system of the image data. Secondly, the revised algorithm solved the non-stability issue of boundary detection in the original DBSCAN. For broader applications, the image dataset can be ordinary 3D images or in general, it can also be a classification result of other type of image data e.g. a multivariate image.

  3. SU-C-206-03: Metal Artifact Reduction in X-Ray Computed Tomography Based On Local Anatomical Similarity

    Energy Technology Data Exchange (ETDEWEB)

    Dong, X; Yang, X; Rosenfield, J; Elder, E; Dhabaan, A [Emory University, Winship Cancer Institute, Atlanta, GA (United States)

    2016-06-15

    Purpose: Metal implants such as orthopedic hardware and dental fillings cause severe bright and dark streaking in reconstructed CT images. These artifacts decrease image contrast and degrade HU accuracy, leading to inaccuracies in target delineation and dose calculation. Additionally, such artifacts negatively impact patient set-up in image guided radiation therapy (IGRT). In this work, we propose a novel method for metal artifact reduction which utilizes the anatomical similarity between neighboring CT slices. Methods: Neighboring CT slices show similar anatomy. Based on this anatomical similarity, the proposed method replaces corrupted CT pixels with pixels from adjacent, artifact-free slices. A gamma map, which is the weighted summation of relative HU error and distance error, is calculated for each pixel in the artifact-corrupted CT image. The minimum value in each pixel’s gamma map is used to identify a pixel from the adjacent CT slice to replace the corresponding artifact-corrupted pixel. This replacement only occurs if the minimum value in a particular pixel’s gamma map is larger than a threshold. The proposed method was evaluated with clinical images. Results: Highly attenuating dental fillings and hip implants cause severe streaking artifacts on CT images. The proposed method eliminates the dark and bright streaking and improves the implant delineation and visibility. In particular, the image non-uniformity in the central region of interest was reduced from 1.88 and 1.01 to 0.28 and 0.35, respectively. Further, the mean CT HU error was reduced from 328 HU and 460 HU to 60 HU and 36 HU, respectively. Conclusions: The proposed metal artifact reduction method replaces corrupted image pixels with pixels from neighboring slices that are free of metal artifacts. This method proved capable of suppressing streaking artifacts, improving HU accuracy and image detectability.

  4. Computed tomography of the chest with model-based iterative reconstruction using a radiation exposure similar to chest X-ray examination: preliminary observations

    Energy Technology Data Exchange (ETDEWEB)

    Neroladaki, Angeliki; Botsikas, Diomidis; Boudabbous, Sana; Becker, Christoph D.; Montet, Xavier [Geneva University Hospital, Department of Radiology, Geneva 4 (Switzerland)

    2013-02-15

    The purpose of this study was to assess the diagnostic image quality of ultra-low-dose chest computed tomography (ULD-CT) obtained with a radiation dose comparable to chest radiography and reconstructed with filtered back projection (FBP), adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR) in comparison with standard dose diagnostic CT (SDD-CT) or low-dose diagnostic CT (LDD-CT) reconstructed with FBP alone. Unenhanced chest CT images of 42 patients acquired with ULD-CT were compared with images obtained with SDD-CT or LDD-CT in the same examination. Noise measurements and image quality, based on conspicuity of chest lesions on all CT data sets were assessed on a five-point scale. The radiation dose of ULD-CT was 0.16 {+-} 0.006 mSv compared with 11.2 {+-} 2.7 mSv for SDD-CT (P < 0.0001) and 2.7 {+-} 0.9 mSv for LDD-CT. Image quality of ULD-CT increased significantly when using MBIR compared with FBP or ASIR (P < 0.001). ULD-CT reconstructed with MBIR enabled to detect as many non-calcified pulmonary nodules as seen on SDD-CT or LDD-CT. However, image quality of ULD-CT was clearly inferior for characterisation of ground glass opacities or emphysema. Model-based iterative reconstruction allows detection of pulmonary nodules with ULD-CT with radiation exposure in the range of a posterior to anterior (PA) and lateral chest X-ray. (orig.)

  5. Computerized tomography using high resolution X-ray imaging system with a microfocus source

    International Nuclear Information System (INIS)

    Zaprazny, Z.; Korytar, D.; Konopka, P.; Ac, V.; Bielecki, J.

    2011-01-01

    In recent years there is an effort to image an internal structure of an object by using not only conventional 2D X-ray radiography but also using high resolution 3D tomography which is based on reconstruction of multiple 2D projections at various angular positions of the object. We have previously reported [1] the development and basic parameters of a high resolution x-ray imaging system with a microfocus source. We report the recent progress using this high resolution X-ray laboratory system in this work. These first findings show that our system is particularly suitable for light weight and nonmetallic objects such as biological objects, plastics, wood, paper, etc. where phase contrast helps to increase the visibility of the finest structures of the object. Phase-contrast X-ray Computerized Tomography is of our special interest because it is an emerging imaging technique that can be implemented at third generation synchrotron radiation sources and also in laboratory conditions using a microfocus X-ray tube or beam conditioning optics. (authors)

  6. Using X-ray computed tomography to predict carcass leanness in pigs

    International Nuclear Information System (INIS)

    Horn, P.; Kover, Gy.; Paszthy, Gy.; Berenyi, E.; Repa, I; Kovacs, G.

    1996-01-01

    Just one hundred years ago. Wilhelm Conrad Rontgen published his paper in Wurzburg describing X-rays and their effects, earning him the first Nobel Prize in Physics, presented in 1901. X-ray based diagnostic equipment revolutionized human diagnostics. A new milestone in the development of radiology was when Godfrey Hotmufield proposed to get additional anatomical information from a cross-sectional plane of the body by computer aided mathematical synthesis of an image from X-ray transmission data obtained from many different angles through the plane in consideration. The idea of the X-ray Computer Aided Tomography (CAT) was born, and the dramatic development of X-ray CAT imaging technology began, enhancing efficiency and scope of human diagnostics in human medicine. The numbers used to characterize the X-ray absorption in each picture element (pixel) of the CAT image are called ''CT'' or Hounsfield numbers (Hounsfield, 1979). The Nobel Prize was awarded to Hounsfield in 1979. X-ray Computer Aided Tomography system and software used were developed for humen medical purposes - mainly to detect anatomical physiological disorders - by all leading high-tech manufacturers in the world. As early as 1980, the potential of the new technique to be utilized in animal science was first recognized in Norway (Skjervold et al., 1981). In 1982, the Agricultural University of Norway acquired a Siemens Somatom 2 CAT system, and pioneering work started to apply X-ray CAT techniques in animal science. Based on the promising results obtained and published by the ''Norwegian school'' (Sehested, 1 984 Vangen, 1984 Allen and Vangen, 1984: Vangen and Standal, 1984), a research project proposal was prepared for the Hungarian Ministry of Agriculture and Food and the World Bank in 1985 to set up a digital imaging center at our Institute. The project was approved in 1986 (Horn, 1991a). The new digital imaging and diagnostic center started its operation in 1990, equipped first with a Siemens

  7. Phase contrast enhanced high resolution X-ray imaging and tomography of soft tissue

    International Nuclear Information System (INIS)

    Jakubek, Jan; Granja, Carlos; Dammer, Jiri; Hanus, Robert; Holy, Tomas; Pospisil, Stanislav; Tykva, Richard; Uher, Josef; Vykydal, Zdenek

    2007-01-01

    A tabletop system for digital high resolution and high sensitivity X-ray micro-radiography has been developed for small-animal and soft-tissue imaging. The system is based on a micro-focus X-ray tube and the semiconductor hybrid position sensitive Medipix2 pixel detector. Transmission radiography imaging, conventionally based only on absorption, is enhanced by exploiting phase-shift effects induced in the X-ray beam traversing the sample. Phase contrast imaging is realized by object edge enhancement. DAQ is done by a novel fully integrated USB-based readout with online image generation. Improved signal reconstruction techniques make use of advanced statistical data analysis, enhanced beam hardening correction and direct thickness calibration of individual pixels. 2D and 3D micro-tomography images of several biological samples demonstrate the applicability of the system for biological and medical purposes including in-vivo and time dependent physiological studies in the life sciences

  8. UGCT: New X-ray radiography and tomography facility

    International Nuclear Information System (INIS)

    Masschaele, B.C.; Cnudde, V.; Dierick, M.; Jacobs, P.; Hoorebeke, L. van; Vlassenbroeck, J.

    2007-01-01

    The UGCT (University Gent Computer Tomography) facility, a cooperation between the Radiation Physics research group and the Sedimentary Geology and Engineering Geology research group is a new CT facility providing a large range of scanning possibilities. Formerly a Skyscan 1072 was used to perform X-ray micro-CT scans at the UGCT facility and although this is a very powerful instrument, there were needs for a higher resolution and more flexibility. Therefore, the UCGT facility started the construction of a multidisciplinary micro-CT scanner inside a shielded room with a maximum flexibility of the set-up. The X-ray tube of this high-resolution CT scanner is a state-of-the-art open-type device with dual head: one head for high power micro-CT and one for sub-micro- or also called nano-CT. An important advantage of this scanner is that different detectors can be used to optimize the scanning conditions of the objects under investigation. The entire set-up is built on a large optical table to obtain the highest possible stability. Due to the flexible set-up and the powerful CT reconstruction software 'Octopus', it is possible to obtain the highest quality and the best signal-to-noise of the reconstructed images for each type of sample

  9. UGCT: New X-ray radiography and tomography facility

    Energy Technology Data Exchange (ETDEWEB)

    Masschaele, B.C. [Department of Subatomic and Radiation Physics, Ghent University, Proeftuinstraat 86, B-9000 Gent (Belgium)], E-mail: bert.masschaele@ugent.be; Cnudde, V. [Department of Geology and Soil Science, Ghent University, Krijgslaan 281, B-9000 Gent (Belgium); Dierick, M. [Department of Subatomic and Radiation Physics, Ghent University, Proeftuinstraat 86, B-9000 Gent (Belgium); Jacobs, P. [Department of Geology and Soil Science, Ghent University, Krijgslaan 281, B-9000 Gent (Belgium); Hoorebeke, L. van; Vlassenbroeck, J. [Department of Subatomic and Radiation Physics, Ghent University, Proeftuinstraat 86, B-9000 Gent (Belgium)

    2007-09-21

    The UGCT (University Gent Computer Tomography) facility, a cooperation between the Radiation Physics research group and the Sedimentary Geology and Engineering Geology research group is a new CT facility providing a large range of scanning possibilities. Formerly a Skyscan 1072 was used to perform X-ray micro-CT scans at the UGCT facility and although this is a very powerful instrument, there were needs for a higher resolution and more flexibility. Therefore, the UCGT facility started the construction of a multidisciplinary micro-CT scanner inside a shielded room with a maximum flexibility of the set-up. The X-ray tube of this high-resolution CT scanner is a state-of-the-art open-type device with dual head: one head for high power micro-CT and one for sub-micro- or also called nano-CT. An important advantage of this scanner is that different detectors can be used to optimize the scanning conditions of the objects under investigation. The entire set-up is built on a large optical table to obtain the highest possible stability. Due to the flexible set-up and the powerful CT reconstruction software 'Octopus', it is possible to obtain the highest quality and the best signal-to-noise of the reconstructed images for each type of sample.

  10. Technical note: a landmark-based approach to the study of the ear ossicles using ultra-high-resolution X-ray computed tomography data.

    Science.gov (United States)

    Schmidt, Jodi L; Cole, Theodore M; Silcox, Mary T

    2011-08-01

    Previous study of the ear ossicles in Primates has demonstrated that they vary on both functional and phylogenetic bases. Such studies have generally employed two-dimensional linear measurements rather than three-dimensional data. The availability of Ultra- high-resolution X-ray computed tomography (UhrCT) has made it possible to accurately image the ossicles so that broadly accepted methodologies for acquiring and studying morphometric data can be applied. Using UhrCT data also allows for the ossicular chain to be studied in anatomical position, so that it is possible to consider the spatial and size relationships of all three bones. One issue impeding the morphometric study of the ear ossicles is a lack of broadly recognized landmarks. Distinguishing landmarks on the ossicles is difficult in part because there are only two areas of articulation in the ossicular chain, one of which (the malleus/incus articulation) has a complex three-dimensional form. A measurement error study is presented demonstrating that a suite of 16 landmarks can be precisely located on reconstructions of the ossicles from UhrCT data. Estimates of measurement error showed that most landmarks were highly replicable, with an average CV for associated interlandmark distances of less than 3%. The positions of these landmarks are chosen to reflect not only the overall shape of the bones in the chain and their relative positions, but also functional parameters. This study should provide a basis for further examination of the smallest bones in the body in three dimensions. Copyright © 2011 Wiley-Liss, Inc.

  11. CCD-based X-ray detectors for X-ray diffraction studies

    International Nuclear Information System (INIS)

    Ito, K.; Amemiya, Y.

    1999-01-01

    CCD-based X-ray detectors are getting to be used for X-ray diffraction studies especially in the studies where real time (automated) measurements and time-resolved measurements are required. Principles and designs of two typical types of CCD-based detectors are described; one is ths system in which x-ray image intensifiers are coupled to maximize the detective quantum efficiency for time-resolved measurements, and the other is the system in which tapered optical fibers are coupled for the reduction of the image into the CCD, which is optimized for automated measurements for protein crystallography. These CCD-based X-ray detectors have an image distortion and non-uniformity of response to be corrected by software. Correction schemes which we have developed are also described. (author)

  12. Characterization of scalar mixing in dense gaseous jets using X-ray computed tomography

    Science.gov (United States)

    Dunnmon, Jared; Sobhani, Sadaf; Kim, Tae Wook; Kovscek, Anthony; Ihme, Matthias

    2015-10-01

    An experimental technique based on X-ray computed tomography (XCT) is used to characterize scalar mixing of a krypton jet with air at turbulent conditions. The high radiodensity of the krypton gas enables non-intrusive volumetric measurements of gas density and mixture composition based on spatial variations in X-ray attenuation. Comparisons of these measurements to both computational results from large-eddy simulations and data from previous experiments are presented, and the viability of this diagnostic technique is assessed. Important aspects of X-ray attenuation theory, XCT practice, and relevant error analysis are considered in data processing, and their impacts on the future development of this technique are discussed.

  13. High temperature x-ray micro-tomography

    Energy Technology Data Exchange (ETDEWEB)

    MacDowell, Alastair A., E-mail: aamacdowell@lbl.gov; Barnard, Harold; Parkinson, Dilworth Y.; Gludovatz, Bernd [Lawrence Berkeley National Lab., Berkeley, CA 94720 (United States); Haboub, Abdel [Lawrence Berkeley National Lab., Berkeley, CA 94720 (United States); current –Lincoln Univ., Jefferson City, Missouri, 65101 (United States); Larson, Natalie; Zok, Frank [University California Santa Barbara, Santa Barbara CA 93106 (United States); Panerai, Francesco; Mansour, Nagi N. [NASA Ames Research Centre, Moffett Field, CA, 94035 (United States); Bale, Hrishikesh [University California Berkeley, Berkeley, CA 94720 (United States); current - Carl Zeiss X-ray Microscopy, 4385 Hopyard Rd #100, Pleasanton, CA 94588 (United States); Acevedo, Claire [Lawrence Berkeley National Lab., Berkeley, CA 94720 (United States); University California San Francisco, San Francisco, CA 94143 (United States); Liu, Dong [University of Bristol, Bristol BS8 1TH (United Kingdom); Ritchie, Robert O. [Lawrence Berkeley National Lab., Berkeley, CA 94720 (United States); University California Berkeley, Berkeley, CA 94720 (United States)

    2016-07-27

    There is increasing demand for 3D micro-scale time-resolved imaging of samples in realistic - and in many cases extreme environments. The data is used to understand material response, validate and refine computational models which, in turn, can be used to reduce development time for new materials and processes. Here we present the results of high temperature experiments carried out at the x-ray micro-tomography beamline 8.3.2 at the Advanced Light Source. The themes involve material failure and processing at temperatures up to 1750°C. The experimental configurations required to achieve the requisite conditions for imaging are described, with examples of ceramic matrix composites, spacecraft ablative heat shields and nuclear reactor core Gilsocarbon graphite.

  14. X-ray machine vision and computed tomography

    International Nuclear Information System (INIS)

    Anon.

    1988-01-01

    This survey examines how 2-D x-ray machine vision and 3-D computed tomography will be used in industry in the 1988-1995 timeframe. Specific applications are described and rank-ordered in importance. The types of companies selling and using 2-D and 3-D systems are profiled, and markets are forecast for 1988 to 1995. It is known that many machine vision and automation companies are now considering entering this field. This report looks at the potential pitfalls and whether recent market problems similar to those recently experienced by the machine vision industry will likely occur in this field. FTS will publish approximately 100 other surveys in 1988 on emerging technology in the fields of AI, manufacturing, computers, sensors, photonics, energy, bioengineering, and materials

  15. Study of brain atrophy using X-ray computed tomography

    International Nuclear Information System (INIS)

    Kawabata, Masayoshi

    1987-01-01

    Cerebrospinal fluid space-cranial cavity ratio (CCR) of 811 subjects with no brain damage were investigated using X-ray computed tomography. Brain volume of healthy adults aged 20 - 59 years was almost constant and decreased gradually after 60 years. CCR of men aged 20 - 49 years kept constant value and increased with aging after 50 years. CCR of women aged 20 - 59 years kept equal value and CCR increased with aging after 60 years. Brain atrophy with aging was investigated in this study also. In retrospective study, CCR of patients in any age diagnosed brain atrophy in daily CT reports were beyond the normal range of CCR of healthy subjects aged 20 - 49 years. In 48 patients with Parkinson's disease, almost of CCR of them were included within normal range of CCR in age-matched control. (author)

  16. Recent observations with phase-contrast x-ray computed tomography

    Science.gov (United States)

    Momose, Atsushi; Takeda, Tohoru; Itai, Yuji; Tu, Jinhong; Hirano, Keiichi

    1999-09-01

    Recent development in phase-contrast X-ray computed tomography using an X-ray interferometer is reported. To observe larger samples than is possible with our previous X-ray interferometer, a large monolithic X-ray interferometer and a separated-type X-ray interferometer were studied. At the present time, 2.5 cm X 1.5 cm interference patterns have been generated with the X-ray interferometers using synchrotron X-rays. The large monolithic X-ray interferometer has produced interference fringes with 80% visibility, and has been used to measure various tissues. To produce images with higher spatial resolution, we fabricated another X-ray interferometer whose wafer was partially thinned by chemical etching. A preliminary test suggested that the spatial resolution has been improved.

  17. Phase-contrast x-ray computed tomography for observing biological specimens and organic materials

    Science.gov (United States)

    Momose, Atsushi; Takeda, Tohoru; Itai, Yuji

    1995-02-01

    A novel three-dimensional x-ray imaging method has been developed by combining a phase-contrast x-ray imaging technique with x-ray computed tomography. This phase-contrast x-ray computed tomography (PCX-CT) provides sectional images of organic specimens that would produce absorption-contrast x-ray CT images with little contrast. Comparing PCX-CT images of rat cerebellum and cancerous rabbit liver specimens with corresponding absorption-contrast CT images shows that PCX-CT is much more sensitive to the internal structure of organic specimens.

  18. X-ray phase radiography and tomography with grating interferometry and the reverse projection technique

    International Nuclear Information System (INIS)

    Wang, Zhili; Gao, Kun; Ge, Xin; Wu, Zhao; Chen, Heng; Wang, Shenghao; Wu, Ziyu; Zhu, Peiping; Yuan, Qingxi; Huang, Wanxia; Zhang, Kai

    2013-01-01

    X-ray grating interferometry provides substantially increased contrast over conventional absorption-based imaging methods, and therefore new and complementary information. Compared with other phase-contrast imaging techniques, x-ray grating interferometry can overcome some of the problems that have impaired the applications of x-ray phase-contrast radiography and phase tomography. Recently, special attention has been paid to the development of quantitative phase retrieval methods, which is mandatory to perform x-ray phase tomography, to achieve material identification, to differentiate distinct tissues, etc. Typically, the phase-stepping approach has been utilized for phase retrieval in grating interferometry. This method requires a grating scanning and acquisition of multiple radiographic projections, and therefore is disadvantageous in terms of imaging speed and radiation damage. Here we present an innovative, highly sensitive approach, dubbed ‘reverse projection’ (RP), for quantitative phase retrieval. Compared with the phase-stepping approach, the present RP method abandons grating scanning completely, and thus is advantageous due to its much higher efficiency and the reduced radiation dose, without the degradation of reconstruction quality. This review presents a detailed explanation of the principle of the RP method. Both radiography and phase tomography experiments are performed to validate the RP method. We believe that this new technique will find widespread applications in biomedical imaging and in vivo studies. (paper)

  19. Three-dimensional monochromatic x-ray computed tomography using synchrotron radiation

    Science.gov (United States)

    Saito, Tsuneo; Kudo, Hiroyuki; Takeda, Tohoru; Itai, Yuji; Tokumori, Kenji; Toyofuku, Fukai; Hyodo, Kazuyuki; Ando, Masami; Nishimura, Katsuyuki; Uyama, Chikao

    1998-08-01

    We describe a technique of 3D computed tomography (3D CT) using monochromatic x rays generated by synchrotron radiation, which performs a direct reconstruction of a 3D volume image of an object from its cone-beam projections. For the development, we propose a practical scanning orbit of the x-ray source to obtain complete 3D information on an object, and its corresponding 3D image reconstruction algorithm. The validity and usefulness of the proposed scanning orbit and reconstruction algorithm were confirmed by computer simulation studies. Based on these investigations, we have developed a prototype 3D monochromatic x-ray CT using synchrotron radiation, which provides exact 3D reconstruction and material-selective imaging by using the K-edge energy subtraction technique.

  20. X-ray tomography investigations on pebble bed structures

    International Nuclear Information System (INIS)

    Reimann, J.; Rolli, R.; Pieritz, R.A.; Ferrero, C.; Di Michiel, M.

    2007-01-01

    Granular materials (pebbles) are used in present ceramic breeder blankets both for the ceramic breeder material and beryllium. The thermal-mechanical behaviour of these pebble beds strongly depends on the arrangement of the pebbles in the bed, their contacts and contact surfaces with other pebbles and with walls. The influence of these quantities is most pronounced for beryllium pebble beds because of the large thermal conductivity ratio of beryllium to helium gas atmosphere. At present, the data base for the pebble bed thermal conductivity (k) and heat transfer coefficient (h) is quite limited for compressed beds and significant discrepancies exist in respect to h. The detailed knowledge of the pebble bed topology is, therefore, essential to better understand the heat transfer mechanisms. In the present work, results from detailed X-ray tomography investigations are reported on pebble topology in i) the pebble bed bulk (which is relevant for k), and ii) the region close to walls with thicknesses of several pebble diameters (relevant for h). At Forschungszentrum Karlsruhe, pebble beds consisting of aluminium spheres with diameters of 2.3 and 5 mm, respectively, (simulating the blanket relevant 1 mm beryllium pebbles), were uniaxially compressed at different pressure levels. High resolution three-dimensional microtomography (MT) experiments were subsequently performed at the European Synchrotron Radiation Facility, Grenoble. Radial and axial void fraction distributions were found to be oscillatory next to the walls and non-oscillatory in the bulk. For non-compressed pebble beds, the bulk void fraction is fairly constant; for compressed beds, a gradient exists along the compression axis. In the bulk, the angular distribution of pebble contacts was found to be fairly constant, indicating that no regular packing structure is induced. In the wall region, the pebble layer touching the wall is composed of zones with hexagonal structures as shown clearly by MT images. This

  1. Hybrid setup for micro- and nano-computed tomography in the hard X-ray range

    Science.gov (United States)

    Fella, Christian; Balles, Andreas; Hanke, Randolf; Last, Arndt; Zabler, Simon

    2017-12-01

    With increasing miniaturization in industry and medical technology, non-destructive testing techniques are an area of ever-increasing importance. In this framework, X-ray microscopy offers an efficient tool for the analysis, understanding, and quality assurance of microscopic samples, in particular as it allows reconstructing three-dimensional data sets of the whole sample's volume via computed tomography (CT). The following article describes a compact X-ray microscope in the hard X-ray regime around 9 keV, based on a highly brilliant liquid-metal-jet source. In comparison to commercially available instruments, it is a hybrid that works in two different modes. The first one is a micro-CT mode without optics, which uses a high-resolution detector to allow scans of samples in the millimeter range with a resolution of 1 μm. The second mode is a microscope, which contains an X-ray optical element to magnify the sample and allows resolving 150 nm features. Changing between the modes is possible without moving the sample. Thus, the instrument represents an important step towards establishing high-resolution laboratory-based multi-mode X-ray microscopy as a standard investigation method.

  2. Nanomaterial-based x-ray sources

    Science.gov (United States)

    Cole, Matthew T.; Parmee, R. J.; Milne, William I.

    2016-02-01

    Following the recent global excitement and investment in the emerging, and rapidly growing, classes of one and two-dimensional nanomaterials, we here present a perspective on one of the viable applications of such materials: field electron emission based x-ray sources. These devices, which have a notable history in medicine, security, industry and research, to date have almost exclusively incorporated thermionic electron sources. Since the middle of the last century, field emission based cathodes were demonstrated, but it is only recently that they have become practicable. We outline some of the technological achievements of the past two decades, and describe a number of the seminal contributions. We explore the foremost market hurdles hindering their roll-out and broader industrial adoption and summarise the recent progress in miniaturised, pulsed and multi-source devices.

  3. Development of industrial x-ray computed tomography and its application to refractories

    International Nuclear Information System (INIS)

    Aiba, Yoshiro; Oki, Kazuo; Nakamura, Shigeo; Fujii, Masashi.

    1985-01-01

    An industrial X-ray computed tomography was developed under the influence of the rapid spread of the use of the X-ray CT scanner in the medical field and improvements of the equipment. Although current nondestructive testing machines of refractories use the ultrasonic inspection method or the X-ray fluoroscopic method, these equipments cannot produce a tomogram or cannot carry out quantitative evaluation. By using an industrial X-ray computed tomography, submerged nozzles for continuous casting of steel were analyzed with interesting results. The features of the industrial X-ray computed tomography applied for refractory nozzles are as follows: (1) It promptly detects interior defects. (2) It can measure dimensions and shapes. (3) It can numerically express the distribution of density. Accordingly, it is expected that the industrial X-ray computed tomography will widely be used in the fields of development and quality control of refractories and advanced ceramic materials. (author)

  4. A phantom-based evaluation of three commercially available patient organ shields for computed tomography X-ray examinations in diagnostic radiology

    International Nuclear Information System (INIS)

    Huggett, J.; Mukonoweshuro, W.; Loader, R.

    2013-01-01

    Three commercially available in-plane patient organ shields (barium eye, bismuth eye and bismuth breast) for computed tomography (CT) examinations were evaluated to determine their effectiveness for dose reduction. Absorbed doses were measured using metal oxide semiconductor field effect transistor dosemeters fastened to a Kyoto CT Torso phantom. Resultant images were visually compared with those minus shielding by an experienced radiologist. Approximate dose reductions of 21, 38 and 50 % were achieved by the barium eye, bismuth eye and bismuth breast shields, respectively, at a cost of increased image noise and streak artefacts. Shielded images produced varied levels of image artefact, particularly those resulting from the eye shields. Measured dose reductions were not consistent with the potential dose savings stated by the manufacturers of the shields. When evaluating the breast shield, similar dose reduction was achieved without shield-induced artefact by simply reducing the X-ray tube current. (authors)

  5. Automated Defect Recognition as a Critical Element of a Three Dimensional X-ray Computed Tomography Imaging-Based Smart Non-Destructive Testing Technique in Additive Manufacturing of Near Net-Shape Parts

    Directory of Open Access Journals (Sweden)

    Istvan Szabo

    2017-11-01

    Full Text Available In this paper, a state of the art automated defect recognition (ADR system is presented that was developed specifically for Non-Destructive Testing (NDT of powder metallurgy (PM parts using three dimensional X-ray Computed Tomography (CT imaging, towards enabling online quality assurance and enhanced integrity confidence. PM parts exhibit typical defects such as microscopic cracks, porosity, and voids, internal to components that without an effective detection system, limit the growth of industrial applications. Compared to typical testing methods (e.g., destructive such as metallography that is based on sampling, cutting, and polishing of parts, CT provides full coverage of defect detection. This paper establishes the importance and advantages of an automated NDT system for the PM industry applications with particular emphasis on image processing procedures for defect recognition. Moreover, the article describes how to establish a reference library based on real 3D X-ray CT images of net-shape parts. The paper follows the development of the ADR system from processing 2D image slices of a measured 3D X-ray image to processing the complete 3D X-ray image as a whole. The introduced technique is successfully integrated into an automated in-line quality control system highly sought by major industry sectors in Oil and Gas, Automotive, and Aerospace.

  6. Dentinal tubules revealed with X-ray tensor tomography.

    Science.gov (United States)

    Jud, Christoph; Schaff, Florian; Zanette, Irene; Wolf, Johannes; Fehringer, Andreas; Pfeiffer, Franz

    2016-09-01

    Dentin is a mineralized material making up most of the tooth bulk. A system of microtubules, so called dentinal tubules, transverses it radially from the pulp chamber to the outside. This highly oriented structure leads to anisotropic mechanical properties directly connected to the tubules orientation and density: the ultimate tensile strength as well as the fracture toughness and the shear strength are largest perpendicular to dentinal tubules. Consequently, the fatigue strength depends on the direction of dentinal tubules, too. However, none of the existing techniques used to investigate teeth provide access to orientation and density of dentinal tubules for an entire specimen in a non-destructive way. In this paper, we measure a third molar human tooth both with conventional micro-CT and X-ray tensor tomography (XTT). While the achievable resolution in micro-CT is too low to directly resolve the dentinal tubules, we provide strong evidence that the direction and density of dentinal tubules can be indirectly measured by XTT, which exploits small-angle X-ray scattering to retrieve a 3D map of scattering tensors. We show that the mean directions of scattering structures correlate to the orientation of dentinal tubules and that the mean effective scattering strength provides an estimation of the relative density of dentinal tubules. Thus, this method could be applied to investigate the connection between tubule orientation and fatigue or tensile properties of teeth for a full sample without cutting one, non-representative peace of tooth out of the full sample. Copyright © 2016 The Academy of Dental Materials. All rights reserved.

  7. Basic technological aspects and optimization problems in X-ray computed tomography (C.T.)

    International Nuclear Information System (INIS)

    Allemand, R.

    1987-01-01

    The current status and future prospects of physical performance are analysed and the optimization problems are approached for X-ray computed tomography. It is concluded that as long as clinical interest in computed tomography continues, technical advances can be expected in the near future to improve the density resolution, the spatial resolution and the X-ray exposure time. (Auth.)

  8. X-ray computed tomography for virtually unrolling damaged papyri

    Energy Technology Data Exchange (ETDEWEB)

    Allegra, Dario; Ciliberto, Paolo; Stanco, Filippo [Universita degli Studi di Catania, Dipartimento di Matematica ed Informatica, Catania (Italy); Ciliberto, Enrico [Universita degli Studi di Catania, Dipartimento di Scienze Chimiche, Catania (Italy); Petrillo, Giuseppe; Trombatore, Claudia [Universita degli Studi di Catania, Dipartimento di Scienze Mediche Chirurgiche e Tecnologie Avanzate, Catania (Italy)

    2016-03-15

    The regular format for ancient works of literature was the papyrus roll. Recently many efforts to perform virtual restoration of this archeological artifact have been done. In fact the case of ancient rolled papyrus is very intriguing. Old papyruses are the substrates of very important historical information, probably being the use of papyrus dated to the Pre-Dynastic Period. Papyrus degradation is often very hard so that physical unrolling is sometime absolutely impossible. In this paper, authors describe their effort in setting a new virtual restoration methodology based on software manipulation of X-ray tomographic images. A realistic model, obtained by painting a hieroglyph inscription of Thutmosis III on a papyrus substrate made by the original method described by Plinius the Elder and by pigments and binders compatible with the Egyptian use (ochers with natural glue), was made for the X-ray investigation. A GE Optima 660 64 slice was used to obtain a stack of tomographic slices of the rolled model. Each slice appears as spiral. The intensity variations along the cross-sectional result from ink on the papyrus. The files were elaborated with original software, written by the use of MATLAB high-level language, and the final result was quite similar to the radiography of the physically unrolled sheet. (orig.)

  9. X-ray computed tomography for virtually unrolling damaged papyri

    International Nuclear Information System (INIS)

    Allegra, Dario; Ciliberto, Paolo; Stanco, Filippo; Ciliberto, Enrico; Petrillo, Giuseppe; Trombatore, Claudia

    2016-01-01

    The regular format for ancient works of literature was the papyrus roll. Recently many efforts to perform virtual restoration of this archeological artifact have been done. In fact the case of ancient rolled papyrus is very intriguing. Old papyruses are the substrates of very important historical information, probably being the use of papyrus dated to the Pre-Dynastic Period. Papyrus degradation is often very hard so that physical unrolling is sometime absolutely impossible. In this paper, authors describe their effort in setting a new virtual restoration methodology based on software manipulation of X-ray tomographic images. A realistic model, obtained by painting a hieroglyph inscription of Thutmosis III on a papyrus substrate made by the original method described by Plinius the Elder and by pigments and binders compatible with the Egyptian use (ochers with natural glue), was made for the X-ray investigation. A GE Optima 660 64 slice was used to obtain a stack of tomographic slices of the rolled model. Each slice appears as spiral. The intensity variations along the cross-sectional result from ink on the papyrus. The files were elaborated with original software, written by the use of MATLAB high-level language, and the final result was quite similar to the radiography of the physically unrolled sheet. (orig.)

  10. X-ray computed tomography for virtually unrolling damaged papyri

    Science.gov (United States)

    Allegra, Dario; Ciliberto, Enrico; Ciliberto, Paolo; Petrillo, Giuseppe; Stanco, Filippo; Trombatore, Claudia

    2016-03-01

    The regular format for ancient works of literature was the papyrus roll. Recently many efforts to perform virtual restoration of this archeological artifact have been done. In fact the case of ancient rolled papyrus is very intriguing. Old papyruses are the substrates of very important historical information, probably being the use of papyrus dated to the Pre-Dynastic Period. Papyrus degradation is often very hard so that physical unrolling is sometime absolutely impossible. In this paper, authors describe their effort in setting a new virtual restoration methodology based on software manipulation of X-ray tomographic images. A realistic model, obtained by painting a hieroglyph inscription of Thutmosis III on a papyrus substrate made by the original method described by Plinius the Elder and by pigments and binders compatible with the Egyptian use (ochers with natural glue), was made for the X-ray investigation. A GE Optima 660 64 slice was used to obtain a stack of tomographic slices of the rolled model. Each slice appears as spiral. The intensity variations along the cross-sectional result from ink on the papyrus. The files were elaborated with original software, written by the use of MATLAB high-level language, and the final result was quite similar to the radiography of the physically unrolled sheet.

  11. Observation of human tissue with phase-contrast x-ray computed tomography

    Science.gov (United States)

    Momose, Atsushi; Takeda, Tohoru; Itai, Yuji; Tu, Jinhong; Hirano, Keiichi

    1999-05-01

    Human tissues obtained from cancerous kidneys fixed in formalin were observed with phase-contrast X-ray computed tomography (CT) using 17.7-keV synchrotron X-rays. By measuring the distributions of the X-ray phase shift caused by samples using an X-ray interferometer, sectional images that map the distribution of the refractive index were reconstructed. Because of the high sensitivity of phase- contrast X-ray CT, a cancerous lesion was differentiated from normal tissue and a variety of other structures were revealed without the need for staining.

  12. Attenuation properties and percentage depth dose of tannin-based Rhizophora spp. particleboard phantoms using computed tomography (CT) and treatment planning system (TPS) at high energy x-ray beams

    Energy Technology Data Exchange (ETDEWEB)

    Yusof, M. F. Mohd, E-mail: mfahmi@usm.my [School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia); School of Health Sciences, Universiti Sains Malaysia, 16150 Kota Bharu, Kelantan (Malaysia); Abdullah, R. [School of Health Sciences, Universiti Sains Malaysia, 16150 Kota Bharu, Kelantan (Malaysia); Tajuddin, A. A. [School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia); Advanced Medical and Dental Institute, Universiti Sains Malaysia, 13200 Kepala Batas, Penang (Malaysia); Hashim, R. [School of Industrial Technologies, Universiti Sains Malaysia, 11800 Penang (Malaysia); Bauk, S. [Physics Section, School of Distance Education, Universiti Sains Malaysia, 11800 Penang (Malaysia)

    2016-01-22

    A set of tannin-based Rhizophora spp. particleboard phantoms with dimension of 30 cm x 30 cm was fabricated at target density of 1.0 g/cm{sup 3}. The mass attenuation coefficient of the phantom was measured using {sup 60}Co gamma source. The phantoms were scanned using Computed Tomography (CT) scanner and the percentage depth dose (PDD) of the phantom was calculated using treatment planning system (TPS) at 6 MV and 10 MV x-ray and compared to that in solid water phantoms. The result showed that the mass attenuation coefficient of tannin-based Rhizohora spp. phantoms was near to the value of water with χ{sup 2} value of 1.2. The measured PDD also showed good agreement with solid water phantom at both 6 MV and 10 MV x-ray with percentage deviation below 8% at depth beyond the maximum dose, Z{sub max}.

  13. Plasma Emission Profile Recreation using Soft X-Ray Tomography

    Science.gov (United States)

    Page, J. W.; Mauel, M. E.; Levesque, J. P.

    2015-11-01

    With sufficient views from multiple diode arrays, soft X-ray tomography is an invaluable plasma diagnostic because it is a non-perturbing method to reconstruct the emission within the interior of the plasma. In preparation for the installation of new SXR arrays in HBT-EP, we compute high-resolution tomographic reconstructions of discharges having kink-like structures that rotate nearly rigidly. By assuming a uniform angular mapping from the kink mode rotation, Δϕ ~ ωΔ t, a temporal sequence from a single 16-diode fan array represents as many as 16 x 100 independent views. We follow the procedure described by Wang and Granetz and use Bessel basis functions to take the inverse Radon transform. This transform is fit to our data using a least-squares method to estimate the internal SXR emissivity as a sum of polar functions. By varying different parameters of the transformation, we optimize the quality of our recreation of the emission profile and quantify how the reconstruction changes with the azimuthal order of the transform. Supported by U.S. DOE Grant DE-FG02-86ER53222.

  14. X-ray computed tomography for additive manufacturing: a review

    International Nuclear Information System (INIS)

    Thompson, A; Maskery, I; Leach, R K

    2016-01-01

    In this review, the use of x-ray computed tomography (XCT) is examined, identifying the requirement for volumetric dimensional measurements in industrial verification of additively manufactured (AM) parts. The XCT technology and AM processes are summarised, and their historical use is documented. The use of XCT and AM as tools for medical reverse engineering is discussed, and the transition of XCT from a tool used solely for imaging to a vital metrological instrument is documented. The current states of the combined technologies are then examined in detail, separated into porosity measurements and general dimensional measurements. In the conclusions of this review, the limitation of resolution on improvement of porosity measurements and the lack of research regarding the measurement of surface texture are identified as the primary barriers to ongoing adoption of XCT in AM. The limitations of both AM and XCT regarding slow speeds and high costs, when compared to other manufacturing and measurement techniques, are also noted as general barriers to continued adoption of XCT and AM. (topical review)

  15. X-ray computed tomography for additive manufacturing: a review

    Science.gov (United States)

    Thompson, A.; Maskery, I.; Leach, R. K.

    2016-07-01

    In this review, the use of x-ray computed tomography (XCT) is examined, identifying the requirement for volumetric dimensional measurements in industrial verification of additively manufactured (AM) parts. The XCT technology and AM processes are summarised, and their historical use is documented. The use of XCT and AM as tools for medical reverse engineering is discussed, and the transition of XCT from a tool used solely for imaging to a vital metrological instrument is documented. The current states of the combined technologies are then examined in detail, separated into porosity measurements and general dimensional measurements. In the conclusions of this review, the limitation of resolution on improvement of porosity measurements and the lack of research regarding the measurement of surface texture are identified as the primary barriers to ongoing adoption of XCT in AM. The limitations of both AM and XCT regarding slow speeds and high costs, when compared to other manufacturing and measurement techniques, are also noted as general barriers to continued adoption of XCT and AM.

  16. Fast synchrotron X-ray tomography study of the rod packing structures

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Xiaodan; Xia Chengjie; Sun Haohua; Wang Yujie [Department of Physics, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240 (China)

    2013-06-18

    We present a fast synchrotron X-ray tomography study of the packing structures of rods under tapping. Utilizing the high flux of the X-rays generated from the third-generation synchrotron source, we can complete a tomography scan within several seconds, after which the three-dimensional (3D) packing structure can be obtained for the subsequent structural analysis. Due to the high-energy nature of the X-ray beam, special image processing steps including image phase-retrieval has been implemented. Overall, this study suggests the possibility of acquiring statistically significant static packing structures within a reasonable time scale using high-intensity X-ray sources.

  17. Pore formation during dehydration of polycrystalline gypsum observed and quantified in a time-series synchrotron radiation based X-ray micro-tomography experiment

    Science.gov (United States)

    Fusseis, F.; Schrank, C.; Liu, J.; Karrech, A.; Llana-Fúnez, S.; Xiao, X.; Regenauer-Lieb, K.

    2011-10-01

    We conducted an in-situ X-ray micro-computed tomography heating experiment at the Advanced Photon Source (USA) to dehydrate an unconfined 2.3 mm diameter cylinder of Volterra Gypsum. We used a purpose-built X-ray transparent furnace to heat the sample to 388 K for a total of 310 min to acquire a three-dimensional time-series tomography dataset comprising nine time steps. The voxel size of 2.2 μm3 proved sufficient to pinpoint reaction initiation and the organization of drainage architecture in space and time. We observed that dehydration commences across a narrow front, which propagates from the margins to the centre of the sample in more than four hours. The advance of this front can be fitted with a square-root function, implying that the initiation of the reaction in the sample can be described as a diffusion process. Novel parallelized computer codes allow quantifying the geometry of the porosity and the drainage architecture from the very large tomographic datasets (6.4 × 109 voxel each) in unprecedented detail. We determined position, volume, shape and orientation of each resolvable pore and tracked these properties over the duration of the experiment. We found that the pore-size distribution follows a power law. Pores tend to be anisotropic but rarely crack-shaped and have a preferred orientation, likely controlled by a pre-existing fabric in the sample. With on-going dehydration, pores coalesce into a single interconnected pore cluster that is connected to the surface of the sample cylinder and provides an effective drainage pathway. Our observations can be summarized in a model in which gypsum is stabilized by thermal expansion stresses and locally increased pore fluid pressures until the dehydration front approaches to within about 100 μm. Then, the internal stresses are released and dehydration happens efficiently, resulting in new pore space. Pressure release, the production of pores and the advance of the front are coupled in a feedback loop. We

  18. Human thyroid specimen imaging by fluorescent x-ray computed tomography with synchrotron radiation

    Science.gov (United States)

    Takeda, Tohoru; Yu, Quanwen; Yashiro, Toru; Yuasa, Tetsuya; Hasegawa, Yasuo; Itai, Yuji; Akatsuka, Takao

    1999-09-01

    Fluorescent x-ray computed tomography (FXCT) is being developed to detect non-radioactive contrast materials in living specimens. The FXCT system consists of a silicon (111) channel cut monochromator, an x-ray slit and a collimator for fluorescent x ray detection, a scanning table for the target organ and an x-ray detector for fluorescent x-ray and transmission x-ray. To reduce Compton scattering overlapped on the fluorescent K(alpha) line, incident monochromatic x-ray was set at 37 keV. The FXCT clearly imaged a human thyroid gland and iodine content was estimated quantitatively. In a case of hyperthyroidism, the two-dimensional distribution of iodine content was not uniform, and thyroid cancer had a small amount of iodine. FXCT can be used to detect iodine within thyroid gland quantitatively and to delineate its distribution.

  19. A new Mumford-Shah total variation minimization based model for sparse-view x-ray computed tomography image reconstruction.

    Science.gov (United States)

    Chen, Bo; Bian, Zhaoying; Zhou, Xiaohui; Chen, Wensheng; Ma, Jianhua; Liang, Zhengrong

    2018-04-12

    Total variation (TV) minimization for the sparse-view x-ray computer tomography (CT) reconstruction has been widely explored to reduce radiation dose. However, due to the piecewise constant assumption for the TV model, the reconstructed images often suffer from over-smoothness on the image edges. To mitigate this drawback of TV minimization, we present a Mumford-Shah total variation (MSTV) minimization algorithm in this paper. The presented MSTV model is derived by integrating TV minimization and Mumford-Shah segmentation. Subsequently, a penalized weighted least-squares (PWLS) scheme with MSTV is developed for the sparse-view CT reconstruction. For simplicity, the proposed algorithm is named as 'PWLS-MSTV.' To evaluate the performance of the present PWLS-MSTV algorithm, both qualitative and quantitative studies were conducted by using a digital XCAT phantom and a physical phantom. Experimental results show that the present PWLS-MSTV algorithm has noticeable gains over the existing algorithms in terms of noise reduction, contrast-to-ratio measure and edge-preservation.

  20. Kharkov X-ray Generator Based On Compton Scattering

    International Nuclear Information System (INIS)

    Shcherbakov, A.; Zelinsky, A.; Mytsykov, A.; Gladkikh, P.; Karnaukhov, I.; Lapshin, V.; Telegin, Y.; Androsov, V.; Bulyak, E.; Botman, J.I.M.; Tatchyn, R.; Lebedev, A.

    2004-01-01

    Nowadays X-ray sources based on storage rings with low beam energy and Compton scattering of intense laser beams are under development in several laboratories. An international cooperative project of an advanced X-ray source of this type at the Kharkov Institute of Physics and Technology (KIPT) is described. The status of the project is reviewed. The design lattice of the storage ring and calculated X-ray beam parameters are presented. The results of numerical simulation carried out for proposed facility show a peak spectral X-ray intensity of about 1014 can be produced

  1. Novel X-ray Communication Based XNAV Augmentation Method Using X-ray Detectors

    Directory of Open Access Journals (Sweden)

    Shibin Song

    2015-09-01

    Full Text Available The further development of X-ray pulsar-based NAVigation (XNAV is hindered by its lack of accuracy, so accuracy improvement has become a critical issue for XNAV. In this paper, an XNAV augmentation method which utilizes both pulsar observation and X-ray ranging observation for navigation filtering is proposed to deal with this issue. As a newly emerged concept, X-ray communication (XCOM shows great potential in space exploration. X-ray ranging, derived from XCOM, could achieve high accuracy in range measurement, which could provide accurate information for XNAV. For the proposed method, the measurement models of pulsar observation and range measurement observation are established, and a Kalman filtering algorithm based on the observations and orbit dynamics is proposed to estimate the position and velocity of a spacecraft. A performance comparison of the proposed method with the traditional pulsar observation method is conducted by numerical experiments. Besides, the parameters that influence the performance of the proposed method, such as the pulsar observation time, the SNR of the ranging signal, etc., are analyzed and evaluated by numerical experiments.

  2. Method and apparatus for scanning x-ray tomography

    International Nuclear Information System (INIS)

    Albert, R.D.

    1988-01-01

    In a method of producing a tomographic image of a subject that includes the steps of generating X-rays at a moving origin point by directing a charged particle beam to a target surface, deflecting the charged particle beam to travel the origin point through a predetermined raster scan at the surface, detecting variations of X-ray intensity during the course of the raster scan at spaced apart detection points situated at the opposite side of the subject from the origin point, generating a first sequence of data values that is indicative of variations of X-ray intensity at a first of the detection points at successive times during the course of the raster scan and generating at least a second sequence of data values that is indicative of variations of X-ray intensity at a second of the detection points at successive times during the course of the same raster scan, the improvement is described comprising: combining successive individual data values of the first sequence that are generated by X-rays from successive particular locations in the raster scan with at least individual data values of the second sequence that are generated by X-rays from predetermined successive different locations in the same raster scan in order to produce a composite sequence of data values, and producing an image corresponding to at least a portion of the raster scan which depicts variations of the magnitude of successive data values of the composite sequence

  3. Biofilm imaging in porous media by laboratory X-Ray tomography: Combining a non-destructive contrast agent with propagation-based phase-contrast imaging tools.

    Science.gov (United States)

    Carrel, Maxence; Beltran, Mario A; Morales, Verónica L; Derlon, Nicolas; Morgenroth, Eberhard; Kaufmann, Rolf; Holzner, Markus

    2017-01-01

    X-ray tomography is a powerful tool giving access to the morphology of biofilms, in 3D porous media, at the mesoscale. Due to the high water content of biofilms, the attenuation coefficient of biofilms and water are very close, hindering the distinction between biofilms and water without the use of contrast agents. Until now, the use of contrast agents such as barium sulfate, silver-coated micro-particles or 1-chloronaphtalene added to the liquid phase allowed imaging the biofilm 3D morphology. However, these contrast agents are not passive and potentially interact with the biofilm when injected into the sample. Here, we use a natural inorganic compound, namely iron sulfate, as a contrast agent progressively bounded in dilute or colloidal form into the EPS matrix during biofilm growth. By combining a very long source-to-detector distance on a X-ray laboratory source with a Lorentzian filter implemented prior to tomographic reconstruction, we substantially increase the contrast between the biofilm and the surrounding liquid, which allows revealing the 3D biofilm morphology. A comparison of this new method with the method proposed by Davit et al (Davit et al., 2011), which uses barium sulfate as a contrast agent to mark the liquid phase was performed. Quantitative evaluations between the methods revealed substantial differences for the volumetric fractions obtained from both methods. Namely, contrast agent-biofilm interactions (e.g. biofilm detachment) occurring during barium sulfate injection caused a reduction of the biofilm volumetric fraction of more than 50% and displacement of biofilm patches elsewhere in the column. Two key advantages of the newly proposed method are that passive addition of iron sulfate maintains the integrity of the biofilm prior to imaging, and that the biofilm itself is marked by the contrast agent, rather than the liquid phase as in other available methods. The iron sulfate method presented can be applied to understand biofilm development

  4. Multiple X-ray tomography using transmitted, scattered and fluorescent radiation

    International Nuclear Information System (INIS)

    Cesareo, R.; Brunetti, A.; Golosio, B.; Lopes, R.T.; Barroso, R.C.; Donativi, M.; Castellano, A.; Quarta, S.

    2003-01-01

    A multiple CT-scanner is described, which contemporaneously uses transmitted, scattered and fluorescent X-rays for Imaging. The scanner is characterized by a small size X-ray tube and by four detectors: a ''pencil'' X-ray NaI(Tl) for transmitted tomography, a larger size NaI(Tl) for 90 C o Compton tomography, a thermoelectrically cooled Si-PIN or CdZnTe for fluorescent imaging and a CdZnTe for Rayleigh (or diffraction) tomography. Examples of applications are shown

  5. Fluorescent X-ray computed tomography using synchrotron radiation for imaging nonradioactive tracer materials

    Energy Technology Data Exchange (ETDEWEB)

    Akiba, Masahiro; Yuasa, Tetsuya; Uchida, Akira; Akatsuka, Takao [Yamagata Univ., Yonezawa (Japan). Electrical and Information of Engineering; Takeda, Tohoru; Hyodo, Kazuyuki; Itai, Yuji

    1997-09-01

    We describe a system of fluorescent X-ray computed tomography using synchrotron radiation (SR-FXCT) to image nonradioactive contrast materials. The system operates on the basis of computed tomography (CT) scanned by the pencil beam. In the previous experiment, we have imaged an acrylic cylindrical phantom with cross-shaped channel, filled with a diluted iodine-based tracer material of 200 {mu}g/ml. This research is aimed to improve image quality, to select the optimum energy of the incident X-ray, to confirm quantitative evaluation of the image, and to demonstrate FXCT image for living body. First, we simulated output energy profile by the Monte Carlo simulation and confirmed to predetermine the incident X-ray energy at 37 keV, in order to separate the fluorescent photons from background scattering components. Next, the imaging experiment was performed by using conventional CT algorithm under the optimum parameter at the Tristan Accumulation Ring, KEK, Japan. An acrylic phantom containing five paraxial channels of 5 and 4 mm in diameter, could be imaged; where each channel was respectively filled with diluted iodine-based contrast materials of 50, 100, 200 and 500 {mu}g/ml. From the reconstructed image, we confirmed quantitativity in the FXCT image. Finally, a rat`s brain was imaged in vitro by FXCT and monochromatic transmission CT. The comparison between these results showed that the iodine-rich region in the FXCT image corresponded with that in the monochromatic transmission CT image. (author)

  6. X-ray Micro-Tomography of Ablative Heat Shield Materials

    Science.gov (United States)

    Panerai, Francesco; Ferguson, Joseph; Borner, Arnaud; Mansour, Nagi N.; Barnard, Harold S.; MacDowell, Alastair A.; Parkinson, Dilworth Y.

    2016-01-01

    X-ray micro-tomography is a non-destructive characterization technique that allows imaging of materials structures with voxel sizes in the micrometer range. This level of resolution makes the technique very attractive for imaging porous ablators used in hypersonic entry systems. Besides providing a high fidelity description of the material architecture, micro-tomography enables computations of bulk material properties and simulations of micro-scale phenomena. This presentation provides an overview of a collaborative effort between NASA Ames Research Center and Lawrence Berkeley National Laboratory, aimed at developing micro-tomography experiments and simulations for porous ablative materials. Measurements are carried using x-rays from the Advanced Light Source at Berkeley Lab on different classes of ablative materials used in NASA entry systems. Challenges, strengths and limitations of the technique for imaging materials such as lightweight carbon-phenolic systems and woven textiles are discussed. Computational tools developed to perform numerical simulations based on micro-tomography are described. These enable computations of material properties such as permeability, thermal and radiative conductivity, tortuosity and other parameters that are used in ablator response models. Finally, we present the design of environmental cells that enable imaging materials under simulated operational conditions, such as high temperature, mechanical loads and oxidizing atmospheres.Keywords: Micro-tomography, Porous media, Ablation

  7. X-ray generator based on Compton scattering

    NARCIS (Netherlands)

    Androsov, V.P.; Agafonov, A.V.; Botman, J.I.M.; Bulyak, E.V.; Drebot, I.; Gladkikh, P.I.; Grevtsev, V.; Ivashchenko, V.; Karnaukhov, I.M.; Lapshin, V.I.

    2005-01-01

    Nowadays, the sources of the X-rays based on a storage ring with low beam energy and Compton scattering of intense laser beam are under development in several laboratories. In the paper the state-of-art in development and construction of cooperative project of a Kharkov advanced X-ray source NESTOR

  8. X-ray computed tomography of the anterior cruciate ligament and patellar tendon

    Science.gov (United States)

    Shearer, Tom; Rawson, Shelley; Castro, Simon Joseph; Balint, Richard; Bradley, Robert Stephen; Lowe, Tristan; Vila-Comamala, Joan; Lee, Peter David; Cartmell, Sarah Harriet

    2014-01-01

    Summary The effect of phosphotungstic acid (PTA) and iodine solution (IKI) staining was investigated as a method of enhancing contrast in the X-ray computed tomography of porcine anterior cruciate ligaments (ACL) and patellar tendons (PT). We show that PTA enhanced surface contrast, but was ineffective at penetrating samples, whereas IKI penetrated more effectively and enhanced contrast after 70 hours of staining. Contrast enhancement was compared when using laboratory and synchrotron based X-ray sources. Using the laboratory source, PT fascicles were tracked and their alignment was measured. Individual ACL fascicles could not be identified, but identifiable features were evident that were tracked. Higher resolution scans of fascicle bundles from the PT and ACL were obtained using synchrotron imaging techniques. These scans exhibited greater contrast between the fascicles and matrix in the PT sample, facilitating the identification of the fascicle edges; however, it was still not possible to detect individual fascicles in the ACL. PMID:25332942

  9. Quantitative 3D imaging of yeast by hard X-ray tomography.

    Science.gov (United States)

    Zheng, Ting; Li, Wenjie; Guan, Yong; Song, Xiangxia; Xiong, Ying; Liu, Gang; Tian, Yangchao

    2012-05-01

    Full-field hard X-ray tomography could be used to obtain three-dimensional (3D) nanoscale structures of biological samples. The image of the fission yeast, Schizosaccharomyces pombe, was clearly visualized based on Zernike phase contrast imaging technique and heavy metal staining method at a spatial resolution better than 50 nm at the energy of 8 keV. The distributions and shapes of the organelles during the cell cycle were clearly visualized and two types of organelle were distinguished. The results for cells during various phases were compared and the ratios of organelle volume to cell volume can be analyzed quantitatively. It showed that the ratios remained constant between growth and division phase and increased strongly in stationary phase, following the shape and size of two types of organelles changes. Our results demonstrated that hard X-ray microscopy was a complementary method for imaging and revealing structural information for biological samples. Copyright © 2011 Wiley Periodicals, Inc.

  10. X-ray phase-contrast micro-tomography and image analysis of wood microstructure

    International Nuclear Information System (INIS)

    Mayo, Sheridan; Evans, Robert; Chen, Fiona; Lagerstrom, Ryan

    2009-01-01

    A number of commercially important properties of wood depend on details of the wood micro- and nano- structure. CSIRO Forest Biosciences have developed SilviScan, an analytical instrument which uses a number of high-speed techniques for analyzing these properties. X-ray micro-tomographic analysis of wood samples provides detailed 3D reconstructions of the wood microstructure which can be used to validate results from SilviScan measurements. A series of wood samples was analysed using laboratory-based phase-contrast x-ray micro-tomography. Image analysis techniques were applied to the 3D data sets to extract significant features and statistical properties of the specimens. These data provide a means of verification of results from the more rapid SilviScan techniques, and will clarify the results of micro-diffraction studies of wood microfibrils.

  11. 3D observation of the solidified structures by x-ray micro computerized tomography

    International Nuclear Information System (INIS)

    Yasuda, Hideyuki; Ohnaka, Itsuo; Tsuchiyama, Akira; Nakano, Tsukasa; Uesugi, Kentaro

    2003-01-01

    The high flux density of the monochromatized and well-collimated X-ray and the high-resolution detector provide a new 3D observation tool for microstructures of metallic alloys and ceramics. The X-ray micro computerized tomography in BL47XU of SPring-8 (SP-μCT) was applied to observe microstructures produced through the eutectic reaction for Sn-based alloys and an Al 2 O 3 -Y 2 O 3 oxide system. The constituent phases in the eutectic structures were three-dimensionally identified, in which the lamellar spacing ranged from several to 10 μm. Since the 3D structure of the unidirectionally solidified specimens contains history of the eutectic structure formation, the 3D structure obtained by SP-μCT gives useful information to consider the microstructure evolution. (author)

  12. Laboratory of computerized tomography and X-ray of Centro Federal de Educacao Tecnologica (CEFET) from Parana State, Brazil

    International Nuclear Information System (INIS)

    Schelin, Hugo R.; Paschuk, Sergei A.; Jakubiak, Rosangela J.; David, Denise E.H.; Gomes, Cintia L.; Soboll, Daniel S.; Ruehle, Gustavo; Carvalho, Arnolfo

    1996-01-01

    The development of X-ray laboratory at CEFET-PR (Brazil) is considered. The advancement and hospital practice application of an Image Quality Program for X-ray and tomography scanning is studied. A project regarding to the modernization of installed X-ray equipment, particularly X-ray detector, software and hardware is reported

  13. In-Line Phase-Contrast X-ray Imaging and Tomography for Materials Science.

    Science.gov (United States)

    Mayo, Sheridan C; Stevenson, Andrew W; Wilkins, Stephen W

    2012-05-24

    X-ray phase-contrast imaging and tomography make use of the refraction of X-rays by the sample in image formation. This provides considerable additional information in the image compared to conventional X-ray imaging methods, which rely solely on X-ray absorption by the sample. Phase-contrast imaging highlights edges and internal boundaries of a sample and is thus complementary to absorption contrast, which is more sensitive to the bulk of the sample. Phase-contrast can also be used to image low-density materials, which do not absorb X-rays sufficiently to form a conventional X-ray image. In the context of materials science, X-ray phase-contrast imaging and tomography have particular value in the 2D and 3D characterization of low-density materials, the detection of cracks and voids and the analysis of composites and multiphase materials where the different components have similar X-ray attenuation coefficients. Here we review the use of phase-contrast imaging and tomography for a wide variety of materials science characterization problems using both synchrotron and laboratory sources and further demonstrate the particular benefits of phase contrast in the laboratory setting with a series of case studies.

  14. Radio astronomical interferometry and x-ray's computerized tomography

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, L F [Universidad Nacional Autonoma de Mexico, Mexico City. Inst. de Astronomia

    1982-01-01

    Radio astronomical interferometry and computerized tomography are techniques of great importance for astronomy and medicine, respectively. In this paper we emphasize that both techniques are based on the same mathematical principles, and present them as an example of interaction between basic and applied science.

  15. [Contribution of X-ray computed tomography in the evaluation of kidney performance].

    Science.gov (United States)

    Lemoine, Sandrine; Rognant, Nicolas; Collet-Benzaquen, Diane; Juillard, Laurent

    2012-07-01

    X-ray computer assisted tomography scanner is an imaging method based on the use of X-ray attenuation in tissue. This attenuation is proportional to the density of the tissue (without or after contrast media injection) in each pixel image of the image. Spiral scanner, the electron beam computed tomography (EBCT) scanner and multidetector computed tomography scanner allow renal anatomical measurements, such as cortical and medullary volume, but also the measurement of renal functional parameters, such as regional renal perfusion, renal blood flow and glomerular filtration rate. These functional parameters are extracted from the modeling of the kinetics of the contrast media concentration in the vascular space and the renal tissue, using two main mathematical models (the gamma variate model and the Patlak model). Renal functional imaging allows measuring quantitative parameters on each kidney separately, in a non-invasive manner, providing significant opportunities in nephrology, both for experimental and clinical studies. However, this method uses contrast media that may alter renal function, thus limiting its use in patients with chronic renal failure. Moreover, the increase irradiation delivered to the patient with multi detector computed tomography (MDCT) should be considered. Copyright © 2011 Association Société de néphrologie. Published by Elsevier SAS. All rights reserved.

  16. Use of micro X-ray computed tomography for development and research into waterjets

    OpenAIRE

    Souček, K. (Kamil); Sitek, L. (Libor); Gurková, L. (Lucie); Georgiovská, L. (Lucie)

    2015-01-01

    Non-destructive methods for analysis of various types of materials have been increasingly applied recently. One of these methods is the industrial micro X-ray computed tomography (CT). This paper presents an overview of experience in using the industrial micro X-ray computed tomography during research activities at the Institute of Geonics of the CAS. It discusses possibilities of the nondestructive visualization of the inner structures of a wide range of materials and objects, includin...

  17. X-ray body scanner for computerised tomography

    International Nuclear Information System (INIS)

    1977-01-01

    An X-ray source is described whose source is collimated into a thin fan-shaped beam. The detector means is spaced from the sources and both are mounted for scanning and orbiting jointly about a body in a partial or complete resolution. The X-ray intensities thus obtained provide data for reconstructing an image. The detector and source combination and the body are moved relative to one another in an axial direction to enable scanning of the body layers in sequence. In one embodiment the X-ray source is pulsed as it scans, and in another the fan-shaped beam is on continuously and readout is done sequentially. Thus in either case a large number of intensities for each layer are obtained. A high precision encoder system is used to synchronize X-ray pulses and readouts spatially and with line frequency. Means are provided for storing the cables leading to the rotatable source, the detectors and other moveable components. An embodiment for scanning a body part such as a breast has means for conditioning and controlling the water in which the part is immersed. (C.F.)

  18. High energy X ray tomography. Development of an industrial

    International Nuclear Information System (INIS)

    Huet, J.; Thomas, G.

    1985-01-01

    From its own experience in nondestructive testing and needs of industry, a versatile 420 kV X-ray tomodensitometer was designed by the CEA to study materials an structures. This project and results obtained with a laboratory prototype are presented [fr

  19. Low-dose phase contrast tomography with conventional x-ray sources

    Energy Technology Data Exchange (ETDEWEB)

    Hagen, C. K., E-mail: charlotte.hagen.10@ucl.ac.uk; Endrizzi, M.; Diemoz, P. C.; Olivo, A. [Department of Medical Physics and Bioengineering, University College London, Malet Place, Gower Street, London WC1E 6BT (United Kingdom); Munro, P. R. T. [Optical + Biomedical Engineering Laboratory, School of Electrical, Electronic and Computer Engineering, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia and Centre for Microscopy, Characterisation, and Analysis, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009 (Australia)

    2014-07-15

    Purpose: The edge illumination (EI) x-ray phase contrast imaging (XPCi) method has been recently further developed to perform tomographic and, thus, volumetric imaging. In this paper, the first tomographic EI XPCi images acquired with a conventional x-ray source at dose levels below that used for preclinical small animal imaging are presented. Methods: Two test objects, a biological sample and a custom-built phantom, were imaged with a laboratory-based EI XPCi setup in tomography mode. Tomographic maps that show the phase shift and attenuating properties of the object were reconstructed, and analyzed in terms of signal-to-noise ratio and quantitative accuracy. Dose measurements using thermoluminescence devices were performed. Results: The obtained images demonstrate that phase based imaging methods can provide superior results compared to attenuation based modalities for weakly attenuating samples also in 3D. Moreover, and, most importantly, they demonstrate the feasibility of low-dose imaging. In addition, the experimental results can be considered quantitative within the constraints imposed by polychromaticity. Conclusions: The results, together with the method's dose efficiency and compatibility with conventional x-ray sources, indicate that tomographic EI XPCi can become an important tool for the routine imaging of biomedical samples.

  20. A laboratory-based hard x-ray monochromator for high-resolution x-ray emission spectroscopy and x-ray absorption near edge structure measurements

    Energy Technology Data Exchange (ETDEWEB)

    Seidler, G. T., E-mail: seidler@uw.edu; Mortensen, D. R.; Remesnik, A. J.; Pacold, J. I.; Ball, N. A.; Barry, N.; Styczinski, M.; Hoidn, O. R. [Physics Department, University of Washington, Seattle, Washington 98195-1560 (United States)

    2014-11-15

    We report the development of a laboratory-based Rowland-circle monochromator that incorporates a low power x-ray (bremsstrahlung) tube source, a spherically bent crystal analyzer, and an energy-resolving solid-state detector. This relatively inexpensive, introductory level instrument achieves 1-eV energy resolution for photon energies of ∼5 keV to ∼10 keV while also demonstrating a net efficiency previously seen only in laboratory monochromators having much coarser energy resolution. Despite the use of only a compact, air-cooled 10 W x-ray tube, we find count rates for nonresonant x-ray emission spectroscopy comparable to those achieved at monochromatized spectroscopy beamlines at synchrotron light sources. For x-ray absorption near edge structure, the monochromatized flux is small (due to the use of a low-powered x-ray generator) but still useful for routine transmission-mode studies of concentrated samples. These results indicate that upgrading to a standard commercial high-power line-focused x-ray tube or rotating anode x-ray generator would result in monochromatized fluxes of order 10{sup 6}–10{sup 7} photons/s with no loss in energy resolution. This work establishes core technical capabilities for a rejuvenation of laboratory-based hard x-ray spectroscopies that could have special relevance for contemporary research on catalytic or electrical energy storage systems using transition-metal, lanthanide, or noble-metal active species.

  1. 3D imaging using X-Ray tomography and SEM combined FIB to study non isothermal creep damage of (111) oriented samples of γ / γ ′ nickel base single crystal superalloy MC2

    KAUST Repository

    Jouiad, Mustapha

    2012-01-01

    An unprecedented investigation consisting of the association of X-Ray tomography and Scanning Electron Microscopy combined with Focus Ion Beam (SEM-FIB) is conducted to perform a 3D reconstruction imaging. These techniques are applied to study the non-isothermal creep behavior of close (111) oriented samples of MC2 nickel base superalloys single crystal. The issue here is to develop a strategy to come out with the 3D rafting of γ\\' particles and its interaction whether with dislocation structures or/and with the preexisting voids. This characterization is uncommonly performed away from the conventional studied orientation [001] in order to feed the viscoplastic modeling leading to its improvement by taking into account the crystal anisotropy. The creep tests were performed at two different conditions: classical isothermal tests at 1050°C under 140 MPa and a non isothermal creep test consisting of one overheating at 1200°C and 30 seconds dwell time during the isothermal creep life. The X-Ray tomography shows a great deformation heterogeneity that is pronounced for the non-isothermal tested samples. This deformation localization seems to be linked to the preexisting voids. Nevertheless, for both tested samples, the voids coalescence is the precursor of the observed damage leading to failure. SEM-FIB investigation by means of slice and view technique gives 3D views of the rafted γ\\' particles and shows that γ corridors evolution seems to be the main creep rate controlling parameter. © 2012 Trans Tech Publications, Switzerland.

  2. The CT Scanner Facility at Stellenbosch University: An open access X-ray computed tomography laboratory

    Science.gov (United States)

    du Plessis, Anton; le Roux, Stephan Gerhard; Guelpa, Anina

    2016-10-01

    The Stellenbosch University CT Scanner Facility is an open access laboratory providing non-destructive X-ray computed tomography (CT) and a high performance image analysis services as part of the Central Analytical Facilities (CAF) of the university. Based in Stellenbosch, South Africa, this facility offers open access to the general user community, including local researchers, companies and also remote users (both local and international, via sample shipment and data transfer). The laboratory hosts two CT instruments, i.e. a micro-CT system, as well as a nano-CT system. A workstation-based Image Analysis Centre is equipped with numerous computers with data analysis software packages, which are to the disposal of the facility users, along with expert supervision, if required. All research disciplines are accommodated at the X-ray CT laboratory, provided that non-destructive analysis will be beneficial. During its first four years, the facility has accommodated more than 400 unique users (33 in 2012; 86 in 2013; 154 in 2014; 140 in 2015; 75 in first half of 2016), with diverse industrial and research applications using X-ray CT as means. This paper summarises the existence of the laboratory's first four years by way of selected examples, both from published and unpublished projects. In the process a detailed description of the capabilities and facilities available to users is presented.

  3. The CT Scanner Facility at Stellenbosch University: An open access X-ray computed tomography laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Plessis, Anton du, E-mail: anton2@sun.ac.za [CT Scanner Facility, Central Analytical Facilities, Stellenbosch University, Stellenbosch (South Africa); Physics Department, Stellenbosch University, Stellenbosch (South Africa); Roux, Stephan Gerhard le, E-mail: lerouxsg@sun.ac.za [CT Scanner Facility, Central Analytical Facilities, Stellenbosch University, Stellenbosch (South Africa); Guelpa, Anina, E-mail: aninag@sun.ac.za [CT Scanner Facility, Central Analytical Facilities, Stellenbosch University, Stellenbosch (South Africa)

    2016-10-01

    The Stellenbosch University CT Scanner Facility is an open access laboratory providing non-destructive X-ray computed tomography (CT) and a high performance image analysis services as part of the Central Analytical Facilities (CAF) of the university. Based in Stellenbosch, South Africa, this facility offers open access to the general user community, including local researchers, companies and also remote users (both local and international, via sample shipment and data transfer). The laboratory hosts two CT instruments, i.e. a micro-CT system, as well as a nano-CT system. A workstation-based Image Analysis Centre is equipped with numerous computers with data analysis software packages, which are to the disposal of the facility users, along with expert supervision, if required. All research disciplines are accommodated at the X-ray CT laboratory, provided that non-destructive analysis will be beneficial. During its first four years, the facility has accommodated more than 400 unique users (33 in 2012; 86 in 2013; 154 in 2014; 140 in 2015; 75 in first half of 2016), with diverse industrial and research applications using X-ray CT as means. This paper summarises the existence of the laboratory’s first four years by way of selected examples, both from published and unpublished projects. In the process a detailed description of the capabilities and facilities available to users is presented.

  4. Fast simulation of Proton Induced X-Ray Emission Tomography using CUDA

    Energy Technology Data Exchange (ETDEWEB)

    Beasley, D.G., E-mail: dgbeasley@itn.pt; Marques, A.C.; Alves, L.C.; Silva, R.C. da

    2013-07-01

    A new 3D Proton Induced X-Ray Emission Tomography (PIXE-T) and Scanning Transmission Ion Microscopy Tomography (STIM-T) simulation software has been developed in Java and uses NVIDIA™ Common Unified Device Architecture (CUDA) to calculate the X-ray attenuation for large detector areas. A challenge with PIXE-T is to get sufficient counts while retaining a small beam spot size. Therefore a high geometric efficiency is required. However, as the detector solid angle increases the calculations required for accurate reconstruction of the data increase substantially. To overcome this limitation, the CUDA parallel computing platform was used which enables general purpose programming of NVIDIA graphics processing units (GPUs) to perform computations traditionally handled by the central processing unit (CPU). For simulation performance evaluation, the results of a CPU- and a CUDA-based simulation of a phantom are presented. Furthermore, a comparison with the simulation code in the PIXE-Tomography reconstruction software DISRA (A. Sakellariou, D.N. Jamieson, G.J.F. Legge, 2001) is also shown. Compared to a CPU implementation, the CUDA based simulation is approximately 30× faster.

  5. Fast simulation of Proton Induced X-Ray Emission Tomography using CUDA

    International Nuclear Information System (INIS)

    Beasley, D.G.; Marques, A.C.; Alves, L.C.; Silva, R.C. da

    2013-01-01

    A new 3D Proton Induced X-Ray Emission Tomography (PIXE-T) and Scanning Transmission Ion Microscopy Tomography (STIM-T) simulation software has been developed in Java and uses NVIDIA™ Common Unified Device Architecture (CUDA) to calculate the X-ray attenuation for large detector areas. A challenge with PIXE-T is to get sufficient counts while retaining a small beam spot size. Therefore a high geometric efficiency is required. However, as the detector solid angle increases the calculations required for accurate reconstruction of the data increase substantially. To overcome this limitation, the CUDA parallel computing platform was used which enables general purpose programming of NVIDIA graphics processing units (GPUs) to perform computations traditionally handled by the central processing unit (CPU). For simulation performance evaluation, the results of a CPU- and a CUDA-based simulation of a phantom are presented. Furthermore, a comparison with the simulation code in the PIXE-Tomography reconstruction software DISRA (A. Sakellariou, D.N. Jamieson, G.J.F. Legge, 2001) is also shown. Compared to a CPU implementation, the CUDA based simulation is approximately 30× faster

  6. Radial lens distortion correction with sub-pixel accuracy for X-ray micro-tomography.

    Science.gov (United States)

    Vo, Nghia T; Atwood, Robert C; Drakopoulos, Michael

    2015-12-14

    Distortion correction or camera calibration for an imaging system which is highly configurable and requires frequent disassembly for maintenance or replacement of parts needs a speedy method for recalibration. Here we present direct techniques for calculating distortion parameters of a non-linear model based on the correct determination of the center of distortion. These techniques are fast, very easy to implement, and accurate at sub-pixel level. The implementation at the X-ray tomography system of the I12 beamline, Diamond Light Source, which strictly requires sub-pixel accuracy, shows excellent performance in the calibration image and in the reconstructed images.

  7. Sources of the X-rays Based on Compton Scattering

    International Nuclear Information System (INIS)

    Androsov, V.; Bulyak, E.; Gladkikh, P.; Karnaukhov, I.; Mytsykov, A.; Telegin, Yu.; Shcherbakov, A.; Zelinsky, A.

    2007-01-01

    The principles of the intense X-rays generation by laser beam scattering on a relativistic electron beam are described and description of facilities assigned to produce the X-rays based on Compton scattering is presented. The possibilities of various types of such facilities are estimated and discussed. The source of the X-rays based on a storage ring with low beam energy is described in details and advantages of the sources of such type are discussed.The results of calculation and numerical simulation carried out for laser electron storage ring NESTOR that is under development in NSC KIPT show wide prospects of the accelerator facility of such type

  8. Development of X-ray detector based on phototransistor

    International Nuclear Information System (INIS)

    Ramacos Fardela; Kusminarto

    2014-01-01

    X-ray interaction with matter can produce phenomenon of fluorescence that emits visible light. This phenomenon has been exploited to design an X-ray detector based on photo transistor by attaching a screen ZnS(Ag) on the surface of the photo transistor which is arranged in a Darlington circuit. Response of detector was done by collimating of X-rays beam from the X-ray generator tube Philips 2000 watts, 60 kV type PW 2215/20 NR 780 026 and measure the detector output voltage (V out ). Varying the current by 5, 10, 15, 20, 25, 30, 35 and 40 mA in the X-ray panel. The experimental results showed that the Darlington circuit can be applied to design the detector of X-ray based on phototransistor. The results show that there is a linear relationship between the change in the intensity of X-ray detectors with voltage output phototransistor when it was closed with fluorescence materials ZnS(Ag), the linearity coefficient was R 2 = 0.99. Sensitivity of detector was obtained to be 3.7 x 10 -2 mV per cpm. (author)

  9. Applications of X-ray Computed Tomography and Emission Computed Tomography

    International Nuclear Information System (INIS)

    Seletchi, Emilia Dana; Sutac, Victor

    2005-01-01

    Computed Tomography is a non-destructive imaging method that allows visualization of internal features within non-transparent objects such as sedimentary rocks. Filtering techniques have been applied to circumvent the artifacts and achieve high-quality images for quantitative analysis. High-resolution X-ray computed tomography (HRXCT) can be used to identify the position of the growth axis in speleothems by detecting subtle changes in calcite density between growth bands. HRXCT imagery reveals the three-dimensional variability of coral banding providing information on coral growth and climate over the past several centuries. The Nuclear Medicine imaging technique uses a radioactive tracer, several radiation detectors, and sophisticated computer technologies to understand the biochemical basis of normal and abnormal functions within the brain. The goal of Emission Computed Tomography (ECT) is to accurately determine the three-dimensional radioactivity distribution resulting from the radiopharmaceutical uptake inside the patient instead of the attenuation coefficient distribution from different tissues as obtained from X-ray Computer Tomography. ECT is a very useful tool for investigating the cognitive functions. Because of the low radiation doses associated with Positron Emission Tomography (PET), this technique has been applied in clinical research, allowing the direct study of human neurological diseases. (authors)

  10. X-ray Tomography using Thin Scintillator Films

    CERN Document Server

    Kozyrev, E A; Lemzyakov, A G; Petrozhitskiy, A V; Popov, A S

    2017-01-01

    2-14 μm thin CsI:Tl scintillation screens with high spatial resolution were prepared by the thermal deposition method for low energy X-ray imaging applications. The spatial resolution was measured as a function of the film thickness. It was proposed that the spatial resolution of the prepared conversion screens can be significantly improved by an additional deposition of a carbon layer.

  11. Low-dose x-ray phase-contrast and absorption CT using equally sloped tomography

    International Nuclear Information System (INIS)

    Fahimian, Benjamin P; Miao Jianwei; Mao Yu; Cloetens, Peter

    2010-01-01

    Tomographic reconstruction from undersampled and noisy projections is often desirable in transmission CT modalities for purposes of low-dose tomography and fast acquisition imaging. However under such conditions, due to the violation of the Nyquist sampling criteria and the presence of noise, reconstructions with acceptable accuracy may not be possible. Recent experiments in transmission electron tomography and coherent diffraction microscopy have shown that the technique of equally sloped tomography (EST), an exact tomographic method utilizing an oversampling iterative Fourier-based reconstruction, provides more accurate image reconstructions when the number of projections is significantly undersampled relative to filtered back projection and algebraic iterative methods. Here we extend this technique by developing new reconstruction algorithms which allow for the incorporation of advanced mathematical regularization constraints, such as the nonlocal means total variational model, in a manner that is consistent with experimental projections. We then evaluate the resulting image quality of the developed algorithm through simulations and experiments at the European Synchrotron Radiation Facility on image quality phantoms using the x-ray absorption and phase contrast CT modalities. Both our simulation and experimental results have indicated that the method can reduce the number of projections by 60-75% in parallel beam modalities, while achieving comparable or better image quality than the conventional reconstructions. As large-scale and compact synchrotron radiation facilities are currently under rapid development worldwide, the implementation of low-dose x-ray absorption and phase-contrast CT can find broad applications in biology and medicine using these advanced x-ray sources.

  12. X-ray detectors based on image sensors

    International Nuclear Information System (INIS)

    Costa, A.P.R.

    1983-01-01

    X-ray detectors based on image sensors are described and a comparison is made between the advantages and the disadvantages of such a kind of detectors with the position sensitive detectors. (L.C.) [pt

  13. Experimental investigation of the diffusion coefficients in porous media by application of X-ray computer tomography

    DEFF Research Database (Denmark)

    Zhelezny, Petr; Shapiro, Alexander

    2006-01-01

    The present work describes a new experimental method that makes it possible to investigate diffusion coefficients in a porous medium. The method is based on application of X-ray computed tomography (CT). The general applicability of this method for the determination of diffusion coefficients...

  14. Performance study of monochromatic synchrotron X-ray computed tomography using a linear array detector

    Energy Technology Data Exchange (ETDEWEB)

    Kazama, Masahiro; Takeda, Tohoru; Itai, Yuji [Tsukuba Univ., Ibaraki (Japan). Inst. of Clinical Medicine; Akiba, Masahiro; Yuasa, Tetsuya; Hyodo, Kazuyuki; Ando, Masami; Akatsuka, Takao

    1997-09-01

    Monochromatic x-ray computed tomography (CT) using synchrotron radiation (SR) is being developed for detection of non-radioactive contrast materials at low concentration for application in clinical diagnosis. A new SR-CT system with improved contrast resolution, was constructed using a linear array detector which provides wide dynamic ranges and a double monochromator. The performance of this system was evaluated in a phantom and a rat model of brain ischemia. This system consists of a silicon (111) double crystal monochromator, an x-ray shutter, an ionization chamber, x-ray slits, a scanning table for the target organ, and an x-ray linear array detector. The research was carried out at the BLNE-5A bending magnet beam line of the Tristan Accumulation Ring in KEK, Japan. In this experiment, the reconstructed image of the spatial-resolution phantom clearly showed the 1 mm holes. At 1 mm slice thickness, the above K-edge image of the phantom showed contrast resolution at the concentration of 200 {mu}g/ml iodine-based contrast materials whereas the K-edge energy subtraction image showed contrast resolution at the concentration of 500 {mu}g/ml contrast materials. The cerebral arteries filled with iodine microspheres were clearly revealed, and the ischemic regions at the right temporal lobe and frontal lobe were depicted as non-vascular regions. The measured minimal detectable concentration of iodine on the above K-edge image is about 6 times higher than the expected value of 35.3 {mu}g/ml because of the high dark current of this detector. Thus, the use of a CCD detector which is cooled by liquid nitrogen to improve the dynamic range of the detector, is being under construction. (author)

  15. Revealing fatigue damage evolution in unidirectional composites for wind turbine blades using x-ray computed tomography

    DEFF Research Database (Denmark)

    Mikkelsen, Lars Pilgaard

    ’. Thereby, it will be possible to lower the cost of energy for wind energy based electricity. In the presented work, a lab-source x-ray computed tomography equipment (Zeiss Xradia 520 Versa) has been used in connection with ex-situ fatigue testing of uni-directional composites in order to identify fibre...... to other comparable x-ray studies) have been used in order to ensure a representative test volume during the ex-situ fatigue testing. Using the ability of the x-ray computed tomography to zoom into regions of interest, non-destructive, the fatigue damage evolution in a repeating ex-situ fatigue loaded test...... improving the fatigue resistance of non-crimp fabric used in the wind turbine industry can be made....

  16. X-ray computed tomography imaging method which is immune to beam hardening effect

    International Nuclear Information System (INIS)

    Kanno, Ikuo; Uesaka, Akio; Nomiya, Seiichiro; Onabe, Hideaki

    2009-01-01

    For the easy treatment of cancers, early finding of them is an important theme of study. X-ray transmission measurement and computed tomography (CT) are powerful tools for finding cancers. The x-ray CT shows cross sectional view of human body and is able to detect small cancers such as 1 cm in diameter. The CT, however, gives very high dose exposure to human body: some 10 to 1000 times higher dose exposure than the chest radiography. It is not possible to have medical health check using CT frequently, in view of both individual and public accumulated dose exposures. The authors have been working on the reduction of dose exposure in x-ray transmission measurements in case of detecting iodine contrast media, which concentrates in cancers. In our method, energy information of x-rays is employed: in conventional x-ray transmission measurements, x-rays are measured as current and the energy of each x-ray is ignored. The numbers of x-ray events, φ 1 and φ 2 , of which energies are lower and higher than the one of iodine K-edge, respectively, are used for the estimation of iodine thickness in cancers. Moreover, high energy x-rays, which are not sensitive to the absorption by iodine, are cut by a filter made of higher atomic number material than iodine. We call this method filtered x-ray energy subtraction (FIX-ES) method. This FIX-ES method was shown twice as sensitive to iodine than current measurement method. With the choice of filter thickness, minimum dose exposure in FIX-ES is 30% of that when white x-rays are employed. In the study described above, we concentrated on the observation of cancer part. In this study, a cancer phantom in normal tissue is observed by FIX-ES method. The results are compared with the ones obtained by current measurement method. (author)

  17. Imaging of Composites by Helical X-Ray Computed Tomography

    DEFF Research Database (Denmark)

    Wang, Ying; Pyka, Grzegorz; Jespersen, Kristine Munk

    Understanding the fatigue damage mechanisms of composite materials used in wind turbine rotor blades could potentially enhance the reliability and energy efficiency of wind turbines by improving the structure design. In this paper, the fatigue damage propagating mechanisms of unidirectional glass...... fibre composites was characterised by helical X-ray CT. The staining approach was used and it was effective to enhance the visibility of thin matrix cracks and partly closed fibre breaks instead of widely opened cracks. Fibre breaks in the centre UD bundle were found to occur locally, instead of being...

  18. Fluorescent x-ray computed tomography to visualize specific material distribution

    Science.gov (United States)

    Takeda, Tohoru; Yuasa, Tetsuya; Hoshino, Atsunori; Akiba, Masahiro; Uchida, Akira; Kazama, Masahiro; Hyodo, Kazuyuki; Dilmanian, F. Avraham; Akatsuka, Takao; Itai, Yuji

    1997-10-01

    Fluorescent x-ray computed tomography (FXCT) is being developed to detect non-radioactive contrast materials in living specimens. The FXCT systems consists of a silicon channel cut monochromator, an x-ray slit and a collimator for detection, a scanning table for the target organ and an x-ray detector for fluorescent x-ray and transmission x-ray. To reduce Compton scattering overlapped on the K(alpha) line, incident monochromatic x-ray was set at 37 keV. At 37 keV Monte Carlo simulation showed almost complete separation between Compton scattering and the K(alpha) line. Actual experiments revealed small contamination of Compton scattering on the K(alpha) line. A clear FXCT image of a phantom was obtained. Using this system the minimal detectable dose of iodine was 30 ng in a volume of 1 mm3, and a linear relationship was demonstrated between photon counts of fluorescent x-rays and the concentration of iodine contrast material. The use of high incident x-ray energy allows an increase in the signal to noise ratio by reducing the Compton scattering on the K(alpha) line.

  19. Study of dielectric liquids at room temperature for high energy x ray Tomography

    International Nuclear Information System (INIS)

    Lepert, S.

    1989-09-01

    The detection of X rays by means of a dielectric liquid detector system, at room temperature, is discussed. The physico-chemical properties of a dielectric liquid, the construction of a cleaning device and of two electrode configurations, and the utilization of different amplifier models are studied. The results allowed the analysis and characterization of the behavior of the dielectric liquid under X ray irradiation. Data obtained is confirmed by computerized simulation. The choice of Tetramethyl-germanium for the X ray tomography, applied in nondestructive analysis, is explained. The investigation of the system parameters allowed the setting of the basis of a prototype project for a multi-detector [fr

  20. TH-AB-209-07: High Resolution X-Ray-Induced Acoustic Computed Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, L; Tang, S [University of Oklahoma, Norman, OK (United States); Ahmad, M [Stanford University, Palo Alto, CA (United States); Xing, L [Stanford University School of Medicine, Stanford, CA (United States)

    2016-06-15

    Purpose: X-ray radiographic absorption imaging is an invaluable tool in medical diagnostics, biology and materials science. However, the use of conventional CT is limited by two factors: the detection sensitivity to weak absorption material and the radiation dose from CT scanning. The purpose of this study is to explore X-ray induced acoustic computed tomography (XACT), a new imaging modality, which combines X-ray absorption contrast and high ultrasonic resolution to address these challenges. Methods: First, theoretical models was built to analyze the XACT sensitivity to X-ray absorption and calculate the minimal radiation dose in XACT imaging. Then, an XACT system comprised of an ultrashort X-ray pulse, a low noise ultrasound detector and a signal acquisition system was built to evaluate the X-ray induced acoustic signal generation. A piece of chicken bone and a phantom with two golden fiducial markers were exposed to 270 kVp X-ray source with 60 ns exposure time, and the X-ray induced acoustic signal was received by a 2.25MHz ultrasound transducer in 200 positions. XACT images were reconstructed by a filtered back-projection algorithm. Results: The theoretical analysis shows that X-ray induced acoustic signals have 100% relative sensitivity to X-ray absorption, but not to X-ray scattering. Applying this innovative technology to breast imaging, we can reduce radiation dose by a factor of 50 compared with newly FDA approved breast CT. The reconstructed images of chicken bone and golden fiducial marker phantom reveal that the spatial resolution of the built XACT system is 350µm. Conclusion: In XACT, the imaging sensitivity to X-ray absorption is improved and the imaging dose is dramatically reduced by using ultrashort pulsed X-ray. Taking advantage of the high ultrasonic resolution, we can also perform 3D imaging with a single X-ray pulse. This new modality has the potential to revolutionize x-ray imaging applications in medicine and biology.

  1. Direct integration of the inverse Radon equation for X-ray computed tomography.

    Science.gov (United States)

    Libin, E E; Chakhlov, S V; Trinca, D

    2016-11-22

    A new mathematical appoach using the inverse Radon equation for restoration of images in problems of linear two-dimensional x-ray tomography is formulated. In this approach, Fourier transformation is not used, and it gives the chance to create the practical computing algorithms having more reliable mathematical substantiation. Results of software implementation show that for especially for low number of projections, the described approach performs better than standard X-ray tomographic reconstruction algorithms.

  2. Metrological study of CFRP drilled holes with x-ray computed tomography

    OpenAIRE

    Kourra, Nadia; Warnett, Jason M.; Attridge, Alex; Kiraci, Ercihan; Gupta, Aniruddha; Barnes, Stuart; Williams, M. A. (Mark A.)

    2015-01-01

    The popularity of composite materials is continuously growing with new varieties being developed and tested with different machining processes to establish their suitability. Destructive as well as non-destructive methods, such as ultrasonics, X-ray radiography and eddy-current, have previously been used to ensure that the combination of particular machining methods and composites provide the required quality that can allow the required lifespan of the final product. X-ray computed tomography...

  3. Computed tomography of x-ray images using neural networks

    Science.gov (United States)

    Allred, Lloyd G.; Jones, Martin H.; Sheats, Matthew J.; Davis, Anthony W.

    2000-03-01

    Traditional CT reconstruction is done using the technique of Filtered Backprojection. While this technique is widely employed in industrial and medical applications, it is not generally understood that FB has a fundamental flaw. Gibbs phenomena states any Fourier reconstruction will produce errors in the vicinity of all discontinuities, and that the error will equal 28 percent of the discontinuity. A number of years back, one of the authors proposed a biological perception model whereby biological neural networks perceive 3D images from stereo vision. The perception model proports an internal hard-wired neural network which emulates the external physical process. A process is repeated whereby erroneous unknown internal values are used to generate an emulated signal with is compared to external sensed data, generating an error signal. Feedback from the error signal is then sued to update the erroneous internal values. The process is repeated until the error signal no longer decrease. It was soon realized that the same method could be used to obtain CT from x-rays without having to do Fourier transforms. Neural networks have the additional potential for handling non-linearities and missing data. The technique has been applied to some coral images, collected at the Los Alamos high-energy x-ray facility. The initial images show considerable promise, in some instances showing more detail than the FB images obtained from the same data. Although routine production using this new method would require a massively parallel computer, the method shows promise, especially where refined detail is required.

  4. Ultra high resolution soft x-ray tomography

    International Nuclear Information System (INIS)

    Haddad, W.S.; Trebes, J.E.; Goodman, D.M.; Lee, H.R.; McNulty, I.; Zalensky, A.O.

    1995-01-01

    Ultra high resolution three dimensional images of a microscopic test object were made with soft x-rays using a scanning transmission x-ray microscope. The test object consisted of two different patterns of gold bars on silicon nitride windows that were separated by ∼5 microm. A series of nine 2-D images of the object were recorded at angles between -50 to +55 degrees with respect to the beam axis. The projections were then combined tomographically to form a 3-D image by means of an algebraic reconstruction technique (ART) algorithm. A transverse resolution of ∼ 1,000 angstrom was observed. Artifacts in the reconstruction limited the overall depth resolution to ∼ 6,000 angstrom, however some features were clearly reconstructed with a depth resolution of ∼ 1,000 angstrom. A specially modified ART algorithm and a constrained conjugate gradient (CCG) code were also developed as improvements over the standard ART algorithm. Both of these methods made significant improvements in the overall depth resolution, bringing it down to ∼ 1,200 angstrom overall. Preliminary projection data sets were also recorded with both dry and re-hydrated human sperm cells over a similar angular range

  5. Ultra high resolution soft x-ray tomography

    International Nuclear Information System (INIS)

    Haddad, W.S.; Trebes, J.E.; Goodman, D.M.

    1995-01-01

    Ultra high resolution three dimensional images of a microscopic test object were made with soft x-rays using a scanning transmission x-ray microscope. The test object consisted of two different patterns of gold bars on silicon nitride windows that were separated by ∼5μm. A series of nine 2-D images of the object were recorded at angles between -50 to +55 degrees with respect to the beam axis. The projections were then combined tomographically to form a 3-D image by means of an algebraic reconstruction technique (ART) algorithm. A transverse resolution of ∼1000 Angstrom was observed. Artifacts in the reconstruction limited the overall depth resolution to ∼6000 Angstrom, however some features were clearly reconstructed with a depth resolution of ∼1000 Angstrom. A specially modified ART algorithm and a constrained conjugate gradient (CCG) code were also developed as improvements over the standard ART algorithm. Both of these methods made significant improvements in the overall depth resolution bringing it down to ∼1200 Angstrom overall. Preliminary projection data sets were also recorded with both dry and re-hydrated human sperm cells over a similar angular range

  6. Ring artifact reduction in synchrotron X-ray tomography through helical acquisition

    NARCIS (Netherlands)

    D.M. Pelt (Daniël); D.Y. Parkinson (Dilworth)

    2017-01-01

    textabstractIn synchrotron X-ray tomography, systematic defects in certain detector elements can result in arc-shaped artifacts in the final reconstructed image of the scanned sample. These ring artifacts are commonly found in many applications of synchrotron tomography, and can make

  7. MMX-I: data-processing software for multimodal X-ray imaging and tomography

    Energy Technology Data Exchange (ETDEWEB)

    Bergamaschi, Antoine, E-mail: antoine.bergamaschi@synchrotron-soleil.fr; Medjoubi, Kadda [Synchrotron SOLEIL, BP 48, Saint-Aubin, 91192 Gif sur Yvette (France); Messaoudi, Cédric; Marco, Sergio [Université Paris-Saclay, CNRS, Université Paris-Saclay, F-91405 Orsay (France); Institut Curie, INSERM, PSL Reseach University, F-91405 Orsay (France); Somogyi, Andrea [Synchrotron SOLEIL, BP 48, Saint-Aubin, 91192 Gif sur Yvette (France)

    2016-04-12

    The MMX-I open-source software has been developed for processing and reconstruction of large multimodal X-ray imaging and tomography datasets. The recent version of MMX-I is optimized for scanning X-ray fluorescence, phase-, absorption- and dark-field contrast techniques. This, together with its implementation in Java, makes MMX-I a versatile and friendly user tool for X-ray imaging. A new multi-platform freeware has been developed for the processing and reconstruction of scanning multi-technique X-ray imaging and tomography datasets. The software platform aims to treat different scanning imaging techniques: X-ray fluorescence, phase, absorption and dark field and any of their combinations, thus providing an easy-to-use data processing tool for the X-ray imaging user community. A dedicated data input stream copes with the input and management of large datasets (several hundred GB) collected during a typical multi-technique fast scan at the Nanoscopium beamline and even on a standard PC. To the authors’ knowledge, this is the first software tool that aims at treating all of the modalities of scanning multi-technique imaging and tomography experiments.

  8. Fluorescent x-ray computed tomography with synchrotron radiation using fan collimator

    Science.gov (United States)

    Takeda, Tohoru; Akiba, Masahiro; Yuasa, Tetsuya; Kazama, Masahiro; Hoshino, Atsunori; Watanabe, Yuuki; Hyodo, Kazuyuki; Dilmanian, F. Avraham; Akatsuka, Takao; Itai, Yuji

    1996-04-01

    We describe a new system of fluorescent x-ray computed tomography applied to image nonradioactive contrast materials in vivo. The system operates on the basis of computed tomography (CT) of the first generation. The experiment was also simulated using the Monte Carlo method. The research was carried out at the BLNE-5A bending-magnet beam line of the Tristan Accumulation Ring in Kek, Japan. An acrylic cylindrical phantom containing five paraxial channels of 5 and 4 mm diameters was imaged. The channels were filled with a diluted iodine-based contrast material, with iodine concentrations of 2 mg/ml and 500 (mu) g/ml. Spectra obtained with the system's high purity germanium (HPGe) detector separated clearly the K(alpha ) and K(beta 1) x-ray fluorescent lines, and the Compton scattering. CT images were reconstructed from projections generated by integrating the counts in these spectral lines. The method had adequate sensitivity and detection power, as shown by the experiment and predicted by the simulations, to show the iodine content of the phantom channels, which corresponded to 1 and 4 (mu) g iodine content per pixel in the reconstructed images.

  9. Application of X-ray scanning and tomography to evaluate the filtercake removal efficiency

    International Nuclear Information System (INIS)

    Lopes, R.T.; Oliveira, L.F. de; Miranda, C.R.; Leite, J.C.

    2004-01-01

    The removal of the filtercake formed during the drilling operation is essential for a successful cementing job. Nowadays, the use of synthetic base fluids brings the necessity of proceeding new evaluations of the efficiency of the washes in removing the filtercake and to guarantee the wettability inversion of the formation from oil to waterwet. It is presented here the application of X-ray tomographic scanning to evaluate the filtercake removal efficiency performed by different washes. This technique uses a natural core with a perforation, where a filtercake is formed by circulating a drilling fluid. The wash is circulated through this perforation and the filtercake removal efficiency is measured precisely by computer tomography scanning. This procedure enables the filtercake removal visualization during the wash circulation through the formation and from the data obtained from the X-ray tomography it is possible to select the most appropriate wash for a given drilling fluid, as well as to predict the necessary contact time between the wash and the formation to achieve an appropriate filtercake removal

  10. Adaptive zooming in X-ray computed tomography.

    Science.gov (United States)

    Dabravolski, Andrei; Batenburg, Kees Joost; Sijbers, Jan

    2014-01-01

    In computed tomography (CT), the source-detector system commonly rotates around the object in a circular trajectory. Such a trajectory does not allow to exploit a detector fully when scanning elongated objects. Increase the spatial resolution of the reconstructed image by optimal zooming during scanning. A new approach is proposed, in which the full width of the detector is exploited for every projection angle. This approach is based on the use of prior information about the object's convex hull to move the source as close as possible to the object, while avoiding truncation of the projections. Experiments show that the proposed approach can significantly improve reconstruction quality, producing reconstructions with smaller errors and revealing more details in the object. The proposed approach can lead to more accurate reconstructions and increased spatial resolution in the object compared to the conventional circular trajectory.

  11. Characteristics of Transmission-type Microfocus X-ray Tube based-on Carbon Nanotube Field Emitter

    International Nuclear Information System (INIS)

    Heo, Sung Hwan; Ihsan, Aamir; Cho, Sung Oh

    2007-01-01

    A high resolution microfocus x-ray source is widely applied to noninvasive detection for industrial demands, material science and engineering, and to diagnostic study of microbiology and micro-tomography. Carbon nanotube (CNT) is regarded as an excellent electron emitter, which outperforms conventional electron sources in point of brightness. It has been suggested that CNT is used as an electron source of a high resolution x-ray tube according to their low threshold field with atomically sharp geometry, chemically robust structure, and electric conductivity. Several researchers have reported miniaturized x-ray tube based on diode structure and micro x-ray radiography and computed tomography systems using triode types with precise emission control and electrostatic focusing. Especially, a microfocus x-ray source of 30 μm resolution has been demonstrated recently using an elliptical CNT cathode and asymmetrical Eingel lens. However, to increase the spatial resolution of x-ray source, a smaller CNT emitter is desired. Electron focusing optics must be corrected to reduce aberrations. A thin wire tip end can provide a micro-area of CNT substrate, and a magnetic lens and transmission x-ray target are proper to reduce the lens aberration and a focal length. Until now, CNT based microfocus x-ray source with less than 10 um resolution has not been shown. Here we report a microfocus x-ray source with 4.7 μm x-ray focal spot consisted of a conical CNT tip, a single solenoid lens, and a transmission type x-ray target. A magnified x-ray image larger than 230 times was resolved with advantage of microfocused focal spot and transmission x-ray target

  12. Microstructural characterization of dental zinc phosphate cements using combined small angle neutron scattering and microfocus X-ray computed tomography

    Czech Academy of Sciences Publication Activity Database

    Viani, Alberto; Sotiriadis, Konstantinos; Kumpová, Ivana; Mancini, L.; Appavou, M.-S.

    2017-01-01

    Roč. 33, č. 4 (2017), s. 402-417 ISSN 0109-5641 R&D Projects: GA MŠk(CZ) LO1219 Keywords : zinc phosphate cements * small angle neutron scattering * X-ray micro-computed tomography * X-ray powder diffraction * zinc oxide * acid-base cements Subject RIV: JJ - Other Materials OBOR OECD: Composites (including laminates, reinforced plastics, cermets, combined natural and synthetic fibre fabrics Impact factor: 4.070, year: 2016 https://www.sciencedirect.com/science/article/pii/S0109564116305127

  13. Evaluation of pore structures and cracking in cement paste exposed to elevated temperatures by X-ray computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kwang Yeom, E-mail: kimky@kict.re.kr [Korea Institute of Construction Technology, 283 Goyangdae-ro, Ilsanseo-gu, Goyang 411-712 (Korea, Republic of); Yun, Tae Sup, E-mail: taesup@yonsei.ac.kr [School of Civil and Environmental Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Park, Kwang Pil, E-mail: bamtol97@kict.re.kr [Korea Institute of Construction Technology, 283 Goyangdae-ro, Ilsanseo-gu, Goyang 411-712 (Korea, Republic of)

    2013-08-15

    When cement-based materials are exposed to the high temperatures induced by fire, which can rapidly cause temperatures of over 1000 °C, the changes in pore structure and density prevail. In the present study, mortar specimens were subjected to a series of increasing temperatures to explore the temperature-dependent evolution of internal pore structure. High-performance X-ray computed tomography (CT) was used to observe the evolution of temperature-induced discontinuities at the sub-millimeter level. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed to investigate the cause of physical changes in the heated mortar specimens. Results exhibit the changes in pore structure caused by elevated temperatures, and thermally induced fractures. We discuss the progressive formation of thermally induced fracture networks, which is a prerequisite for spalling failure of cement-based materials by fire, based on visual observations of the 3D internal structures revealed by X-ray CT.

  14. Evaluation of pore structures and cracking in cement paste exposed to elevated temperatures by X-ray computed tomography

    International Nuclear Information System (INIS)

    Kim, Kwang Yeom; Yun, Tae Sup; Park, Kwang Pil

    2013-01-01

    When cement-based materials are exposed to the high temperatures induced by fire, which can rapidly cause temperatures of over 1000 °C, the changes in pore structure and density prevail. In the present study, mortar specimens were subjected to a series of increasing temperatures to explore the temperature-dependent evolution of internal pore structure. High-performance X-ray computed tomography (CT) was used to observe the evolution of temperature-induced discontinuities at the sub-millimeter level. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed to investigate the cause of physical changes in the heated mortar specimens. Results exhibit the changes in pore structure caused by elevated temperatures, and thermally induced fractures. We discuss the progressive formation of thermally induced fracture networks, which is a prerequisite for spalling failure of cement-based materials by fire, based on visual observations of the 3D internal structures revealed by X-ray CT

  15. Spherical grating based x-ray Talbot interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Cong, Wenxiang, E-mail: congw@rpi.edu, E-mail: xiy2@rpi.edu, E-mail: wangg6@rpi.edu; Xi, Yan, E-mail: congw@rpi.edu, E-mail: xiy2@rpi.edu, E-mail: wangg6@rpi.edu; Wang, Ge, E-mail: congw@rpi.edu, E-mail: xiy2@rpi.edu, E-mail: wangg6@rpi.edu [Biomedical Imaging Center, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

    2015-11-15

    Purpose: Grating interferometry is a state-of-the-art x-ray imaging approach, which can acquire information on x-ray attenuation, phase shift, and small-angle scattering simultaneously. Phase-contrast imaging and dark-field imaging are very sensitive to microstructural variation and offers superior contrast resolution for biological soft tissues. However, a common x-ray tube is a point-like source. As a result, the popular planar grating imaging configuration seriously restricts the flux of photons and decreases the visibility of signals, yielding a limited field of view. The purpose of this study is to extend the planar x-ray grating imaging theory and methods to a spherical grating scheme for a wider range of preclinical and clinical applications. Methods: A spherical grating matches the wave front of a point x-ray source very well, allowing the perpendicular incidence of x-rays on the grating to achieve a higher visibility over a larger field of view than the planer grating counterpart. A theoretical analysis of the Talbot effect for spherical grating imaging is proposed to establish a basic foundation for x-ray spherical gratings interferometry. An efficient method of spherical grating imaging is also presented to extract attenuation, differential phase, and dark-field images in the x-ray spherical grating interferometer. Results: Talbot self-imaging with spherical gratings is analyzed based on the Rayleigh–Sommerfeld diffraction formula, featuring a periodic angular distribution in a polar coordinate system. The Talbot distance is derived to reveal the Talbot self-imaging pattern. Numerical simulation results show the self-imaging phenomenon of a spherical grating interferometer, which is in agreement with the theoretical prediction. Conclusions: X-ray Talbot interferometry with spherical gratings has a significant practical promise. Relative to planar grating imaging, spherical grating based x-ray Talbot interferometry has a larger field of view and

  16. Spherical grating based x-ray Talbot interferometry

    International Nuclear Information System (INIS)

    Cong, Wenxiang; Xi, Yan; Wang, Ge

    2015-01-01

    Purpose: Grating interferometry is a state-of-the-art x-ray imaging approach, which can acquire information on x-ray attenuation, phase shift, and small-angle scattering simultaneously. Phase-contrast imaging and dark-field imaging are very sensitive to microstructural variation and offers superior contrast resolution for biological soft tissues. However, a common x-ray tube is a point-like source. As a result, the popular planar grating imaging configuration seriously restricts the flux of photons and decreases the visibility of signals, yielding a limited field of view. The purpose of this study is to extend the planar x-ray grating imaging theory and methods to a spherical grating scheme for a wider range of preclinical and clinical applications. Methods: A spherical grating matches the wave front of a point x-ray source very well, allowing the perpendicular incidence of x-rays on the grating to achieve a higher visibility over a larger field of view than the planer grating counterpart. A theoretical analysis of the Talbot effect for spherical grating imaging is proposed to establish a basic foundation for x-ray spherical gratings interferometry. An efficient method of spherical grating imaging is also presented to extract attenuation, differential phase, and dark-field images in the x-ray spherical grating interferometer. Results: Talbot self-imaging with spherical gratings is analyzed based on the Rayleigh–Sommerfeld diffraction formula, featuring a periodic angular distribution in a polar coordinate system. The Talbot distance is derived to reveal the Talbot self-imaging pattern. Numerical simulation results show the self-imaging phenomenon of a spherical grating interferometer, which is in agreement with the theoretical prediction. Conclusions: X-ray Talbot interferometry with spherical gratings has a significant practical promise. Relative to planar grating imaging, spherical grating based x-ray Talbot interferometry has a larger field of view and

  17. X-ray Computed Tomography Assessment of Air Void Distribution in Concrete

    Science.gov (United States)

    Lu, Haizhu

    Air void size and spatial distribution have long been regarded as critical parameters in the frost resistance of concrete. In cement-based materials, entrained air void systems play an important role in performance as related to durability, permeability, and heat transfer. Many efforts have been made to measure air void parameters in a more efficient and reliable manner in the past several decades. Standardized measurement techniques based on optical microscopy and stereology on flat cut and polished surfaces are widely used in research as well as in quality assurance and quality control applications. Other more automated methods using image processing have also been utilized, but still starting from flat cut and polished surfaces. The emergence of X-ray computed tomography (CT) techniques provides the capability of capturing the inner microstructure of materials at the micrometer and nanometer scale. X-ray CT's less demanding sample preparation and capability to measure 3D distributions of air voids directly provide ample prospects for its wider use in air void characterization in cement-based materials. However, due to the huge number of air voids that can exist within a limited volume, errors can easily arise in the absence of a formalized data processing procedure. In this study, air void parameters in selected types of cement-based materials (lightweight concrete, structural concrete elements, pavements, and laboratory mortars) have been measured using micro X-ray CT. The focus of this study is to propose a unified procedure for processing the data and to provide solutions to deal with common problems that arise when measuring air void parameters: primarily the reliable segmentation of objects of interest, uncertainty estimation of measured parameters, and the comparison of competing segmentation parameters.

  18. Fine Output Voltage Control Method considering Time-Delay of Digital Inverter System for X-ray Computed Tomography

    Science.gov (United States)

    Shibata, Junji; Kaneko, Kazuhide; Ohishi, Kiyoshi; Ando, Itaru; Ogawa, Mina; Takano, Hiroshi

    This paper proposes a new output voltage control for an inverter system, which has time-delay and nonlinear load. In the next generation X-ray computed tomography of a medical device (X-ray CT) that uses the contactless power transfer method, the feedback signal often contains time-delay due to AD/DA conversion and error detection/correction time. When the PID controller of the inverter system is received the adverse effects of the time-delay, the controller often has an overshoot and a oscillated response. In order to overcome this problem, this paper proposes a compensation method based on the Smith predictor for an inverter system having a time-delay and the nonlinear loads which are the diode bridge rectifier and X-ray tube. The proposed compensation method consists of the hybrid Smith predictor system based on an equivalent analog circuit and DSP. The experimental results confirm the validity of the proposed system.

  19. Grating-based X-ray phase contrast for biomedical imaging applications

    International Nuclear Information System (INIS)

    Pfeiffer, Franz; Willner, Marian; Chabior, Michael; Herzen, Julia; Helmholtz-Zentrum Geesthacht, Geesthacht; Auweter, Sigrid; Reiser, Maximilian; Bamberg, Fabian

    2013-01-01

    In this review article we describe the development of grating-based X-ray phase-contrast imaging, with particular emphasis on potential biomedical applications of the technology. We review the basics of image formation in grating-based phase-contrast and dark-field radiography and present some exemplary multimodal radiography results obtained with laboratory X-ray sources. Furthermore, we discuss the theoretical concepts to extend grating-based multimodal radiography to quantitative transmission, phase-contrast, and dark-field scattering computed tomography. (orig.)

  20. Improving x-ray fluorescence signal for benchtop polychromatic cone-beam x-ray fluorescence computed tomography by incident x-ray spectrum optimization: a Monte Carlo study.

    Science.gov (United States)

    Manohar, Nivedh; Jones, Bernard L; Cho, Sang Hyun

    2014-10-01

    To develop an accurate and comprehensive Monte Carlo (MC) model of an experimental benchtop polychromatic cone-beam x-ray fluorescence computed tomography (XFCT) setup and apply this MC model to optimize incident x-ray spectrum for improving production/detection of x-ray fluorescence photons from gold nanoparticles (GNPs). A detailed MC model, based on an experimental XFCT system, was created using the Monte Carlo N-Particle (MCNP) transport code. The model was validated by comparing MC results including x-ray fluorescence (XRF) and scatter photon spectra with measured data obtained under identical conditions using 105 kVp cone-beam x-rays filtered by either 1 mm of lead (Pb) or 0.9 mm of tin (Sn). After validation, the model was used to investigate the effects of additional filtration of the incident beam with Pb and Sn. Supplementary incident x-ray spectra, representing heavier filtration (Pb: 2 and 3 mm; Sn: 1, 2, and 3 mm) were computationally generated and used with the model to obtain XRF/scatter spectra. Quasimonochromatic incident x-ray spectra (81, 85, 90, 95, and 100 keV with 10 keV full width at half maximum) were also investigated to determine the ideal energy for distinguishing gold XRF signal from the scatter background. Fluorescence signal-to-dose ratio (FSDR) and fluorescence-normalized scan time (FNST) were used as metrics to assess results. Calculated XRF/scatter spectra for 1-mm Pb and 0.9-mm Sn filters matched (r ≥ 0.996) experimental measurements. Calculated spectra representing additional filtration for both filter materials showed that the spectral hardening improved the FSDR at the expense of requiring a much longer FNST. In general, using Sn instead of Pb, at a given filter thickness, allowed an increase of up to 20% in FSDR, more prominent gold XRF peaks, and up to an order of magnitude decrease in FNST. Simulations using quasimonochromatic spectra suggested that increasing source x-ray energy, in the investigated range of 81-100 ke

  1. An algebraic iterative reconstruction technique for differential X-ray phase-contrast computed tomography.

    Science.gov (United States)

    Fu, Jian; Schleede, Simone; Tan, Renbo; Chen, Liyuan; Bech, Martin; Achterhold, Klaus; Gifford, Martin; Loewen, Rod; Ruth, Ronald; Pfeiffer, Franz

    2013-09-01

    Iterative reconstruction has a wide spectrum of proven advantages in the field of conventional X-ray absorption-based computed tomography (CT). In this paper, we report on an algebraic iterative reconstruction technique for grating-based differential phase-contrast CT (DPC-CT). Due to the differential nature of DPC-CT projections, a differential operator and a smoothing operator are added to the iterative reconstruction, compared to the one commonly used for absorption-based CT data. This work comprises a numerical study of the algorithm and its experimental verification using a dataset measured at a two-grating interferometer setup. Since the algorithm is easy to implement and allows for the extension to various regularization possibilities, we expect a significant impact of the method for improving future medical and industrial DPC-CT applications. Copyright © 2012. Published by Elsevier GmbH.

  2. Imaging of metastatic lymph nodes by X-ray phase-contrast micro-tomography.

    Directory of Open Access Journals (Sweden)

    Torben Haugaard Jensen

    Full Text Available Invasive cancer causes a change in density in the affected tissue, which can be visualized by x-ray phase-contrast tomography. However, the diagnostic value of this method has so far not been investigated in detail. Therefore, the purpose of this study was, in a blinded manner, to investigate whether malignancy could be revealed by non-invasive x-ray phase-contrast tomography in lymph nodes from breast cancer patients. Seventeen formalin-fixed paraffin-embedded lymph nodes from 10 female patients (age range 37-83 years diagnosed with invasive ductal carcinomas were analyzed by X-ray phase-contrast tomography. Ten lymph nodes had metastatic deposits and 7 were benign. The phase-contrast images were analyzed according to standards for conventional CT images looking for characteristics usually only visible by pathological examinations. Histopathology was used as reference. The result of this study was that the diagnostic sensitivity of the image analysis for detecting malignancy was 100% and the specificity was 87%. The positive predictive value was 91% for detecting malignancy and the negative predictive value was 100%. We conclude that x-ray phase-contrast imaging can accurately detect density variations to obtain information regarding lymph node involvement previously inaccessible with standard absorption x-ray imaging.

  3. Bayesian soft X-ray tomography using non-stationary Gaussian Processes

    International Nuclear Information System (INIS)

    Li, Dong; Svensson, J.; Thomsen, H.; Werner, A.; Wolf, R.; Medina, F.

    2013-01-01

    In this study, a Bayesian based non-stationary Gaussian Process (GP) method for the inference of soft X-ray emissivity distribution along with its associated uncertainties has been developed. For the investigation of equilibrium condition and fast magnetohydrodynamic behaviors in nuclear fusion plasmas, it is of importance to infer, especially in the plasma center, spatially resolved soft X-ray profiles from a limited number of noisy line integral measurements. For this ill-posed inversion problem, Bayesian probability theory can provide a posterior probability distribution over all possible solutions under given model assumptions. Specifically, the use of a non-stationary GP to model the emission allows the model to adapt to the varying length scales of the underlying diffusion process. In contrast to other conventional methods, the prior regularization is realized in a probability form which enhances the capability of uncertainty analysis, in consequence, scientists who concern the reliability of their results will benefit from it. Under the assumption of normally distributed noise, the posterior distribution evaluated at a discrete number of points becomes a multivariate normal distribution whose mean and covariance are analytically available, making inversions and calculation of uncertainty fast. Additionally, the hyper-parameters embedded in the model assumption can be optimized through a Bayesian Occam's Razor formalism and thereby automatically adjust the model complexity. This method is shown to produce convincing reconstructions and good agreements with independently calculated results from the Maximum Entropy and Equilibrium-Based Iterative Tomography Algorithm methods

  4. Bayesian soft X-ray tomography using non-stationary Gaussian Processes

    Science.gov (United States)

    Li, Dong; Svensson, J.; Thomsen, H.; Medina, F.; Werner, A.; Wolf, R.

    2013-08-01

    In this study, a Bayesian based non-stationary Gaussian Process (GP) method for the inference of soft X-ray emissivity distribution along with its associated uncertainties has been developed. For the investigation of equilibrium condition and fast magnetohydrodynamic behaviors in nuclear fusion plasmas, it is of importance to infer, especially in the plasma center, spatially resolved soft X-ray profiles from a limited number of noisy line integral measurements. For this ill-posed inversion problem, Bayesian probability theory can provide a posterior probability distribution over all possible solutions under given model assumptions. Specifically, the use of a non-stationary GP to model the emission allows the model to adapt to the varying length scales of the underlying diffusion process. In contrast to other conventional methods, the prior regularization is realized in a probability form which enhances the capability of uncertainty analysis, in consequence, scientists who concern the reliability of their results will benefit from it. Under the assumption of normally distributed noise, the posterior distribution evaluated at a discrete number of points becomes a multivariate normal distribution whose mean and covariance are analytically available, making inversions and calculation of uncertainty fast. Additionally, the hyper-parameters embedded in the model assumption can be optimized through a Bayesian Occam's Razor formalism and thereby automatically adjust the model complexity. This method is shown to produce convincing reconstructions and good agreements with independently calculated results from the Maximum Entropy and Equilibrium-Based Iterative Tomography Algorithm methods.

  5. Calibration-free quantification of interior properties of porous media with x-ray computed tomography

    International Nuclear Information System (INIS)

    Hussein, Esam M.A.; Agbogun, H.M.D.; Al, Tom A.

    2015-01-01

    A method is presented for interpreting the values of x-ray attenuation coefficients reconstructed in computed tomography of porous media, while overcoming the ambiguity caused by the multichromatic nature of x-rays, dilution by void, and material heterogeneity. The method enables determination of porosity without relying on calibration or image segmentation or thresholding to discriminate pores from solid material. It distinguishes between solution-accessible and inaccessible pores, and provides the spatial and frequency distributions of solid-matrix material in a heterogeneous medium. This is accomplished by matching an image of a sample saturated with a contrast solution with that saturated with a transparent solution. Voxels occupied with solid-material and inaccessible pores are identified by the fact that they maintain the same location and image attributes in both images, with voxels containing inaccessible pores appearing empty in both images. Fully porous and accessible voxels exhibit the maximum contrast, while the rest are porous voxels containing mixtures of pore solutions and solid. This matching process is performed with an image registration computer code, and image processing software that requires only simple subtraction and multiplication (scaling) processes. The process is demonstrated in dolomite (non-uniform void distribution, homogeneous solid matrix) and sandstone (nearly uniform void distribution, heterogeneous solid matrix) samples, and its overall performance is shown to compare favorably with a method based on calibration and thresholding. - Highlights: • A method is presented for quantifying x-ray CT data for porous media. • The method neither requires calibration nor segmentation nor thresholding. • We use voxel matching between images of a sample saturated with two distinct solutions. • Method is demonstrated for micro-CT images of dolomite and sandstone samples. • Overall performance compares favorably with a calibration

  6. 3D visualization of subcellular structures of Schizosaccharomyces pombe by hard X-ray tomography.

    Science.gov (United States)

    Yang, Y; Li, W; Liu, G; Zhang, X; Chen, J; Wu, W; Guan, Y; Xiong, Y; Tian, Y; Wu, Z

    2010-10-01

    Cellular structures of the fission yeast, Schizosaccharomyces pombe, were examined by using hard X-ray tomography. Since cells are nearly transparent to hard X-rays, Zernike phase contrast and heavy metal staining were introduced to improve image contrast. Through using such methods, images taken at 8 keV displayed sufficient contrast for observing cellular structures. The cell wall, the intracellular organelles and the entire structural organization of the whole cells were visualized in three-dimensional at a resolution better than 100 nm. Comparison between phase contrast and absorption contrast was also made, indicating the obvious advantage of phase contrast for cellular imaging at this energy. Our results demonstrate that hard X-ray tomography with Zernike phase contrast is suitable for cellular imaging. Its unique abilities make it have potential to become a useful tool for revealing structural information from cells, especially thick eukaryotic cells. © 2010 The Authors Journal compilation © 2010 The Royal Microscopical Society.

  7. MMX-I: data-processing software for multimodal X-ray imaging and tomography.

    Science.gov (United States)

    Bergamaschi, Antoine; Medjoubi, Kadda; Messaoudi, Cédric; Marco, Sergio; Somogyi, Andrea

    2016-05-01

    A new multi-platform freeware has been developed for the processing and reconstruction of scanning multi-technique X-ray imaging and tomography datasets. The software platform aims to treat different scanning imaging techniques: X-ray fluorescence, phase, absorption and dark field and any of their combinations, thus providing an easy-to-use data processing tool for the X-ray imaging user community. A dedicated data input stream copes with the input and management of large datasets (several hundred GB) collected during a typical multi-technique fast scan at the Nanoscopium beamline and even on a standard PC. To the authors' knowledge, this is the first software tool that aims at treating all of the modalities of scanning multi-technique imaging and tomography experiments.

  8. Hard X-ray submicrometer tomography of human brain tissue at Diamond Light Source

    Science.gov (United States)

    Khimchenko, A.; Bikis, C.; Schulz, G.; Zdora, M.-C.; Zanette, I.; Vila-Comamala, J.; Schweighauser, G.; Hench, J.; Hieber, S. E.; Deyhle, H.; Thalmann, P.; Müller, B.

    2017-06-01

    There is a lack of the necessary methodology for three-dimensional (3D) investigation of soft tissues with cellular resolution without staining or tissue transformation. Synchrotron radiation based hard X-ray in-line phase contrast tomography using single-distance phase reconstruction (SDPR) provides high spatial resolution and density contrast for the visualization of individual cells using a standard specimen preparation and data reconstruction. In this study, we demonstrate the 3D characterization of a formalin-fixed paraffin-embedded (FFPE) human cerebellum specimen by SDPR at the Diamond-Manchester Imaging Branchline I13-2 (Diamond Light Source, UK) at pixel sizes down to 0.45 μm. The approach enables visualization of cerebellar layers (Stratum moleculare and Stratum granulosum), the 3D characterization of individual cells (Purkinje, stellate and granule cells) and can even resolve some subcellular structures (nucleus and nucleolus of Purkinje cells). The tomographic results are qualitatively compared to hematoxylin and eosin (H&E) stained histological sections. We demonstrate the potential benefits of hard X-ray microtomography for the investigations of biological tissues in comparison to conventional histology.

  9. Hard X-ray submicrometer tomography of human brain tissue at Diamond Light Source

    International Nuclear Information System (INIS)

    Khimchenko, A; Bikis, C; Schulz, G; Hieber, S E; Deyhle, H; Thalmann, P; Müller, B; Zdora, M-C; Zanette, I; Vila-Comamala, J; Schweighauser, G; Hench, J

    2017-01-01

    There is a lack of the necessary methodology for three-dimensional (3D) investigation of soft tissues with cellular resolution without staining or tissue transformation. Synchrotron radiation based hard X-ray in-line phase contrast tomography using single-distance phase reconstruction (SDPR) provides high spatial resolution and density contrast for the visualization of individual cells using a standard specimen preparation and data reconstruction. In this study, we demonstrate the 3D characterization of a formalin-fixed paraffin-embedded (FFPE) human cerebellum specimen by SDPR at the Diamond-Manchester Imaging Branchline I13-2 (Diamond Light Source, UK) at pixel sizes down to 0.45 μm. The approach enables visualization of cerebellar layers ( Stratum moleculare and Stratum granulosum ), the 3D characterization of individual cells (Purkinje, stellate and granule cells) and can even resolve some subcellular structures (nucleus and nucleolus of Purkinje cells). The tomographic results are qualitatively compared to hematoxylin and eosin (H and E) stained histological sections. We demonstrate the potential benefits of hard X-ray microtomography for the investigations of biological tissues in comparison to conventional histology. (paper)

  10. Six dimensional X-ray Tensor Tomography with a compact laboratory setup

    Science.gov (United States)

    Sharma, Y.; Wieczorek, M.; Schaff, F.; Seyyedi, S.; Prade, F.; Pfeiffer, F.; Lasser, T.

    2016-09-01

    Attenuation based X-ray micro computed tomography (XCT) provides three-dimensional images with micrometer resolution. However, there is a trade-off between the smallest size of the structures that can be resolved and the measurable sample size. In this letter, we present an imaging method using a compact laboratory setup that reveals information about micrometer-sized structures within samples that are several orders of magnitudes larger. We combine the anisotropic dark-field signal obtained in a grating interferometer and advanced tomographic reconstruction methods to reconstruct a six dimensional scattering tensor at every spatial location in three dimensions. The scattering tensor, thus obtained, encodes information about the orientation of micron-sized structures such as fibres in composite materials or dentinal tubules in human teeth. The sparse acquisition schemes presented in this letter enable the measurement of the full scattering tensor at every spatial location and can be easily incorporated in a practical, commercially feasible laboratory setup using conventional X-ray tubes, thus allowing for widespread industrial applications.

  11. Assessing potato tuber diel growth by means of X-ray computed tomography.

    Science.gov (United States)

    Pérez-Torres, Eduardo; Kirchgessner, Norbert; Pfeifer, Johannes; Walter, Achim

    2015-11-01

    The formation and development of belowground organs is difficult to study. X-ray computed tomography (CT) provides the possibility to analyse and interpret subtle volumetric changes of belowground organs such as tubers, storage roots and nodules. Here, we report on the establishment of a method based on a voxel dimension of 240 μm and precision (standard deviation) of 30 μL that allows interpreting growth differences among potato tubers happening within 3 h. Plants were not stressed by the application of X-ray radiation, which was shown both by morphological comparison with control plants and by analysis of lipid peroxidation as a measure of oxidative stress. Diel (24 h) tuber growth fluctuations of three potato genotypes were monitored in soil-filled pots of 10 L. In contrast to the results from previous reports, most tubers grew at similar rates during day and night. Tuber growth was not related to the developmental stage of plants and tubers. Pronounced differences were observed between average growth rates in different tubers within a plant. These results are discussed in the context of restrictions of past methods to study tuber growth and in the context of their potential for the characterization of the formation and development of other belowground plant organs. © 2015 John Wiley & Sons Ltd.

  12. Calibration-free quantification of interior properties of porous media with x-ray computed tomography.

    Science.gov (United States)

    Hussein, Esam M A; Agbogun, H M D; Al, Tom A

    2015-03-01

    A method is presented for interpreting the values of x-ray attenuation coefficients reconstructed in computed tomography of porous media, while overcoming the ambiguity caused by the multichromatic nature of x-rays, dilution by void, and material heterogeneity. The method enables determination of porosity without relying on calibration or image segmentation or thresholding to discriminate pores from solid material. It distinguishes between solution-accessible and inaccessible pores, and provides the spatial and frequency distributions of solid-matrix material in a heterogeneous medium. This is accomplished by matching an image of a sample saturated with a contrast solution with that saturated with a transparent solution. Voxels occupied with solid-material and inaccessible pores are identified by the fact that they maintain the same location and image attributes in both images, with voxels containing inaccessible pores appearing empty in both images. Fully porous and accessible voxels exhibit the maximum contrast, while the rest are porous voxels containing mixtures of pore solutions and solid. This matching process is performed with an image registration computer code, and image processing software that requires only simple subtraction and multiplication (scaling) processes. The process is demonstrated in dolomite (non-uniform void distribution, homogeneous solid matrix) and sandstone (nearly uniform void distribution, heterogeneous solid matrix) samples, and its overall performance is shown to compare favorably with a method based on calibration and thresholding. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Experiments on vertical gas-liquid pipe flows using ultrafast X-ray tomography

    Energy Technology Data Exchange (ETDEWEB)

    Banowski, M.; Beyer, M.; Lucas, D.; Hoppe, D.; Barthel, F. [Helmholtz-Zentrum Dresden-Rossendorf (Germany). Inst. fuer Sicherheitsforschung

    2016-12-15

    For the qualification and validation of two-phase CFD-models for medium and large-scale industrial applications dedicated experiments providing data with high temporal and spatial resolution are required. Fluid dynamic parameter like gas volume fraction, bubble size distribution, velocity or turbulent kinetic energy should be measured locally. Considering the fact, that the used measurement techniques should not affect the flow characteristics, radiation based tomographic methods are the favourite candidate for such measurements. Here the recently developed ultrafast X-ray tomography, is applied to measure the local and temporal gas volume fraction distribution in a vertical pipe. To obtain the required frame rate a rotating X-ray source by a massless electron beam and a static detector ring are used. Experiments on a vertical pipe are well suited for development and validation of closure models for two-phase flows. While vertical pipe flows are axially symmetrically, the boundary conditions are well defined. The evolution of the flow along the pipe can be investigated as well. This report documents the experiments done for co-current upwards and downwards air-water and steam-water flows as well as for counter-current air-water flows. The details of the setup, measuring technique and data evaluation are given. The report also includes a discussion on selected results obtained and on uncertainties.

  14. Laboratory Scale X-ray Fluorescence Tomography: Instrument Characterization and Application in Earth and Environmental Science.

    Science.gov (United States)

    Laforce, Brecht; Vermeulen, Bram; Garrevoet, Jan; Vekemans, Bart; Van Hoorebeke, Luc; Janssen, Colin; Vincze, Laszlo

    2016-03-15

    A new laboratory scale X-ray fluorescence (XRF) imaging instrument, based on an X-ray microfocus tube equipped with a monocapillary optic, has been developed to perform XRF computed tomography experiments with both higher spatial resolution (20 μm) and a better energy resolution (130 eV @Mn-K(α)) than has been achieved up-to-now. This instrument opens a new range of possible applications for XRF-CT. Next to the analytical characterization of the setup by using well-defined model/reference samples, demonstrating its capabilities for tomographic imaging, the XRF-CT microprobe has been used to image the interior of an ecotoxicological model organism, Americamysis bahia. This had been exposed to elevated metal (Cu and Ni) concentrations. The technique allowed the visualization of the accumulation sites of copper, clearly indicating the affected organs, i.e. either the gastric system or the hepatopancreas. As another illustrative application, the scanner has been employed to investigate goethite spherules from the Cretaceous-Paleogene boundary, revealing the internal elemental distribution of these valuable distal ejecta layer particles.

  15. X-ray phase-contrast tomography for high-spatial-resolution zebrafish muscle imaging

    Science.gov (United States)

    Vågberg, William; Larsson, Daniel H.; Li, Mei; Arner, Anders; Hertz, Hans M.

    2015-11-01

    Imaging of muscular structure with cellular or subcellular detail in whole-body animal models is of key importance for understanding muscular disease and assessing interventions. Classical histological methods for high-resolution imaging methods require excision, fixation and staining. Here we show that the three-dimensional muscular structure of unstained whole zebrafish can be imaged with sub-5 μm detail with X-ray phase-contrast tomography. Our method relies on a laboratory propagation-based phase-contrast system tailored for detection of low-contrast 4-6 μm subcellular myofibrils. The method is demonstrated on 20 days post fertilization zebrafish larvae and comparative histology confirms that we resolve individual myofibrils in the whole-body animal. X-ray imaging of healthy zebrafish show the expected structured muscle pattern while specimen with a dystrophin deficiency (sapje) displays an unstructured pattern, typical of Duchenne muscular dystrophy. The method opens up for whole-body imaging with sub-cellular detail also of other types of soft tissue and in different animal models.

  16. Ptychographic X-ray Tomography of Silk Fiber Hydration

    DEFF Research Database (Denmark)

    Esmaeili, Morteza; Fløystad, Jostein B.; Diaz, Ana

    2013-01-01

    Studying noninvasively the internal nanoporous structure of a single Tussah silk fiber under different humidity conditions, we demonstrate for the first time the feasibility of in-situ ptychographic tomography. The resulting 3D images of the silk fiber interior, obtained at both dry and humid con...... normal to the fiber axis. Exploiting quantitative information on the fiber’s electron density, hydration was found to proceed through interaction with the silk protein rather than filling of pores....

  17. Fast automatic segmentation of anatomical structures in x-ray computed tomography images to improve fluorescence molecular tomography reconstruction.

    Science.gov (United States)

    Freyer, Marcus; Ale, Angelique; Schulz, Ralf B; Zientkowska, Marta; Ntziachristos, Vasilis; Englmeier, Karl-Hans

    2010-01-01

    The recent development of hybrid imaging scanners that integrate fluorescence molecular tomography (FMT) and x-ray computed tomography (XCT) allows the utilization of x-ray information as image priors for improving optical tomography reconstruction. To fully capitalize on this capacity, we consider a framework for the automatic and fast detection of different anatomic structures in murine XCT images. To accurately differentiate between different structures such as bone, lung, and heart, a combination of image processing steps including thresholding, seed growing, and signal detection are found to offer optimal segmentation performance. The algorithm and its utilization in an inverse FMT scheme that uses priors is demonstrated on mouse images.

  18. Quantitative phase tomography by using x-ray microscope with Foucault knife-edge scanning filter

    International Nuclear Information System (INIS)

    Watanabe, Norio; Tsuburaya, Yuji; Shimada, Akihiro; Aoki, Sadao

    2016-01-01

    Quantitative phase tomography was evaluated by using a differential phase microscope with a Foucault knife-edge scanning filter. A 3D x-ray phase image of polystyrene beads was obtained at 5.4 keV. The reconstructed refractive index was fairly good agreement with the Henke’s tabulated data

  19. Quantitative phase tomography by using x-ray microscope with Foucault knife-edge scanning filter

    Science.gov (United States)

    Watanabe, Norio; Tsuburaya, Yuji; Shimada, Akihiro; Aoki, Sadao

    2016-01-01

    Quantitative phase tomography was evaluated by using a differential phase microscope with a Foucault knife-edge scanning filter. A 3D x-ray phase image of polystyrene beads was obtained at 5.4 keV. The reconstructed refractive index was fairly good agreement with the Henke's tabulated data.

  20. X-ray tomography of feed-to-glass transition of simulated borosilicate waste glasses

    Czech Academy of Sciences Publication Activity Database

    Harris, W.H.; Guillen, D.P.; Kloužek, Jaroslav; Pokorný, P.; Yano, T.; Lee, S.; Schweiger, M. J.; Hrma, P.

    2017-01-01

    Roč. 100, č. 9 (2017), s. 3883-3894 ISSN 0002-7820 Institutional support: RVO:67985891 Keywords : borosilicate glass * computed tomography * glass melting * morphology * nuclear waste * X-ray Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass OBOR OECD: Ceramics Impact factor: 2.841, year: 2016

  1. Quantitative phase tomography by using x-ray microscope with Foucault knife-edge scanning filter

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Norio; Tsuburaya, Yuji; Shimada, Akihiro; Aoki, Sadao [Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8573 (Japan)

    2016-01-28

    Quantitative phase tomography was evaluated by using a differential phase microscope with a Foucault knife-edge scanning filter. A 3D x-ray phase image of polystyrene beads was obtained at 5.4 keV. The reconstructed refractive index was fairly good agreement with the Henke’s tabulated data.

  2. X-ray micro-Tomography at the Advanced Light Source

    Science.gov (United States)

    The X-ray micro-Tomography Facility at the Advanced Light Source has been in operation since 2004. The source is a superconducting bend magnet of critical energy 10.5KeV; photon energy coverage is 8-45 KeV in monochromatic mode, and a filtered white light option yields useful photons up to 50 KeV. A...

  3. Characterization of feed channel spacer performance using geometries obtained by X-ray computed tomography

    KAUST Repository

    Haaksman, Viktor A.; Siddiqui, Amber; Schellenberg, Carsten; Kidwell, James; Vrouwenvelder, Johannes S.; Picioreanu, Cristian

    2016-01-01

    design from X-ray computed tomography (CT) scans. The method revealed that the filaments of industrial spacers have a highly variable cross-section size and shape, which impact the flow characteristics in the feed channel. The pressure drop and friction

  4. A Monte Carlo simulation of scattering reduction in spectral x-ray computed tomography

    DEFF Research Database (Denmark)

    Busi, Matteo; Olsen, Ulrik Lund; Bergbäck Knudsen, Erik

    2017-01-01

    In X-ray computed tomography (CT), scattered radiation plays an important role in the accurate reconstruction of the inspected object, leading to a loss of contrast between the different materials in the reconstruction volume and cupping artifacts in the images. We present a Monte Carlo simulation...

  5. Ultrafast X-ray tomography for two-phase flow analysis in centrifugal pumps

    International Nuclear Information System (INIS)

    Schaefer, Thomas; Hampel, Uwe; Technische Univ. Dresden

    2017-01-01

    The unsteady behavior of gas-liquid two-phase flow in a centrifugal pump impeller has been visualized, using ultrafast X-ray tomography. Based on the reconstructed tomographic images an evaluation and detailed analysis of the flow conditions has been done. Here, the high temporal resolution of the tomographic images offered the opportunity to get a deep insight into the flow to perform a detailed description of the transient gas-liquid phase distribution inside the impeller. Significant properties of the occurring two-phase flow and characteristic flow patterns have been disclosed. Furthermore, the effects of different air entrainment conditions have been investigated and typical phase distributions inside the impeller have been shown.

  6. Study on Sintering Mechanism of Stainless Steel Fiber Felts by X-ray Computed Tomography

    Directory of Open Access Journals (Sweden)

    Jun Ma

    2016-01-01

    Full Text Available The microstructure evolution of Fe-17 wt. % Cr-12 wt. % Ni-2 wt. % Mo stainless steel fiber felts during the fast sintering process was investigated by the synchrotron radiation X-ray computed tomography technique. The equation of dynamics of stable inter-fiber neck growth was established for the first time based on the geometry model of sintering joints of two fibers and Kucsynski’s two-sphere model. The specific evolutions of different kinds of sintering joints were observed in the three-dimensional images. The sintering mechanisms during sintering were proposed as plastic flow and grain boundary diffusion, the former leading to a quick growth of sintering joints.

  7. Introduction: a brief overview of iterative algorithms in X-ray computed tomography.

    Science.gov (United States)

    Soleimani, M; Pengpen, T

    2015-06-13

    This paper presents a brief overview of some basic iterative algorithms, and more sophisticated methods are presented in the research papers in this issue. A range of algebraic iterative algorithms are covered here including ART, SART and OS-SART. A major limitation of the traditional iterative methods is their computational time. The Krylov subspace based methods such as the conjugate gradients (CG) algorithm and its variants can be used to solve linear systems of equations arising from large-scale CT with possible implementation using modern high-performance computing tools. The overall aim of this theme issue is to stimulate international efforts to develop the next generation of X-ray computed tomography (CT) image reconstruction software. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  8. Ultrafast X-ray tomography for two-phase flow analysis in centrifugal pumps

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, Thomas [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany). Inst. of Fluid Dynamics; Hampel, Uwe [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany). Inst. of Fluid Dynamics; Technische Univ. Dresden (Germany). AREVA Endowed Chair of Imaging Techniques in Energy and Process Engineering

    2017-07-15

    The unsteady behavior of gas-liquid two-phase flow in a centrifugal pump impeller has been visualized, using ultrafast X-ray tomography. Based on the reconstructed tomographic images an evaluation and detailed analysis of the flow conditions has been done. Here, the high temporal resolution of the tomographic images offered the opportunity to get a deep insight into the flow to perform a detailed description of the transient gas-liquid phase distribution inside the impeller. Significant properties of the occurring two-phase flow and characteristic flow patterns have been disclosed. Furthermore, the effects of different air entrainment conditions have been investigated and typical phase distributions inside the impeller have been shown.

  9. Statistical x-ray computed tomography imaging from photon-starved measurements

    Science.gov (United States)

    Chang, Zhiqian; Zhang, Ruoqiao; Thibault, Jean-Baptiste; Sauer, Ken; Bouman, Charles

    2013-03-01

    Dose reduction in clinical X-ray computed tomography (CT) causes low signal-to-noise ratio (SNR) in photonsparse situations. Statistical iterative reconstruction algorithms have the advantage of retaining image quality while reducing input dosage, but they meet their limits of practicality when significant portions of the sinogram near photon starvation. The corruption of electronic noise leads to measured photon counts taking on negative values, posing a problem for the log() operation in preprocessing of data. In this paper, we propose two categories of projection correction methods: an adaptive denoising filter and Bayesian inference. The denoising filter is easy to implement and preserves local statistics, but it introduces correlation between channels and may affect image resolution. Bayesian inference is a point-wise estimation based on measurements and prior information. Both approaches help improve diagnostic image quality at dramatically reduced dosage.

  10. Particle coagulation in molten metal based on three-dimensional analysis of cluster by x-ray micro-computer tomography (CT)

    International Nuclear Information System (INIS)

    Li, Tao; Shimasaki, Shin-ichi; Taniguchi, Shoji; Narita, Shunsuke; Uesugi, Kentaro

    2013-01-01

    Particle coagulation plays a key role in steel refining process to remove inclusions. Many research works focus on the behaviors of particle coagulation. To reveal its mechanism water model experiments have been performed by some researchers including the authors' group. In this paper, experiments of particle coagulation were carried out with molten Al including SiC particles in a mechanically agitated crucible with two baffles. Particle coagulation and formation of clusters were observed on the microscopy images of as-polished samples. Three-dimensional (3D) analysis of the clusters in solidified Al was implemented by X-ray micro CT available at SPring-8. The methods to distinguish clusters on two-dimensional (2D) cross-sectional images were discussed, which were established in the previous works by the present authors' group. The characteristics of the 3D SiC clusters and their 2D cross-sections were analyzed. The statistical ranges of the parameters for 2D clusters were used as criterions to distinguish the clusters on 2D microscopy images from the as-polished samples. The kinetics of SiC particle coagulation was studied by the measured cluster number density and size using our program to distinguish cluster in 2D cross-sectional images according to 3D information (DC-2D-3D). The calculated and experimental results of the SiC particle coagulation in molten Al agree well with each other. (author)

  11. Imaging performance of a hybrid x-ray computed tomography-fluorescence molecular tomography system using priors.

    Science.gov (United States)

    Ale, Angelique; Schulz, Ralf B; Sarantopoulos, Athanasios; Ntziachristos, Vasilis

    2010-05-01

    The performance is studied of two newly introduced and previously suggested methods that incorporate priors into inversion schemes associated with data from a recently developed hybrid x-ray computed tomography and fluorescence molecular tomography system, the latter based on CCD camera photon detection. The unique data set studied attains accurately registered data of high spatially sampled photon fields propagating through tissue along 360 degrees projections. Approaches that incorporate structural prior information were included in the inverse problem by adding a penalty term to the minimization function utilized for image reconstructions. Results were compared as to their performance with simulated and experimental data from a lung inflammation animal model and against the inversions achieved when not using priors. The importance of using priors over stand-alone inversions is also showcased with high spatial sampling simulated and experimental data. The approach of optimal performance in resolving fluorescent biodistribution in small animals is also discussed. Inclusion of prior information from x-ray CT data in the reconstruction of the fluorescence biodistribution leads to improved agreement between the reconstruction and validation images for both simulated and experimental data.

  12. Assessment of natural enamel lesions with optical coherence tomography in comparison with microfocus x-ray computed tomography

    Science.gov (United States)

    Espigares, Jorge; Sadr, Alireza; Hamba, Hidenori; Shimada, Yasushi; Otsuki, Masayuki; Tagami, Junji; Sumi, Yasunori

    2015-01-01

    Abstract. A technology to characterize early enamel lesions is needed in dentistry. Optical coherence tomography (OCT) is a noninvasive method that provides high-resolution cross-sectional images. The aim of this study is to compare OCT with microfocus x-ray computed tomography (μCT) for assessment of natural enamel lesions in vitro. Ten human teeth with visible white spot-like changes on the enamel smooth surface and no cavitation (ICDAS code 2) were subjected to imaging by μCT (SMX-100CT, Shimadzu) and 1300-nm swept-source OCT (Dental SS-OCT, Panasonic Health Care). In μCT, the lesions appeared as radiolucent dark areas, while in SS-OCT, they appeared as areas of increased signal intensity beneath the surface. An SS-OCT attenuation coefficient based on Beer–Lambert law could discriminate lesions from sound enamel. Lesion depth ranged from 175 to 606  μm in SS-OCT. A correlation between μCT and SS-OCT was found regarding lesion depth (R=0.81, p<0.001) and also surface layer thickness (R=0.76, p<0.005). The images obtained clinically in real time using the dental SS-OCT system are suitable for the assessment of natural subsurface lesions and their surface layer, providing comparable images to a laboratory high-resolution μCT without the use of x-ray. PMID:26158079

  13. Gaussian process tomography for soft x-ray spectroscopy at WEST without equilibrium information

    Science.gov (United States)

    Wang, T.; Mazon, D.; Svensson, J.; Li, D.; Jardin, A.; Verdoolaege, G.

    2018-06-01

    Gaussian process tomography (GPT) is a recently developed tomography method based on the Bayesian probability theory [J. Svensson, JET Internal Report EFDA-JET-PR(11)24, 2011 and Li et al., Rev. Sci. Instrum. 84, 083506 (2013)]. By modeling the soft X-ray (SXR) emissivity field in a poloidal cross section as a Gaussian process, the Bayesian SXR tomography can be carried out in a robust and extremely fast way. Owing to the short execution time of the algorithm, GPT is an important candidate for providing real-time reconstructions with a view to impurity transport and fast magnetohydrodynamic control. In addition, the Bayesian formalism allows quantifying uncertainty on the inferred parameters. In this paper, the GPT technique is validated using a synthetic data set expected from the WEST tokamak, and the results are shown of its application to the reconstruction of SXR emissivity profiles measured on Tore Supra. The method is compared with the standard algorithm based on minimization of the Fisher information.

  14. Unitary bases for x-ray photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Patterson, C.W.; Harter, W.G.; Schneider, W.D.

    1979-01-01

    A Gelfand basis is used to derive the coefficients of fractional parentage (CFP's) used to calculate intensities for x-ray photoelectron spectroscopy of atoms. Using associated Gelfand bases, we show that it is easy to derive the Racah CFP relations between particles and holes

  15. A bromine-based dichroic X-ray polarization analyser

    CERN Document Server

    Collins, S P; Brown, S D; Thompson, P

    2001-01-01

    We have demonstrated the advantages offered by dichroic X-ray polarization filters for linear polarization analysis, and describe such a device, based on a dibromoalkane/urea inclusion compound. The polarizer has been successfully tested by analysing the polarization of magnetic diffraction from holmium.

  16. X-Ray Micro-Tomography Applied to Nasa's Materials Research: Heat Shields, Parachutes and Asteroids

    Science.gov (United States)

    Panerai, Francesco; Borner, Arnaud; Ferguson, Joseph C.; Mansour, Nagi N.; Stern, Eric C.; Barnard, Harold S.; Macdowell, Alastair A.; Parkinson, Dilworth Y.

    2017-01-01

    X-ray micro-tomography is used to support the research on materials carried out at NASA Ames Research Center. The technique is applied to a variety of applications, including the ability to characterize heat shield materials for planetary entry, to study the Earth- impacting asteroids, and to improve broadcloths of spacecraft parachutes. From micro-tomography images, relevant morphological and transport properties are determined and validated against experimental data.

  17. High resolution X-ray tomography for stationary multiphase flows

    International Nuclear Information System (INIS)

    Schmitz, D.; Reinecke, N.; Petritsch, G.; Mewes, D.

    1998-01-01

    The high resolution which can be obtained by computer assisted tomography is used to investigate the liquid distribution and void fraction in random and structured packing. With a spatial resolution of 0.4x0.4mm 2 it is possible even to detect thin liquid films on structured packings. The experimental set-up consists of a custom-built second generation tomograph. The imaged object consists of a column filled with either a random ceramic packing of spheres or a structured metal packing. The liquid and void fraction distribution in random and structured packings with a quiescent gaseous phase is visualized. The water/air system is used. The liquid distributor consists of a perforated plate. The experimental hold-up values averaged over the column cross-section are in good agreement with empirical equations. (author)

  18. Optimization of soft X-ray tomography on the COMPASS tokamak

    Czech Academy of Sciences Publication Activity Database

    Imríšek, Martin; Mlynář, Jan; Löffelmann, Viktor; Weinzettl, Vladimír; Odstrčil, T.; Odstrčil, M.; Tomeš, Matěj

    2016-01-01

    Roč. 61, č. 4 (2016), s. 403-408 ISSN 0029-5922. [Summer School of Plasma Diagnostics PhDiaFusion 2015: “Soft X-ray Diagnostics for Fusion Plasma”. Bezmiechowa, 16.06.2015-20.06.2015] R&D Projects: GA MŠk(CZ) LM2011021; GA MŠk LG14002; GA MŠk(CZ) 8D15001 EU Projects: European Commission(XE) 633053 - EUROfusion Institutional support: RVO:61389021 Keywords : soft X-ray * tomography * Tikhonov regularization * tokamak Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.760, year: 2016 http://www.ichtj.waw.pl/nukleonikaa/?p=1256

  19. Analyser-based x-ray imaging for biomedical research

    International Nuclear Information System (INIS)

    Suortti, Pekka; Keyriläinen, Jani; Thomlinson, William

    2013-01-01

    Analyser-based imaging (ABI) is one of the several phase-contrast x-ray imaging techniques being pursued at synchrotron radiation facilities. With advancements in compact source technology, there is a possibility that ABI will become a clinical imaging modality. This paper presents the history of ABI as it has developed from its laboratory source to synchrotron imaging. The fundamental physics of phase-contrast imaging is presented both in a general sense and specifically for ABI. The technology is dependent on the use of perfect crystal monochromator optics. The theory of the x-ray optics is developed and presented in a way that will allow optimization of the imaging for specific biomedical systems. The advancement of analytical algorithms to produce separate images of the sample absorption, refraction angle map and small-angle x-ray scattering is detailed. Several detailed applications to biomedical imaging are presented to illustrate the broad range of systems and body sites studied preclinically to date: breast, cartilage and bone, soft tissue and organs. Ultimately, the application of ABI in clinical imaging will depend partly on the availability of compact sources with sufficient x-ray intensity comparable with that of the current synchrotron environment. (paper)

  20. OBSERVATIONS ON THE PERFORMANCE OF X-RAY COMPUTED TOMOGRAPHY FOR DIMENSIONAL METROLOGY

    Directory of Open Access Journals (Sweden)

    H. C. Corcoran

    2016-06-01

    Full Text Available X-ray computed tomography (XCT is a rising technology within many industries and sectors with a demand for dimensional metrology, defect, void analysis and reverse engineering. There are many variables that can affect the dimensional metrology of objects imaged using XCT, this paper focusses on the effects of beam hardening due to the orientation of the workpiece, in this case a holeplate, and the volume of material the X-rays travel through. Measurements discussed include unidirectional and bidirectional dimensions, radii of cylinders, fit point deviations of the fitted shapes and cylindricity. Results indicate that accuracy and precision of these dimensional measurements are affected in varying amounts, both by the amount of material the X-rays have travelled through and the orientation of the object.

  1. Observations on the Performance of X-Ray Computed Tomography for Dimensional Metrology

    Science.gov (United States)

    Corcoran, H. C.; Brown, S. B.; Robson, S.; Speller, R. D.; McCarthy, M. B.

    2016-06-01

    X-ray computed tomography (XCT) is a rising technology within many industries and sectors with a demand for dimensional metrology, defect, void analysis and reverse engineering. There are many variables that can affect the dimensional metrology of objects imaged using XCT, this paper focusses on the effects of beam hardening due to the orientation of the workpiece, in this case a holeplate, and the volume of material the X-rays travel through. Measurements discussed include unidirectional and bidirectional dimensions, radii of cylinders, fit point deviations of the fitted shapes and cylindricity. Results indicate that accuracy and precision of these dimensional measurements are affected in varying amounts, both by the amount of material the X-rays have travelled through and the orientation of the object.

  2. Generalized algorithm for X-ray projections generation in cone-beam tomography

    International Nuclear Information System (INIS)

    Qin Zhongyuan; Mu Xuanqin; Wang Ping; Cai Yuanlong; Hou Chuanjian

    2002-01-01

    In order to get rid of random factors in the measurement so as to support proceeding 3D reconstruction, a general approach is presented to obtain the X-ray projections in cone-beam tomography. The phantom is firstly discretized into cubic volume through inverse transformation then a generalized projection procedure is proposed to the digitized result without concerning what the phantom exactly is. In the second step, line integrals are calculated to obtain the projection of each X-ray through accumulation of tri-linear interpolation. Considering projection angles, a rotation matrix is proposed to the X-ray source and the detector plane so projections in arbitrary angles can be got. In this approach the algorithm is easy to be extended and irregular objects can also be processed. The algorithm is implemented in Visual C++ and experiments are done using different models. Satisfactory results are obtained. It makes good preparation for the proceeding reconstruction

  3. Imaging osteoarthritis in the knee joints using x-ray guided diffuse optical tomography

    Science.gov (United States)

    Zhang, Qizhi; Yuan, Zhen; Sobel, Eric S.; Jiang, Huabei

    2010-02-01

    In our previous studies, near-infrared (NIR) diffuse optical tomography (DOT) had been successfully applied to imaging osteoarthritis (OA) in the finger joints where significant difference in optical properties of the joint tissues was evident between healthy and OA finger joints. Here we report for the first time that large joints such as the knee can also be optically imaged especially when DOT is combined with x-ray tomosynthesis where the 3D image of the bones from x-ray is incorporated into the DOT reconstruction as spatial a priori structural information. This study demonstrates that NIR light can image large joints such as the knee in addition to finger joints, which will drastically broaden the clinical utility of our x-ray guided DOT technique for OA diagnosis.

  4. Eigenvector decomposition of full-spectrum x-ray computed tomography.

    Science.gov (United States)

    Gonzales, Brian J; Lalush, David S

    2012-03-07

    Energy-discriminated x-ray computed tomography (CT) data were projected onto a set of basis functions to suppress the noise in filtered back-projection (FBP) reconstructions. The x-ray CT data were acquired using a novel x-ray system which incorporated a single-pixel photon-counting x-ray detector to measure the x-ray spectrum for each projection ray. A matrix of the spectral response of different materials was decomposed using eigenvalue decomposition to form the basis functions. Projection of FBP onto basis functions created a de facto image segmentation of multiple contrast agents. Final reconstructions showed significant noise suppression while preserving important energy-axis data. The noise suppression was demonstrated by a marked improvement in the signal-to-noise ratio (SNR) along the energy axis for multiple regions of interest in the reconstructed images. Basis functions used on a more coarsely sampled energy axis still showed an improved SNR. We conclude that the noise-resolution trade off along the energy axis was significantly improved using the eigenvalue decomposition basis functions.

  5. X-ray micro-tomography for investigations of brain tissues on cellular level

    Science.gov (United States)

    Khimchenko, Anna; Schulz, Georg; Deyhle, Hans; Thalmann, Peter; Zanette, Irene; Zdora, Marie-Christine; Bikis, Christos; Hipp, Alexander; Hieber, Simone E.; Schweighauser, Gabriel; Hench, Jürgen; Müller, Bert

    2016-10-01

    X-ray imaging in absorption contrast mode is well established for hard tissue visualization. However, performance for lower density materials is limited due to a reduced contrast. Our aim is three-dimensional (3D) characterization of micro-morphology of human brain tissues down to (sub-)cellular resolution within a laboratory environment. Using the laboratory-based microtomography (μCT) system nanotom m (GE Sensing and Inspection Technologies GmbH, Wunstorf, Germany) and synchrotron radiation at the Diamond-Manchester Imaging Branchline I13-2 (Diamond Light Source, Didcot, UK), we have acquired 3D data with a resolution down to 0.45 μm for visualization of a human cerebellum specimen down to cellular level. We have shown that all selected modalities, namely laboratory-based absorption contrast micro-tomography (LBμCT), synchrotron radiation based in-line single distance phase contrast tomography (SDPR) and synchrotron radiation based single-grating interferometry (GI), can reach cellular resolution for tissue samples with a size in the mm-range. The results are discussed qualitatively in comparison to optical microscopy of haematoxylin and eosin (HE) stained sections. As phase contrast yields to a better data quality for soft tissues and in order to overcome restrictions of limited beamline access for phase contrast measurements, we have equipped the μCT system nanotom m with a double-grating phase contrast set-up. Preliminary experimental results of a knee sample consisting of a bony part and a cartilage demonstrate that phase contrast data exhibits better quality compared to absorption contrast. Currently, the set-up is under adjustment. It is expected that cellular resolution would also be achieved. The questions arise (1) what would be the quality gain of laboratory-based phase contrast in comparison to laboratory-based absorption contrast tomography and (2) could laboratory-based phase contrast data provide comparable results to synchrotron radiation based

  6. Dose fractionation in synchrotron radiation x-ray phase micro-tomography

    International Nuclear Information System (INIS)

    Frachon, Thibaut; Weber, Loriane; Hesse, Bernhard; Rit, Simon; Dong, Pei; Olivier, Cecile; Peyrin, Françoise; Langer, Max

    2015-01-01

    Phase sensitive x-ray imaging expands the applicability of standard attenuation based techniques by offering several orders of magnitude of increase in sensitivity. Due to the short wavelength, x-ray phase is not directly measurable, but has to be put in evidence by the use of phase contrast techniques. The phase can then be reconstructed from one or several phase contrast images. In this study, we consider synchrotron x-ray phase micro-computed tomography (μCT) based on free space propagation for heterogeneous and strongly absorbing objects. This technique generally relies on acquiring several scans of the sample at different detector distances. It is also generally believed that multi-distance phase μCT needs a higher dose input than single distance phase μCT. The purpose of this work is to study the impact of different means of dose fractionation on the reconstructed image quality. We define different acquistion schemes in multi-distance in-line phase μCT. Previously, the exposure time at each sample-to-detector distance was usually kept the same. Here, we let not only the number of distances vary but also the fraction of exposure time at each distance, the total exposure time being kept constant. Phase retrieval is performed with the mixed approach algorithm. The reconstructed μCT images are compared in terms of accuracy, precision and resolution. In addition, we also compare the result of dose fractionated multi distance phase μCT to single distance phase μCT using the same total radiation dose. In the multi-distance approach, we find that using different exposure times on each distance improves the image quality in the reconstructed image. Further, we show that, despite having the same total dose delivery, the multi distance imaging method gives better image quality than the single distance method, at the cost of an additional overhead from camera displacements and reference images. We show that by optimizing the acquistion parameters in terms of

  7. Compositional Determination of Shale with Simultaneous Neutron and X-ray Tomography

    Science.gov (United States)

    LaManna, J.; Hussey, D. S.; Baltic, E.; Jacobson, D. L.

    2017-12-01

    Understanding the distribution of organic material, mineral inclusions, and porosity are critical to properly model the flow of fluids through rock formations in applications ranging from hydraulic fracturing and gas extraction, CO2 sequestration, geothermal power, and aquifer management. Typically, this information is obtained on the pore scale using destructive techniques such as focused ion beam scanning electron microscopy. Neutrons and X-rays provide non-destructive, complementary probes to gain three-dimensional distributions of porosity, minerals, and organic content along with fluid interactions in fractures and pore networks on the core scale. By capturing both neutron and X-ray tomography simultaneously it is possible to capture slowly dynamic or stochastic processes with both imaging modes. To facilitate this, NIST offers a system for simultaneous neutron and X-ray tomography at the Center for Neutron Research. This instrument provides neutron and X-ray beams capable of penetrating through pressure vessels to image the specimen inside at relevant geological conditions at resolutions ranging from 15 micrometers to 100 micrometers. This talk will discuss current efforts at identifying mineral and organic content and fracture and wettability in shales relevant to gas extraction.

  8. An Intraoral Miniature X-ray Tube Based on Carbon Nanotubes for Dental Radiography

    OpenAIRE

    Hyun Jin Kim; Hyun Nam Kim; Hamid Saeed Raza; Han Beom Park; Sung Oh Cho

    2016-01-01

    A miniature X-ray tube based on a carbon-nanotube electron emitter has been employed for the application to a dental radiography. The miniature X-ray tube has an outer diameter of 7 mm and a length of 47 mm. The miniature X-ray tube is operated in a negative high-voltage mode in which the X-ray target is electrically grounded. In addition, X-rays are generated only to the teeth directions using a collimator while X-rays generated to other directions are shielded. Hence, the X-ray tube can be ...

  9. Quantitative reconstruction of PIXE-tomography data for thin samples using GUPIX X-ray emission yields

    Energy Technology Data Exchange (ETDEWEB)

    Michelet, C., E-mail: michelet@cenbg.in2p3.fr [Univ. Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Barberet, Ph., E-mail: barberet@cenbg.in2p3.fr [Univ. Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Devès, G., E-mail: deves@cenbg.in2p3.fr [Univ. Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Bouguelmouna, B., E-mail: bbouguel@gmail.com [Univ. Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Bourret, S., E-mail: bourret@cenbg.in2p3.fr [Univ. Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Delville, M.-H., E-mail: delville@icmcb-bordeaux.cnrs.fr [Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB, UPR9048) CNRS, Université de Bordeaux, 87 avenue du Dr. A. Schweitzer, Pessac F-33608 (France); Le Trequesser, Q., E-mail: letreque@cenbg.in2p3.fr [Univ. Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB, UPR9048) CNRS, Université de Bordeaux, 87 avenue du Dr. A. Schweitzer, Pessac F-33608 (France); Gordillo, N., E-mail: nuri.gordillo@gmail.com [Univ. Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Beasley, D.G., E-mail: d.beasley@ucl.ac.uk [Center of Medical Imaging Computing (CMIC), Department of Medical Physics & Bioengineering, University College London, Gower Street, London WC1E 6BT (United Kingdom); and others

    2015-04-01

    We present here a new development of the TomoRebuild software package, to perform quantitative Particle Induced X-ray Emission Tomography (PIXET) reconstruction. X-ray yields are obtained from the GUPIX code. The GUPIX data base is available for protons up to 5 MeV and also in the 20–100 MeV energy range, deuterons up to 6 MeV, {sup 3}He and alphas up to 12 MeV. In this version, X-ray yields are calculated for thin samples, i.e. without simulating X-ray attenuation. PIXET data reconstruction is kept as long as possible independent from Scanning Transmission Ion Microscopy Tomography (STIMT). In this way, the local mass distribution (in g/cm{sup 3}) of each X-ray emitting element is reconstructed in all voxels of the analyzed volume, only from PIXET data, without the need of associated STIMT data. Only the very last step of data analysis requires STIMT data, in order to normalize PIXET data to obtain concentration distributions, in terms of normalized mass fractions (in μg/g). For this, a noise correction procedure has been designed in ImageJ. Moreover sinogram or image misalignment can be corrected, as well as the difference in beam size between the two experiments. The main features of the TomoRebuild code, user friendly design and modular C++ implementation, were kept. The software package is portable and can run on Windows and Linux operating systems. An optional user-friendly graphic interface was designed in Java, as a plugin for the ImageJ graphic software package. Reconstruction examples are presented from biological specimens of Caenorhabditis elegans – a small nematode constituting a reference model for biology studies. The reconstruction results are compared between the different codes TomoRebuild, DISRA and JPIXET, and different reconstruction methods: Filtered BackProjection (FBP) and Maximum Likelihood Expectation Maximization (MLEM)

  10. 3-D growth of a short fatigue crack within a polycrystalline microstructure studied using combined diffraction and phase-contrast X-ray tomography

    DEFF Research Database (Denmark)

    Herbig, M.; King, Andrew; Reischig, Peter

    2011-01-01

    X-ray diffraction contrast tomography is a recently developed, non-destructive synchrotron imaging technique which characterizes microstructure and grain orientation in polycrystalline materials in three dimensions. By combining it with propagation-based phase-contrast tomography it is possible t...

  11. Characterization of porosity in a 19th century painting ground by synchrotron radiation X-ray tomography

    Energy Technology Data Exchange (ETDEWEB)

    Gervais, Claire [Swiss Institute for Art Research (SIK-ISEA), Zuerich (Switzerland); Bern University of the Arts, Bern (Switzerland); Boon, Jaap J. [Swiss Institute for Art Research (SIK-ISEA), Zuerich (Switzerland); JAAP Enterprise for MOLART Advice, Amsterdam (Netherlands); Marone, Federica [Paul Scherrer Institute, Swiss Light Source (SLS), Villigen (Switzerland); Ferreira, Ester S.B. [Swiss Institute for Art Research (SIK-ISEA), Zuerich (Switzerland)

    2013-04-15

    The study of the early oeuvre of the Swiss painter Cuno Amiet (1868-1961) has revealed that, up to 1907, many of his grounds were hand applied and are mainly composed of chalk, bound in protein. These grounds are not only lean and absorbent, but also, as Synchrotron radiation X-ray microtomography has shown, porous. Our approach to the characterization of pore structure and quantity, their connectivity, and homogeneity is based on image segmentation and application of a clustering algorithm to high-resolution X-ray tomographic data. The issues associated with the segmentation of the different components of a ground sample based on X-ray imaging data are discussed. The approach applied to a sample taken from ''Portrait of Max Leu'' (1899) by Amiet revealed the presence of three sublayers within the ground with distinct porosity features, which had not been observed optically in cross-section. The upper and lower layers are highly porous with important connectivity and thus prone to water uptake/storage. The middle layer however shows low and nonconnected porosity at the resolution level of the X-ray tomography images, so that few direct water absorption paths through the entire sample exist. The potential of the method to characterize porosity and to understand moisture-related issues in paint layer degradation are discussed. (orig.)

  12. Characterization of porosity in a 19th century painting ground by synchrotron radiation X-ray tomography

    International Nuclear Information System (INIS)

    Gervais, Claire; Boon, Jaap J.; Marone, Federica; Ferreira, Ester S.B.

    2013-01-01

    The study of the early oeuvre of the Swiss painter Cuno Amiet (1868-1961) has revealed that, up to 1907, many of his grounds were hand applied and are mainly composed of chalk, bound in protein. These grounds are not only lean and absorbent, but also, as Synchrotron radiation X-ray microtomography has shown, porous. Our approach to the characterization of pore structure and quantity, their connectivity, and homogeneity is based on image segmentation and application of a clustering algorithm to high-resolution X-ray tomographic data. The issues associated with the segmentation of the different components of a ground sample based on X-ray imaging data are discussed. The approach applied to a sample taken from ''Portrait of Max Leu'' (1899) by Amiet revealed the presence of three sublayers within the ground with distinct porosity features, which had not been observed optically in cross-section. The upper and lower layers are highly porous with important connectivity and thus prone to water uptake/storage. The middle layer however shows low and nonconnected porosity at the resolution level of the X-ray tomography images, so that few direct water absorption paths through the entire sample exist. The potential of the method to characterize porosity and to understand moisture-related issues in paint layer degradation are discussed. (orig.)

  13. Ex-situ X-ray tomography characterization of porosity during high-temperature creep in a Ni-based single-crystal superalloy: Toward understanding what is damage

    Energy Technology Data Exchange (ETDEWEB)

    Graverend, Jean-Briac le, E-mail: jblgpublications@gmail.com [Texas A& M University, Department of Aerospace Engineering and Materials Science Engineering, TAMU 3141, College Station, TX 77843 (United States); Adrien, Jérome [Université de Lyon, INSA-Lyon, MATEIS CNRS UMR5510, F-69621 Villeurbanne (France); Cormier, Jonathan [Institut Pprime, CNRS-ENSMA-Université de Poitiers, UPR CNRS 3346, Département Physique et Mécanique des Matériaux, ISAE-ENSMA, 1 avenue Clément Ader, BP 40109, F86961 Futuroscope Chasseneuil cedex (France)

    2017-05-17

    Creep damage by void nucleation and growth limits the lifetime of components subjected to mechanical loads at high temperatures. For the first time, the porosity of a Ni-based single crystal superalloy subjected to high temperature creep tests (T≥1000 °C) is followed by ex-situ X-ray computed tomography. A large experimental campaign consisting of nine temperature/stress conditions is carried out to determine the kinetics of the damage accumulation by voids. It is, indeed, essential to characterize their evolution to create internal variables describing properly the evolution of damage in a Continuum Damage Mechanics framework. Nonetheless, it is pointed out that the increase in the plastic strain rate during the tertiary creep stage is not necessarily related to the increase in the pore volume fraction for the alloy and temperature range explored (1000–1100 °C). Therefore, it seems that the changes in the microstructure, i.e. precipitation coarsening and γ/γ′ topological inversion, and the shearing of the γ′ particles have to be considered further to properly describe the damage evolution. Thus, the Continuum Damage Mechanics theory is undermined and should be replaced by a transformative paradigm taken into consideration microstructural evolutions in order to improve the predictability of further damage models.

  14. Bayesian soft x-ray tomography and MHD mode analysis on HL-2A

    Science.gov (United States)

    Li, Dong; Liu, Yi; Svensson, J.; Liu, Y. Q.; Song, X. M.; Yu, L. M.; Mao, Rui; Fu, B. Z.; Deng, Wei; Yuan, B. S.; Ji, X. Q.; Xu, Yuan; Chen, Wei; Zhou, Yan; Yang, Q. W.; Duan, X. R.; Liu, Yong; HL-2A Team

    2016-03-01

    A Bayesian based tomography method using so-called Gaussian processes (GPs) for the emission model has been applied to the soft x-ray (SXR) diagnostics on HL-2A tokamak. To improve the accuracy of reconstructions, the standard GP is extended to a non-stationary version so that different smoothness between the plasma center and the edge can be taken into account in the algorithm. The uncertainty in the reconstruction arising from measurement errors and incapability can be fully analyzed by the usage of Bayesian probability theory. In this work, the SXR reconstructions by this non-stationary Gaussian processes tomography (NSGPT) method have been compared with the equilibrium magnetic flux surfaces, generally achieving a satisfactory agreement in terms of both shape and position. In addition, singular-value-decomposition (SVD) and Fast Fourier Transform (FFT) techniques have been applied for the analysis of SXR and magnetic diagnostics, in order to explore the spatial and temporal features of the saturated long-lived magnetohydrodynamics (MHD) instability induced by energetic particles during neutral beam injection (NBI) on HL-2A. The result shows that this ideal internal kink instability has a dominant m/n  =  1/1 mode structure along with a harmonics m/n  =  2/2, which are coupled near the q  =  1 surface with a rotation frequency of 12 kHz.

  15. Cone beam x-ray luminescence computed tomography: a feasibility study.

    Science.gov (United States)

    Chen, Dongmei; Zhu, Shouping; Yi, Huangjian; Zhang, Xianghan; Chen, Duofang; Liang, Jimin; Tian, Jie

    2013-03-01

    The appearance of x-ray luminescence computed tomography (XLCT) opens new possibilities to perform molecular imaging by x ray. In the previous XLCT system, the sample was irradiated by a sequence of narrow x-ray beams and the x-ray luminescence was measured by a highly sensitive charge coupled device (CCD) camera. This resulted in a relatively long sampling time and relatively low utilization of the x-ray beam. In this paper, a novel cone beam x-ray luminescence computed tomography strategy is proposed, which can fully utilize the x-ray dose and shorten the scanning time. The imaging model and reconstruction method are described. The validity of the imaging strategy has been studied in this paper. In the cone beam XLCT system, the cone beam x ray was adopted to illuminate the sample and a highly sensitive CCD camera was utilized to acquire luminescent photons emitted from the sample. Photons scattering in biological tissues makes it an ill-posed problem to reconstruct the 3D distribution of the x-ray luminescent sample in the cone beam XLCT. In order to overcome this issue, the authors used the diffusion approximation model to describe the photon propagation in tissues, and employed the sparse regularization method for reconstruction. An incomplete variables truncated conjugate gradient method and permissible region strategy were used for reconstruction. Meanwhile, traditional x-ray CT imaging could also be performed in this system. The x-ray attenuation effect has been considered in their imaging model, which is helpful in improving the reconstruction accuracy. First, simulation experiments with cylinder phantoms were carried out to illustrate the validity of the proposed compensated method. The experimental results showed that the location error of the compensated algorithm was smaller than that of the uncompensated method. The permissible region strategy was applied and reduced the reconstruction error to less than 2 mm. The robustness and stability were then

  16. Performances for confocal X-ray diffraction technology based on polycapillary slightly focusing X-ray optics

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hehe; Liu, Zhiguo [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Sun, Tianxi, E-mail: stxbeijing@163.com [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Peng, Song [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Ma, Yongzhong [Center for Disease Control and Prevention of Beijing, Beijing 100013 (China); Sun, Weiyuan; Li, Yude; Lin, Xiaoyan; Zhao, Weigang; Zhao, Guangcui; Luo, Ping; Pan, Qiuli; Ding, Xunliang [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China)

    2013-09-21

    The confocal X-ray diffraction (XRD) technology based on a polycapillary slightly focusing X-ray lens (PSFXRL) in excitation channel and a polycapillary parallel X-ray lens (PPXRL) with a long input focal distance in detection channel was developed. The output focal spot of the PSFXRL and the input focal spot of the PPXRL were adjusted in confocal configuration, and only the X-rays from the volume overlapped by these foci could be accordingly detected. This confocal configuration was helpful in decreasing background. The convergence of the beam focused by the PSFXRL and divergence of the beam which could be collected by the PPXRL with a long input focal distance were both about 9 mrad at 8 keV. This was helpful in improving the resolution of lattice spacing of this confocal XRD technology. The gain in power density of such PSFXRL and PPXRL was about 120 and 7 at 11 keV, respectively, which was helpful in using the low power source to perform XRD analysis efficiently. The performances of this confocal XRD technology were provided, and some common plastics were analyzed. The experimental results demonstrated that the confocal diffraction technology base on polycapillary slightly focusing X-ray optics had wide potential applications.

  17. X-ray and neutron tomography on the bony inner ear of baleen whales

    International Nuclear Information System (INIS)

    Arlt, Tobias; Wieder, Frank; Hampe, Oliver; Manke, Ingo; Ritsche, Indira; Fahlke, Julia M.

    2018-01-01

    During their evolution whales and dolphins developed a highly specialized hearing organ for orientation in their deep sea territory covering a broad acoustic spectrum. The internal anatomy of the periotic bone, especially the morphology of the cochlea, has a significant influence on the hearing capability of mammals. The bony and fossilized cochleae of several fossil representatives of extinct baleen whales (e.g., Cetotheriidae) and modern rorquals (Balaenopteridae) and right whales, as well as cochleae of an archaeocete and some land mammals are investigated by X-ray and neutron tomography in order to record morphological changes that may be responsible for the development of low frequency hearing. Differences in the cochlear morphology have been determined by means of morphometric parameters, such as the number of turns, the length of the cochlea, and the curvature of the cochlear canal. In particular, X-ray tomography enables a high resolution display of the bony inner ear.

  18. Thermal characterisation of ceramic/metal joining techniques for fusion applications using X-ray tomography

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Ll.M., E-mail: llion.evans@ccfe.ac.uk [School of Materials, University of Manchester, Grosvenor Street, Manchester M1 7HS (United Kingdom); Margetts, L. [School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Williamson Building, Manchester M13 9PL (United Kingdom); Casalegno, V. [Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, I-10129 Torino (Italy); Leonard, F.; Lowe, T.; Lee, P.D. [School of Materials, University of Manchester, Grosvenor Street, Manchester M1 7HS (United Kingdom); Schmidt, M.; Mummery, P.M. [School of Mechanical, Aerospace and Civil Engineering (MACE), University of Manchester, Manchester M13 9PL (United Kingdom)

    2014-06-15

    This work investigates the thermal performance of four novel CFC–Cu joining techniques. Two involve direct casting and brazing of Cu onto a chromium modified CFC surface, the other two pre-coat a brazing alloy with chromium using galvanisation and sputtering processes. The chromium carbide layer at the interface has been shown to improve adhesion. Thermal conductivity across the join interface was measured by laser flash analysis. X-ray tomography was performed to investigate micro-structures that might influence the thermal behaviour. It was found that thermal conductivity varied by up to 72%. Quantification of the X-ray tomography data showed that the dominant feature in reducing thermal conductivity was the lateral spread of voids at the interface. Correlations were made to estimate the extent of this effect.

  19. Building lab-scale x-ray tube based irradiators

    International Nuclear Information System (INIS)

    Haff, Ron; Jackson, Eric; Gomez, Joseph; Light, Doug; Follett, Peter; Simmons, Greg; Higbee, Brad

    2016-01-01

    Here we report the use of x-ray tube based irradiators as alternatives to gamma sources for laboratory scale irradiation. Irradiators were designed with sample placement in closest possible proximity to the source, allowing high dose rates for small samples. Designs using 1000 W x-ray tubes in single tube, double tube, and four tube configurations are described, as well as various cabinet construction techniques. Relatively high dose rates were achieved for small samples, demonstrating feasibility for laboratory based irradiators for research purposes. Dose rates of 9.76, 5.45, and 1.7 Gy/min/tube were measured at the center of a 12.7 cm container of instant rice at 100 keV, 70 keV, and 40 keV, respectively. Dose uniformity varies dramatically as the distance from source to container. For 2.54 cm diameter sample containers containing adult Navel Orangeworm, dose rates of 50–60 Gy/min were measured in the four tube system. - Highlights: • X-ray is demonstrated as an alternative to gamma for lab-based irradiation. • Cabinets using one, two, and four 1000 W tubes are reported. • Dose rate of 9.8 Gy/min/tube at the center of a 12.7 cm container of instant rice. • Dose uniformity varies dramatically as the distance from source to container.

  20. Characterization of breast tissue using energy-dispersive X-ray diffraction computed tomography

    International Nuclear Information System (INIS)

    Pani, S.; Cook, E.J.; Horrocks, J.A.; Jones, J.L.; Speller, R.D.

    2010-01-01

    A method for sample characterization using energy-dispersive X-ray diffraction computed tomography (EDXRDCT) is presented. The procedures for extracting diffraction patterns from the data and the corrections applied are discussed. The procedures were applied to the characterization of breast tissue samples, 6 mm in diameter. Comparison with histological sections of the samples confirmed the possibility of grouping the patterns into five families, corresponding to adipose tissue, fibrosis, poorly differentiated cancer, well differentiated cancer and benign tumour.

  1. An X-Ray computed tomography/positron emission tomography system designed specifically for breast imaging.

    Science.gov (United States)

    Boone, John M; Yang, Kai; Burkett, George W; Packard, Nathan J; Huang, Shih-ying; Bowen, Spencer; Badawi, Ramsey D; Lindfors, Karen K

    2010-02-01

    Mammography has served the population of women who are at-risk for breast cancer well over the past 30 years. While mammography has undergone a number of changes as digital detector technology has advanced, other modalities such as computed tomography have experienced technological sophistication over this same time frame as well. The advent of large field of view flat panel detector systems enable the development of breast CT and several other niche CT applications, which rely on cone beam geometry. The breast, it turns out, is well suited to cone beam CT imaging because the lack of bones reduces artifacts, and the natural tapering of the breast anteriorly reduces the x-ray path lengths through the breast at large cone angle, reducing cone beam artifacts as well. We are in the process of designing a third prototype system which will enable the use of breast CT for image guided interventional procedures. This system will have several copies fabricated so that several breast CT scanners can be used in a multi-institutional clinical trial to better understand the role that this technology can bring to breast imaging.

  2. Cone-beam X-ray phase-contrast tomography for the observation of single cells in whole organs

    International Nuclear Information System (INIS)

    Krenkel, Martin

    2015-01-01

    X-ray imaging enables the nondestructive investigation of interior structures in otherwise opaque samples. In particular the use of computed tomography (CT) allows for arbitrary virtual slices through the object and 3D information about intricate structures can be obtained. However, when it comes to image very small structures like single cells, the classical CT approach is limited by the weak absorption of soft-tissue. The use of phase information, encoded in measureable intensity images by free-space propagation of coherent X-rays, allows a huge increase in contrast, which enables 3D reconstructions at higher resolutions. In this work the application of propagation-based phase-contrast tomography to lung tissue samples is demonstrated in close to in vivo conditions. Reconstructions of the lung structure of whole mice at down to 5 µm resolution are obtained at a selfbuilt CT setup, which is based on a liquid-metal jet X-ray source. To reach even higher resolutions, synchrotron radiation in combination with suitable holographic phase-retrieval algorithms is employed. Due to optimized cone-beam geometry, field of view and resolution can be varied over a wide range of parameters, so that information on different length scales can be achieved, covering several millimeters field of view down to a 3D resolution of 50 nm. Thus, the sub-cellular 3D imaging of single cells embedded in large pieces of tissue is enabled, which paves the way for future biomedical research.

  3. Compact X-ray source based on Compton backscattering

    CERN Document Server

    Bulyak, E V; Zelinsky, A; Karnaukhov, I; Kononenko, S; Lapshin, V G; Mytsykov, A; Telegin, Yu P; Khodyachikh, A; Shcherbakov, A; Molodkin, V; Nemoshkalenko, V; Shpak, A

    2002-01-01

    The feasibility study of an intense X-ray source based on the interaction between the electron beam in a compact storage ring and the laser pulse accumulated in an optical resonator is carried out. We propose to reconstruct the 160 MeV electron storage ring N-100, which was shutdown several years ago. A new magnetic lattice will provide a transverse of electron beam size of approx 35 mu m at the point of electron beam-laser beam interaction. The proposed facility is to generate X-ray beams of intensity approx 2.6x10 sup 1 sup 4 s sup - sup 1 and spectral brightness approx 10 sup 1 sup 2 phot/0.1%bw/s/mm sup 2 /mrad sup 2 in the energy range from 10 keV up to 0.5 MeV. These X-ray beam parameters meet the requirements for most of technological and scientific applications. Besides, we plan to use the new facility for studying the laser cooling effect.

  4. Compact X-ray source based on Compton backscattering

    Energy Technology Data Exchange (ETDEWEB)

    Bulyak, E.; Gladkikh, P.; Zelinsky, A. E-mail: zelinsky@kipt.kharkov.ua; Karnaukhov, I.; Kononenko, S.; Lapshin, V.; Mytsykov, A.; Telegin, Yu.; Khodyachikh, A.; Shcherbakov, A.; Molodkin, V.; Nemoshkalenko, V.; Shpak, A

    2002-07-21

    The feasibility study of an intense X-ray source based on the interaction between the electron beam in a compact storage ring and the laser pulse accumulated in an optical resonator is carried out. We propose to reconstruct the 160 MeV electron storage ring N-100, which was shutdown several years ago. A new magnetic lattice will provide a transverse of electron beam size of {approx}35 {mu}m at the point of electron beam-laser beam interaction. The proposed facility is to generate X-ray beams of intensity {approx}2.6x10{sup 14} s{sup -1} and spectral brightness {approx}10{sup 12} phot/0.1%bw/s/mm{sup 2}/mrad{sup 2} in the energy range from 10 keV up to 0.5 MeV. These X-ray beam parameters meet the requirements for most of technological and scientific applications. Besides, we plan to use the new facility for studying the laser cooling effect.

  5. Introducing minimum Fisher regularisation tomography to AXUV and soft x-ray diagnostic systems of the COMPASS tokamak

    International Nuclear Information System (INIS)

    Mlynar, J.; Weinzettl, V.; Imrisek, M.; Odstrcil, M.; Havlicek, J.; Janky, F.; Alper, B.; Murari, A.

    2012-01-01

    The contribution focuses on plasma tomography via the minimum Fisher regularisation (MFR) algorithm applied on data from the recently commissioned tomographic diagnostics on the COMPASS tokamak. The MFR expertise is based on previous applications at Joint European Torus (JET), as exemplified in a new case study of the plasma position analyses based on JET soft x-ray (SXR) tomographic reconstruction. Subsequent application of the MFR algorithm on COMPASS data from cameras with absolute extreme ultraviolet (AXUV) photodiodes disclosed a peaked radiating region near the limiter. Moreover, its time evolution indicates transient plasma edge cooling following a radial plasma shift. In the SXR data, MFR demonstrated that a high resolution plasma positioning independent of the magnetic diagnostics would be possible provided that a proper calibration of the cameras on an x-ray source is undertaken.

  6. Incoherent-scatter computed tomography with monochromatic synchrotron x ray: feasibility of multi-CT imaging system for simultaneous measurement-of fluorescent and incoherent scatter x rays

    Science.gov (United States)

    Yuasa, T.; Akiba, M.; Takeda, T.; Kazama, M.; Hoshino, A.; Watanabe, Y.; Hyodo, K.; Dilmanian, F. A.; Akatsuka, T.; Itai, Y.

    1997-10-01

    We describe a new system of incoherent scatter computed tomography (ISCT) using monochromatic synchrotron X rays, and we discuss its potential to be used in in vivo imaging for medical use. The system operates on the basis of computed tomography (CT) of the first generation. The reconstruction method for ISCT uses the least squares method with singular value decomposition. The research was carried out at the BLNE-5A bending magnet beam line of the Tristan Accumulation Ring in KEK, Japan. An acrylic cylindrical phantom of 20-mm diameter containing a cross-shaped channel was imaged. The channel was filled with a diluted iodine solution with a concentration of 200 /spl mu/gI/ml. Spectra obtained with the system's high purity germanium (HPGe) detector separated the incoherent X-ray line from the other notable peaks, i.e., the iK/sub /spl alpha// and K/sub /spl beta/1/ X-ray fluorescent lines and the coherent scattering peak. CT images were reconstructed from projections generated by integrating the counts In the energy window centering around the incoherent scattering peak and whose width was approximately 2 keV. The reconstruction routine employed an X-ray attenuation correction algorithm. The resulting image showed more homogeneity than one without the attenuation correction.

  7. Limited-angle x-ray luminescence tomography: methodology and feasibility study

    International Nuclear Information System (INIS)

    Carpenter, C M; Pratx, G; Sun, C; Xing, L

    2011-01-01

    X-ray luminescence tomography (XLT) has recently been proposed as a new imaging modality for biological imaging applications. This modality utilizes phosphor nanoparticles which luminesce near-infrared light when excited by x-ray photons. The advantages of this modality are that it uniquely combines the high sensitivity of radioluminescent nanoparticles and the high spatial localization of collimated x-ray beams. Currently, XLT has been demonstrated using x-ray spatial encoding to resolve the imaging volume. However, there are applications where the x-ray excitation may be limited by geometry, where increased temporal resolution is desired, or where a lower dose is mandatory. This paper extends the utility of XLT to meet these requirements by incorporating a photon propagation model into the reconstruction algorithm in an x-ray limited-angle (LA) geometry. This enables such applications as image-guided surgery, where the ability to resolve lesions at depths of several centimeters can be the key to successful resection. The hybrid x-ray/diffuse optical model is first formulated and then demonstrated in a breast-sized phantom, simulating a breast lumpectomy geometry. Both numerical and experimental phantoms are tested, with lesion-simulating objects of various sizes and depths. Results show localization accuracy with median error of 2.2 mm, or 4% of object depth, for small 2-14 mm diameter lesions positioned from 1 to 4.5 cm in depth. This compares favorably with fluorescence optical imaging, which is not able to resolve such small objects at this depth. The recovered lesion size has lower size bias in the x-ray excitation direction than the optical direction, which is expected due to the increased optical scatter. However, the technique is shown to be quite invariant in recovered size with respect to depth, as the standard deviation is less than 2.5 mm. Sensitivity is a function of dose; radiological doses are found to provide sufficient recovery for μg ml -1

  8. Patient size and x-ray technique factors in head computed tomography examinations. II. Image quality

    International Nuclear Information System (INIS)

    Huda, Walter; Lieberman, Kristin A.; Chang, Jack; Roskopf, Marsha L.

    2004-01-01

    We investigated how patient head characteristics, as well as the choice of x-ray technique factors, affect lesion contrast and noise values in computed tomography (CT) images. Head sizes and mean Hounsfield unit (HU) values were obtained from head CT images for five classes of patients ranging from the newborn to adults. X-ray spectra with tube voltages ranging from 80 to 140 kV were used to compute the average photon energy, and energy fluence, transmitted through the heads of patients of varying size. Image contrast, and the corresponding contrast to noise ratios (CNRs), were determined for lesions of fat, muscle, and iodine relative to a uniform water background. Maintaining a constant image CNR for each lesion, the patient energy imparted was also computed to identify the x-ray tube voltage that minimized the radiation dose. For adults, increasing the tube voltage from 80 to 140 kV changed the iodine HU from 2.62x10 5 to 1.27x10 5 , the fat HU from -138 to -108, and the muscle HU from 37.1 to 33.0. Increasing the x-ray tube voltage from 80 to 140 kV increased the percentage energy fluence transmission by up to a factor of 2. For a fixed x-ray tube voltage, the percentage transmitted energy fluence in adults was more than a factor of 4 lower than for newborns. For adults, increasing the x-ray tube voltage from 80 to 140 kV improved the CNR for muscle lesions by 130%, for fat lesions by a factor of 2, and for iodine lesions by 25%. As the size of the patient increased from newborn to adults, lesion CNR was reduced by about a factor of 2. The mAs value can be reduced by 80% when scanning newborns while maintaining the same lesion CNR as for adults. Maintaining the CNR of an iodine lesion at a constant level, use of 140 kV increases the energy imparted to an adult patient by nearly a factor of 3.5 in comparison to 80 kV. For fat and muscle lesions, raising the x-ray tube voltage from 80 to 140 kV at a constant CNR increased the patient dose by 37% and 7

  9. Image alignment for tomography reconstruction from synchrotron X-ray microscopic images.

    Directory of Open Access Journals (Sweden)

    Chang-Chieh Cheng

    Full Text Available A synchrotron X-ray microscope is a powerful imaging apparatus for taking high-resolution and high-contrast X-ray images of nanoscale objects. A sufficient number of X-ray projection images from different angles is required for constructing 3D volume images of an object. Because a synchrotron light source is immobile, a rotational object holder is required for tomography. At a resolution of 10 nm per pixel, the vibration of the holder caused by rotating the object cannot be disregarded if tomographic images are to be reconstructed accurately. This paper presents a computer method to compensate for the vibration of the rotational holder by aligning neighboring X-ray images. This alignment process involves two steps. The first step is to match the "projected feature points" in the sequence of images. The matched projected feature points in the x-θ plane should form a set of sine-shaped loci. The second step is to fit the loci to a set of sine waves to compute the parameters required for alignment. The experimental results show that the proposed method outperforms two previously proposed methods, Xradia and SPIDER. The developed software system can be downloaded from the URL, http://www.cs.nctu.edu.tw/~chengchc/SCTA or http://goo.gl/s4AMx.

  10. A hyperspectral X-ray computed tomography system for enhanced material identification

    Science.gov (United States)

    Wu, Xiaomei; Wang, Qian; Ma, Jinlei; Zhang, Wei; Li, Po; Fang, Zheng

    2017-08-01

    X-ray computed tomography (CT) can distinguish different materials according to their absorption characteristics. The hyperspectral X-ray CT (HXCT) system proposed in the present work reconstructs each voxel according to its X-ray absorption spectral characteristics. In contrast to a dual-energy or multi-energy CT system, HXCT employs cadmium telluride (CdTe) as the x-ray detector, which provides higher spectral resolution and separate spectral lines according to the material's photon-counter working principle. In this paper, a specimen containing ten different polymer materials randomly arranged was adopted for material identification by HXCT. The filtered back-projection algorithm was applied for image and spectral reconstruction. The first step was to sort the individual material components of the specimen according to their cross-sectional image intensity. The second step was to classify materials with similar intensities according to their reconstructed spectral characteristics. The results demonstrated the feasibility of the proposed material identification process and indicated that the proposed HXCT system has good prospects for a wide range of biomedical and industrial nondestructive testing applications.

  11. Progress in Cell Marking for Synchrotron X-ray Computed Tomography

    Science.gov (United States)

    Hall, Christopher; Sturm, Erica; Schultke, Elisabeth; Arfelli, Fulvia; Menk, Ralf-Hendrik; Astolfo, Alberto; Juurlink, Bernhard H. J.

    2010-07-01

    Recently there has been an increase in research activity into finding ways of marking cells in live animals for pre-clinical trials. Development of certain drugs and other therapies crucially depend on tracking particular cells or cell types in living systems. Therefore cell marking techniques are required which will enable longitudinal studies, where individuals can be examined several times over the course of a therapy or study. The benefits of being able to study both disease and therapy progression in individuals, rather than cohorts are clear. The need for high contrast 3-D imaging, without harming or altering the biological system requires a non-invasive yet penetrating imaging technique. The technique will also have to provide an appropriate spatial and contrast resolution. X-ray computed tomography offers rapid acquisition of 3-D images and is set to become one of the principal imaging techniques in this area. Work by our group over the last few years has shown that marking cells with gold nano-particles (GNP) is an effective means of visualising marked cells in-vivo using x-ray CT. Here we report the latest results from these studies. Synchrotron X-ray CT images of brain lesions in rats taken using the SYRMEP facility at the Elettra synchrotron in 2009 have been compared with histological examination of the tissues. Some deductions are drawn about the visibility of the gold loaded cells in both light microscopy and x-ray imaging.

  12. Image alignment for tomography reconstruction from synchrotron X-ray microscopic images.

    Science.gov (United States)

    Cheng, Chang-Chieh; Chien, Chia-Chi; Chen, Hsiang-Hsin; Hwu, Yeukuang; Ching, Yu-Tai

    2014-01-01

    A synchrotron X-ray microscope is a powerful imaging apparatus for taking high-resolution and high-contrast X-ray images of nanoscale objects. A sufficient number of X-ray projection images from different angles is required for constructing 3D volume images of an object. Because a synchrotron light source is immobile, a rotational object holder is required for tomography. At a resolution of 10 nm per pixel, the vibration of the holder caused by rotating the object cannot be disregarded if tomographic images are to be reconstructed accurately. This paper presents a computer method to compensate for the vibration of the rotational holder by aligning neighboring X-ray images. This alignment process involves two steps. The first step is to match the "projected feature points" in the sequence of images. The matched projected feature points in the x-θ plane should form a set of sine-shaped loci. The second step is to fit the loci to a set of sine waves to compute the parameters required for alignment. The experimental results show that the proposed method outperforms two previously proposed methods, Xradia and SPIDER. The developed software system can be downloaded from the URL, http://www.cs.nctu.edu.tw/~chengchc/SCTA or http://goo.gl/s4AMx.

  13. Design and implemention of a multi-functional x-ray computed tomography system

    Science.gov (United States)

    Li, Lei; Xi, Xiaoqi; Han, Yu; Yan, Bin; Zhang, Xiang; Deng, Lin; Chen, Siyu; Jin, Zhao; Li, Zengguang

    2015-10-01

    A powerful volume X-ray tomography system has been designed and constructed to provide an universal tool for the three-dimensional nondestructive testing and investigation of industrial components, automotive, electronics, aerospace components, new materials, etc. The combined system is equipped with two commercial X-ray sources, sharing one flat panel detector of 400mm×400mm. The standard focus 450kV high-energy x-ray source is optimized for complex and high density components such as castings, engine blocks and turbine blades. And the microfocus 225kV x-ray source is to meet the demands of micro-resolution characterization applications. Thus the system's penetration capability allows to scan large objects up to 200mm thick dense materials, and the resolution capability can meet the demands of 20μm microstructure inspection. A high precision 6-axis manipulator system is fitted, capable of offset scanning mode in large field of view requirements. All the components are housed in a room with barium sulphate cement. On the other hand, the presented system expands the scope of applications such as dual energy research and testing. In this paper, the design and implemention of the flexible system is described, as well as the preliminary tomographic imaging results of an automobile engine block.

  14. Metal artifact removal (MAR) analysis for the security inspections using the X-ray computed tomography

    International Nuclear Information System (INIS)

    Cho, Hyo Sung; Woo, Tae Ho; Park, Chul Kyu

    2016-01-01

    Using the metal artifact property, it is analyzed for the X-ray computed tomography (CT) in the aspect of the security on the examined places like airport and surveillance areas. Since the importance of terror prevention strategy has been increased, the security application of X-ray CT has the significant remark. One shot X-ray image has the limitation to find out the exact shape to property in the closed box, which could be solved by the CT scanning without the tearing off the box in this work. Cleaner images can be obtained by the advanced technology if the CT scanning is utilized in the security purposes on the secured areas. A metal sample is treated by the metal artifact removal (MAR) method for the enhanced image. The mimicked explosive is experimented for the imaging processing application where the cleaner one is obtained. The procedure is explained and the further study is discussed. - Highlights: • The X-ray image is used for the nuclear inspections which are made by the image processing. • Nuclear security has been performed for counterterrorism. • Easy and fast inspections are needed. • Metal shows the characteristics of the noises.

  15. FMT-XCT: in vivo animal studies with hybrid fluorescence molecular tomography-X-ray computed tomography.

    Science.gov (United States)

    Ale, Angelique; Ermolayev, Vladimir; Herzog, Eva; Cohrs, Christian; de Angelis, Martin Hrabé; Ntziachristos, Vasilis

    2012-06-01

    The development of hybrid optical tomography methods to improve imaging performance has been suggested over a decade ago and has been experimentally demonstrated in animals and humans. Here we examined in vivo performance of a camera-based hybrid fluorescence molecular tomography (FMT) system for 360° imaging combined with X-ray computed tomography (XCT). Offering an accurately co-registered, information-rich hybrid data set, FMT-XCT has new imaging possibilities compared to stand-alone FMT and XCT. We applied FMT-XCT to a subcutaneous 4T1 tumor mouse model, an Aga2 osteogenesis imperfecta model and a Kras lung cancer mouse model, using XCT information during FMT inversion. We validated in vivo imaging results against post-mortem planar fluorescence images of cryoslices and histology data. Besides offering concurrent anatomical and functional information, FMT-XCT resulted in the most accurate FMT performance to date. These findings indicate that addition of FMT optics into the XCT gantry may be a potent upgrade for small-animal XCT systems.

  16. Microscale reconstruction of biogeochemical substrates using multimode X-ray tomography and scanning electron microscopy

    Science.gov (United States)

    Miller, M.; Miller, E.; Liu, J.; Lund, R. M.; McKinley, J. P.

    2012-12-01

    X-ray computed tomography (CT), scanning electron microscopy (SEM), electron microprobe analysis (EMP), and computational image analysis are mature technologies used in many disciplines. Cross-discipline combination of these imaging and image-analysis technologies is the focus of this research, which uses laboratory and light-source resources in an iterative approach. The objective is to produce images across length scales, taking advantage of instrumentation that is optimized for each scale, and to unify them into a single compositional reconstruction. Initially, CT images will be collected using both x-ray absorption and differential phase contrast modes. The imaged sample will then be physically sectioned and the exposed surfaces imaged and characterized via SEM/EMP. The voxel slice corresponding to the physical sample surface will be isolated computationally, and the volumetric data will be combined with two-dimensional SEM images along CT image planes. This registration step will take advantage of the similarity between the X-ray absorption (CT) and backscattered electron (SEM) coefficients (both proportional to average atomic number in the interrogated volume) as well as the images' mutual information. Elemental and solid-phase distributions on the exposed surfaces, co-registered with SEM images, will be mapped using EMP. The solid-phase distribution will be propagated into three-dimensional space using computational methods relying on the estimation of compositional distributions derived from the CT data. If necessary, solid-phase and pore-space boundaries will be resolved using X-ray differential phase contrast tomography, x-ray fluorescence tomography, and absorption-edge microtomography at a light-source facility. Computational methods will be developed to register and model images collected over varying scales and data types. Image resolution, physically and dynamically, is qualitatively different for the electron microscopy and CT methodologies. Routine

  17. A novel PFIB sample preparation protocol for correlative 3D X-ray CNT and FIB-TOF-SIMS tomography

    Energy Technology Data Exchange (ETDEWEB)

    Priebe, Agnieszka, E-mail: agnieszka.priebe@gmail.com [Univ. Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, F-38054 Grenoble (France); Audoit, Guillaume; Barnes, Jean-Paul [Univ. Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, F-38054 Grenoble (France)

    2017-02-15

    We present a novel sample preparation method that allows correlative 3D X-ray Computed Nano-Tomography (CNT) and Focused Ion Beam Time-Of-Flight Secondary Ion Mass Spectrometry (FIB-TOF-SIMS) tomography to be performed on the same sample. In addition, our invention ensures that samples stay unmodified structurally and chemically between the subsequent experiments. The main principle is based on modifying the topography of the X-ray CNT experimental setup before FIB-TOF-SIMS measurements by incorporating a square washer around the sample. This affects the distribution of extraction field lines and therefore influences the trajectories of secondary ions that are now guided more efficiently towards the detector. As the result, secondary ion detection is significantly improved and higher, i.e. statistically better, signals are obtained. - Highlights: • Novel sample preparation for correlative 3D X-ray CNT and FIB-TOF-SIMS is presented. • Two experiments are conducted on exactly the same sample without any modifications. • Introduction of a square washer around the sample leads to increased ion detection.

  18. Noise propagation in x-ray phase-contrast imaging and computed tomography

    International Nuclear Information System (INIS)

    Nesterets, Yakov I; Gureyev, Timur E

    2014-01-01

    Three phase-retrieval algorithms, based on the transport-of-intensity equation and on the contrast transfer function for propagation-based imaging, and on the linearized geometrical optics approximation for analyser-based imaging, are investigated. The algorithms are compared in terms of their effect on propagation of noise from projection images to the corresponding phase-retrieved images and further to the computed tomography (CT) images/slices of a monomorphous object reconstructed using filtered backprojection algorithm. The comparison is carried out in terms of an integral noise characteristic, the variance, as well as in terms of a simple figure-of-merit, i.e. signal-to-noise ratio per unit dose. A gain factor is introduced that quantitatively characterizes the effect of phase retrieval on the variance of noise in the reconstructed projection images and in the axial slices of the object. Simple analytical expressions are derived for the gain factor and the signal-to-noise ratio, which indicate that the application of phase-retrieval algorithms can increase these parameters by up to two orders of magnitude compared to raw projection images and conventional CT, thus allowing significant improvement in the image quality and/or reduction of the x-ray dose delivered to the patient. (paper)

  19. A reconstruction method for cone-beam differential x-ray phase-contrast computed tomography.

    Science.gov (United States)

    Fu, Jian; Velroyen, Astrid; Tan, Renbo; Zhang, Junwei; Chen, Liyuan; Tapfer, Arne; Bech, Martin; Pfeiffer, Franz

    2012-09-10

    Most existing differential phase-contrast computed tomography (DPC-CT) approaches are based on three kinds of scanning geometries, described by parallel-beam, fan-beam and cone-beam. Due to the potential of compact imaging systems with magnified spatial resolution, cone-beam DPC-CT has attracted significant interest. In this paper, we report a reconstruction method based on a back-projection filtration (BPF) algorithm for cone-beam DPC-CT. Due to the differential nature of phase contrast projections, the algorithm restrains from differentiation of the projection data prior to back-projection, unlike BPF algorithms commonly used for absorption-based CT data. This work comprises a numerical study of the algorithm and its experimental verification using a dataset measured with a three-grating interferometer and a micro-focus x-ray tube source. Moreover, the numerical simulation and experimental results demonstrate that the proposed method can deal with several classes of truncated cone-beam datasets. We believe that this feature is of particular interest for future medical cone-beam phase-contrast CT imaging applications.

  20. Physical characterization and performance evaluation of an x-ray micro-computed tomography system for dimensional metrology applications

    DEFF Research Database (Denmark)

    Hiller, Jochen; Maisl, Michael; Reindl, Leonard M

    2012-01-01

    This paper presents physical and metrological characterization measurements conducted for an industrial x-ray micro-computed tomography (CT) system. As is well known in CT metrology, many factors, e.g., in the scanning and reconstruction process, the image processing, and the 3D data evaluation...... components of a CT scanner, i.e. the x-ray tube and the flat-panel detector, are characterized. The contrast and noise transfer property of the scanner is obtained using image-processing methods based on linear systems theory. A long-term temperature measurement in the scanner cabinet has been carried out....... The dimensional measurement property has been quantified by using a calibrated ball-bar and uncertainty budgeting. Information about the performance of a CT scanner system in terms of contrast and noise transmission and sources of geometrical errors will help plan CT scans more efficiently. In particular...

  1. Simulation and application of micro X-ray fluorescence based on an ellipsoidal capillary

    Science.gov (United States)

    Yang, Jing; Li, Yude; Wang, Xingyi; Zhang, Xiaoyun; Lin, Xiaoyan

    2017-06-01

    A micro X-ray fluorescence setup was presented, based on an ellipsoidal capillary and a traditional laboratorial X-ray source. Using Ray-tracing principle, we have simulated the transmission path of X-ray beam in the ellipsoidal capillary and designed the optimal parameters of the ellipsoidal capillary for the micro X-ray fluorescence setup. We demonstrate that ellipsoidal capillary is well suited as condenser for the micro X-ray fluorescence based on traditional laboratorial X-ray source. Furthermore, we obtain the 2D mapping image of the leaf blade sample by using the ellipsoidal capillary we designed.

  2. A mirror for lab-based quasi-monochromatic parallel x-rays.

    Science.gov (United States)

    Nguyen, Thanhhai; Lu, Xun; Lee, Chang Jun; Jung, Jin-Ho; Jin, Gye-Hwan; Kim, Sung Youb; Jeon, Insu

    2014-09-01

    A multilayered parabolic mirror with six W/Al bilayers was designed and fabricated to generate monochromatic parallel x-rays using a lab-based x-ray source. Using this mirror, curved bright bands were obtained in x-ray images as reflected x-rays. The parallelism of the reflected x-rays was investigated using the shape of the bands. The intensity and monochromatic characteristics of the reflected x-rays were evaluated through measurements of the x-ray spectra in the band. High intensity, nearly monochromatic, and parallel x-rays, which can be used for high resolution x-ray microscopes and local radiation therapy systems, were obtained.

  3. Pore-scale evaporation-condensation dynamics resolved by synchrotron x-ray tomography.

    Science.gov (United States)

    Shahraeeni, Ebrahim; Or, Dani

    2012-01-01

    Capillary processes greatly influence vapor mediated transport dynamics and associated changes in liquid phase content of porous media. Rapid x-ray synchrotron tomography measurements were used to resolve liquid-vapor interfacial dynamics during evaporation and condensation within submillimetric pores forming between sintered glass bead samples subjected to controlled ambient temperature and relative humidity. Evolution of gas-liquid interfacial shapes were in agreement with predictions based on our analytical model for interfacial dynamics in confined wedge-shaped pores. We also compared literature experimental data at the nanoscale to illustrate the capability of our model to describe early stages of condensation giving rise to the onset of capillary forces between rough surfaces. The study provides high resolution, synchrotron-based observations of capillary evaporation-condensation dynamics at the pore scale as the confirmation of the pore scale analytical model for capillary condensation in a pore and enables direct links with evolution of macroscopic vapor gradients within a sintered glass bead sample through their effect on configuration and evolution of the local interfaces. Rapid condensation processes play a critical role in the onset of capillary-induced friction affecting mechanical behavior of physical systems and industrial applications.

  4. High-resolution x-ray computed tomography to understand ruminant phylogeny

    Science.gov (United States)

    Costeur, Loic; Schulz, Georg; Müller, Bert

    2014-09-01

    High-resolution X-ray computed tomography has become a vital technique to study fossils down to the true micrometer level. Paleontological research requires the non-destructive analysis of internal structures of fossil specimens. We show how X-ray computed tomography enables us to visualize the inner ear of extinct and extant ruminants without skull destruction. The inner ear, a sensory organ for hearing and balance has a rather complex three-dimensional morphology and thus provides relevant phylogenetical information what has been to date essentially shown in primates. We made visible the inner ears of a set of living and fossil ruminants using the phoenix x-ray nanotom®m (GE Sensing and Inspection Technologies GmbH). Because of the high absorbing objects a tungsten target was used and the experiments were performed with maximum accelerating voltage of 180 kV and a beam current of 30 μA. Possible stem ruminants of the living families are known in the fossil record but extreme morphological convergences in external structures such as teeth is a strong limitation to our understanding of the evolutionary history of this economically important group of animals. We thus investigate the inner ear to assess its phylogenetical potential for ruminants and our first results show strong family-level morphological differences.

  5. Toward Rapid Unattended X-ray Tomography of Large Planar Samples at 50-nm Resolution

    International Nuclear Information System (INIS)

    Rudati, J.; Tkachuk, A.; Gelb, J.; Hsu, G.; Feng, Y.; Pastrick, R.; Lyon, A.; Trapp, D.; Beetz, T.; Chen, S.; Hornberger, B.; Seshadri, S.; Kamath, S.; Zeng, X.; Feser, M.; Yun, W.; Pianetta, P.; Andrews, J.; Brennan, S.; Chu, Y. S.

    2009-01-01

    X-ray tomography at sub-50 nm resolution of small areas (∼15 μmx15 μm) are routinely performed with both laboratory and synchrotron sources. Optics and detectors for laboratory systems have been optimized to approach the theoretical efficiency limit. Limited by the availability of relatively low-brightness laboratory X-ray sources, exposure times for 3-D data sets at 50 nm resolution are still many hours up to a full day. However, for bright synchrotron sources, the use of these optimized imaging systems results in extremely short exposure times, approaching live-camera speeds at the Advanced Photon Source at Argonne National Laboratory near Chicago in the US These speeds make it possible to acquire a full tomographic dataset at 50 nm resolution in less than a minute of true X-ray exposure time. However, limits in the control and positioning system lead to large overhead that results in typical exposure times of ∼15 min currently.We present our work on the reduction and elimination of system overhead and toward complete automation of the data acquisition process. The enhancements underway are primarily to boost the scanning rate, sample positioning speed, and illumination homogeneity to performance levels necessary for unattended tomography of large areas (many mm 2 in size). We present first results on this ongoing project.

  6. Optimal Contrast Agent Staining of Ligaments and Tendons for X-Ray Computed Tomography.

    Science.gov (United States)

    Balint, Richard; Lowe, Tristan; Shearer, Tom

    2016-01-01

    X-ray computed tomography has become an important tool for studying the microstructures of biological soft tissues, such as ligaments and tendons. Due to the low X-ray attenuation of such tissues, chemical contrast agents are often necessary to enhance contrast during scanning. In this article, the effects of using three different contrast agents--iodine potassium iodide solution, phosphotungstic acid and phosphomolybdic acid--are evaluated and compared. Porcine anterior cruciate ligaments, patellar tendons, medial collateral ligaments and lateral collateral ligaments were used as the basis of the study. Three samples of each of the four ligament/tendon types were each assigned a different contrast agent (giving a total of twelve samples), and the progression of that agent through the tissue was monitored by performing a scan every day for a total period of five days (giving a total of sixty scans). Since the samples were unstained on day one, they had been stained for a total of four days by the time of the final scans. The relative contrast enhancement and tissue deformation were measured. It was observed that the iodine potassium iodide solution penetrated the samples fastest and caused the least sample shrinkage on average (although significant deformation was observed by the time of the final scans), whereas the phosphomolybdic acid caused the greatest sample shrinkage. Equations describing the observed behaviour of the contrast agents, which can be used to predict optimal staining times for ligament and tendon X-ray computed tomography, are presented.

  7. X-ray Micro Tomography as a Tool for Studying Localized Damage / Deformation in Clay Rock

    International Nuclear Information System (INIS)

    Viggiani, Gioacchino; Besuelle, Pierre; Desrues, Jacques

    2013-01-01

    Deformation in geo-materials (soils, rocks, concrete, etc.) is often localized, e.g., in the form of shear bands or fractures. In experimental analysis of the mechanical behavior of such materials, standard laboratory methods are insufficient as the majority of measurements are made at the sample scale and rarely at a local scale. X-ray tomography monitoring during loading allows high-resolution full-field observation of the development of deformation. However, such images only indicate clearly the de-formation when there are significant changes in material density (i.e., volume changes) that produce a change in x-ray absorption. As such 3D Digital Image Correlation (DIC) approaches have been developed that allow quantification of the full strain tensor field throughout the imaged volume. This paper presents results from triaxial compression tests on a clay rock (Callovo-Oxfordian argillite) with in situ synchrotron x-ray micro tomography imaging providing complete 3D images of the specimen at several stages throughout the test. These images have been analyzed using 3D DIC to provide full-field displacement and strain measurements, which allowed the detection of the onset of strain localization and its timing relative to the load peak plus insight into the 3D structure of the localized zone. The paper concludes with a few general remarks concerning the lessons learned from this study and perspectives for current and future work. (authors)

  8. Investigation of optimal scanning protocol for X-ray computed tomography polymer gel dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Sellakumar, P. [Bangalore Institute of Oncology, 44-45/2, II Cross, RRMR Extension, Bangalore 560 027 (India)], E-mail: psellakumar@rediffmail.com; James Jebaseelan Samuel, E. [School of Science and Humanities, VIT University, Vellore 632 014 (India); Supe, Sanjay S. [Department of Radiation Physics, Kidwai Memorial Institute of Oncology, Hosur Road, Bangalore 560 027 (India)

    2007-11-15

    X-ray computed tomography is one of the potential tool used to evaluate the polymer gel dosimeters in three dimensions. The purpose of this study is to investigate the factors which affect the image noise for X-ray CT polymer gel dosimetry. A cylindrical water filled phantom was imaged with single slice Siemens Somatom Emotion CT scanner. The imaging parameters like tube voltage, tube current, slice scan time, slice thickness and reconstruction algorithm were varied independently to study the dependence of noise on each other. Reductions of noise with number of images to be averaged and spatial uniformity of the image were also investigated. Normoxic polymer gel PAGAT was manufactured and irradiated using Siemens Primus linear accelerator. The radiation induced change in CT number was evaluated using X-ray CT scanner. From this study it is clear that image noise is reduced with increase in tube voltage, tube current, slice scan time, slice thickness and also reduced with increasing the number of images averaged. However to reduce the tube load and total scan time, it was concluded that tube voltage of 130 kV, tube current of 200 mA, scan time of 1.5 s, slice thickness of 3 mm for high dose gradient and 5 mm for low dose gradient were optimal scanning protocols for this scanner. Optimum number of images to be averaged was concluded to be 25 for X-ray CT polymer gel dosimetry. Choice of reconstruction algorithm was also critical. From the study it is also clear that CT number increase with imaging tube voltage and shows the energy dependency of polymer gel dosimeter. Hence for evaluation of polymer gel dosimeters with X-ray CT scanner needs the optimization of scanning protocols to reduce the image noise.

  9. Development of full-field x-ray phase-tomographic microscope based on laboratory x-ray source

    Science.gov (United States)

    Takano, H.; Wu, Y.; Momose, A.

    2017-09-01

    An X-ray phase tomographic microscope that can quantitatively measure the refractive index of a sample in three dimensions with a high spatial resolution was developed by installing a Lau interferometer consisting of an absorption grating and a π/2 phase grating into the optics of an X-ray microscope. The optics comprises a Cu rotating anode X-ray source, capillary condenser optics, and a Fresnel zone plate for the objective. The microscope has two optical modes: a large-field-of-view mode (field of view: 65 μm x 65 μm) and a high-resolution mode (spatial resolution: 50 nm). Optimizing the parameters of the interferometer yields a self-image of the phase grating with 60% visibility. Through the normal fringe-scanning measurement, a twin phase image, which has an overlap of two phase image of opposite contrast with a shear distance much larger than system resolution, is generated. Although artifacts remain to some extent currently when a phase image is calculated from the twin phase image, this system can obtain high-spatial-resolution images resolving 50-nm structures. Phase tomography with this system has also been demonstrated using a phase object.

  10. Combined optic system based on polycapillary X-ray optics and single-bounce monocapillary optics for focusing X-rays from a conventional laboratory X-ray source

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Xuepeng; Liu, Zhiguo [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Sun, Tianxi, E-mail: stx@bnu.edu.cn [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Yi, Longtao; Sun, Weiyuan; Li, Fangzuo; Jiang, Bowen [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Ma, Yongzhong [Center for Disease Control and Prevention of Beijing, Beijing 100013 (China); Ding, Xunliang [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China)

    2015-12-01

    Two combined optic systems based on polycapillary X-ray optics and single-bounce monocapillary optics (SBMO) were designed for focusing the X-rays from a conventional laboratory X-ray source. One was based on a polycapillary focusing X-ray lens (PFXRL) and a single-bounce ellipsoidal capillary (SBEC), in which the output focal spot with the size of tens of micrometers of the PFXRL was used as the “virtual” X-ray source for the SBEC. The other system was based on a polycapillary parallel X-ray lens (PPXRL) and a single-bounce parabolic capillary (SBPC), in which the PPXRL transformed the divergent X-ray beam from an X-ray source into a quasi-parallel X-ray beam with the divergence of sever milliradians as the incident illumination of the SBPC. The experiment results showed that the combined optic systems based on PFXRL and SBEC with a Mo rotating anode X-ray generator with the focal spot with a diameter of 300 μm could obtain a focal spot with the total gain of 14,300 and focal spot size of 37.4 μm, and the combined optic systems based on PPXRL and SBPC with the same X-ray source mentioned above could acquire a focal spot with the total gain of 580 and focal spot size of 58.3 μm, respectively. The two combined optic systems have potential applications in micro X-ray diffraction, micro X-ray fluorescence, micro X-ray absorption near edge structure, full field X-ray microscopes and so on.

  11. Qualitative comparison of bremsstrahlung X-rays and 800 MeV protons for tomography of urania fuel pellets

    Energy Technology Data Exchange (ETDEWEB)

    Morris, C. L.; Bourke, M.; Byler, D. D.; Chen, C. F.; Hogan, G.; Hunter, J. F.; Kwiatkowski, K.; Mariam, F. G.; McClellan, K. J.; Merrill, F.; Morley, D. J.; Saunders, A. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2013-02-15

    We present an assessment of x-rays and proton tomography as tools for studying the time dependence of the development of damage in fuel rods. We also show data taken with existing facilities at Los Alamos National Laboratory that support this assessment. Data on surrogate fuel rods have been taken using the 800 MeV proton radiography (pRad) facility at the Los Alamos Neutron Science Center (LANSCE), and with a 450 keV bremsstrahlung X-ray tomography facility. The proton radiography pRad facility at LANSCE can provide good position resolution (<70 {mu}m has been demonstrate, 20 {mu}m seems feasible with minor changes) for tomography on activated fuel rods. Bremsstrahlung x-rays may be able to provide better than 100 {mu}m resolution but further development of sources, collimation, and detectors is necessary for x-rays to deal with the background radiation for tomography of activated fuel rods.

  12. Qualitative comparison of bremsstrahlung X-rays and 800 MeV protons for tomography of urania fuel pellets

    International Nuclear Information System (INIS)

    Morris, C. L.; Bourke, M.; Byler, D. D.; Chen, C. F.; Hogan, G.; Hunter, J. F.; Kwiatkowski, K.; Mariam, F. G.; McClellan, K. J.; Merrill, F.; Morley, D. J.; Saunders, A.

    2013-01-01

    We present an assessment of x-rays and proton tomography as tools for studying the time dependence of the development of damage in fuel rods. We also show data taken with existing facilities at Los Alamos National Laboratory that support this assessment. Data on surrogate fuel rods have been taken using the 800 MeV proton radiography (pRad) facility at the Los Alamos Neutron Science Center (LANSCE), and with a 450 keV bremsstrahlung X-ray tomography facility. The proton radiography pRad facility at LANSCE can provide good position resolution (<70 μm has been demonstrate, 20 μm seems feasible with minor changes) for tomography on activated fuel rods. Bremsstrahlung x-rays may be able to provide better than 100 μm resolution but further development of sources, collimation, and detectors is necessary for x-rays to deal with the background radiation for tomography of activated fuel rods.

  13. Enabling three-dimensional densitometric measurements using laboratory source X-ray micro-computed tomography

    Science.gov (United States)

    Pankhurst, M. J.; Fowler, R.; Courtois, L.; Nonni, S.; Zuddas, F.; Atwood, R. C.; Davis, G. R.; Lee, P. D.

    2018-01-01

    We present new software allowing significantly improved quantitative mapping of the three-dimensional density distribution of objects using laboratory source polychromatic X-rays via a beam characterisation approach (c.f. filtering or comparison to phantoms). One key advantage is that a precise representation of the specimen material is not required. The method exploits well-established, widely available, non-destructive and increasingly accessible laboratory-source X-ray tomography. Beam characterisation is performed in two stages: (1) projection data are collected through a range of known materials utilising a novel hardware design integrated into the rotation stage; and (2) a Python code optimises a spectral response model of the system. We provide hardware designs for use with a rotation stage able to be tilted, yet the concept is easily adaptable to virtually any laboratory system and sample, and implicitly corrects the image artefact known as beam hardening.

  14. Reduction of variable-truncation artifacts from beam occlusion during in situ x-ray tomography

    DEFF Research Database (Denmark)

    Borg, Leise; Jørgensen, Jakob Sauer; Frikel, Jürgen

    2017-01-01

    Many in situ x-ray tomography studies require experimental rigs which may partially occlude the beam and cause parts of the projection data to be missing. In a study of fluid flow in porous chalk using a percolation cell with four metal bars drastic streak artifacts arise in the filtered...... and artifact-reduction methods are designed in context of FBP reconstruction motivated by computational efficiency practical for large, real synchrotron data. While a specific variable-truncation case is considered, the proposed methods can be applied to general data cut-offs arising in different in situ x-ray...... backprojection (FBP) reconstruction at certain orientations. Projections with non-trivial variable truncation caused by the metal bars are the source of these variable-truncation artifacts. To understand the artifacts a mathematical model of variable-truncation data as a function of metal bar radius and distance...

  15. Multiple energy computed tomography with monochromatic x rays from the NSLS

    International Nuclear Information System (INIS)

    Dilmanian, F.A.; Nachaliel, E.; Garrett, R.F.; Thomlinson, W.C.; Chapman, L.D.; Moulin, H.R.; Oversluizen, T.; Rarback, H.M.; Rivers, M.; Spanne, P.; Thompson, A.C.; Zeman, H.D.

    1991-01-01

    We used monochromatic x rays from the X17 superconducting wiggler beamline at the National Synchrotron Light Source (NSLS), Brookhaven National Laboratory, for dual-energy quantitative computed tomography (CT) of a 27 mm-diameter phantom containing solutions of different KOH concentrations in cylindrical holes of 5-mm diameter. The CT configuration was a fixed horizontal fan-shaped beam of 1.5 mm height and 30 mm width, and a subject rotating around a vertical axis. The transmitted x rays were detected by a linear-array Si(Li) detector with 120 elements of 0.25 mm width each. We used a two-crystal Bragg-Bragg fixed-exit monochromator with Si crystals. Dual photon absorptiometry (DPA) CT data were taken at 20 and 38 keV. The reconstructed phantom images show the potential of the system for quantitative CT

  16. In Vitro Validation of an Artefact Suppression Algorithm in X-Ray Phase-Contrast Computed Tomography.

    Science.gov (United States)

    Sunaguchi, Naoki; Yuasa, Tetsuya; Hirano, Shin-Ichi; Gupta, Rajiv; Ando, Masami

    2015-01-01

    X-ray phase-contrast tomography can significantly increase the contrast-resolution of conventional attenuation-contrast imaging, especially for soft-tissue structures that have very similar attenuation. Just as in attenuation-based tomography, phase contrast tomography requires a linear dependence of aggregate beam direction on the incremental direction alteration caused by individual voxels along the path of the X-ray beam. Dense objects such as calcifications in biological specimens violate this condition. There are extensive beam deflection artefacts in the vicinity of such structures because they result in large distortion of wave front due to the large difference of refractive index; for such large changes in beam direction, the transmittance of the silicon analyzer crystal saturates and is no longer linearly dependent on the angle of refraction. This paper describes a method by which these effects can be overcome and excellent soft-tissue contrast of phase tomography can be preserved in the vicinity of such artefact-producing structures.

  17. X-ray beam hardening correction for measuring density in linear accelerator industrial computed tomography

    International Nuclear Information System (INIS)

    Zhou Rifeng; Wang Jue; Chen Weimin

    2009-01-01

    Due to X-ray attenuation being approximately proportional to material density, it is possible to measure the inner density through Industrial Computed Tomography (ICT) images accurately. In practice, however, a number of factors including the non-linear effects of beam hardening and diffuse scattered radiation complicate the quantitative measurement of density variations in materials. This paper is based on the linearization method of beam hardening correction, and uses polynomial fitting coefficient which is obtained by the curvature of iron polychromatic beam data to fit other materials. Through theoretical deduction, the paper proves that the density measure error is less than 2% if using pre-filters to make the spectrum of linear accelerator range mainly 0.3 MeV to 3 MeV. Experiment had been set up at an ICT system with a 9 MeV electron linear accelerator. The result is satisfactory. This technique makes the beam hardening correction easy and simple, and it is valuable for measuring the ICT density and making use of the CT images to recognize materials. (authors)

  18. Design of 4D x-ray tomography experiments for reconstruction using regularized iterative algorithms

    Science.gov (United States)

    Mohan, K. Aditya

    2017-10-01

    4D X-ray computed tomography (4D-XCT) is widely used to perform non-destructive characterization of time varying physical processes in various materials. The conventional approach to improving temporal resolution in 4D-XCT involves the development of expensive and complex instrumentation that acquire data faster with reduced noise. It is customary to acquire data with many tomographic views at a high signal to noise ratio. Instead, temporal resolution can be improved using regularized iterative algorithms that are less sensitive to noise and limited views. These algorithms benefit from optimization of other parameters such as the view sampling strategy while improving temporal resolution by reducing the total number of views or the detector exposure time. This paper presents the design principles of 4D-XCT experiments when using regularized iterative algorithms derived using the framework of model-based reconstruction. A strategy for performing 4D-XCT experiments is presented that allows for improving the temporal resolution by progressively reducing the number of views or the detector exposure time. Theoretical analysis of the effect of the data acquisition parameters on the detector signal to noise ratio, spatial reconstruction resolution, and temporal reconstruction resolution is also presented in this paper.

  19. Analysis of iterative region-of-interest image reconstruction for x-ray computed tomography

    Science.gov (United States)

    Sidky, Emil Y.; Kraemer, David N.; Roth, Erin G.; Ullberg, Christer; Reiser, Ingrid S.; Pan, Xiaochuan

    2014-01-01

    Abstract. One of the challenges for iterative image reconstruction (IIR) is that such algorithms solve an imaging model implicitly, requiring a complete representation of the scanned subject within the viewing domain of the scanner. This requirement can place a prohibitively high computational burden for IIR applied to x-ray computed tomography (CT), especially when high-resolution tomographic volumes are required. In this work, we aim to develop an IIR algorithm for direct region-of-interest (ROI) image reconstruction. The proposed class of IIR algorithms is based on an optimization problem that incorporates a data fidelity term, which compares a derivative of the estimated data with the available projection data. In order to characterize this optimization problem, we apply it to computer-simulated two-dimensional fan-beam CT data, using both ideal noiseless data and realistic data containing a level of noise comparable to that of the breast CT application. The proposed method is demonstrated for both complete field-of-view and ROI imaging. To demonstrate the potential utility of the proposed ROI imaging method, it is applied to actual CT scanner data. PMID:25685824

  20. Reconstruction of sparse-view X-ray computed tomography using adaptive iterative algorithms.

    Science.gov (United States)

    Liu, Li; Lin, Weikai; Jin, Mingwu

    2015-01-01

    In this paper, we propose two reconstruction algorithms for sparse-view X-ray computed tomography (CT). Treating the reconstruction problems as data fidelity constrained total variation (TV) minimization, both algorithms adapt the alternate two-stage strategy: projection onto convex sets (POCS) for data fidelity and non-negativity constraints and steepest descent for TV minimization. The novelty of this work is to determine iterative parameters automatically from data, thus avoiding tedious manual parameter tuning. In TV minimization, the step sizes of steepest descent are adaptively adjusted according to the difference from POCS update in either the projection domain or the image domain, while the step size of algebraic reconstruction technique (ART) in POCS is determined based on the data noise level. In addition, projection errors are used to compare with the error bound to decide whether to perform ART so as to reduce computational costs. The performance of the proposed methods is studied and evaluated using both simulated and physical phantom data. Our methods with automatic parameter tuning achieve similar, if not better, reconstruction performance compared to a representative two-stage algorithm. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Analysis of iterative region-of-interest image reconstruction for x-ray computed tomography.

    Science.gov (United States)

    Sidky, Emil Y; Kraemer, David N; Roth, Erin G; Ullberg, Christer; Reiser, Ingrid S; Pan, Xiaochuan

    2014-10-03

    One of the challenges for iterative image reconstruction (IIR) is that such algorithms solve an imaging model implicitly, requiring a complete representation of the scanned subject within the viewing domain of the scanner. This requirement can place a prohibitively high computational burden for IIR applied to x-ray computed tomography (CT), especially when high-resolution tomographic volumes are required. In this work, we aim to develop an IIR algorithm for direct region-of-interest (ROI) image reconstruction. The proposed class of IIR algorithms is based on an optimization problem that incorporates a data fidelity term, which compares a derivative of the estimated data with the available projection data. In order to characterize this optimization problem, we apply it to computer-simulated two-dimensional fan-beam CT data, using both ideal noiseless data and realistic data containing a level of noise comparable to that of the breast CT application. The proposed method is demonstrated for both complete field-of-view and ROI imaging. To demonstrate the potential utility of the proposed ROI imaging method, it is applied to actual CT scanner data.

  2. Visualization of monomer and polymer inside porous stones by using X-ray tomography

    International Nuclear Information System (INIS)

    Brunetti, Antonio; Princi, Elisabetta; Vicini, Silvia; Pincin, Silvia; Bidali, Simone; Mariani, Alberto

    2004-01-01

    Estimate of sorption of liquid materials inside porous stones is an important parameter in industrial material testing and cultural heritage conservation. In the latter case, a suitable polymer can be used for both consolidation and conservation, it being applied either in the final form or as its parent monomer, which is subsequently allowed to polymerize in situ by the classical method or by frontal polymerization. However, the sorption of such materials through the stone is often difficult because of their viscosity and/or stone porosity. For this reason, the amount of monomer (or polymer) is a parameter of great interest in order to determine the extent of protection reachable by the treatment. In this paper a new methodology based on X-ray tomography is presented. The methodology makes use of a contrast agent added to the monomer that does not interact with its propagation inside the stone and allows to increase the absorption coefficient and so to observe the monomer inside the sample, which is finally frontally polymerized

  3. Theory of X-ray microcomputed tomography in dental research: application for the caries research

    Directory of Open Access Journals (Sweden)

    Young-Seok Park

    2011-03-01

    Full Text Available Caries remains prevalent throughout modern society and is the main disease in the field of dentistry. Although studies of this disease have used diverse methodology, recently, X-ray microtomography has gained popularity as a non-destructive, 3-dimensional (3D analytical technique, and has several advantages over the conventional methods. According to X-ray source, it is classified as monochromatic or polychromatic with the latter being more widely used due to the high cost of the monochromatic source despite some advantages. The determination of mineral density profiles based on changes in X-ray attenuation is the principle of this method and calibration and image processing procedures are needed for the better image and reproducible measurements. Using this tool, 3D reconstruction is also possible and it enables to visualize the internal structures of dental caries. With the advances in the computer technology, more diverse applications are being studied, such automated caries assessment algorithms.

  4. Analysis of computed X-ray tomography of the brain in incontinence patients with senile dementia

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Yasuyuki; Machida, Toyohei; Oishi, Yukihiko [Jikei Univ., Tokyo (Japan). School of Medicine; Kamachi, Chikahumi; Okabe, Tsutomu; Akazawa, Kouhei; Takasaka, Satoshi

    1994-02-01

    To evaluate the condition of incontinence in patients with senile dementia, we performed computed tomography X-rays to the brain and analyzed the relationship among the circulatory defect of the brain, the brain atrophy and the degree of incontinence. There were 92 patients subjected to this study who were hospitalised due to senile dementia; 74 patients had vascular dementia, 10 patients had senile dementia of Alzheimer type, and 8 patients had the mixed type. (age range: 54-95 years; mean: 80.3 years). The degree of incontinence in these patients varied as follows: 18 patients with continence, 16 patients with moderate incontinence, 58 patients with total incontinence. The diagnosis of circulatory defect of the brain was based on computed tomography observation of periventricular lucency (P.V.L.), and the degree of brain atrophy was evaluated based on 4 criteria: the Lateral body ratio, the Huckman number, the Evans ratio, and the enlargement of the subarachnoid space. Among the 92 patients, P.V.L. was present in 31 patients, among them 27 patients suffered from incontinence. There was a significant correlation between P.V.L. and incontinence (p<0.001). As the incontinence progressively worsened (Continence, Moderate incontinence, Total incontinence), the lateral body ratio increased to 24.8, 27.8, 28.6, (p<0.05). The Huckman number also increased to 18.3, 19.3, 21.3, (p<0.01), and the evans ratio likewise 29.9, 32.3, 33.7 (p<0.01). The enlargement of the subarachnoid space was also correlated with the severity of incontinence. We conclude that urinary incontinence originating from senile dememtia is connected to brain atrophy and is strongly influenced by the circulatory disorders of the brain. (author).

  5. Combined X-ray fluorescence and absorption computed tomography using a synchrotron beam

    International Nuclear Information System (INIS)

    Hall, C

    2013-01-01

    X-ray computed tomography (CT) and fluorescence X-ray computed tomography (FXCT) using synchrotron sources are both useful tools in biomedical imaging research. Synchrotron CT (SRCT) in its various forms is considered an important technique for biomedical imaging since the phase coherence of SR beams can be exploited to obtain images with high contrast resolution. Using a synchrotron as the source for FXCT ensures a fluorescence signal that is optimally detectable by exploiting the beam monochromaticity and polarisation. The ability to combine these techniques so that SRCT and FXCT images are collected simultaneously, would bring distinct benefits to certain biomedical experiments. Simultaneous image acquisition would alleviate some of the registration difficulties which comes from collecting separate data, and it would provide increased information about the sample: functional X-ray images from the FXCT, with the morphological information from the SRCT. A method is presented for generating simultaneous SRCT and FXCT images. Proof of principle modelling has been used to show that it is possible to recover a fluorescence image of a point-like source from an SRCT apparatus by suitably modulating the illuminating planar X-ray beam. The projection image can be successfully used for reconstruction by removing the static modulation from the sinogram in the normal flat and dark field processing. Detection of the modulated fluorescence signal using an energy resolving detector allows the position of a fluorescent marker to be obtained using inverse reconstruction techniques. A discussion is made of particular reconstruction methods which might be applied by utilising both the CT and FXCT data.

  6. Characterization of a spectroscopic detector for application in x-ray computed tomography

    Science.gov (United States)

    Dooraghi, Alex A.; Fix, Brian J.; Smith, Jerel A.; Brown, William D.; Azevedo, Stephen G.; Martz, Harry E.

    2017-09-01

    Recent advances in cadmium telluride (CdTe) energy-discriminating pixelated detectors have enabled the possibility of Multi-Spectral X-ray Computed Tomography (MSXCT) to incorporate spectroscopic information into CT. MultiX ME 100 V2 is a CdTe-based spectroscopic x-ray detector array capable of recording energies from 20 to 160 keV in 1.1 keV energy bin increments. Hardware and software have been designed to perform radiographic and computed tomography tasks with this spectroscopic detector. Energy calibration is examined using the end-point energy of a bremsstrahlung spectrum and radioisotope spectral lines. When measuring the spectrum from Am-241 across 500 detector elements, the standard deviation of the peak-location and FWHM measurements are +/- 0.4 and +/- 0.6 keV, respectively. As these values are within the energy bin size (1.1 keV), detector elements are consistent with each other. The count rate is characterized, using a nonparalyzable model with a dead time of 64 +/- 5 ns. This is consistent with the manufacturer's quoted per detector-element linear-deviation at 2 Mpps (million photons per sec) of 8.9 % (typical) and 12 % (max). When comparing measured and simulated spectra, a low-energy tail is visible in the measured data due to the spectral response of the detector. If no valid photon detections are expected in the low-energy tail, then a background subtraction may be applied to allow for a possible first-order correction. If photons are expected in the low-energy tail, a detailed model must be implemented. A radiograph of an aluminum step wedge with a maximum height of 20 mm shows an underestimation of attenuation by about 10 % at 60 keV. This error is due to partial energy deposition from higher energy (>60 keV) photons into a lower-energy ( 60 keV) bin, reducing the apparent attenuation. A radiograph of a polytetrafluoroethylene (PTFE) cylinder taken using a bremsstrahlung spectrum from an x-ray voltage of 100 kV filtered by 1.3 mm Cu is

  7. Characterization of a spectroscopic detector for application in x-ray computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Dooraghi, A. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Fix, B. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Smith, J. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Brown, W. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Azevedo, S. G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Martz, H. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-04-21

    Recent advances in cadmium telluride (CdTe) energy-discriminating pixelated detectors have enabled the possibility of Multi-Spectral X-ray Computed Tomography (MSXCT) to incorporate spectroscopic information into CT. MultiX ME 100 V2 is a CdTe-based spectroscopic x-ray detector array capable of recording energies from 20 to 160 keV in 1.1 keV energy bin increments. Hardware and software have been designed to perform radiographic and computed tomography tasks with this spectroscopic detector. Energy calibration is examined using the end-point energy of a bremsstrahlung spectrum and radioisotope spectral lines. When measuring the spectrum from Am-241 across 500 detector elements, the standard deviation of the peak-location and FWHM measurements are ±0.4 and ±0.6 keV, respectively. As these values are within the energy bin size (1.1 keV), detector elements are consistent with each other. The count rate is characterized, using a nonparalyzable model with a dead time of 64 ± 5 ns. This is consistent with the manufacturer’s quoted per detector-element linear-deviation at 2 Mpps (million photons per sec) of 8.9% (typical) and 12% (max). When comparing measured and simulated spectra, a low-energy tail is visible in the measured data due to the spectral response of the detector. If no valid photon detections are expected in the low-energy tail, then a background subtraction may be applied to allow for a possible first-order correction. If photons are expected in the low-energy tail, a detailed model must be implemented. A radiograph of an aluminum step wedge with a maximum height of about 20 mm shows an underestimation of attenuation by about 10% at 60 keV. This error is due to partial energy deposition from higher-energy (> 60 keV) photons into a lower-energy (~60 keV) bin, reducing the apparent attenuation. A radiograph of a PTFE cylinder taken using a bremsstrahlung spectrum from an x-ray voltage of 100 kV filtered by 1.3 mm Cu is reconstructed using Abel inversion

  8. Comparison of x-ray computed tomography, through-transmission ultrasound, and low-kV x-ray imaging for characterizing green-state ceramics

    International Nuclear Information System (INIS)

    Roberts, R.A.; Ellingson, W.A.; Vannier, M.W.

    1985-06-01

    Green-state MgAl 2 O 4 compact disk specimens have been studied by x-ray computed tomography (CT), through-transmission pulsed ultrasound, and low-kV x-ray imaging to compare the abilities of these nondestructive evaluation (NDE) methods to detect flaws and density variations. X-ray computed tomographic images were obtained from a 125-kV (peak) imaging system with a 512 x 512 matrix and a pixel size of 100 μm. A 3- to 10- MHz focused-beam ultrasonic transducer was used, together with special immersion techniques, to obtain topographical maps of acoustic attenuation and phase velocity; a 30 x 30 matrix was used in the ultrasonic scans. A 35-kV x-ray system with high-resolution type RR film was used to obtain conventional radiographs. Large-scale nonuniform density gradients were detected with CT and ultrasonics in supposedly uniform ceramic disks. In addition, inclusions in the green-state samples were detected by all three methods, with each method providing certain advantages. The influence of grain structure and other ceramic powder characteristics will be examined in the future. 5 refs., 9 figs

  9. A compact X-ray source based on Compton scattering

    Energy Technology Data Exchange (ETDEWEB)

    Bulyak, E.; Gladkikh, P.; Grigor' ev, Yu.; Guk, I.; Karnaukhov, I.; Khodyachikh, A.; Kononenko, S.; Mocheshnikov, N.; Mytsykov, A.; Shcherbakov, A. E-mail: shcherbakov@kipt.kharkov.ua; Tarasenko, A.; Telegin, Yu.; Zelinsky, A

    2001-07-21

    The main parameters of Kharkov electron storage ring N-100 with a beam energy range from 70 to 150 MeV are presented. The main results that were obtained in experimental researches are briefly described. The future of the N-100 upgrade to the development of the X-ray generator based on Compton back-scattering are presented. The electron beam energy range will be extended up to 250 MeV and the circumference of the storage ring will be 13.72 m. The lattice, parameters of the electron beam and the Compton back-scattering photons flux are described.

  10. A compact X-ray source based on Compton scattering

    International Nuclear Information System (INIS)

    Bulyak, E.; Gladkikh, P.; Grigor'ev, Yu.; Guk, I.; Karnaukhov, I.; Khodyachikh, A.; Kononenko, S.; Mocheshnikov, N.; Mytsykov, A.; Shcherbakov, A.; Tarasenko, A.; Telegin, Yu.; Zelinsky, A.

    2001-01-01

    The main parameters of Kharkov electron storage ring N-100 with a beam energy range from 70 to 150 MeV are presented. The main results that were obtained in experimental researches are briefly described. The future of the N-100 upgrade to the development of the X-ray generator based on Compton back-scattering are presented. The electron beam energy range will be extended up to 250 MeV and the circumference of the storage ring will be 13.72 m. The lattice, parameters of the electron beam and the Compton back-scattering photons flux are described

  11. DETERMINATION OF HLW GLASS MELT RATE USING X-RAY COMPUTED TOMOGRAPHY

    Energy Technology Data Exchange (ETDEWEB)

    Choi, A.; Miller, D.; Immel, D.

    2011-10-06

    , a significant amount of glassy material interspersed among the gas bubbles will be excluded, thus underestimating the melt rate. Likewise, if they are drawn too high, many large voids will be counted as glass, thus overestimating the melt rate. As will be shown later in this report, there is also no guarantee that a given distribution of glass and gas bubbles along a particular sectioned plane will always be representative of the entire sample volume. Poor reproducibility seen in some LMR data may be related to these difficulties of the visual method. In addition, further improvement of the existing melt rate model requires that the overall impact of feed chemistry on melt rate be reflected on measured data at a greater quantitative resolution on a more consistent basis than the visual method can provide. An alternate method being pursued is X-ray computed tomography (CT). It involves X-ray scanning of glass samples, performing CT on the 2-D X-ray images to build 3-D volumetric data, and adaptive segmentation analysis of CT results to not only identify but quantify the distinct regions within each sample based on material density and morphologies. The main advantage of this new method is that it can determine the relative local density of the material remaining in the beaker after the heat treatment regardless of its morphological conditions by selectively excluding all the voids greater than a given volumetric pixel (voxel) size, thus eliminating much of the subjectivity involved in the visual method. As a result, the melt rate data obtained from CT scan will give quantitative descriptions not only on the fully-melted glass, but partially-melted and unmelted feed materials. Therefore, the CT data are presumed to be more reflective of the actual melt rate trends in continuously-fed melters than the visual data. In order to test the applicability of X-ray CT scan to the HLW glass melt rate study, several new series of HLW simulant/frit mixtures were melted in the

  12. Phase-contrast imaging and tomography at 60 keV using a conventional x-ray tube source

    International Nuclear Information System (INIS)

    Donath, Tilman; Bunk, Oliver; Groot, Waldemar; Bednarzik, Martin; Gruenzweig, Christian; David, Christian; Pfeiffer, Franz; Hempel, Eckhard; Popescu, Stefan; Hoheisel, Martin

    2009-01-01

    Phase-contrast imaging at laboratory-based x-ray sources using grating interferometers has been developed over the last few years for x-ray energies of up to 28 keV. Here, we show first phase-contrast projection and tomographic images recorded at significantly higher x-ray energies, produced by an x-ray tube source operated at 100 kV acceleration voltage. We find our measured tomographic phase images in good agreement with tabulated data. The extension of phase-contrast imaging to this significantly higher x-ray energy opens up many applications of the technique in medicine and industrial nondestructive testing.

  13. Performance dependence of hybrid x-ray computed tomography/fluorescence molecular tomography on the optical forward problem.

    Science.gov (United States)

    Hyde, Damon; Schulz, Ralf; Brooks, Dana; Miller, Eric; Ntziachristos, Vasilis

    2009-04-01

    Hybrid imaging systems combining x-ray computed tomography (CT) and fluorescence tomography can improve fluorescence imaging performance by incorporating anatomical x-ray CT information into the optical inversion problem. While the use of image priors has been investigated in the past, little is known about the optimal use of forward photon propagation models in hybrid optical systems. In this paper, we explore the impact on reconstruction accuracy of the use of propagation models of varying complexity, specifically in the context of these hybrid imaging systems where significant structural information is known a priori. Our results demonstrate that the use of generically known parameters provides near optimal performance, even when parameter mismatch remains.

  14. Bone histomorphometric quantification by X-ray phase contrast and transmission 3D SR microcomputed tomography

    International Nuclear Information System (INIS)

    Nogueira, L.P.; Pinheiro, C.J.G.; Braz, D.; Oliveira, L.F.; Barroso, R.C.

    2008-01-01

    Full text: Conventional histomorphometry is an important method for quantitative evaluation of bone microstructure. X-ray computed tomography is a noninvasive technique, which can be used to evaluate histomorphometric indices. In this technique, the output 3D images are used to quantify the whole sample, differently from the conventional one, in which the quantification is performed in 2D slices and extrapolated for 3D case. Looking for better resolutions and visualization of soft tissues, X-ray phase contrast imaging technique was developed. The objective of this work was to perform histomorphometric quantification of human cancellous bone using 3D synchrotron X ray computed microtomography, using two distinct techniques: transmission and phase contrast, in order to compare the results and evaluate the viability of applying the same methodology of quantification for both technique. All experiments were performed at the ELETTRA Synchrotron Light Laboratory in Trieste (Italy). MicroCT data sets were collected using the CT set-up on the SYRMEP (Synchrotron Radiation for Medical Physics) beamline. Results showed that there is a better correlation between histomorphometric parameters of both techniques when morphological filters had been used. However, using these filters, some important information given by phase contrast are lost and they shall be explored by new techniques of quantification

  15. In situ flash x-ray high-speed computed tomography for the quantitative analysis of highly dynamic processes

    Science.gov (United States)

    Moser, Stefan; Nau, Siegfried; Salk, Manfred; Thoma, Klaus

    2014-02-01

    The in situ investigation of dynamic events, ranging from car crash to ballistics, often is key to the understanding of dynamic material behavior. In many cases the important processes and interactions happen on the scale of milli- to microseconds at speeds of 1000 m s-1 or more. Often, 3D information is necessary to fully capture and analyze all relevant effects. High-speed 3D-visualization techniques are thus required for the in situ analysis. 3D-capable optical high-speed methods often are impaired by luminous effects and dust, while flash x-ray based methods usually deliver only 2D data. In this paper, a novel 3D-capable flash x-ray based method, in situ flash x-ray high-speed computed tomography is presented. The method is capable of producing 3D reconstructions of high-speed processes based on an undersampled dataset consisting of only a few (typically 3 to 6) x-ray projections. The major challenges are identified, discussed and the chosen solution outlined. The application is illustrated with an exemplary application of a 1000 m s-1 high-speed impact event on the scale of microseconds. A quantitative analysis of the in situ measurement of the material fragments with a 3D reconstruction with 1 mm voxel size is presented and the results are discussed. The results show that the HSCT method allows gaining valuable visual and quantitative mechanical information for the understanding and interpretation of high-speed events.

  16. Using x-ray computed tomography in hydrology: Systems, resolutions, and limitations

    DEFF Research Database (Denmark)

    Wildenschild, Dorthe; Hopmans, J.W.; Vaz, C.M.P.

    2002-01-01

    media, obtained with different scanning systems and sample sizes, to illustrate advantages and limitations of these various systems, including topics of spatial resolution and contrast. In addition, we present examples of our most recent three-dimensional high-resolution images, for which......A combination of advances in experimental techniques and mathematical analysis has made it possible to characterize phase distribution and pore geometry in porous media using non-destructive X-ray computed tomography (CT). We present qualitative and quantitative CT results for partially saturated...

  17. Inside marginal adaptation of crowns by X-ray micro-computed tomography

    International Nuclear Information System (INIS)

    Dos Santos, T. M.; Lima, I.; Lopes, R. T.; Author, S. B. Jr.

    2015-01-01

    The objective of this work was to access dental arcade by using X-ray micro-computed tomography. For this purpose high resolution system was used and three groups were studied: Zirkonzahn CAD-CAM system, IPS e.max Press, and metal ceramic. The three systems assessed in this study showed results of marginal and discrepancy gaps clinically accepted. The great result of 2D and 3D evaluations showed that the used technique is a powerful method to investigate quantitative characteristics of dental arcade. (authors)

  18. Image covariance and lesion detectability in direct fan-beam x-ray computed tomography.

    Science.gov (United States)

    Wunderlich, Adam; Noo, Frédéric

    2008-05-21

    We consider noise in computed tomography images that are reconstructed using the classical direct fan-beam filtered backprojection algorithm, from both full- and short-scan data. A new, accurate method for computing image covariance is presented. The utility of the new covariance method is demonstrated by its application to the implementation of a channelized Hotelling observer for a lesion detection task. Results from the new covariance method and its application to the channelized Hotelling observer are compared with results from Monte Carlo simulations. In addition, the impact of a bowtie filter and x-ray tube current modulation on reconstruction noise and lesion detectability are explored for full-scan reconstruction.

  19. Inside marginal adaptation of crowns by X-ray micro-computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Dos Santos, T. M.; Lima, I.; Lopes, R. T. [Nuclear Instrumentation Laboratory, Nuclear Engineering Program, Federal University of Rio de Janeiro, RJ, (Brazil); Author, S. B. Jr. [Department of Physics, Colorado State University, Ft. Collins, CO 80523, (United States)

    2015-07-01

    The objective of this work was to access dental arcade by using X-ray micro-computed tomography. For this purpose high resolution system was used and three groups were studied: Zirkonzahn CAD-CAM system, IPS e.max Press, and metal ceramic. The three systems assessed in this study showed results of marginal and discrepancy gaps clinically accepted. The great result of 2D and 3D evaluations showed that the used technique is a powerful method to investigate quantitative characteristics of dental arcade. (authors)

  20. Quantitative analysis of scaling error compensation methods in dimensional X-ray computed tomography

    DEFF Research Database (Denmark)

    Müller, P.; Hiller, Jochen; Dai, Y.

    2015-01-01

    X-ray Computed Tomography (CT) has become an important technology for quality control of industrial components. As with other technologies, e.g., tactile coordinate measurements or optical measurements, CT is influenced by numerous quantities which may have negative impact on the accuracy...... errors of the manipulator system (magnification axis). This article also introduces a new compensation method for scaling errors using a database of reference scaling factors and discusses its advantages and disadvantages. In total, three methods for the correction of scaling errors – using the CT ball...

  1. Damage evolution in TWIP and standard austenitic steel by means of 3D X ray tomography

    Energy Technology Data Exchange (ETDEWEB)

    Fabrègue, D., E-mail: damien.fabregue@insa-lyon.fr [Université de Lyon, CNRS, F-69621 Villeurbanne (France); INSA-Lyon, MATEIS UMR5510, F-69621 Villeurbanne (France); Landron, C. [Université de Lyon, CNRS, F-69621 Villeurbanne (France); INSA-Lyon, MATEIS UMR5510, F-69621 Villeurbanne (France); Bouaziz, O. [ArcelorMittal Research, Voie Romaine-BP30320, F-57283 Maizières les Metz (France); Maire, E. [Université de Lyon, CNRS, F-69621 Villeurbanne (France); INSA-Lyon, MATEIS UMR5510, F-69621 Villeurbanne (France)

    2013-09-01

    The evolution of ductile damage of Fe–22Mn–0.6C austenitic TWIP steel by means of 3D X ray tomography in-situ tensile tests is reported for the first time. The comparison with another fully austenitic steel (316 stainless steel) is also carried out. The damage process of TWIP steel involves intense nucleation of small voids combined with the significant growth of the biggest cavities whereas macroscopical triaxiality remains constant. Due to this high nucleation rate, the average cavity diameter remains constant unlike the 316 stainless steel.

  2. Chest X-ray and computed tomography in the evaluation of pulmonary emphysema

    International Nuclear Information System (INIS)

    Irion, Klaus Loureiro; Porto, Nelson da Silva; Santana, Pablo Rydz

    2007-01-01

    Emphysema is a condition of the lung, characterized by the abnormal increase in the size of the airspace distal to the terminal bronchioles. Currently, emphysema is the fourth leading cause of death in the USA, affecting 14 million people. The present article describes the principal tools in the imaging diagnosis of emphysema, from the early days until the present. We describe traditional techniques, such as chest X-ray, together with the evolution of computed tomography (CT) to more advanced forms, such as high resolution CT, as well as three-dimensional CT densitometry and volumetric assessment. (author)

  3. Advanced X-ray radiography and tomography in several engineering applications

    Czech Academy of Sciences Publication Activity Database

    Vavřík, Daniel; Dammer, J.; Jakůbek, J.; Jeon, I.; Jiroušek, Ondřej; Kroupa, M.; Zlámal, Petr

    2011-01-01

    Roč. 633, č. 1 (2011), s. 152-155 ISSN 0168-9002. [International workshop on radiation imaging detectors /11./. Praha, 26.06.2009-02.07.2009] R&D Projects: GA ČR(CZ) GA103/09/2101 Grant - others:GA MŠk(CZ) LC06041 Program:LC Institutional research plan: CEZ:AV0Z20710524 Keywords : digital radiography * computed tomography * X-ray crack imaging Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 1.207, year: 2011 http://dx.doi.org/10.1016/j.nima.2010.06.152

  4. Image covariance and lesion detectability in direct fan-beam x-ray computed tomography

    International Nuclear Information System (INIS)

    Wunderlich, Adam; Noo, Frederic

    2008-01-01

    We consider noise in computed tomography images that are reconstructed using the classical direct fan-beam filtered backprojection algorithm, from both full- and short-scan data. A new, accurate method for computing image covariance is presented. The utility of the new covariance method is demonstrated by its application to the implementation of a channelized Hotelling observer for a lesion detection task. Results from the new covariance method and its application to the channelized Hotelling observer are compared with results from Monte Carlo simulations. In addition, the impact of a bowtie filter and x-ray tube current modulation on reconstruction noise and lesion detectability are explored for full-scan reconstruction

  5. Artifact Elimination Technique in Tomogram of X-ray Computed Tomography

    International Nuclear Information System (INIS)

    Rasif Mohd Zain

    2015-01-01

    Artifacts of tomogram are main commonly problems occurred in x-ray computed tomography. The artifacts will be appearing in tomogram due to noise, beam hardening, and scattered radiation. The study has been carried out using CdTe time pix detector. The new technique has been developed to eliminate the artifact occurred in hardware and software. The hardware setup involved the careful alignment all of the components of the system and the introduction of a collimator beam. Meanwhile, in software development deal with the flat field correction, noise filter and data projection algorithm. The results show the technique developed produce good quality images and eliminate the artifacts. (author)

  6. X-ray apparatus

    International Nuclear Information System (INIS)

    Sell, L.J.

    1981-01-01

    A diagnostic x-ray device, readily convertible between conventional radiographic and tomographic operating modes, is described. An improved drive system interconnects and drives the x-ray source and the imaging device through coordinated movements for tomography

  7. Imaging-therapy computed tomography with quasi-monochromatic X-rays

    International Nuclear Information System (INIS)

    Jost, Gregor; Golfier, Sven; Lawaczeck, Ruediger; Weinmann, Hanns-Joachim; Gerlach, Martin; Cibik, Levent; Krumrey, Michael; Fratzscher, Daniel; Rabe, Johannis; Arkadiev, Vladimir; Haschke, Michael; Langhoff, Norbert; Wedell, Reiner

    2008-01-01

    Introduction: Computed tomography (CT) is a widespread and highly precise technique working in the energy range around 50-100 keV. For radiotherapy, however, the MeV energy range enables a better dose distribution. This gap between diagnosis and therapy can be overcome by the use of a modified CT machine in combination with heavy elements targeted to the tumour and used as photoelectric radiation enhancer. Materials and methods: The experimental setup consists of an X-ray optical module mounted at the exit of the X-ray tube of a clinical CT. The module converts the standard fan-shaped beam into a high intensity, monochromatized and focused beam. The radiation was characterized using an energy-dispersive detection system calibrated by synchrotron radiation and gel dosimetry. The photoelectric radiation enhancement for different elements was calculated and experimentally verified. Results: The X-ray optical module filters selectively the energy of the tungsten Kα-emission line (59.3 keV) with a full width at half maximum (FWHM) of 5 keV and focused the radiation onto a focal spot which coincides with the isocentre of the gantry. This results in a steep dose gradient at the centre of rotation qualified for locoregional radiation therapy. The photon energy of the quasi-monochromatic radiation agrees with the energy range of maximal photoelectric dose enhancement for gadolinium and iodine. Conclusion: An additional X-ray optical module optimized for targeted therapy and photoelectric dose enhancement allows the combination of diagnosis and radiotherapy on a clinical CT

  8. Imaging-therapy computed tomography with quasi-monochromatic X-rays.

    Science.gov (United States)

    Jost, Gregor; Golfier, Sven; Lawaczeck, Ruediger; Weinmann, Hanns-Joachim; Gerlach, Martin; Cibik, Levent; Krumrey, Michael; Fratzscher, Daniel; Rabe, Johannis; Arkadiev, Vladimir; Haschke, Michael; Langhoff, Norbert; Wedell, Reiner; Luedemann, Lutz; Wust, Peter; Pietsch, Hubertus

    2008-12-01

    Computed tomography (CT) is a widespread and highly precise technique working in the energy range around 50-100 keV. For radiotherapy, however, the MeV energy range enables a better dose distribution. This gap between diagnosis and therapy can be overcome by the use of a modified CT machine in combination with heavy elements targeted to the tumour and used as photoelectric radiation enhancer. The experimental setup consists of an X-ray optical module mounted at the exit of the X-ray tube of a clinical CT. The module converts the standard fan-shaped beam into a high intensity, monochromatized and focused beam. The radiation was characterized using an energy-dispersive detection system calibrated by synchrotron radiation and gel dosimetry. The photoelectric radiation enhancement for different elements was calculated and experimentally verified. The X-ray optical module filters selectively the energy of the tungsten K alpha-emission line (59.3 keV) with a full width at half maximum (FWHM) of 5 keV and focused the radiation onto a focal spot which coincides with the isocentre of the gantry. This results in a steep dose gradient at the centre of rotation qualified for locoregional radiation therapy. The photon energy of the quasi-monochromatic radiation agrees with the energy range of maximal photoelectric dose enhancement for gadolinium and iodine. An additional X-ray optical module optimized for targeted therapy and photoelectric dose enhancement allows the combination of diagnosis and radiotherapy on a clinical CT.

  9. Imaging-therapy computed tomography with quasi-monochromatic X-rays

    Energy Technology Data Exchange (ETDEWEB)

    Jost, Gregor [Bayer Schering Pharma AG, Contrast Media Research, Muellerstrasse 178, 13353 Berlin (Germany)], E-mail: gregor.jost@bayerhealthcare.com; Golfier, Sven [Bayer Schering Pharma AG, Contrast Media Research, Muellerstrasse 178, 13353 Berlin (Germany)], E-mail: sven.golfier@bayerhealthcare.com; Lawaczeck, Ruediger [Bayer Schering Pharma AG, Contrast Media Research, Muellerstrasse 178, 13353 Berlin (Germany)], E-mail: ruediger.lawaczeck@bayerhealthcare.com; Weinmann, Hanns-Joachim [Bayer Schering Pharma AG, Contrast Media Research, Muellerstrasse 178, 13353 Berlin (Germany)], E-mail: hanns-joachim.weinmann@bayerhealthcare.com; Gerlach, Martin [Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, 10587 Berlin (Germany)], E-mail: martin.gerlach@ptb.de; Cibik, Levent [Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, 10587 Berlin (Germany)], E-mail: levent.cibik@ptb.de; Krumrey, Michael [Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, 10587 Berlin (Germany)], E-mail: michael.krumrey@ptb.de; Fratzscher, Daniel [Institute for Scientific Instruments GmbH, Rudower Chaussee 29/31, 12489 Berlin (Germany)], E-mail: Fratzscher@ifg-adlershof.de; Rabe, Johannis [Institute for Scientific Instruments GmbH, Rudower Chaussee 29/31, 12489 Berlin (Germany)], E-mail: Rabe@ifg-adlershof.de; Arkadiev, Vladimir [Institute for Scientific Instruments GmbH, Rudower Chaussee 29/31, 12489 Berlin (Germany)], E-mail: Arkadiev@ifg-adlershof.de; Haschke, Michael [Institute for Scientific Instruments GmbH, Rudower Chaussee 29/31, 12489 Berlin (Germany)], E-mail: Haschke@ifg-adlershof.de; Langhoff, Norbert [Institute for Scientific Instruments GmbH, Rudower Chaussee 29/31, 12489 Berlin (Germany)], E-mail: Langhoff@ifg-adlershof.de; Wedell, Reiner [Institut fuer angewandte Photonik e.V., Rudower Chaussee 29/31, 12489 Berlin (Germany)], E-mail: wedell-iap@ifg-adlershof.de (and others)

    2008-12-15

    Introduction: Computed tomography (CT) is a widespread and highly precise technique working in the energy range around 50-100 keV. For radiotherapy, however, the MeV energy range enables a better dose distribution. This gap between diagnosis and therapy can be overcome by the use of a modified CT machine in combination with heavy elements targeted to the tumour and used as photoelectric radiation enhancer. Materials and methods: The experimental setup consists of an X-ray optical module mounted at the exit of the X-ray tube of a clinical CT. The module converts the standard fan-shaped beam into a high intensity, monochromatized and focused beam. The radiation was characterized using an energy-dispersive detection system calibrated by synchrotron radiation and gel dosimetry. The photoelectric radiation enhancement for different elements was calculated and experimentally verified. Results: The X-ray optical module filters selectively the energy of the tungsten K{alpha}-emission line (59.3 keV) with a full width at half maximum (FWHM) of 5 keV and focused the radiation onto a focal spot which coincides with the isocentre of the gantry. This results in a steep dose gradient at the centre of rotation qualified for locoregional radiation therapy. The photon energy of the quasi-monochromatic radiation agrees with the energy range of maximal photoelectric dose enhancement for gadolinium and iodine. Conclusion: An additional X-ray optical module optimized for targeted therapy and photoelectric dose enhancement allows the combination of diagnosis and radiotherapy on a clinical CT.

  10. Discriminating cosmic muons and X-rays based on rise time using a GEM detector

    Science.gov (United States)

    Wu, Hui-Yin; Zhao, Sheng-Ying; Wang, Xiao-Dong; Zhang, Xian-Ming; Qi, Hui-Rong; Zhang, Wei; Wu, Ke-Yan; Hu, Bi-Tao; Zhang, Yi

    2016-08-01

    Gas electron multiplier (GEM) detectors have been used in cosmic muon scattering tomography and neutron imaging over the last decade. In this work, a triple GEM device with an effective readout area of 10 cm × 10 cm is developed, and a method of discriminating between cosmic muons and X-rays based on rise time is tested. The energy resolution of the GEM detector is tested by 55Fe ray source to prove the GEM detector has a good performance. Analysis of the complete signal-cycles allows us to get the rise time and pulse heights. The experiment result indicates that cosmic muons and X-rays can be discriminated with an appropriate rise time threshold. Supported by National Natural Science Foundation of China (11135002, 11275235, 11405077, 11575073)

  11. A miniature X-ray tube based on carbon nanotube for an intraoral dental radiography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun Jin; Park, Han Beom; Lee, Ju Hyuk; Cho, Sung Oh [KAIST, Daejeon (Korea, Republic of)

    2016-05-15

    The number of human teeth that can be radiographically taken is limited. Moreover, at least two X-ray shots are required to get images of teeth from both sides of the mouth. In order to overcome the disadvantages of conventional dental radiography, a dental radiograph has been proposed in which an X-ray tube is inserted into the mouth while an X-ray detector is placed outside the mouth. The miniature X-ray tube is required small size to insert into the mouth. Recently, we have fabricated a miniature x-ray tube with the diameter of 7 mm using a carbon nanotube (CNT) field. But, commercialized miniature X-ray tube were adopted a thermionic type using tungsten filament. The X-ray tubes adopted thermionic emission has a disadvantage of increasing temperature of x-ray tube. So it need to cooling system to cool x-ray tube. On the other hands, X-ray tubes adopted CNT field emitters don't need cooling systems because electrons are emitted from CNT by applying high voltage without heating. We have developed the miniature x-ray tube that produce x-ray with uniform spatial distribution based on carbon nanotube field emitters. The fabricated miniature x-ray tube can be stably and reliably operated at 50kV without any vacuum pump. The developed miniature X-ray tube was applied for intraoral dental radiography that employs an intra-oral CNT-based miniature X-ray tube and extra-oral X-ray detectors. An X-ray image of many teeth was successfully obtained by a single X-ray shot using the intra-oral miniature X-ray tube system. Furthermore, images of both molar teeth of pig were simultaneously obtained by a single X-ray shot. These results show that the intraoral dental radiography, which employs an intraoral miniature X-ray tube and an extraoral X-ray detector, performs better than conventional dental radiography.

  12. A miniature X-ray tube based on carbon nanotube for an intraoral dental radiography

    International Nuclear Information System (INIS)

    Kim, Hyun Jin; Park, Han Beom; Lee, Ju Hyuk; Cho, Sung Oh

    2016-01-01

    The number of human teeth that can be radiographically taken is limited. Moreover, at least two X-ray shots are required to get images of teeth from both sides of the mouth. In order to overcome the disadvantages of conventional dental radiography, a dental radiograph has been proposed in which an X-ray tube is inserted into the mouth while an X-ray detector is placed outside the mouth. The miniature X-ray tube is required small size to insert into the mouth. Recently, we have fabricated a miniature x-ray tube with the diameter of 7 mm using a carbon nanotube (CNT) field. But, commercialized miniature X-ray tube were adopted a thermionic type using tungsten filament. The X-ray tubes adopted thermionic emission has a disadvantage of increasing temperature of x-ray tube. So it need to cooling system to cool x-ray tube. On the other hands, X-ray tubes adopted CNT field emitters don't need cooling systems because electrons are emitted from CNT by applying high voltage without heating. We have developed the miniature x-ray tube that produce x-ray with uniform spatial distribution based on carbon nanotube field emitters. The fabricated miniature x-ray tube can be stably and reliably operated at 50kV without any vacuum pump. The developed miniature X-ray tube was applied for intraoral dental radiography that employs an intra-oral CNT-based miniature X-ray tube and extra-oral X-ray detectors. An X-ray image of many teeth was successfully obtained by a single X-ray shot using the intra-oral miniature X-ray tube system. Furthermore, images of both molar teeth of pig were simultaneously obtained by a single X-ray shot. These results show that the intraoral dental radiography, which employs an intraoral miniature X-ray tube and an extraoral X-ray detector, performs better than conventional dental radiography

  13. Quantifying the distribution of paste-void spacing of hardened cement paste using X-ray computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Tae Sup, E-mail: taesup@yonsei.ac.kr [School of Civil and Environmental Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-749 (Korea, Republic of); Kim, Kwang Yeom, E-mail: kimky@kict.re.kr [Korea Institute of Construction Technology, 283 Goyangdae-ro, Ilsanseo-gu, Goyang, 411-712 (Korea, Republic of); Choo, Jinhyun, E-mail: jinhyun@stanford.edu [Department of Civil and Environmental Engineering, Stanford University, Stanford, CA 94305 (United States); Kang, Dong Hun, E-mail: timeriver@naver.com [School of Civil and Environmental Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-749 (Korea, Republic of)

    2012-11-15

    The distribution of paste-void spacing in cement-based materials is an important feature related to the freeze-thaw durability of these materials, but its reliable estimation remains an unresolved problem. Herein, we evaluate the capability of X-ray computed tomography (CT) for reliable quantification of the distribution of paste-void spacing. Using X-ray CT images of three mortar specimens having different air-entrainment characteristics, we calculate the distributions of paste-void spacing of the specimens by applying previously suggested methods for deriving the exact spacing of air-void systems. This methodology is assessed by comparing the 95th percentile of the cumulative distribution function of the paste-void spacing with spacing factors computed by applying the linear-traverse method to 3D air-void system and reconstructing equivalent air-void distribution in 3D. Results show that the distributions of equivalent void diameter and paste-void spacing follow lognormal and normal distributions, respectively, and the ratios between the 95th percentile paste-void spacing value and the spacing factors reside within the ranges reported by previous numerical studies. This experimental finding indicates that the distribution of paste-void spacing quantified using X-ray CT has the potential to be the basis for a statistical assessment of the freeze-thaw durability of cement-based materials. - Highlights: Black-Right-Pointing-Pointer The paste-void spacing in 3D can be quantified by X-ray CT. Black-Right-Pointing-Pointer The distribution of the paste-void spacing follows normal distribution. Black-Right-Pointing-Pointer The spacing factor and 95th percentile of CDF of paste-void spacing are correlated.

  14. Time-resolved X-ray diffraction with accelerator- and laser-plasma-based X-ray sources

    International Nuclear Information System (INIS)

    Nicoul, Matthieu

    2010-01-01

    Femtosecond X-ray pulses are a powerful tool to investigate atomic motions triggered by femtosecond pump pulses. This thesis is dedicated to the production of such pulses and their use in optical pump - X-ray probe measurement. This thesis describes the laser-plasma-based sources available at the University of Duisburg-Essen. Part of it consists of the description of the design, built-up and characterization of a new ''modular'' X-ray source dedicated to optimize the X-ray flux onto the sample under investigation. The acoustic wave generation in femtosecond optically excited semiconductor (gallium arsenide) and metal (gold) was performed using the sources of the University of Duisburg-Essen. The physical answer of the material was modeled by a simple strain model for the semiconductor, pressure model for the metal, in order to gain information on the interplay of the electronic and thermal pressures rising after excitation. Whereas no reliable information could be obtain in gallium arsenide (principally due to the use of a bulk), the model for gold achieved very good agreement, providing useful information. The relaxation time of the electron to lattice energy was found to be (5.0±0.3) ps, and the ratio of the Grueneisen parameters was found to be γ e / γ i = (0.5±0.1). This thesis also describes the Sub-Picosecond Pulse Source (SPPS) which existed at the (formally) Stanford Linear Accelerator Center, an accelerator-based X-ray source, and two measurements performed with it. The first one is the detailed investigation of the phonon softening of the A 1g mode launch in bismuth upon fluence excitation. Detailed information concerning the new equilibrium position and phonon frequency were obtained over extended laser pump fluences. The second measurement concerned the study of the liquid phase dynamics in a newly formed liquid phase following ultrafast melting in indium antimonide. The formation of the liquid phase and its development for excitations close to the

  15. Time-resolved X-ray diffraction with accelerator- and laser-plasma-based X-ray sources

    Energy Technology Data Exchange (ETDEWEB)

    Nicoul, Matthieu

    2010-09-01

    Femtosecond X-ray pulses are a powerful tool to investigate atomic motions triggered by femtosecond pump pulses. This thesis is dedicated to the production of such pulses and their use in optical pump - X-ray probe measurement. This thesis describes the laser-plasma-based sources available at the University of Duisburg-Essen. Part of it consists of the description of the design, built-up and characterization of a new ''modular'' X-ray source dedicated to optimize the X-ray flux onto the sample under investigation. The acoustic wave generation in femtosecond optically excited semiconductor (gallium arsenide) and metal (gold) was performed using the sources of the University of Duisburg-Essen. The physical answer of the material was modeled by a simple strain model for the semiconductor, pressure model for the metal, in order to gain information on the interplay of the electronic and thermal pressures rising after excitation. Whereas no reliable information could be obtain in gallium arsenide (principally due to the use of a bulk), the model for gold achieved very good agreement, providing useful information. The relaxation time of the electron to lattice energy was found to be (5.0{+-}0.3) ps, and the ratio of the Grueneisen parameters was found to be {gamma}{sub e} / {gamma}{sub i} = (0.5{+-}0.1). This thesis also describes the Sub-Picosecond Pulse Source (SPPS) which existed at the (formally) Stanford Linear Accelerator Center, an accelerator-based X-ray source, and two measurements performed with it. The first one is the detailed investigation of the phonon softening of the A{sub 1g} mode launch in bismuth upon fluence excitation. Detailed information concerning the new equilibrium position and phonon frequency were obtained over extended laser pump fluences. The second measurement concerned the study of the liquid phase dynamics in a newly formed liquid phase following ultrafast melting in indium antimonide. The formation of the liquid phase

  16. Observation of glassy state relaxation during annealing of frozen sugar solutions by X-ray computed tomography.

    Science.gov (United States)

    Nakagawa, Kyuya; Tamiya, Shinri; Do, Gabsoo; Kono, Shinji; Ochiai, Takaaki

    2018-06-01

    Glassy phase formation in a frozen product determines various properties of the freeze-dried products. When an aqueous solution is subjected to freezing, a glassy phase forms as a consequence of freeze-concentration. During post-freezing annealing, the relaxation of the glassy phase and the ripening of ice crystals (i.e. Ostwald ripening) spontaneously occur, where the kinetics are controlled by the annealing and glass transition temperatures. This study was motivated to observe the progress of glassy state relaxation separate from ice coarsening during annealing. X-ray computed tomography (CT) was used to observe a frozen and post-freezing annealed solutions by using monochromatized X-ray from the synchrotron radiation. CT images were successfully obtained, and the frozen matrix were analyzed based on the gray level values that were equivalent to the linear X-ray attenuation coefficients of the observed matters. The CT images obtained from rapidly frozen sucrose and dextrin solutions with different concentrations gave clear linear relationships between the linear X-ray attenuation coefficients values and the solute concentrations. It was confirmed that the glassy state relaxation progressed as increasing annealing time, and this trend was larger in the order of the glass transition temperature of the maximally freeze-concentrated phase. The sucrose-water system required nearly 20 h of annealing time at -5 °C for the completion of the glassy phase relaxation, whereas dextrin-water systems required much longer periods because of their higher glass transition temperatures. The trends of ice coarsening, however, did not perfectly correspond to the trends of the relaxation, suggesting that the glassy phase relaxation and Ostwald ripening would jointly control the ice crystal growth/ripening kinetics, and the dominant mechanism differed by the annealing stage. Copyright © 2018 Elsevier B.V. All rights reserved.

  17. Computational Methods for Nanoscale X-ray Computed Tomography Image Analysis of Fuel Cell and Battery Materials

    Science.gov (United States)

    Kumar, Arjun S.

    optics. We solve for the artifact-free images through an optimization function that uses novel edge detection and fast image interpolation methods. We use this optics-based segmentation method in two main research problems - 1) the characterization of a failure mechanism in the internal structure of Li-ion battery electrodes and 2) the measurement of Li metal dendrite morphology for different current and temperature parameters of Li-ion battery cell operation. The second problem we address is the development of a space+time (4D) reconstruction method for in-operando imaging of samples undergoing temporal change, particularly for X-ray sources with low throughput and nanoscale spatial resolutions. The challenge in using such systems is achieving a sufficient temporal resolution despite exposure times of a 2D projection on the order of 1 minute. We develop a 4D dynamic X-ray computed tomography (CT) reconstruction method, capable of reconstructing a temporal 3D image every 2 to 8 projections. Its novel properties are its projection angle sequence and the probabilistic detection of experimental change. We show its accuracy on phantom and experimental datasets to show its promise in temporally resolving Li metal dendrite growth and in elucidating mitigation strategies.

  18. An Intraoral Miniature X-ray Tube Based on Carbon Nanotubes for Dental Radiography

    Directory of Open Access Journals (Sweden)

    Hyun Jin Kim

    2016-06-01

    Full Text Available A miniature X-ray tube based on a carbon-nanotube electron emitter has been employed for the application to a dental radiography. The miniature X-ray tube has an outer diameter of 7 mm and a length of 47 mm. The miniature X-ray tube is operated in a negative high-voltage mode in which the X-ray target is electrically grounded. In addition, X-rays are generated only to the teeth directions using a collimator while X-rays generated to other directions are shielded. Hence, the X-ray tube can be safely inserted into a human mouth. Using the intra-oral X-ray tube, a dental radiography is demonstrated where the positions of an X-ray source and a sensor are reversed compared with a conventional dental radiography system. X-ray images of five neighboring teeth are obtained and, furthermore, both left and right molar images are achieved by a single X-ray shot of the miniature X-ray tube.

  19. An intraoral miniature x-ray tube based on carbon nanotubes for dental radiography

    International Nuclear Information System (INIS)

    Kim, Hyun Jin; Kim, Hyun Nam; Raza, Hamid Saeed; Park, Han Beom; Cho, Sung Oh

    2016-01-01

    A miniature X-ray tube based on a carbon-nanotube electron emitter has been employed for the application to a dental radiography. The miniature X-ray tube has an outer diameter of 7 mm and a length of 47 mm. The miniature X-ray tube is operated in a negative high-voltage mode in which the X-ray target is electrically grounded. In addition, X-rays are generated only to the teeth directions using a collimator while X-rays generated to other directions are shielded. Hence, the X-ray tube can be safely inserted into a human mouth. Using the intra-oral X-ray tube, a dental radiography is demonstrated where the positions of an X-ray source and a sensor are reversed compared with a conventional dental radiography system. X-ray images of five neighboring teeth are obtained and, furthermore, both left and right molar images are achieved by a single X-ray shot of the miniature X-ray tube

  20. An intraoral miniature x-ray tube based on carbon nanotubes for dental radiography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun Jin; Kim, Hyun Nam; Raza, Hamid Saeed; Park, Han Beom; Cho, Sung Oh [Dept. of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2016-06-15

    A miniature X-ray tube based on a carbon-nanotube electron emitter has been employed for the application to a dental radiography. The miniature X-ray tube has an outer diameter of 7 mm and a length of 47 mm. The miniature X-ray tube is operated in a negative high-voltage mode in which the X-ray target is electrically grounded. In addition, X-rays are generated only to the teeth directions using a collimator while X-rays generated to other directions are shielded. Hence, the X-ray tube can be safely inserted into a human mouth. Using the intra-oral X-ray tube, a dental radiography is demonstrated where the positions of an X-ray source and a sensor are reversed compared with a conventional dental radiography system. X-ray images of five neighboring teeth are obtained and, furthermore, both left and right molar images are achieved by a single X-ray shot of the miniature X-ray tube.

  1. Mechanical behaviour and rupture in clayey rocks studied by x-ray micro tomography

    International Nuclear Information System (INIS)

    Lenoir, N.

    2006-03-01

    Within the framework of feasibility studies of underground repositories for radioactive waste, the study of permeability evolution with damage of the host layer is crucial. The goals of this work were: (i) to characterize experimentally the damage of two clayey rocks (BEAUCAIRE MARL and EAST SHALE) with x-ray micro tomography, (ii) to develop a high pressure triaxial set-up adapted to permeability measurement on very low permeability rocks.A number of original triaxial devices have been realised to characterize damage of clayey rocks, under deviatoric loading, with x-ray micro tomography on a synchrotron beamline at the ESRF (Grenoble). Localized damage and its evolution have been characterized at a fine scale (of order of ten microns). Digital image correlation techniques, extended to 3d images, have been used to measure incremental strain fields from tomographic images. we demonstrated that these techniques are very useful in the study of the localized damage of geo-materials and especially for the initiation. A high pressure triaxial device has been realised to measure permeability evolution of the east shale as a function of applied stress (isotropic and deviatoric). The particularity of this set-up is the small size of the test specimen (cylinder of 10 mm in diameter and 20 mm in height) which allows significant reduction of test duration. (author)

  2. Characterization by X-ray tomography of granulated alumina powder during in situ die compaction

    Energy Technology Data Exchange (ETDEWEB)

    Cottrino, Sandrine; Jorand, Yves, E-mail: yves.jorand@insa-lyon.fr; Maire, Eric; Adrien, Jérôme

    2013-07-15

    Compaction process, the aim of which being to obtain green bodies with low porosity and small size, is often used before sintering treatment. Prior to die filling, the ceramic powder is generally granulated to improve flowability. However during compaction, density heterogeneity and critical size defects may appear due to intergranule and granule-die wall frictions. In this work, the influence of granule formulation on the compact morphology has been studied. To do so, a compaction setup was installed inside an X-ray tomography equipment so that the evolution of the compact morphology could be analysed during the whole compaction process. We have demonstrated that high humidity rate and the addition of binder in the granule formulation increase density heterogeneity and generate larger defects. - Highlights: • An original compaction set up was installed inside an X-Ray tomography equipment. • The compaction process of granulated ceramic powder is imaged. • The compact green microstructure is quantified and related to the compaction stages. • The most detrimental defects of dry-pressed parts are caused by hollow granules. • Formulations without binder allow a reduction of the number of large defects.

  3. Application of X-ray Computed Tomography to Cultural Heritage diagnostics

    International Nuclear Information System (INIS)

    Morigi, M.P.; Casali, F.; Bettuzzi, M.; Brancaccio, R.; D'Errico, V.

    2010-01-01

    Physical methods of diagnosis are more and more frequently applied in the field of Cultural Heritage either for scientific investigations or for restoration and conservation purposes. X-ray Computed Tomography (CT) is one of the most powerful non-destructive testing techniques for the full-volume inspection of an object, as it is able to give morphological and physical information on the inner structure of the investigated sample. The great variety of size and composition that characterizes archaeological findings and art objects requires the development of tomographic systems specifically designed for Cultural Heritage analysis. In the last few years our research group has developed several acquisition systems for Digital Radiography and X-ray CT. We are able to perform high resolution micro-tomography of small objects (voxel size of few microns) as well as CT of large objects (up to 2 m of size). In this paper we will mainly focus the attention on the results of the investigation recently performed on two Japanese wooden statues with our CT system for large works of art. The CT analysis was carried out on site at the Conservation and Restoration Center ''La Venaria Reale'', where the statues have been restored before their exposition at the Oriental Art Museum in Turin. (orig.)

  4. A General Method for Motion Compensation in X-ray Computed Tomography

    CERN Document Server

    AUTHOR|(CDS)2067162; Dosanjh, Manjit; Soleimani, Manuchehr

    2017-01-01

    Motion during data acquisition is a known source of error in medical tomography, resulting in blur artefacts in the regions that move. It is critical to reduce these artefacts in applications such as image-guided radiation therapy as a clearer image translates into a more accurate treatment and the sparing of healthy tissue close to a tumour site. Most research in 4D X-ray tomography involving the thorax relies on respiratory phase binning of the acquired data and reconstructing each of a set of images using the limited subset of data per phase. In this work, we demonstrate a motion-compensation method to reconstruct images from the complete dataset taken during breathing without recourse to phase-binning or breath-hold techniques. As long as the motion is sufficiently well known, the new method can accurately reconstruct an image at any time during the acquisition time span. It can be applied to any iterative reconstruction algorithm.

  5. A convolutional neural network approach to calibrating the rotation axis for X-ray computed tomography.

    Science.gov (United States)

    Yang, Xiaogang; De Carlo, Francesco; Phatak, Charudatta; Gürsoy, Dogˇa

    2017-03-01

    This paper presents an algorithm to calibrate the center-of-rotation for X-ray tomography by using a machine learning approach, the Convolutional Neural Network (CNN). The algorithm shows excellent accuracy from the evaluation of synthetic data with various noise ratios. It is further validated with experimental data of four different shale samples measured at the Advanced Photon Source and at the Swiss Light Source. The results are as good as those determined by visual inspection and show better robustness than conventional methods. CNN has also great potential for reducing or removing other artifacts caused by instrument instability, detector non-linearity, etc. An open-source toolbox, which integrates the CNN methods described in this paper, is freely available through GitHub at tomography/xlearn and can be easily integrated into existing computational pipelines available at various synchrotron facilities. Source code, documentation and information on how to contribute are also provided.

  6. A general method for motion compensation in x-ray computed tomography.

    Science.gov (United States)

    Biguri, Ander; Dosanjh, Manjit; Hancock, Steven; Soleimani, Manuchehr

    2017-07-24

    Motion during data acquisition is a known source of error in medical tomography, resulting in blur artefacts in the regions that move. It is critical to reduce these artefacts in applications such as image-guided radiation therapy as a clearer image translates into a more accurate treatment and the sparing of healthy tissue close to a tumour site. Most research in 4D x-ray tomography involving the thorax relies on respiratory phase binning of the acquired data and reconstructing each of a set of images using the limited subset of data per phase. In this work, we demonstrate a motion-compensation method to reconstruct images from the complete dataset taken during breathing without recourse to phase-binning or breath-hold techniques. As long as the motion is sufficiently well known, the new method can accurately reconstruct an image at any time during the acquisition time span. It can be applied to any iterative reconstruction algorithm.

  7. A multiresolution approach to iterative reconstruction algorithms in X-ray computed tomography.

    Science.gov (United States)

    De Witte, Yoni; Vlassenbroeck, Jelle; Van Hoorebeke, Luc

    2010-09-01

    In computed tomography, the application of iterative reconstruction methods in practical situations is impeded by their high computational demands. Especially in high resolution X-ray computed tomography, where reconstruction volumes contain a high number of volume elements (several giga voxels), this computational burden prevents their actual breakthrough. Besides the large amount of calculations, iterative algorithms require the entire volume to be kept in memory during reconstruction, which quickly becomes cumbersome for large data sets. To overcome this obstacle, we present a novel multiresolution reconstruction, which greatly reduces the required amount of memory without significantly affecting the reconstructed image quality. It is shown that, combined with an efficient implementation on a graphical processing unit, the multiresolution approach enables the application of iterative algorithms in the reconstruction of large volumes at an acceptable speed using only limited resources.

  8. A general method for motion compensation in x-ray computed tomography

    Science.gov (United States)

    Biguri, Ander; Dosanjh, Manjit; Hancock, Steven; Soleimani, Manuchehr

    2017-08-01

    Motion during data acquisition is a known source of error in medical tomography, resulting in blur artefacts in the regions that move. It is critical to reduce these artefacts in applications such as image-guided radiation therapy as a clearer image translates into a more accurate treatment and the sparing of healthy tissue close to a tumour site. Most research in 4D x-ray tomography involving the thorax relies on respiratory phase binning of the acquired data and reconstructing each of a set of images using the limited subset of data per phase. In this work, we demonstrate a motion-compensation method to reconstruct images from the complete dataset taken during breathing without recourse to phase-binning or breath-hold techniques. As long as the motion is sufficiently well known, the new method can accurately reconstruct an image at any time during the acquisition time span. It can be applied to any iterative reconstruction algorithm.

  9. Identification of strain fields in pure Al and hybrid Ni/Al metal foams using X-ray micro-tomography under loading

    International Nuclear Information System (INIS)

    Fíla, T.; Jiroušek, O.; Jung, A.; Kumpová, I.

    2016-01-01

    Hybrid foams are materials formed by a core from a standard open cell metal foam that is during the process of electrodeposition coated by a thin layer of different nanocrystalline metals. The material properties of the base metal foam are in this way modified resulting in higher plateau stress and, more importantly, by introduction of strain-rate dependence to its deformation response. In this paper, we used time-lapse X-ray micro-tomography for the mechanical characterization of Ni/Al hybrid foams (aluminium open cell foams with nickel coating layer). To fully understand the effects of the coating layer on the material's effective properties, we compared the compressive response of the base uncoated foam to the response of the material with coating thickness of 50 and 75 μm. Digital volume correlation (DVC) was applied to obtain volumetric strain fields of the deforming micro-structure up to the densification region of the deforming cellular structure. The analysis was performed as a compressive mechanical test with simultaneous observation using X-ray radiography and tomography. A custom design experimental device was used for compression of the foam specimens in several deformation states directly in the X-ray setup. Planar X-ray images were taken during the loading phases and a X-ray tomography was performed at the end of each loading phase (up to engineering strain 22%). The samples were irradiated using micro-focus reflection type X-ray tube and images were taken using a large area flat panel detector. Tomography reconstructions were used for an identification of a strain distribution in the foam using digital volumetric correlation. A comparison of the deformation response of the coated and the uncoated foam in uniaxial quasi-static compression is summarized in the paper.

  10. Biological soft X-ray tomography on beamline 2.1 at the Advanced Light Source.

    Science.gov (United States)

    Le Gros, Mark A; McDermott, Gerry; Cinquin, Bertrand P; Smith, Elizabeth A; Do, Myan; Chao, Weilun L; Naulleau, Patrick P; Larabell, Carolyn A

    2014-11-01

    Beamline 2.1 (XM-2) is a transmission soft X-ray microscope in sector 2 of the Advanced Light Source at Lawrence Berkeley National Laboratory. XM-2 was designed, built and is now operated by the National Center for X-ray Tomography as a National Institutes of Health Biomedical Technology Research Resource. XM-2 is equipped with a cryogenic rotation stage to enable tomographic data collection from cryo-preserved cells, including large mammalian cells. During data collection the specimen is illuminated with `water window' X-rays (284-543 eV). Illuminating photons are attenuated an order of magnitude more strongly by biomolecules than by water. Consequently, differences in molecular composition generate quantitative contrast in images of the specimen. Soft X-ray tomography is an information-rich three-dimensional imaging method that can be applied either as a standalone technique or as a component modality in correlative imaging studies.

  11. Projection-type X-ray microscope based on a spherical compound refractive X-ray lens

    OpenAIRE

    Dudchik, Yu. I.; Gary, C. K.; Park, H.; Pantell, R. H.; Piestrup, M. A.

    2007-01-01

    New projection- type X-ray microscope with a compound refractive lens as the optical element is presented. The microscope consists of an X-ray source that is 1-2 mm in diameter, compound X-ray lens and X-ray camera that are placed in-line to satisfy the lens formula. The lens forms an image of the X-ray source at camera sensitive plate. An object is placed between the X-ray source and the lens as close as possible to the source, and the camera shows a shadow image of the object. Spatial resol...

  12. Simulation and application of micro X-ray fluorescence based on an ellipsoidal capillary

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jing; Li, Yude; Wang, Xingyi; Zhang, Xiaoyun; Lin, Xiaoyan, E-mail: yangjing_928@126.com

    2017-06-15

    Highlights: • A micro X-ray fluorescence setup based on an ellipsoidal capillary was presented. • The optimal parameters of ellipsoidal capillary were designed. • The 2D mapping image of biological sample was obtained. - Abstract: A micro X-ray fluorescence setup was presented, based on an ellipsoidal capillary and a traditional laboratorial X-ray source. Using Ray-tracing principle, we have simulated the transmission path of X-ray beam in the ellipsoidal capillary and designed the optimal parameters of the ellipsoidal capillary for the micro X-ray fluorescence setup. We demonstrate that ellipsoidal capillary is well suited as condenser for the micro X-ray fluorescence based on traditional laboratorial X-ray source. Furthermore, we obtain the 2D mapping image of the leaf blade sample by using the ellipsoidal capillary we designed.

  13. Patient size and x-ray technique factors in head computed tomography examinations. I. Radiation doses

    International Nuclear Information System (INIS)

    Huda, Walter; Lieberman, Kristin A.; Chang, Jack; Roskopf, Marsha L.

    2004-01-01

    We investigated how patient age, size and composition, together with the choice of x-ray technique factors, affect radiation doses in head computed tomography (CT) examinations. Head size dimensions, cross-sectional areas, and mean Hounsfield unit (HU) values were obtained from head CT images of 127 patients. For radiation dosimetry purposes patients were modeled as uniform cylinders of water. Dose computations were performed for 18x7 mm sections, scanned at a constant 340 mAs, for x-ray tube voltages ranging from 80 to 140 kV. Values of mean section dose, energy imparted, and effective dose were computed for patients ranging from the newborn to adults. There was a rapid growth of head size over the first two years, followed by a more modest increase of head size until the age of 18 or so. Newborns have a mean HU value of about 50 that monotonically increases with age over the first two decades of life. Average adult A-P and lateral dimensions were 186±8 mm and 147±8 mm, respectively, with an average HU value of 209±40. An infant head was found to be equivalent to a water cylinder with a radius of ∼60 mm, whereas an adult head had an equivalent radius 50% greater. Adult males head dimensions are about 5% larger than for females, and their average x-ray attenuation is ∼20 HU greater. For adult examinations performed at 120 kV, typical values were 32 mGy for the mean section dose, 105 mJ for the total energy imparted, and 0.64 mSv for the effective dose. Increasing the x-ray tube voltage from 80 to 140 kV increases patient doses by about a factor of 5. For the same technique factors, mean section doses in infants are 35% higher than in adults. Energy imparted for adults is 50% higher than for infants, but infant effective doses are four times higher than for adults. CT doses need to take into account patient age, head size, and composition as well as the selected x-ray technique factors

  14. Pulmonary tumor measurements from x-ray computed tomography in one, two, and three dimensions.

    Science.gov (United States)

    Villemaire, Lauren; Owrangi, Amir M; Etemad-Rezai, Roya; Wilson, Laura; O'Riordan, Elaine; Keller, Harry; Driscoll, Brandon; Bauman, Glenn; Fenster, Aaron; Parraga, Grace

    2011-11-01

    We evaluated the accuracy and reproducibility of three-dimensional (3D) measurements of lung phantoms and patient tumors from x-ray computed tomography (CT) and compared these to one-dimensional (1D) and two-dimensional (2D) measurements. CT images of three spherical and three irregularly shaped tumor phantoms were evaluated by three observers who performed five repeated measurements. Additionally, three observers manually segmented 29 patient lung tumors five times each. Follow-up imaging was performed for 23 tumors and response criteria were compared. For a single subject, imaging was performed on nine occasions over 2 years to evaluate multidimensional tumor response. To evaluate measurement accuracy, we compared imaging measurements to ground truth using analysis of variance. For estimates of precision, intraobserver and interobserver coefficients of variation and intraclass correlations (ICC) were used. Linear regression and Pearson correlations were used to evaluate agreement and tumor response was descriptively compared. For spherical shaped phantoms, all measurements were highly accurate, but for irregularly shaped phantoms, only 3D measurements were in high agreement with ground truth measurements. All phantom and patient measurements showed high intra- and interobserver reproducibility (ICC >0.900). Over a 2-year period for a single patient, there was disagreement between tumor response classifications based on 3D measurements and those generated using 1D and 2D measurements. Tumor volume measurements were highly reproducible and accurate for irregular, spherical phantoms and patient tumors with nonuniform dimensions. Response classifications obtained from multidimensional measurements suggest that 3D measurements provide higher sensitivity to tumor response. Copyright © 2011 AUR. Published by Elsevier Inc. All rights reserved.

  15. Correlative cryogenic tomography of cells using light and soft x-rays

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Elizabeth A.; Cinquin, Bertrand P.; Do, Myan; McDermott, Gerry [Department of Anatomy, School of Medicine, University of California San Francisco, San Francisco, CA (United States); National Center for X-ray Tomography, Advanced Light Source, Berkeley, CA (United States); Le Gros, Mark A., E-mail: MALegros@lbl.gov [Department of Anatomy, School of Medicine, University of California San Francisco, San Francisco, CA (United States); Physical BioSciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA (United States); National Center for X-ray Tomography, Advanced Light Source, Berkeley, CA (United States); Larabell, Carolyn A., E-mail: carolyn.larabell@ucsf.edu [Department of Anatomy, School of Medicine, University of California San Francisco, San Francisco, CA (United States); Physical BioSciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA (United States); National Center for X-ray Tomography, Advanced Light Source, Berkeley, CA (United States)

    2014-08-01

    Correlated imaging is the process of imaging a specimen with two complementary modalities, and then combining the two data sets to create a highly informative, composite view. A recent implementation of this concept has been the combination of soft x-ray tomography (SXT) with fluorescence cryogenic microscopy (FCM). SXT–FCM is used to visualize cells that are held in a near-native, cryopreserved. The resultant images are, therefore, highly representative of both the cellular architecture and molecular organization in vivo. SXT quantitatively visualizes the cell and sub-cellular structures; FCM images the spatial distribution of fluorescently labeled molecules. Here, we review the characteristics of SXT–FCM, and briefly discuss how this method compares with existing correlative imaging techniques. We also describe how the incorporation of a cryo-rotation stage into a cryogenic fluorescence microscope allows acquisition of fluorescence cryogenic tomography (FCT) data. FCT is optimally suited for correlation with SXT, since both techniques image the specimen in 3-D, potentially with similar, isotropic spatial resolution. - Highlights: • We describe a new correlated imaging modality: soft x-ray tomography combined (SXT) with confocal fluorescence tomography (CFT). • Data from the two modalities are combined accurately and precisely using fiducials visible in both types of data. • Cells imaged by SXT–CFT are maintained close to their native state by cryo-preservation. • SXT–CFT is applicable to most cell types, especially cells grown in suspension. • ‘Super-resolution’ microscopes being developed for CFT data acquisition match the spatial resolution of SXT.

  16. Construction and Test of Low Cost X-Ray Tomography Scanner for Physical-Chemical Analysis and Nondestructive Inspections

    International Nuclear Information System (INIS)

    Oliveira, Jose Martins Jr. de; Martins, Antonio Cesar Germano

    2009-01-01

    X-ray computed tomography (CT) refers to the cross-sectional imaging of an object measuring the transmitted radiation at different directions. In this work, we describe the development of a low cost micro-CT X-ray scanner that is being developed for nondestructive testing. This tomograph operates using a microfocus X-ray source and contains a silicon photodiode as detectors. The performance of the system, by its spatial resolution, has been estimated through its Modulation Transfer Function-MTF and the obtained value at 10% of MTF is 661 μm. It was built as a general purpose nondestructive testing device.

  17. Position sensitive X-ray or X-ray detector and 3-D-tomography using same

    International Nuclear Information System (INIS)

    1975-01-01

    A fan-shaped beam of penetrating radiation, such as X-ray or γ-ray radiation, is directed through a slice of the body to be analyzed into a position sensitive detector for deriving a shadowgraph of transmission or absorption of the penetrating radiation by the body. A number of such shadowgraphs are obtained for different angles of rotation of the fan-shaped beam relative to the center of the slice being analyzed. The detected fan beam shadowgraph data is reordered into shadowgraph data corresponding to sets of parallel paths of radiation through the body. The reordered parallel path shadowgraph data is then convoluted in accordance with a 3-D reconstruction method by convolution in a computer to derive a 3-D reconstructed tomograph of the body under analysis. In a preferred embodiment, the position sensitive detector comprises a multiwire detector wherein the wires are arrayed parallel to the direction of the divergent penetrating rays to be detected. A focussed grid collimator is interposed between the body and the position sensitive detector for collimating the penetrating rays to be detected. The source of penetrating radiation is preferably a monochromatic source

  18. Computerized tomography with X-rays: an instrument in the analysis physico-chemical between formations and drilling fluids interactions

    International Nuclear Information System (INIS)

    Coelho, Marcus Vinicius Cavalcante

    1998-01-01

    In this study it is demonstrated the applicability of the Computerized Tomography technique with x-rays to evaluate the reactivity degree between various drilling fluids and argillaceous sediments (Shales and Sandstones). The research has been conducted in the Rock-Fluid Interaction Pressure Simulator (RFIPS), where the possible physico-chemical alterations can be observed through successive tomography images, which are obtained during the flow of the fluid through the samples. In addition, it was noticed the formation of mud cake in Berea Sandstones samples in the RFIPS, though the Computerized Tomography with X-rays, when utilizing drilling fluids weighted with the baryte. (author)

  19. Analysis of inner structure changes of concretes exposed to high temperatures using micro X-ray computed tomography

    OpenAIRE

    Sitek, L. (Libor); Bodnárová, L.; Souček, K. (Kamil); Staš, L. (Lubomír); Gurková, L. (Lucie)

    2015-01-01

    The X-ray Computed Tomography (X-ray CT) repr esents a progressive non-destructive metho d of analysing the inner structure of materials. The method was used for monitoring changes in inner structure of concrete samples of different composition before and after their exposure to various thermal loads. Eight types of concrete samples were prepared which differed by cement and aggregate types. We intentionally used such composition of concrete mixtures which increased their resist...

  20. The feasibility study on 3-dimensional fluorescent x-ray computed tomography using the pinhole effect for biomedical applications.

    Science.gov (United States)

    Sunaguchi, Naoki; Yuasa, Tetsuya; Hyodo, Kazuyuki; Zeniya, Tsutomu

    2013-01-01

    We propose a 3-dimensional fluorescent x-ray computed tomography (CT) pinhole collimator, aimed at providing molecular imaging with quantifiable measures and sub-millimeter spatial resolution. In this study, we demonstrate the feasibility of this concept and investigate imaging properties such as spatial resolution, contrast resolution and quantifiable measures, by imaging physical phantoms using a preliminary imaging system developed with monochromatic synchrotron x rays constructed at the BLNE-7A experimental line at KEK, Japan.

  1. Reconstruction method for fluorescent X-ray computed tomography by least-squares method using singular value decomposition

    Science.gov (United States)

    Yuasa, T.; Akiba, M.; Takeda, T.; Kazama, M.; Hoshino, A.; Watanabe, Y.; Hyodo, K.; Dilmanian, F. A.; Akatsuka, T.; Itai, Y.

    1997-02-01

    We describe a new attenuation correction method for fluorescent X-ray computed tomography (FXCT) applied to image nonradioactive contrast materials in vivo. The principle of the FXCT imaging is that of computed tomography of the first generation. Using monochromatized synchrotron radiation from the BLNE-5A bending-magnet beam line of Tristan Accumulation Ring in KEK, Japan, we studied phantoms with the FXCT method, and we succeeded in delineating a 4-mm-diameter channel filled with a 500 /spl mu/g I/ml iodine solution in a 20-mm-diameter acrylic cylindrical phantom. However, to detect smaller iodine concentrations, attenuation correction is needed. We present a correction method based on the equation representing the measurement process. The discretized equation system is solved by the least-squares method using the singular value decomposition. The attenuation correction method is applied to the projections by the Monte Carlo simulation and the experiment to confirm its effectiveness.

  2. X-ray micro computed tomography characterization of cellular SiC foams for their applications in chemical engineering

    Energy Technology Data Exchange (ETDEWEB)

    Ou, Xiaoxia [School of Chemical Engineering and Analytical Science, The University of Manchester, M13 9PL (United Kingdom); Zhang, Xun; Lowe, Tristan [Henry Moseley X-ray Imaging Facility, Materials Science Centre, School of Materials, The University of Manchester, M13 9PL (United Kingdom); Blanc, Remi [FEI, 3 Impasse Rudolf Diesel, BP 50227, 33708 Mérignac (France); Rad, Mansoureh Norouzi [School of Chemical Engineering and Analytical Science, The University of Manchester, M13 9PL (United Kingdom); Wang, Ying [Henry Moseley X-ray Imaging Facility, Materials Science Centre, School of Materials, The University of Manchester, M13 9PL (United Kingdom); Batail, Nelly; Pham, Charlotte [SICAT SARL, 20 Place des Halles, 67000 Strasbourg (France); Shokri, Nima; Garforth, Arthur A. [School of Chemical Engineering and Analytical Science, The University of Manchester, M13 9PL (United Kingdom); Withers, Philip J. [Henry Moseley X-ray Imaging Facility, Materials Science Centre, School of Materials, The University of Manchester, M13 9PL (United Kingdom); Fan, Xiaolei, E-mail: xiaolei.fan@manchester.ac.uk [School of Chemical Engineering and Analytical Science, The University of Manchester, M13 9PL (United Kingdom)

    2017-01-15

    Open-cell SiC foams clearly are promising materials for continuous-flow chemical applications such as heterogeneous catalysis and distillation. X-ray micro computed tomography characterization of cellular β-SiC foams at a spatial voxel size of 13.6{sup 3} μm{sup 3} and the interpretation of morphological properties of SiC open-cell foams with implications to their transport properties are presented. Static liquid hold-up in SiC foams was investigated through in-situ draining experiments for the first time using the μ-CT technique providing thorough 3D information about the amount and distribution of liquid hold-up inside the foam. This will enable better modeling and design of structured reactors based on SiC foams in the future. In order to see more practical uses, μ-CT data of cellular foams must be exploited to optimize the design of the morphology of foams for a specific application. - Highlights: •Characterization of SiC foams using novel X-ray micro computed tomography. •Interpretation of structural properties of SiC foams regarding to their transport properties. •Static liquid hold-up analysis of SiC foams through in-situ draining experiments.

  3. Systematic calibration of an integrated x-ray and optical tomography system for preclinical radiation research

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yidong, E-mail: yidongyang@med.miami.edu [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21231 and Department of Radiation Oncology, University of Miami School of Medicine, Miami, Florida 33136 (United States); Wang, Ken Kang-Hsin; Wong, John W. [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21231 (United States); Eslami, Sohrab; Iordachita, Iulian I. [Laboratory for Computational Sensing and Robotics, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Patterson, Michael S. [Juravinski Cancer Centre and Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ontario L8S4K1 (Canada)

    2015-04-15

    .0% difference between simulated and measured signal. The calibration of the entire system was confirmed through the CBCT and BLT reconstruction of a bioluminescence source placed inside a tissue-simulating optical phantom. Using a spatial region constraint, the source position was reconstructed with less than 1 mm error and the source strength reconstructed with less than 24% error. Conclusions: A practical and systematic method has been developed to calibrate an integrated x-ray and optical tomography imaging system, including the respective CBCT and optical tomography system calibration and the geometrical calibration of the entire system. The method can be modified and adopted to calibrate CBCT and optical tomography systems that are operated independently or hybrid x-ray and optical tomography imaging systems.

  4. Systematic calibration of an integrated x-ray and optical tomography system for preclinical radiation research

    International Nuclear Information System (INIS)

    Yang, Yidong; Wang, Ken Kang-Hsin; Wong, John W.; Eslami, Sohrab; Iordachita, Iulian I.; Patterson, Michael S.

    2015-01-01

    .0% difference between simulated and measured signal. The calibration of the entire system was confirmed through the CBCT and BLT reconstruction of a bioluminescence source placed inside a tissue-simulating optical phantom. Using a spatial region constraint, the source position was reconstructed with less than 1 mm error and the source strength reconstructed with less than 24% error. Conclusions: A practical and systematic method has been developed to calibrate an integrated x-ray and optical tomography imaging system, including the respective CBCT and optical tomography system calibration and the geometrical calibration of the entire system. The method can be modified and adopted to calibrate CBCT and optical tomography systems that are operated independently or hybrid x-ray and optical tomography imaging systems

  5. Measurement of bone mineral density in the tunnel regions for anterior cruciate ligament reconstruction by dual-energy X-ray absorptiometry, computed tomography scan, and the immersion technique based on Archimedes' principle.

    Science.gov (United States)

    Tie, Kai; Wang, Hua; Wang, Xin; Chen, Liaobin

    2012-10-01

    To determine, for anterior cruciate ligament (ACL) reconstruction, whether the bone mineral density (BMD) of the femoral tunnel was higher than that of the tibial tunnel, to provide objective evidence for choosing the appropriate diameter of interference screws. Two groups were enrolled. One group comprised 30 normal volunteers, and the other comprised 9 patients with ACL rupture. Dual-energy X-ray absorptiometry was used to measure the BMD of the femoral and tibial tunnel regions of the volunteers' right knees by choosing a circular area covering the screw fixation region. The knees were also scanned by spiral computed tomography (CT), and the 3-dimensional reconstruction technique was used to determine the circular sections passing through the longitudinal axis of the femoral and tibial tunnels. Grayscale CT values of the cross-sectional area were measured. Cylindrical cancellous bone blocks were removed from the femoral and tibial tunnels during the ACL reconstruction for the patients. The volumetric BMD of the bone blocks was measured using a standardized immersion technique according to Archimedes' principle. As measured by dual-energy X-ray absorptiometry, the BMD of the femoral and tibial tunnel regions was 1.162 ± 0.034 g/cm(2) and 0.814 ± 0.038 g/cm(2), respectively (P difference in both femoral and tibial tunnel regions. For ACL reconstruction, the BMD of the femoral tunnel is higher than that of the tibial tunnel. This implies that a proportionally larger-diameter interference screw should be used for fixation in the proximal tibia than that used for fixation in the distal femur. Level IV, therapeutic case series. Copyright © 2012 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

  6. Six-dimensional real and reciprocal space small-angle X-ray scattering tomography.

    Science.gov (United States)

    Schaff, Florian; Bech, Martin; Zaslansky, Paul; Jud, Christoph; Liebi, Marianne; Guizar-Sicairos, Manuel; Pfeiffer, Franz

    2015-11-19

    When used in combination with raster scanning, small-angle X-ray scattering (SAXS) has proven to be a valuable imaging technique of the nanoscale, for example of bone, teeth and brain matter. Although two-dimensional projection imaging has been used to characterize various materials successfully, its three-dimensional extension, SAXS computed tomography, poses substantial challenges, which have yet to be overcome. Previous work using SAXS computed tomography was unable to preserve oriented SAXS signals during reconstruction. Here we present a solution to this problem and obtain a complete SAXS computed tomography, which preserves oriented scattering information. By introducing virtual tomography axes, we take advantage of the two-dimensional SAXS information recorded on an area detector and use it to reconstruct the full three-dimensional scattering distribution in reciprocal space for each voxel of the three-dimensional object in real space. The presented method could be of interest for a combined six-dimensional real and reciprocal space characterization of mesoscopic materials with hierarchically structured features with length scales ranging from a few nanometres to a few millimetres--for example, biomaterials such as bone or teeth, or functional materials such as fuel-cell or battery components.

  7. X-ray phase-contrast computed tomography visualizes the microstructure and degradation profile of implanted biodegradable scaffolds after spinal cord injury

    Energy Technology Data Exchange (ETDEWEB)

    Takashima, Kenta, E-mail: takashima-k@med.tohoku.ac.jp [Tohoku University Graduate School of Medicine, Sendai (Japan); University of Tokyo, Tokyo (Japan); Hoshino, Masato; Uesugi, Kentaro; Yagi, Naoto [SPring-8, Hyogo (Japan); Matsuda, Shojiro [Gunze Limited, Shiga (Japan); Nakahira, Atsushi [Osaka Prefecture University, Osaka (Japan); Osumi, Noriko; Kohzuki, Masahiro [Tohoku University Graduate School of Medicine, Sendai (Japan); Onodera, Hiroshi [University of Tokyo, Tokyo (Japan)

    2015-01-01

    X-ray phase-contrast computed tomography imaging based on the Talbot grating interferometer is described, and the way it can visualize the polyglycolic acid scaffold, including its microfibres, after implantation into the injured spinal cord is shown. Tissue engineering strategies for spinal cord repair are a primary focus of translational medicine after spinal cord injury (SCI). Many tissue engineering strategies employ three-dimensional scaffolds, which are made of biodegradable materials and have microstructure incorporated with viable cells and bioactive molecules to promote new tissue generation and functional recovery after SCI. It is therefore important to develop an imaging system that visualizes both the microstructure of three-dimensional scaffolds and their degradation process after SCI. Here, X-ray phase-contrast computed tomography imaging based on the Talbot grating interferometer is described and it is shown how it can visualize the polyglycolic acid scaffold, including its microfibres, after implantation into the injured spinal cord. Furthermore, X-ray phase-contrast computed tomography images revealed that degradation occurred from the end to the centre of the braided scaffold in the 28 days after implantation into the injured spinal cord. The present report provides the first demonstration of an imaging technique that visualizes both the microstructure and degradation of biodegradable scaffolds in SCI research. X-ray phase-contrast imaging based on the Talbot grating interferometer is a versatile technique that can be used for a broad range of preclinical applications in tissue engineering strategies.

  8. Quantitative evaluation of the disintegration of orally rapid disintegrating tablets by X-ray computed tomography.

    Science.gov (United States)

    Otsuka, Makoto; Yamanaka, Azusa; Uchino, Tomohiro; Otsuka, Kuniko; Sadamoto, Kiyomi; Ohshima, Hiroyuki

    2012-01-01

    To measure the rapid disintegration of Oral Disintegrating Tablets (ODT), a new test (XCT) was developed using X-ray computing tomography (X-ray CT). Placebo ODT, rapid disintegration candy (RDC) and Gaster®-D-Tablets (GAS) were used as model samples. All these ODTs were used to measure oral disintegration time (DT) in distilled water at 37±2°C by XCT. DTs were affected by the width of mesh screens, and degree to which the tablet holder vibrated from air bubbles. An in-vivo tablet disintegration test was performed for RDC using 11 volunteers. DT by the in-vivo method was significantly longer than that using the conventional tester. The experimental conditions for XCT such as the width of the mesh screen and degree of vibration were adjusted to be consistent with human DT values. Since DTs by the XCT method were almost the same as the human data, this method was able to quantitatively evaluate the rapid disintegration of ODT under the same conditions as inside the oral cavity. The DTs of four commercially available ODTs were comparatively evaluated by the XCT method, conventional tablet disintegration test and in-vivo method.

  9. Iterative reconstruction for x-ray computed tomography using prior-image induced nonlocal regularization.

    Science.gov (United States)

    Zhang, Hua; Huang, Jing; Ma, Jianhua; Bian, Zhaoying; Feng, Qianjin; Lu, Hongbing; Liang, Zhengrong; Chen, Wufan

    2014-09-01

    Repeated X-ray computed tomography (CT) scans are often required in several specific applications such as perfusion imaging, image-guided biopsy needle, image-guided intervention, and radiotherapy with noticeable benefits. However, the associated cumulative radiation dose significantly increases as comparison with that used in the conventional CT scan, which has raised major concerns in patients. In this study, to realize radiation dose reduction by reducing the X-ray tube current and exposure time (mAs) in repeated CT scans, we propose a prior-image induced nonlocal (PINL) regularization for statistical iterative reconstruction via the penalized weighted least-squares (PWLS) criteria, which we refer to as "PWLS-PINL". Specifically, the PINL regularization utilizes the redundant information in the prior image and the weighted least-squares term considers a data-dependent variance estimation, aiming to improve current low-dose image quality. Subsequently, a modified iterative successive overrelaxation algorithm is adopted to optimize the associative objective function. Experimental results on both phantom and patient data show that the present PWLS-PINL method can achieve promising gains over the other existing methods in terms of the noise reduction, low-contrast object detection, and edge detail preservation.

  10. Optimal iodine staining of cardiac tissue for X-ray computed tomography.

    Science.gov (United States)

    Butters, Timothy D; Castro, Simon J; Lowe, Tristan; Zhang, Yanmin; Lei, Ming; Withers, Philip J; Zhang, Henggui

    2014-01-01

    X-ray computed tomography (XCT) has been shown to be an effective imaging technique for a variety of materials. Due to the relatively low differential attenuation of X-rays in biological tissue, a high density contrast agent is often required to obtain optimal contrast. The contrast agent, iodine potassium iodide ([Formula: see text]), has been used in several biological studies to augment the use of XCT scanning. Recently I2KI was used in XCT scans of animal hearts to study cardiac structure and to generate 3D anatomical computer models. However, to date there has been no thorough study into the optimal use of I2KI as a contrast agent in cardiac muscle with respect to the staining times required, which has been shown to impact significantly upon the quality of results. In this study we address this issue by systematically scanning samples at various stages of the staining process. To achieve this, mouse hearts were stained for up to 58 hours and scanned at regular intervals of 6-7 hours throughout this process. Optimal staining was found to depend upon the thickness of the tissue; a simple empirical exponential relationship was derived to allow calculation of the required staining time for cardiac samples of an arbitrary size.

  11. High energy x-ray radiography and computed tomography of bridge pins

    International Nuclear Information System (INIS)

    Green, R E; Logan, C M; Martz, H E; Updike, E; Waters, A M

    1999-01-01

    Bridge pins were used in the hanger assemblies for some multi-span steel bridges built prior to the 1980's, and are sometimes considered fracture critical elements of a bridge. During a test on a bridge conducted by the Federal Highway Administration (FHWA), ultrasonic field inspection results indicated that at least two pins contained cracks. Several pins were removed and selected for further examination. This provided an excellent opportunity to learn more about these pins and the application of x-ray systems at Lawrence Livermore National Laboratory (LLNL), as well as to learn more about the application of different detectors recently obtained by LLNL. Digital radiographs and computed tomography (CT) were used to characterize the bridge pins, using a LINAC x-ray source with a 9-MV bremsstrahlung spectrum. We will describe the performance of two different digital radiographic detectors. One is a detector system frequently used at LLNL consisting of a scintillator glass optically coupled to a CCD camera. The other detector is a new amorphous silicon detector recently acquired by LLNL

  12. Selection for Oil Content During Soybean Domestication Revealed by X-Ray Tomography of Ancient Beans

    Science.gov (United States)

    Zong, Yunbing; Yao, Shengkun; Crawford, Gary W.; Fang, Hui; Lang, Jianfeng; Fan, Jiadong; Sun, Zhibin; Liu, Yang; Zhang, Jianhua; Duan, Xiulan; Zhou, Guangzhao; Xiao, Tiqiao; Luan, Fengshi; Wang, Qing; Chen, Xuexiang; Jiang, Huaidong

    2017-02-01

    When and under what circumstances domestication related traits evolved in soybean (Glycine max) is not well understood. Seed size has been a focus of archaeological attention because increased soybean seed weight/size is a trait that distinguishes most modern soybeans from their ancestors; however, archaeological seed size analysis has had limited success. Modern domesticated soybean has a significantly higher oil content than its wild counterpart so oil content is potentially a source of new insight into soybean domestication. We investigated soybean oil content using X-ray computed tomography (CT; specifically, synchrotron radiation X-ray CT or SRX-CT) of charred, archaeological soybean seeds. CT identified holes in the specimens that are associated with oil content. A high oil content facilitates the development of small holes, whereas a high protein content results in larger holes. The volume of small holes increased slowly from 7,500 to 4,000 cal B.P. We infer that human selection for higher oil content began as early as 7,500 cal B.P. and that high oil content cultivars were well established by 4,000 cal B.P.

  13. Segmentation-free statistical image reconstruction for polyenergetic x-ray computed tomography with experimental validation

    International Nuclear Information System (INIS)

    Elbakri, Idris A; Fessler, Jeffrey A

    2003-01-01

    This paper describes a statistical image reconstruction method for x-ray CT that is based on a physical model that accounts for the polyenergetic x-ray source spectrum and the measurement nonlinearities caused by energy-dependent attenuation. Unlike our earlier work, the proposed algorithm does not require pre-segmentation of the object into the various tissue classes (e.g., bone and soft tissue) and allows mixed pixels. The attenuation coefficient of each voxel is modelled as the product of its unknown density and a weighted sum of energy-dependent mass attenuation coefficients. We formulate a penalized-likelihood function for this polyenergetic model and develop an iterative algorithm for estimating the unknown density of each voxel. Applying this method to simulated x-ray CT measurements of objects containing both bone and soft tissue yields images with significantly reduced beam hardening artefacts relative to conventional beam hardening correction methods. We also apply the method to real data acquired from a phantom containing various concentrations of potassium phosphate solution. The algorithm reconstructs an image with accurate density values for the different concentrations, demonstrating its potential for quantitative CT applications

  14. Segmentation-free statistical image reconstruction for polyenergetic x-ray computed tomography with experimental validation.

    Science.gov (United States)

    Idris A, Elbakri; Fessler, Jeffrey A

    2003-08-07

    This paper describes a statistical image reconstruction method for x-ray CT that is based on a physical model that accounts for the polyenergetic x-ray source spectrum and the measurement nonlinearities caused by energy-dependent attenuation. Unlike our earlier work, the proposed algorithm does not require pre-segmentation of the object into the various tissue classes (e.g., bone and soft tissue) and allows mixed pixels. The attenuation coefficient of each voxel is modelled as the product of its unknown density and a weighted sum of energy-dependent mass attenuation coefficients. We formulate a penalized-likelihood function for this polyenergetic model and develop an iterative algorithm for estimating the unknown density of each voxel. Applying this method to simulated x-ray CT measurements of objects containing both bone and soft tissue yields images with significantly reduced beam hardening artefacts relative to conventional beam hardening correction methods. We also apply the method to real data acquired from a phantom containing various concentrations of potassium phosphate solution. The algorithm reconstructs an image with accurate density values for the different concentrations, demonstrating its potential for quantitative CT applications.

  15. L-shell x-ray fluorescence computed tomography (XFCT) imaging of Cisplatin

    International Nuclear Information System (INIS)

    Bazalova, Magdalena; Ahmad, Moiz; Pratx, Guillem; Xing, Lei

    2014-01-01

    X-ray fluorescence computed tomography (XFCT) imaging has been focused on the detection of K-shell x-rays. The potential utility of L-shell x-ray XFCT is, however, not well studied. Here we report the first Monte Carlo (MC) simulation of preclinical L-shell XFCT imaging of Cisplatin. We built MC models for both L- and K-shell XFCT with different excitation energies (15 and 30 keV for L-shell and 80 keV for K-shell XFCT). Two small-animal sized imaging phantoms of 2 and 4 cm diameter containing a series of objects of 0.6 to 2.7 mm in diameter at 0.7 to 16 mm depths with 10 to 250 µg mL −1  concentrations of Pt are used in the study. Transmitted and scattered x-rays were collected with photon-integrating transmission detector and photon-counting detector arc, respectively. Collected data were rearranged into XFCT and transmission CT sinograms for image reconstruction. XFCT images were reconstructed with filtered back-projection and with iterative maximum-likelihood expectation maximization without and with attenuation correction. While K-shell XFCT was capable of providing an accurate measurement of Cisplatin concentration, its sensitivity was 4.4 and 3.0 times lower than that of L-shell XFCT with 15 keV excitation beam for the 2 cm and 4 cm diameter phantom, respectively. With the inclusion of excitation and fluorescence beam attenuation correction, we found that L-shell XFCT was capable of providing fairly accurate information of Cisplatin concentration distribution. With a dose of 29 and 58 mGy, clinically relevant Cisplatin Pt concentrations of 10 µg mg −1  could be imaged with L-shell XFCT inside a 2 cm and 4 cm diameter object, respectively. (paper)

  16. Unsteady void measurements within debris beds using high speed X-ray tomography

    Energy Technology Data Exchange (ETDEWEB)

    Laurien, E., E-mail: Laurien@ike.uni-stuttgart.de; Stürzel, T., E-mail: thilo.stuerzel@stihl.de; Zhou, M., E-mail: mi.zhou@ike.uni-stuttgart.de

    2017-02-15

    Highlights: • A high speed X-ray tomography facility has been built for the investigation on two-phase flow. • The two-phase flow through beds of packed plastic spheres has been investigated in the facility. • 3D-reconstructions from the measurements show the fluxes in the two-phase flow. • The gas fraction has been calculated from the reconstruction and used for validation of the modeling. • A new bed with closest regular spheres arrangement has been manufactured by 3D-plotter and used in the measurement. - Abstract: Two-phase flow and boiling within debris beds representing a destroyed reactor core after a severe accident with core fragmentation can be simulated by using the porous media approach. In this approach, a local pressure drop and the heat transfer between the solid debris particles and the two-phase flow is modelled with the help flow-pattern maps, in which the boundaries between bubbly, slug, and annular flow are assumed. In order to support further understanding of these flows we have developed a very fast X-ray measurement device to visualize the 3D-void distribution within particle beds or porous media, which are otherwise un-accessible internally. The experimental setup uses a scanned electron beam directed in circles on a tungsten target to generate the X-rays. The particle bed, which has a diameter of 70 mm, is located between this target and a field of 256 X-ray detectors, which are arranged on a circle concentric to the target. The void distribution is reconstructed numerically from the attenuation of signals, which penetrates the particle bed and the two-phase flow inside. A 3D frame rate of up to 1000 Hz can be reached. The spatial resolution is such that bubbles with a diameter > 1.7 mm can be detected. We have investigated two-phase flows air/water through beds of packed plastic spheres (diameter between 3 and 15 mm) as well as through plastic beds, which were manufactured using a ‘3D-plotter’. Flow patterns can be

  17. Measurement of grain size of polycrystalline materials with confocal energy dispersive micro-X-ray diffraction technology based on polycapillary X-ray optics

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Weiyuan; Liu, Zhiguo [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Sun, Tianxi, E-mail: stx@bnu.edu.cn [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Peng, Song [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Ma, Yongzhong [Center for Disease Control and Prevention of Beijing, Beijing 100013 (China); Li, Fangzuo; Sun, Xuepeng; Ding, Xunliang [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China)

    2014-11-11

    The confocal energy dispersive micro-X-ray diffraction (EDMXRD) based on polycapillary X-ray optics was used to determine the grain size of polycrystalline materials. The grain size of a metallographic specimen of nickel base alloy was measured by using the confocal EDMXRD. The experimental results demonstrated that the confocal EDMXRD had potential applications in measuring large grain size.

  18. Iterative metal artifact reduction for x-ray computed tomography using unmatched projector/backprojector pairs

    International Nuclear Information System (INIS)

    Zhang, Hanming; Wang, Linyuan; Li, Lei; Cai, Ailong; Hu, Guoen; Yan, Bin

    2016-01-01

    Purpose: Metal artifact reduction (MAR) is a major problem and a challenging issue in x-ray computed tomography (CT) examinations. Iterative reconstruction from sinograms unaffected by metals shows promising potential in detail recovery. This reconstruction has been the subject of much research in recent years. However, conventional iterative reconstruction methods easily introduce new artifacts around metal implants because of incomplete data reconstruction and inconsistencies in practical data acquisition. Hence, this work aims at developing a method to suppress newly introduced artifacts and improve the image quality around metal implants for the iterative MAR scheme. Methods: The proposed method consists of two steps based on the general iterative MAR framework. An uncorrected image is initially reconstructed, and the corresponding metal trace is obtained. The iterative reconstruction method is then used to reconstruct images from the unaffected sinogram. In the reconstruction step of this work, an iterative strategy utilizing unmatched projector/backprojector pairs is used. A ramp filter is introduced into the back-projection procedure to restrain the inconsistency components in low frequencies and generate more reliable images of the regions around metals. Furthermore, a constrained total variation (TV) minimization model is also incorporated to enhance efficiency. The proposed strategy is implemented based on an iterative FBP and an alternating direction minimization (ADM) scheme, respectively. The developed algorithms are referred to as “iFBP-TV” and “TV-FADM,” respectively. Two projection-completion-based MAR methods and three iterative MAR methods are performed simultaneously for comparison. Results: The proposed method performs reasonably on both simulation and real CT-scanned datasets. This approach could reduce streak metal artifacts effectively and avoid the mentioned effects in the vicinity of the metals. The improvements are evaluated by

  19. X-ray Tomography Characterisation of Lattice Structures Processed by Selective Electron Beam Melting

    Directory of Open Access Journals (Sweden)

    Everth Hernández-Nava

    2017-08-01

    Full Text Available Metallic lattice structures intentionally contain open porosity; however, they can also contain unwanted closed porosity within the structural members. The entrained porosity and defects within three different geometries of Ti-6Al-4V lattices, fabricated by Selective Electron Beam Melting (SEBM, is assessed from X-ray computed tomography (CT scans. The results suggest that horizontal struts that are built upon loose powder show particularly high (~20 × 10−3 vol % levels of pores, as do nodes at which many (in our case 24 struts meet. On the other hand, for struts more closely aligned (0° to 54° to the build direction, the fraction of porosity appears to be much lower (~0.17 × 10−3% arising mainly from pores contained within the original atomised powder particles.

  20. Evaluation on correction factor for in-line X-ray phase contrast computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Mingli; Huang, Zhifeng; Zhang, Li; Zhang, Ran [Tsinghua Univ., Beijing (China). Dept. of Engineering Physics; Ministry of Education, Beijing (China). Key Laboratory of Particle and Radiation Imaging; Yin, Hongxia; Liu, Yunfu; Wang, Zhenchang [Capital Medical Univ., Beijing (China). Medical Imaging Center; Xiao, Tiqiao [Chinese Academy of Sciences, Shanghai (China). Shanghai Inst. of Applied Physics

    2011-07-01

    X-ray in-line phase contrast computed tomography (CT) is an effective nondestructive tool, providing 3D distribution of the refractive index of weakly absorbing low-Z object with high resolution and image contrast, especially with high-brilliance third-generation synchrotron radiation sources. Modified Bronnikov's algorithm (MBA), one of the in-line phase contrast CT reconstruction algorithms, can reconstruct the refractive index distribution of a pure phase object with a single computed tomographic data set. The key idea of the MBA is to use a correction factor in the filter function to stabilize the behavior at low frequencies. In this paper, we evaluate the influences of the correction factor to the final reconstruction results of the absorption-phase-mixed objects with analytical simulation and actual experiments. The limitations of the MBA are discussed finally. (orig.)

  1. In-Situ X-ray Tomography Study of Cement Exposed to CO2 Saturated Brine

    DEFF Research Database (Denmark)

    Chavez Panduro, E. A.; Torsæter, M.; Gawel, K.

    2017-01-01

    For successful CO2 storage in underground reservoirs, the potential problem of CO2 leakage needs to be addressed. A profoundly improved understanding of the behavior of fractured cement under realistic subsurface conditions including elevated temperature, high pressure and the presence of CO2...... saturated brine is required. Here, we report in situ X-ray micro computed tomography (μ-CT) studies visualizing the microstructural changes upon exposure of cured Portland cement with an artificially engineered leakage path (cavity) to CO2 saturated brine at high pressure. Carbonation of the bulk cement......, self-healing of the leakage path in the cement specimen, and leaching of CaCO3 were thus directly observed. The precipitation of CaCO3, which is of key importance as a possible healing mechanism of fractured cement, was found to be enhanced in confined regions having limited access to CO2...

  2. Characterization of filters and filtration process using X-ray computerized tomography

    International Nuclear Information System (INIS)

    Maschio, Celio; Arruda, Antonio Celso Fonseca de

    1999-01-01

    The objective of this work is to present the potential of X-Ray computerized tomography as a tool for internal characterization of filters used in the solid-liquid separation, mainly the water filters. Cartridge filters (for industrial and domestic applications) contaminated with glass beads were used. The scanning process was carried out both with and without contaminant in the filter to compare the attenuation coefficient of the clean filter and the contaminated filter. The images showed that is possible the mapping the internal structure of the filters and the distribution of the contaminant, permitting a local analysis, that is not possible through the standard tests used by the manufactures. These standard tests reveal only global characteristics of the filter media. The possibility of application for manufacturing process control was also shown, because the non invasive nature is a important advantage of the technique, which also permitted damage detection in filters submitted to severe operational conditions. (author)

  3. Development of direct observation aparatus of coal carbonization process by x-ray computerized tomography method

    International Nuclear Information System (INIS)

    Sakawa, Mitsuhiro; Shiraishi, Katsuhiko; Sakurai, Yoshihisa; Shimomura, Yasuto

    1987-01-01

    Coke production by chamber ovens has a long history and efforts are being continued to make the manufacturing process efficient and to preserve the environment. In this production by this method, however, it is hardly possible to obtain direct information during coal carbonization. Since the elements that compose coal and coke are carbon, hydrogen, oxygen, etc. and are similar to those of the human body, authors has developed a coke oven that permits the direct observation of the coal carbonization process using a soft X-ray computerized tomography (CT) apparatus used in medical treatment. The following phenomena can be observed as images by the coke oven for the CT method : 1) Changes in the bulk density of charge coal (including the difference in the water content), 2) Width of the plastic layer and movement of the plastic layer in the coke oven chamber, 3) Expansion and shrinkage of the charge in the coke oven chamber, 4) Initiation and growth of cracks. (author)

  4. Present and perspective roles of soft X-ray tomography in tokamak plasma position measurements

    International Nuclear Information System (INIS)

    Mlynar, J.; Duval, B.P.; Horacek, J.; Lister, J.B.

    2003-01-01

    This paper shows the importance and feasibility of real-time tomography in fusion experiments for the example of soft X-ray (SXR) position measurements. The requirement of non-magnetic real-time diagnostics in low frequencies for ITER is discussed. This is illustrated by recent results of rapid tomographic inversion of SXR measurements on tokamak TCV. Comparison with the magnetic reconstruction data has not only shown the valuable resolution capabilities of both techniques, but also revealed a slight dependence of magnetic measurements on toroidal magnetic field and an unnoticed drift of plasma position observer. A feasibility study using current hardware capacities for programmable real-time tomographic system with plasma position feedback output was carried out. A compact solution is found to be tractable opening wide perspectives for development

  5. X-ray computed tomography datasets for forensic analysis of vertebrate fossils

    Science.gov (United States)

    Rowe, Timothy B.; Luo, Zhe-Xi; Ketcham, Richard A.; Maisano, Jessica A.; Colbert, Matthew W.

    2016-01-01

    We describe X-ray computed tomography (CT) datasets from three specimens recovered from Early Cretaceous lakebeds of China that illustrate the forensic interpretation of CT imagery for paleontology. Fossil vertebrates from thinly bedded sediments often shatter upon discovery and are commonly repaired as amalgamated mosaics grouted to a solid backing slab of rock or plaster. Such methods are prone to inadvertent error and willful forgery, and once required potentially destructive methods to identify mistakes in reconstruction. CT is an efficient, nondestructive alternative that can disclose many clues about how a specimen was handled and repaired. These annotated datasets illustrate the power of CT in documenting specimen integrity and are intended as a reference in applying CT more broadly to evaluating the authenticity of comparable fossils. PMID:27272251

  6. Prediction of intramuscular fat levels in Texel lamb loins using X-ray computed tomography scanning.

    Science.gov (United States)

    Clelland, N; Bunger, L; McLean, K A; Conington, J; Maltin, C; Knott, S; Lambe, N R

    2014-10-01

    For the consumer, tenderness, juiciness and flavour are often described as the most important factors for meat eating quality, all of which have a close association with intramuscular fat (IMF). X-ray computed tomography (CT) can measure fat, muscle and bone volumes and weights, in vivo in sheep and CT predictions of carcass composition have been used in UK sheep breeding programmes over the last few decades. This study aimed to determine the most accurate combination of CT variables to predict IMF percentage of M. longissimus lumborum in Texel lambs. As expected, predicted carcass fat alone accounted for a moderate amount of the variation (R(2)=0.51) in IMF. Prediction accuracies were significantly improved (Adj R(2)>0.65) using information on fat and muscle densities measured from three CT reference scans, showing that CT can provide an accurate prediction of IMF in the loin of purebred Texel sheep. Copyright © 2014. Published by Elsevier Ltd.

  7. Three dimensional characterization of laser ablation craters using high resolution X-ray computed tomography

    Science.gov (United States)

    Galmed, A. H.; du Plessis, A.; le Roux, S. G.; Hartnick, E.; Von Bergmann, H.; Maaza, M.

    2018-01-01

    Laboratory X-ray computed tomography is an emerging technology for the 3D characterization and dimensional analysis of many types of materials. In this work we demonstrate the usefulness of this characterization method for the full three dimensional analysis of laser ablation craters, in the context of a laser induced breakdown spectroscopy setup. Laser induced breakdown spectroscopy relies on laser ablation for sampling the material of interest. We demonstrate here qualitatively (in images) and quantitatively (in terms of crater cone angles, depths, diameters and volume) laser ablation crater analysis in 3D for metal (aluminum) and rock (false gold ore). We show the effect of a Gaussian beam profile on the resulting crater geometry, as well as the first visual evidence of undercutting in the rock sample, most likely due to ejection of relatively large grains. The method holds promise for optimization of laser ablation setups especially for laser induced breakdown spectroscopy.

  8. Excitation-resolved cone-beam x-ray luminescence tomography.

    Science.gov (United States)

    Liu, Xin; Liao, Qimei; Wang, Hongkai; Yan, Zhuangzhi

    2015-07-01

    Cone-beam x-ray luminescence computed tomography (CB-XLCT), as an emerging imaging technique, plays an important role in in vivo small animal imaging studies. However, CB-XLCT suffers from low-spatial resolution due to the ill-posed nature of reconstruction. We improve the imaging performance of CB-XLCT by using a multiband excitation-resolved imaging scheme combined with principal component analysis. To evaluate the performance of the proposed method, the physical phantom experiment is performed with a custom-made XLCT/XCT imaging system. The experimental results validate the feasibility of the method, where two adjacent nanophosphors (with an edge-to-edge distance of 2.4 mm) can be located.

  9. Porosity characterization of fiber-reinforced ceramic matrix composite using synchrotron X-ray computed tomography

    International Nuclear Information System (INIS)

    Zou, C.; Li, B.; Zhang, C.; Wang, S.; Marrow, T.J.; Reinhard, C.

    2016-01-01

    The pore structure and porosity of a continuous fiber reinforced ceramic matrix composite has been characterized using high-resolution synchrotron X-ray computed tomography (XCT). Segmentation of the reconstructed tomograph images reveals different types of pores within the composite, the inter-fiber bundle open pores displaying a 'node-bond' geometry, and the intra-fiber bundle isolated micropores showing a piping shape. The 3D morphology of the pores is resolved and each pore is labeled. The quantitative filtering of the pores measures a total porosity 8.9% for the composite, amid which there is about 7.1∼ 9.3% closed micropores

  10. Relationship of brain imaging with radionuclides and with x-ray computed tomography

    International Nuclear Information System (INIS)

    Kuhl, D.E.

    1981-01-01

    Because of high sensitivity and specificity for altered local cerebral structure, x-ray computed tomography (CT) is the preferred initial diagnostic imaging study under most circumstances when cerebral disease is suspected. CT has no competitor for detecting fresh intracerebral hemorrhage. Radionuclide imaging (RN) scan is preferred when relative perfusion is to be assessed, in patients allergic to contrast media, and when an adequate CT study is not technically possible. (RN) plays an important complementary role to CT, especially for patients suspected of subacute or chronic subdura hematoma, cerebral infarction, arteriovenous malformations, meningitis, encephalitis, normal pressure hydrocephalus, or when CT findings are inconclusive. When CT is not available, RN serves as a good screening study for suspected cerebral tumor, infection, recent infarction, arteriovenous malformation, and chronic subdural hematoma

  11. Novel X-ray phase-contrast tomography method for quantitative studies of heat induced structural changes in meat

    DEFF Research Database (Denmark)

    Miklos, Rikke; Nielsen, Mikkel Schou; Einarsdottir, Hildur

    2014-01-01

    The objective of this study was to evaluate the use of X-ray phase-contrast tomography combined with 3D image segmentation to investigate the heat induced structural changes in meat. The measurements were performed at the Swiss synchrotron radiation light source using a grating interferometric...... and separated into a water phase and a gel phase formed by the sarcoplasmic proteins in the exudate. The results show that X-ray phase contrast tomography offers unique possibilities in studies both the meat structure and the different meat component such as water, fat, connective tissue and myofibrils...

  12. Reduction of variable-truncation artifacts from beam occlusion during in situ x-ray tomography

    Science.gov (United States)

    Borg, Leise; Jørgensen, Jakob S.; Frikel, Jürgen; Sporring, Jon

    2017-12-01

    Many in situ x-ray tomography studies require experimental rigs which may partially occlude the beam and cause parts of the projection data to be missing. In a study of fluid flow in porous chalk using a percolation cell with four metal bars drastic streak artifacts arise in the filtered backprojection (FBP) reconstruction at certain orientations. Projections with non-trivial variable truncation caused by the metal bars are the source of these variable-truncation artifacts. To understand the artifacts a mathematical model of variable-truncation data as a function of metal bar radius and distance to sample is derived and verified numerically and with experimental data. The model accurately describes the arising variable-truncation artifacts across simulated variations of the experimental setup. Three variable-truncation artifact-reduction methods are proposed, all aimed at addressing sinogram discontinuities that are shown to be the source of the streaks. The ‘reduction to limited angle’ (RLA) method simply keeps only non-truncated projections; the ‘detector-directed smoothing’ (DDS) method smooths the discontinuities; while the ‘reflexive boundary condition’ (RBC) method enforces a zero derivative at the discontinuities. Experimental results using both simulated and real data show that the proposed methods effectively reduce variable-truncation artifacts. The RBC method is found to provide the best artifact reduction and preservation of image features using both visual and quantitative assessment. The analysis and artifact-reduction methods are designed in context of FBP reconstruction motivated by computational efficiency practical for large, real synchrotron data. While a specific variable-truncation case is considered, the proposed methods can be applied to general data cut-offs arising in different in situ x-ray tomography experiments.

  13. Technology development of the soft X-ray tomography system in Wendelstein 7-X stellarator

    Energy Technology Data Exchange (ETDEWEB)

    Schülke, M., E-mail: mathias.schuelke@ipp.mpg.de [Max Planck Institute for Plasma Physics, EURATOM Association, Wendelsteinstr. 1, 17491 Greifswald (Germany); Cardella, A.; Hathiramani, D.; Mettchen, S.; Thomsen, H.; Weißflog, S.; Zacharias, D. [Max Planck Institute for Plasma Physics, EURATOM Association, Wendelsteinstr. 1, 17491 Greifswald (Germany)

    2013-10-15

    Highlights: ► Engineering and design of soft X-ray Multi Camera Tomography System. ► Requirements of in-vessel diagnostics in Wendelstein 7-X. ► Development of internal cooling system including FEM-Analysis. ► Development of lateral shield system with testing for microwave stray radiation compatibility. ► Development of multipin feedthrough including welding qualification and leak tests. -- Abstract: The engineering and design of the soft X-ray Multi Camera Tomography System (XMCTS) in Wendelstein 7-X stellarator (W7-X) must fulfill several additional requirements compared to short pulse machines. The XMCTS has to withstand irradiation and electron cyclotron microwave loads in addition to being ultra high vacuum compatible, having low magnetic permeability and using low neutron activation materials (e.g. Co ≤ 2000 ppm). A further difficulty is the limited space inside the plasma vessel, which requires special engineering solutions. After detailed design development, supported by finite element analyses, prototypes have been manufactured and tested. At the end all test results have successfully proven that the components fulfill the requirements and that reliable and stable measurements will be possible with the XMCTS diagnostics during W7-X operation. The paper describes the design and the technological development, in particular on the electric multipin feedthrough (UHV barrier between in vessel detectors and the preamplifiers), the active cooling of the electronic components (reducing dark current/noise increase), the pneumatic shutter (protection of the detectors from sputtering and during baking) and the fiber optics illumination system (calibration of the detectors)

  14. Comparative review of computed tomography of the spinal column and conventional x-ray films

    Energy Technology Data Exchange (ETDEWEB)

    Shin, H.; Yamaura, A.; Horie, T.; Makino, H. (Chiba Univ. (Japan). School of Medicine)

    1982-04-01

    Computerized tomography (CT) of the cervical spinal column was carried out in 39 patients using a GE.CT/T or Toshiba TCT60A scanner. There were 22 cervical disk lesions, 4 spinal neoplasms, 5 narrow spinal canals with or without ossification of the posterior longitudinal ligament, 2 syringomyelias, 5 traumas, and one Arnold-Chiari malformation. In all the patients, tomography was done after conventional spinal X-ray studies. The correlation between the CT findings and conventional X-ray films revealed the excellent capability of the CT. The measurement of the midline sagittal diameter of the spinal canal in the patient with the narrowest canal in this series showed 7.4 mm when done by CT and 9.6 mm when done by the conventional plain film at the C/sub 5/ level. To ascertain the precise sagittal diameter of the cord itself, CT myelography is indispensable after the intrathecal injection of metrizamide A; metrizamide CT myelogram is useful in determining the nature of the disease, the risk of and best approach to surgery, and the evaluation after a surgical procedure. Although the range of motion of cervical joints and intervertebral foramen are visible with the conventional films, the size of the spinal tumors, the degree of bony change, and the tumor extension to the paraspinal connective tissue can be precisely demonstrated only by CT. A CT study of the spine is a simple procedure and is less likely to produce complication, even with a metrizamide CT myelogram, though there are certain limitations in the examination.

  15. X-ray exposure in utero and school performance: a population-based study of X-ray pelvimetry

    International Nuclear Information System (INIS)

    Nordenskjöld, A.C.; Palme, M.; Kaijser, M.

    2015-01-01

    Aim: To investigate the association between exposure to ionising radiation from pelvimetric examinations in utero and school performance. Material and methods: This was a population-based cohort study comprising 46,066 children born in the county of Östergötland, Sweden, from 1980 through 1990. Through record linkage between Swedish registers, children exposed in utero to X-ray pelvimetry examination were compared to other children born in the same county during the study period, as well as to their unexposed siblings. Outcome variable was primary school grades, expressed in centiles and calculated through linear regression. Results: In the univariate analysis, children exposed to X-ray pelvimetry in utero had higher school grades compared to unexposed children (point estimate 3 centiles, 95% confidence interval [CI]: 1.5 to 4.6). When sex, mother's education and income, birth order, and birth position were included in the analysis; however, the difference was reduced and the association was no longer statistically significant (PE 1.4, 95% CI: –0.1 to 2.8). Comparing exposed children with their siblings showed no statistical difference in univariate analysis or in multivariate analysis. Conclusion: No suggestion was found of a negative effect on school performance from in utero exposure of diagnostic X-ray pelvimetry. -- Highlights: •Pelvimetric examinations expose fetus to low levels of radiation. •No detectable effect on childrens final primary school grades from pelvimetric examinations. •Pelvimetric examinations is a safe procedure for the fetus regarding shool performance

  16. Methodological study of aging effects on fuel cells using X-ray synchrotron radiography and tomography

    International Nuclear Information System (INIS)

    Arlt, Tobias

    2012-01-01

    In the present work, new and advanced methods for the investigation of methanol and hydrogen powered fuel cells were analyzed. Synchrotron radiography and tomography were applied to investigate materials and transport processes in operating fuel cells ''in-situ'' and non-destructively. The corrosion of ruthenium is a key issue during aging of direct methanol fuel cells (DMFC). Therefore the influence of different aging processes on the distribution of ruthenium is of great interesting. An imaging method based on X-ray absorption spectroscopy (XAS) was applied to investigate the changes in the distribution of fuel cell catalysts three-dimensionally. Using monoenergetic synchrotron radiation it was shown that the distribution of ruthenium (Ru) in the anode catalyst changes after application of an accelerated aging procedure. A strong influence on the flowfield and the gas diffusion layer structures on the Ru distribution were found in the gas diffusion electrode at the anode side. Additionally some ruthenium moves through the membrane from the anode to the cathode. The redistribution caused by the accelerated aging procedure strongly differs from that obtained after aging under realistic stack operation (here over 1700 h) of a fuel cell in a pallet transporter. For the tomographic investigations samples were taken out from a stack operation in aged membrane electrode assembly (MEA) and were analyzed ex-situ. It was shown that the Ru redistribution can be attributed to mass transport processes (CO 2 and H 2 O) in the gas diffusion layer (GDL). Other high energy resolved measurements showed that the strength of the oxidation of ruthenium and platinum depends on the spatial distribution of the ruthenium. Last mentioned - also for the platinum catalyst - could be given quantitatively by means of this newly developed method. In the second part of this work high temperature polymer electrolyte fuel cells (HT-PEFC) were investigated. No liquid water can

  17. 15 Mcps photon-counting X-ray computed tomography system using a ZnO-MPPC detector and its application to gadolinium imaging

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Eiichi, E-mail: dresato@iwate-med.ac.jp [Department of Physics, Iwate Medical University, 2-1-1 Nishitokuta, Yahaba, Iwate 028-3694 (Japan); Sugimura, Shigeaki [Tokyo Denpa Co. Ltd., 82-5 Ueno, Ichinohe, Iwate 028-5321 (Japan); Endo, Haruyuki [Iwate Industrial Research Insutitute 3, 3-35-2 Shinden, Iioka, Morioka, Iwate 020-0852 (Japan); Oda, Yasuyuki [Department of Physics, Iwate Medical University, 2-1-1 Nishitokuta, Yahaba, Iwate 028-3694 (Japan); Abudurexiti, Abulajiang [Faculty of Software and Information Science, Iwate Prefectural University, 152-52 Sugo, Takizawa, Iwate 020-0193 (Japan); Hagiwara, Osahiko; Osawa, Akihiro; Matsukiyo, Hiroshi; Enomoto, Toshiyuki; Watanabe, Manabu; Kusachi, Shinya [3rd Department of Surgery, Toho University School of Medicine, 2-17-6 Ohashi, Meguro-ku, Tokyo 153-8515 (Japan); Sato, Shigehiro [Department of Microbiology, School of Medicine, Iwate Medical University, 19-1 Uchimaru, Morioka, Iwate 020-0023 (Japan); Ogawa, Akira [Department of Neurosurgery, School of Medicine, Iwate Medical University, 19-1 Uchimaru, Morioka, Iwate 020-0023 (Japan); Onagawa, Jun [Department of Electronics, Faculty of Engineering, Tohoku Gakuin University, 1-13-1 Chuo, Tagajo, Miyagi 985-8537 (Japan)

    2012-01-15

    15 Mcps photon-counting X-ray computed tomography (CT) system is a first-generation type and consists of an X-ray generator, a turntable, a translation stage, a two-stage controller, a detector consisting of a 2 mm-thick zinc-oxide (ZnO) single-crystal scintillator and an MPPC (multipixel photon counter) module, a counter card (CC), and a personal computer (PC). High-speed photon counting was carried out using the detector in the X-ray CT system. The maximum count rate was 15 Mcps (mega counts per second) at a tube voltage of 100 kV and a tube current of 1.95 mA. Tomography is accomplished by repeated translations and rotations of an object, and projection curves of the object are obtained by the translation. The pulses of the event signal from the module are counted by the CC in conjunction with the PC. The minimum exposure time for obtaining a tomogram was 15 min, and photon-counting CT was accomplished using gadolinium-based contrast media. - Highlights: Black-Right-Pointing-Pointer We developed a first-generation 15 Mcps photon-counting X-ray computed tomography (CT) system. Black-Right-Pointing-Pointer High-speed photon counting was carried out using a zinc-oxide (ZnO) single-crystal scintillator and an MPPC (multipixel photon counter) module in the X-ray CT system. Black-Right-Pointing-Pointer Tomography is accomplished by repeated translations and rotations of an object. Black-Right-Pointing-Pointer The minimum exposure time for obtaining a tomogram was 15 min. Black-Right-Pointing-Pointer The photon-counting CT was accomplished using gadolinium-based contrast media.

  18. X-ray nanoprobes and diffraction-limited storage rings: opportunities and challenges of fluorescence tomography of biological specimens

    Energy Technology Data Exchange (ETDEWEB)

    Jonge, Martin D. de, E-mail: martin.dejonge@synchrotron.org.au [Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168 (Australia); Ryan, Christopher G. [CSIRO Earth Science and Research Engineering, Clayton, Victoria 3168 (Australia); Jacobsen, Chris J. [Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Department of Physics, Chemistry of Life Processes Institute, Northwestern University, 2170 Campus Drive, Evanston, IL 60208 (United States); Chemistry of Life Processes Institute, Northwestern University, 2170 Campus Drive, Evanston, IL 60208 (United States)

    2014-08-27

    Nanoscale X-ray scanning microscopes, or X-ray nanoprobes, will benefit greatly from diffraction-limited storage rings. Here the requirements for nanoscale fluorescence tomography are explored to gain insight into the scientific opportunities and technical challenges that such sources offer. X-ray nanoprobes require coherent illumination to achieve optic-limited resolution, and so will benefit directly from diffraction-limited storage rings. Here, the example of high-resolution X-ray fluorescence tomography is focused on as one of the most voracious demanders of coherent photons, since the detected signal is only a small fraction of the incident flux. Alternative schemes are considered for beam delivery, sample scanning and detectors. One must consider as well the steps before and after the X-ray experiment: sample preparation and examination conditions, and analysis complexity due to minimum dose requirements and self-absorption. By understanding the requirements and opportunities for nanoscale fluorescence tomography, one gains insight into the R&D challenges in optics and instrumentation needed to fully exploit the source advances that diffraction-limited storage rings offer.

  19. Rapid phenotyping of crop root systems in undisturbed field soils using X-ray computed tomography.

    Science.gov (United States)

    Pfeifer, Johannes; Kirchgessner, Norbert; Colombi, Tino; Walter, Achim

    2015-01-01

    X-ray computed tomography (CT) has become a powerful tool for root phenotyping. Compared to rather classical, destructive methods, CT encompasses various advantages. In pot experiments the growth and development of the same individual root can be followed over time and in addition the unaltered configuration of the 3D root system architecture (RSA) interacting with a real field soil matrix can be studied. Yet, the throughput, which is essential for a more widespread application of CT for basic research or breeding programs, suffers from the bottleneck of rapid and standardized segmentation methods to extract root structures. Using available methods, root segmentation is done to a large extent manually, as it requires a lot of interactive parameter optimization and interpretation and therefore needs a lot of time. Based on commercially available software, this paper presents a protocol that is faster, more standardized and more versatile compared to existing segmentation methods, particularly if used to analyse field samples collected in situ. To the knowledge of the authors this is the first study approaching to develop a comprehensive segmentation method suitable for comparatively large columns sampled in situ which contain complex, not necessarily connected root systems from multiple plants grown in undisturbed field soil. Root systems from several crops were sampled in situ and CT-volumes determined with the presented method were compared to root dry matter of washed root samples. A highly significant (P < 0.01) and strong correlation (R(2) = 0.84) was found, demonstrating the value of the presented method in the context of field research. Subsequent to segmentation, a method for the measurement of root thickness distribution has been used. Root thickness is a central RSA trait for various physiological research questions such as root growth in compacted soil or under oxygen deficient soil conditions, but hardly assessable in high throughput until today, due

  20. X-ray computed tomography reconstruction on non-standard trajectories for robotized inspection

    International Nuclear Information System (INIS)

    Banjak, Hussein

    2016-01-01

    The number of industrial applications of computed tomography (CT) is large and rapidly increasing with typical areas of use in the aerospace, automotive and transport industry. To support this growth of CT in the industrial field, the identified requirements concern firstly software development to improve the reconstruction algorithms and secondly the automation of the inspection process. Indeed, the use of robots gives more flexibility in the acquisition trajectory and allows the control of large and complex objects, which cannot be inspected using classical CT systems. In this context of new CT trend, a robotic platform has been installed at CEA LIST to better understand and solve specific challenges linked to the robotization of the CT process. The considered system integrates two robots that move the X-ray generator and detector. This thesis aims at achieving this new development. In particular, the objective is to develop and implement analytical and iterative reconstruction algorithms adapted to such robotized trajectories. The main focus of this thesis is concerned with helical-like scanning trajectories. We consider two main problems that could occur during acquisition process: truncated and limited-angle data. We present in this work experimental results for reconstruction on such non-standard trajectories. CIVA software is used to simulate these complex inspections and our developed algorithms are integrated as reconstruction tools. This thesis contains three parts. In the first part, we introduce the basic principles of CT and we present an overview of existing analytical and iterative algorithms for non-standard trajectories. In the second part, we modify the approximate helical FDK algorithm to deal with transversely truncated data and we propose a modified FDK algorithm adapted to reverse helical trajectory with the scan range less than 360 degrees. For iterative reconstruction, we propose two algebraic methods named SART-FISTA-TV and DART

  1. 3D algebraic iterative reconstruction for cone-beam x-ray differential phase-contrast computed tomography.

    Science.gov (United States)

    Fu, Jian; Hu, Xinhua; Velroyen, Astrid; Bech, Martin; Jiang, Ming; Pfeiffer, Franz

    2015-01-01

    Due to the potential of compact imaging systems with magnified spatial resolution and contrast, cone-beam x-ray differential phase-contrast computed tomography (DPC-CT) has attracted significant interest. The current proposed FDK reconstruction algorithm with the Hilbert imaginary filter will induce severe cone-beam artifacts when the cone-beam angle becomes large. In this paper, we propose an algebraic iterative reconstruction (AIR) method for cone-beam DPC-CT and report its experiment results. This approach considers the reconstruction process as the optimization of a discrete representation of the object function to satisfy a system of equations that describes the cone-beam DPC-CT imaging modality. Unlike the conventional iterative algorithms for absorption-based CT, it involves the derivative operation to the forward projections of the reconstructed intermediate image to take into account the differential nature of the DPC projections. This method is based on the algebraic reconstruction technique, reconstructs the image ray by ray, and is expected to provide better derivative estimates in iterations. This work comprises a numerical study of the algorithm and its experimental verification using a dataset measured with a three-grating interferometer and a mini-focus x-ray tube source. It is shown that the proposed method can reduce the cone-beam artifacts and performs better than FDK under large cone-beam angles. This algorithm is of interest for future cone-beam DPC-CT applications.

  2. Comparative investigation of two-dimensional imaging methods and X-ray tomography in the characterization of microstructure

    Energy Technology Data Exchange (ETDEWEB)

    Bacaicoa, Inigo; Luetje, Martin [Kassel Univ. (Germany). Inst. of Materials Engineering, Quality and Reliability; Saelzer, Philipp [Kassel Univ. (Germany). Abt. Materialentwicklung und Verbundwerkstoffe; Umbach, Cristin [Kassel Univ. (Germany). Inst. for Structural Engineering; Brueckner-Foit, Angelika [Kassel Univ. (Germany). Inst. of Materials Engineering; Heim, Hans-Peter [Kassel Univ. (Germany). Plastics Engineering; Middendorf, Bernhard [Kassel Univ. (Germany). Dept. of Building Materials and Construction Chemistry

    2017-11-01

    The microstructural features of three different materials have been quantified by means of 2D image analysis and X-ray micro-computer tomography (CT) and the results were compared to determine the reliability of the 2D analysis in the material characterization. The 3D quantification of shrinkage pores and Fe-rich inclusions of an Al-Si-Cu alloy by X-ray tomography was compared with the statistical analysis of the 2D metallographic pictures and a significant difference in the results was found due to the complex morphology of shrinkage pores and Fe-rich particles. Furthermore, wood particles of a wood-plastic composite were measured by dynamic image analysis and X-ray tomography. Similar results were obtained for the maximum length of the particles, although the results of width differ considerably, which leads to a miscalculation of the particles aspect ratio. Finally, air voids of a foam concrete were investigated by the analysis of the 2D pictures in ImageJ and the results of the 2D circularity were compared with the values of the 3D elongation obtained by micro-computed tomography. The 3D analysis of the air voids in the foam concrete showed a more precise description of the morphology, although the 2D result are in good agreement with the results obtained by X-ray micro-tomography.

  3. Comparative investigation of two-dimensional imaging methods and X-ray tomography in the characterization of microstructure

    International Nuclear Information System (INIS)

    Bacaicoa, Inigo; Luetje, Martin; Saelzer, Philipp; Umbach, Cristin; Brueckner-Foit, Angelika; Heim, Hans-Peter; Middendorf, Bernhard

    2017-01-01

    The microstructural features of three different materials have been quantified by means of 2D image analysis and X-ray micro-computer tomography (CT) and the results were compared to determine the reliability of the 2D analysis in the material characterization. The 3D quantification of shrinkage pores and Fe-rich inclusions of an Al-Si-Cu alloy by X-ray tomography was compared with the statistical analysis of the 2D metallographic pictures and a significant difference in the results was found due to the complex morphology of shrinkage pores and Fe-rich particles. Furthermore, wood particles of a wood-plastic composite were measured by dynamic image analysis and X-ray tomography. Similar results were obtained for the maximum length of the particles, although the results of width differ considerably, which leads to a miscalculation of the particles aspect ratio. Finally, air voids of a foam concrete were investigated by the analysis of the 2D pictures in ImageJ and the results of the 2D circularity were compared with the values of the 3D elongation obtained by micro-computed tomography. The 3D analysis of the air voids in the foam concrete showed a more precise description of the morphology, although the 2D result are in good agreement with the results obtained by X-ray micro-tomography.

  4. X-ray Imaging and preliminary studies of the X-ray self-emission from an innovative plasma-trap based on the Bernstein waves heating mechanism

    Science.gov (United States)

    Caliri, C.; Romano, F. P.; Mascali, D.; Gammino, S.; Musumarra, A.; Castro, G.; Celona, L.; Neri, L.; Altana, C.

    2013-10-01

    Electron Cyclotron Resonance Ion Sources (ECRIS) are based on ECR heated plasmas emitting high fluxes of X-rays. Here we illustrate a pilot study of the X-ray emission from a compact plasma-trap in which an off-resonance microwave-plasma interaction has been attempted, highlighting a possible Bernstein-Waves based heating mechanism. EBWs-heating is obtained via the inner plasma EM-to-ES wave conversion and enables to reach densities much larger than the cut-off ones. At LNS-INFN, an innovative diagnostic technique based on the design of a Pinhole Camera (PHC) coupled to a CCD device for X-ray Imaging of the plasma (XRI) has been developed, in order to integrate X-ray traditional diagnostics (XRS). The complementary use of electrostatic probes measurements and X-ray diagnostics enabled us to gain knowledge about the high energy electrons density and temperature and about the spatial structure of the source. The combination of the experimental data with appropriate modeling of the plasma-source allowed to estimate the X-ray emission intensity in different energy domains (ranging from EUV up to Hard X-rays). The use of ECRIS as X-ray source for multidisciplinary applications, is now a concrete perspective due to the intense fluxes produced by the new plasma heating mechanism.

  5. Low cost ESR based X-ray beamline for lithography experimentation

    Energy Technology Data Exchange (ETDEWEB)

    Kovacs, S.; Doumas, A.; Truncale, M. (Grumman Corp., Bethpage, NY (United States). Space and Electronics Div.)

    1992-08-01

    Any application of the electron storage ring (ESR) based X-ray lithography technology requires an X-ray radiation transport system to transfer the synchrotron radiation into a spectrum defined by the lithography process requirements. Structure of this transport system (i.e. the beamline) depends on the nature of the application. In this paper a beamline conceptual design will be discussed. The beamline is intended for the developmment of X-ray lithography technology. (orig.).

  6. A MEMS-based high frequency x-ray chopper

    Energy Technology Data Exchange (ETDEWEB)

    Siria, A; Schwartz, W; Chevrier, J [Institut Neel, CNRS-Universite Joseph Fourier Grenoble, BP 166, F-38042 Grenoble Cedex 9 (France); Dhez, O; Comin, F [ESRF, 6 rue Jules Horowitz, F-38043 Grenoble Cedex 9 (France); Torricelli, G [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom)

    2009-04-29

    Time-resolved x-ray experiments require intensity modulation at high frequencies (advanced rotating choppers have nowadays reached the kHz range). We here demonstrate that a silicon microlever oscillating at 13 kHz with nanometric amplitude can be used as a high frequency x-ray chopper. We claim that using micro-and nanoelectromechanical systems (MEMS and NEMS), it will be possible to achieve higher frequencies in excess of hundreds of megahertz. Working at such a frequency can open a wealth of possibilities in chemistry, biology and physics time-resolved experiments.

  7. A development of laser-plasma-based soft x-ray microscope system

    International Nuclear Information System (INIS)

    Nam, Ki Yong; Kim, Kyong Woo; Kim, Kyu Gyeom; Kwon, Young Man; Yoon, Kwon Ha

    2003-01-01

    Soft x-ray nano-imaging microscopy system for biomedical application with a high resolution about 50 nm has been designed and described, and its integrated techniques also have been studied. The system is mainly composed of soft x-ray generation system, nano-scaled control system, x-ray optical device like a condenser or object mirror, a CCD camera coupled with multichannel plate (MCP) and vacuum system. In the system, soft x-ray is generated from the laser-based plasma by focusing Nd:YAG laser beam on tantalum (Ta) target. In an x-ray optical system, a wolter mirror has been considering condensing the x-ray beam on a biological specimen and zone plate was adapted as an object mirror. A Si 3 N 4 was used as specimen holder for keeping a biological sample alive in atmosphere conditions. A back-illuminated-CCD camera coupled with multichannel plate was determined to set up.

  8. Development of an X-ray Computed Tomography System for Non-Invasive Imaging of Industrial Materials

    International Nuclear Information System (INIS)

    Abdullah, J.; Sipaun, S. M.; Mustapha, I.; Zain, R. M.; Rahman, M. F. A.; Mustapha, M.; Shaari, M. R.; Hassan, H.; Said, M. K. M.; Mohamad, G. H. P.; Ibrahim, M. M.

    2008-01-01

    X-ray computed tomography is a powerful non-invasive imaging technique for viewing an object's inner structures in two-dimensional cross-section images without the need to physically section it. The invention of CT techniques revolutionised the field of medical diagnostic imaging because it provided more detailed and useful information than any previous non-invasive imaging techniques. The method is increasingly being used in industry, aerospace, geosciences and archaeology. This paper describes the development of an X-ray computed tomography system for imaging of industrial materials. The theoretical aspects of CT scanner, the system configurations and the adopted algorithm for image reconstruction are discussed. The penetrating rays from a 160 kV industrial X-ray machine were used to investigate structures that manifest in a manufactured component or product. Some results were presented in this paper

  9. Nanoscale characterization of local structures and defects in photonic crystals using synchrotron-based transmission soft X-ray microscopy

    Science.gov (United States)

    Nho, Hyun Woo; Kalegowda, Yogesh; Shin, Hyun-Joon; Yoon, Tae Hyun

    2016-01-01

    For the structural characterization of the polystyrene (PS)-based photonic crystals (PCs), fast and direct imaging capabilities of full field transmission X-ray microscopy (TXM) were demonstrated at soft X-ray energy. PS-based PCs were prepared on an O2-plasma treated Si3N4 window and their local structures and defects were investigated using this label-free TXM technique with an image acquisition speed of ~10 sec/frame and marginal radiation damage. Micro-domains of face-centered cubic (FCC (111)) and hexagonal close-packed (HCP (0001)) structures were dominantly found in PS-based PCs, while point and line defects, FCC (100), and 12-fold symmetry structures were also identified as minor components. Additionally, in situ observation capability for hydrated samples and 3D tomographic reconstruction of TXM images were also demonstrated. This soft X-ray full field TXM technique with faster image acquisition speed, in situ observation, and 3D tomography capability can be complementally used with the other X-ray microscopic techniques (i.e., scanning transmission X-ray microscopy, STXM) as well as conventional characterization methods (e.g., electron microscopic and optical/fluorescence microscopic techniques) for clearer structure identification of self-assembled PCs and better understanding of the relationship between their structures and resultant optical properties. PMID:27087141

  10. A practical material decomposition method for x-ray dual spectral computed tomography.

    Science.gov (United States)

    Hu, Jingjing; Zhao, Xing

    2016-03-17

    X-ray dual spectral CT (DSCT) scans the measured object with two different x-ray spectra, and the acquired rawdata can be used to perform the material decomposition of the object. Direct calibration methods allow a faster material decomposition for DSCT and can be separated in two groups: image-based and rawdata-based. The image-based method is an approximative method, and beam hardening artifacts remain in the resulting material-selective images. The rawdata-based method generally obtains better image quality than the image-based method, but this method requires geometrically consistent rawdata. However, today's clinical dual energy CT scanners usually measure different rays for different energy spectra and acquire geometrically inconsistent rawdata sets, and thus cannot meet the requirement. This paper proposes a practical material decomposition method to perform rawdata-based material decomposition in the case of inconsistent measurement. This method first yields the desired consistent rawdata sets from the measured inconsistent rawdata sets, and then employs rawdata-based technique to perform material decomposition and reconstruct material-selective images. The proposed method was evaluated by use of simulated FORBILD thorax phantom rawdata and dental CT rawdata, and simulation results indicate that this method can produce highly quantitative DSCT images in the case of inconsistent DSCT measurements.

  11. Improving limited-projection-angle fluorescence molecular tomography using a co-registered x-ray computed tomography scan.

    Science.gov (United States)

    Radrich, Karin; Ale, Angelique; Ermolayev, Vladimir; Ntziachristos, Vasilis

    2012-12-01

    We examine the improvement in imaging performance, such as axial resolution and signal localization, when employing limited-projection-angle fluorescence molecular tomography (FMT) together with x-ray computed tomography (XCT) measurements versus stand-alone FMT. For this purpose, we employed living mice, bearing a spontaneous lung tumor model, and imaged them with FMT and XCT under identical geometrical conditions using fluorescent probes for cancer targeting. The XCT data was employed, herein, as structural prior information to guide the FMT reconstruction. Gold standard images were provided by fluorescence images of mouse cryoslices, providing the ground truth in fluorescence bio-distribution. Upon comparison of FMT images versus images reconstructed using hybrid FMT and XCT data, we demonstrate marked improvements in image accuracy. This work relates to currently disseminated FMT systems, using limited projection scans, and can be employed to enhance their performance.

  12. Compression of Born ratio for fluorescence molecular tomography/x-ray computed tomography hybrid imaging: methodology and in vivo validation.

    Science.gov (United States)

    Mohajerani, Pouyan; Ntziachristos, Vasilis

    2013-07-01

    The 360° rotation geometry of the hybrid fluorescence molecular tomography/x-ray computed tomography modality allows for acquisition of very large datasets, which pose numerical limitations on the reconstruction. We propose a compression method that takes advantage of the correlation of the Born-normalized signal among sources in spatially formed clusters to reduce the size of system model. The proposed method has been validated using an ex vivo study and an in vivo study of a nude mouse with a subcutaneous 4T1 tumor, with and without inclusion of a priori anatomical information. Compression rates of up to two orders of magnitude with minimum distortion of reconstruction have been demonstrated, resulting in large reduction in weight matrix size and reconstruction time.

  13. Simulation tools for scattering corrections in spectrally resolved x-ray computed tomography using McXtrace

    Science.gov (United States)

    Busi, Matteo; Olsen, Ulrik L.; Knudsen, Erik B.; Frisvad, Jeppe R.; Kehres, Jan; Dreier, Erik S.; Khalil, Mohamad; Haldrup, Kristoffer

    2018-03-01

    Spectral computed tomography is an emerging imaging method that involves using recently developed energy discriminating photon-counting detectors (PCDs). This technique enables measurements at isolated high-energy ranges, in which the dominating undergoing interaction between the x-ray and the sample is the incoherent scattering. The scattered radiation causes a loss of contrast in the results, and its correction has proven to be a complex problem, due to its dependence on energy, material composition, and geometry. Monte Carlo simulations can utilize a physical model to estimate the scattering contribution to the signal, at the cost of high computational time. We present a fast Monte Carlo simulation tool, based on McXtrace, to predict the energy resolved radiation being scattered and absorbed by objects of complex shapes. We validate the tool through measurements using a CdTe single PCD (Multix ME-100) and use it for scattering correction in a simulation of a spectral CT. We found the correction to account for up to 7% relative amplification in the reconstructed linear attenuation. It is a useful tool for x-ray CT to obtain a more accurate material discrimination, especially in the high-energy range, where the incoherent scattering interactions become prevailing (>50 keV).

  14. A computationally inexpensive model for estimating dimensional measurement uncertainty due to x-ray computed tomography instrument misalignments

    Science.gov (United States)

    Ametova, Evelina; Ferrucci, Massimiliano; Chilingaryan, Suren; Dewulf, Wim

    2018-06-01

    The recent emergence of advanced manufacturing techniques such as additive manufacturing and an increased demand on the integrity of components have motivated research on the application of x-ray computed tomography (CT) for dimensional quality control. While CT has shown significant empirical potential for this purpose, there is a need for metrological research to accelerate the acceptance of CT as a measuring instrument. The accuracy in CT-based measurements is vulnerable to the instrument geometrical configuration during data acquisition, namely the relative position and orientation of x-ray source, rotation stage, and detector. Consistency between the actual instrument geometry and the corresponding parameters used in the reconstruction algorithm is critical. Currently available procedures provide users with only estimates of geometrical parameters. Quantification and propagation of uncertainty in the measured geometrical parameters must be considered to provide a complete uncertainty analysis and to establish confidence intervals for CT dimensional measurements. In this paper, we propose a computationally inexpensive model to approximate the influence of errors in CT geometrical parameters on dimensional measurement results. We use surface points extracted from a computer-aided design (CAD) model to model discrepancies in the radiographic image coordinates assigned to the projected edges between an aligned system and a system with misalignments. The efficacy of the proposed method was confirmed on simulated and experimental data in the presence of various geometrical uncertainty contributors.

  15. Transient thermal finite element analysis of CFC–Cu ITER monoblock using X-ray tomography data

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Ll.M., E-mail: llion.evans@ccfe.ac.uk [CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); School of Materials, University of Manchester, Grosvenor Street, Manchester M1 7HS (United Kingdom); Margetts, L. [School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Williamson Building, Manchester M13 9PL (United Kingdom); Casalegno, V. [Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, I-10129 Torino (Italy); Lever, L.M. [IT Services for Research, University of Manchester, Devonshire House, Oxford Road, Manchester M13 9PL (United Kingdom); Bushell, J.; Lowe, T.; Wallwork, A. [School of Materials, University of Manchester, Grosvenor Street, Manchester M1 7HS (United Kingdom); Young, P. [Simpleware Ltd., Bradninch Hall, Castle Street, Exeter EX4 3PL (United Kingdom); Lindemann, A. [NETZSCH-Gerätebau GmbH, Wittelsbacherstraße 42, D-95100 Selb, Bayern (Germany); Schmidt, M.; Mummery, P.M. [School of Mechanical, Aerospace and Civil Engineering (MACE), University of Manchester, Manchester M13 9PL (United Kingdom)

    2015-11-15

    Highlights: • Thermal performance of a fusion power heat exchange component was investigated. • Microstructures effecting performance were determined using X-ray tomography. • This data was used to perform a microstructurally faithful finite element analysis. • FEA demonstrated that manufacturing defects had an appreciable effect on performance. • This image-based modelling showed which regions could be targeted for improvements. - Abstract: The thermal performance of a carbon fibre composite-copper monoblock, a sub-component of a fusion reactor divertor, was investigated by finite element analysis. High-accuracy simulations were created using an emerging technique, image-based finite element modelling, which converts X-ray tomography data into micro-structurally faithful models, capturing details such as manufacturing defects. For validation, a case study was performed where the thermal analysis by laser flash of a carbon fibre composite-copper disc was simulated such that computational and experimental results could be compared directly. Results showed that a high resolution image-based simulation (102 million elements of 32 μm width) provided increased accuracy over a low resolution image-based simulation (0.6 million elements of 194 μm width) and idealised computer aided design simulations. Using this technique to analyse a monoblock mock-up, it was possible to detect and quantify the effects of debonding regions at the carbon fibre composite-copper interface likely to impact both component performance and expected lifetime. These features would not have been accounted for in idealised computer aided design simulations.

  16. Transient thermal finite element analysis of CFC–Cu ITER monoblock using X-ray tomography data

    International Nuclear Information System (INIS)

    Evans, Ll.M.; Margetts, L.; Casalegno, V.; Lever, L.M.; Bushell, J.; Lowe, T.; Wallwork, A.; Young, P.; Lindemann, A.; Schmidt, M.; Mummery, P.M.

    2015-01-01

    Highlights: • Thermal performance of a fusion power heat exchange component was investigated. • Microstructures effecting performance were determined using X-ray tomography. • This data was used to perform a microstructurally faithful finite element analysis. • FEA demonstrated that manufacturing defects had an appreciable effect on performance. • This image-based modelling showed which regions could be targeted for improvements. - Abstract: The thermal performance of a carbon fibre composite-copper monoblock, a sub-component of a fusion reactor divertor, was investigated by finite element analysis. High-accuracy simulations were created using an emerging technique, image-based finite element modelling, which converts X-ray tomography data into micro-structurally faithful models, capturing details such as manufacturing defects. For validation, a case study was performed where the thermal analysis by laser flash of a carbon fibre composite-copper disc was simulated such that computational and experimental results could be compared directly. Results showed that a high resolution image-based simulation (102 million elements of 32 μm width) provided increased accuracy over a low resolution image-based simulation (0.6 million elements of 194 μm width) and idealised computer aided design simulations. Using this technique to analyse a monoblock mock-up, it was possible to detect and quantify the effects of debonding regions at the carbon fibre composite-copper interface likely to impact both component performance and expected lifetime. These features would not have been accounted for in idealised computer aided design simulations.

  17. X-ray structure based evaluation of analogs of citalopram

    DEFF Research Database (Denmark)

    Topiol, Sid; Bang-Andersen, Benny; Sanchez, Connie

    2017-01-01

    The recent publication of X-ray structures of SERT includes structures with the potent antidepressant S-Citalopram (S-Cit). Earlier predictions of ligand binding at both a primary (S1) and an allosteric modulator site (S2), were confirmed. We provide herein examples of a series of Citalopram anal...

  18. Characterization of impact damage in metallic/nonmetallic composites using x-ray computed tomography imaging

    International Nuclear Information System (INIS)

    Green, William H.; Wells, Joseph M.

    1999-01-01

    Characterizing internal impact damage in composites can be difficult, especially in structurally complex composites or those consisting of many materials. Many methods for nondestructive inspection/nondestructive testing (NDI/NDT) of materials have been known and in use for many years, including x-ray film, real-time, and digital radiographic techniques, and ultrasonic techniques. However, these techniques are generally not capable of three-dimensional (3D) mapping of complex damage patterns, which is necessary to visualize and understand damage cracking modes. Conventional x-ray radiography suffers from the loss of 3D information. Structural complexity and signal dispersion in materials with many interfaces significantly effect ultrasonic inspection techniques. This makes inspection scan interpretation difficult, especially in composites containing a number of different materials (i.e., polymer, ceramic, and metallic). X-ray computed tomography (CT) is broadly applicable to any material or test object through which a beam of penetrating radiation may be passed and detected, including metals, plastics, ceramics, metallic/nonmetallic composites, and assemblies. The principal advantage of CT is that it provides densitometric (that is, radiological density and geometry) images of thin cross sections through an object. Because of the absence of structural superposition, images are much easier to interpret than conventional radiological images. The user can quickly learn to read CT data because images correspond more closely to the way the human mind visualizes 3D structures than projection radiology (that is, film radiography, real-time radiography (RTR), and digital radiography (DR)). Any number of CT images, or slices, from scanning an object can be volumetrically reconstructed to produce a 3D attenuation map of the object. The 3D attenuation data can be rendered using multiplanar or 3D solid visualization. In multiplanar visualization there are four planes of view

  19. Confocal total reflection X-ray fluorescence technology based on an elliptical monocapillary and a parallel polycapillary X-ray optics.

    Science.gov (United States)

    Zhu, Yu; Wang, Yabing; Sun, Tianxi; Sun, Xuepeng; Zhang, Xiaoyun; Liu, Zhiguo; Li, Yufei; Zhang, Fengshou

    2018-07-01

    A total reflection X-ray fluorescence (TXRF) spectrometer based on an elliptical monocapillary X-ray lens (MXRL) and a parallel polycapillary X-ray lens (PPXRL) was designed. This TXRF instrument has micro focal spot, low divergence and high intensity of incident X-ray beam. The diameter of the focal spot of MXRL was 16.5 µm, and the divergence of the incident X-ray beam was 3.4 mrad. We applied this TXRF instrument to the micro analysis of a single-layer film containing Ni deposited on a Si substrate by metal vapor vacuum arc ion source. Copyright © 2018 Elsevier Ltd. All rights reserved.

  20. Development of a micro-X-ray fluorescence system based on polycapillary X-ray optics for non-destructive analysis of archaeological objects

    Science.gov (United States)

    Cheng, Lin; Ding, Xunliang; Liu, Zhiguo; Pan, Qiuli; Chu, Xuelian

    2007-08-01

    A new micro-X-ray fluorescence (micro-XRF) system based on rotating anode X-ray generator and polycapillary X-ray optics has been set up in XOL Lab, BNU, China, in order to be used for analysis of archaeological objects. The polycapillary X-ray optics used here can focus the primary X-ray beam down to tens of micrometers in diameter that allows for non-destructive and local analysis of sub-mm samples with minor/trace level sensitivity. The analytical characteristics and potential of this micro-XRF system in archaeological research are discussed. Some described uses of this instrument include studying Chinese ancient porcelain.

  1. Development of a micro-X-ray fluorescence system based on polycapillary X-ray optics for non-destructive analysis of archaeological objects

    Energy Technology Data Exchange (ETDEWEB)

    Cheng Lin [Key Laboratory of Beam Technology and Material Modification of Ministry of Education, Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing Radiation Center, Beijing, 100875 (China)], E-mail: chenglin@bnu.edu.cn; Ding Xunliang; Liu Zhiguo; Pan Qiuli; Chu Xuelian [Key Laboratory of Beam Technology and Material Modification of Ministry of Education, Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing Radiation Center, Beijing, 100875 (China)

    2007-08-15

    A new micro-X-ray fluorescence (micro-XRF) system based on rotating anode X-ray generator and polycapillary X-ray optics has been set up in XOL Lab, BNU, China, in order to be used for analysis of archaeological objects. The polycapillary X-ray optics used here can focus the primary X-ray beam down to tens of micrometers in diameter that allows for non-destructive and local analysis of sub-mm samples with minor/trace level sensitivity. The analytical characteristics and potential of this micro-XRF system in archaeological research are discussed. Some described uses of this instrument include studying Chinese ancient porcelain.

  2. Microstructural analysis of TRISO particles using multi-scale X-ray computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Lowe, T., E-mail: tristan.lowe@manchester.ac.uk [Manchester X-ray Imaging Facility, School of Materials, University of Manchester, M13 9PL (United Kingdom); Bradley, R.S. [Manchester X-ray Imaging Facility, School of Materials, University of Manchester, M13 9PL (United Kingdom); Yue, S. [Manchester X-ray Imaging Facility, School of Materials, University of Manchester, M13 9PL (United Kingdom); The Research Complex at Harwell, Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0FA (United Kingdom); Barii, K. [School of Mechanical Engineering, University of Manchester, M13 9PL (United Kingdom); Gelb, J. [Zeiss Xradia Inc., Pleasanton, CA (United States); Rohbeck, N. [Manchester X-ray Imaging Facility, School of Materials, University of Manchester, M13 9PL (United Kingdom); Turner, J. [School of Mechanical Engineering, University of Manchester, M13 9PL (United Kingdom); Withers, P.J. [Manchester X-ray Imaging Facility, School of Materials, University of Manchester, M13 9PL (United Kingdom); The Research Complex at Harwell, Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0FA (United Kingdom)

    2015-06-15

    TRISO particles, a composite nuclear fuel built up by ceramic and graphitic layers, have outstanding high temperature resistance. TRISO fuel is the key technology for High Temperature Reactors (HTRs) and the Generation IV Very High Temperature Reactor (VHTR) variant. TRISO offers unparalleled containment of fission products and is extremely robust during accident conditions. An understanding of the thermal performance and mechanical properties of TRISO fuel requires a detailed knowledge of pore sizes, their distribution and interconnectivity. Here 50 nm, nano-, and 1 μm resolution, micro-computed tomography (CT), have been used to quantify non-destructively porosity of a surrogate TRISO particle at the 0.3–10 μm and 3–100 μm scales respectively. This indicates that pore distributions can reliably be measured down to a size approximately 3 times the pixel size which is consistent with the segmentation process. Direct comparison with Scanning Electron Microscopy (SEM) sections indicates that destructive sectioning can introduce significant levels of coarse damage, especially in the pyrolytic carbon layers. Further comparative work is required to identify means of minimizing such damage for SEM studies. Finally since it is non-destructive, multi-scale time-lapse X-ray CT opens the possibility of intermittently tracking the degradation of TRISO structure under thermal cycles or radiation conditions in order to validate models of degradation such as kernel movement. X-ray CT in-situ experimentation of TRISO particles under load and temperature could also be used to understand the internal changes that occur in the particles under accident conditions.

  3. X-ray scatter correction method for dedicated breast computed tomography: improvements and initial patient testing

    International Nuclear Information System (INIS)

    Ramamurthy, Senthil; D’Orsi, Carl J; Sechopoulos, Ioannis

    2016-01-01

    A previously proposed x-ray scatter correction method for dedicated breast computed tomography was further developed and implemented so as to allow for initial patient testing. The method involves the acquisition of a complete second set of breast CT projections covering 360° with a perforated tungsten plate in the path of the x-ray beam. To make patient testing feasible, a wirelessly controlled electronic positioner for the tungsten plate was designed and added to a breast CT system. Other improvements to the algorithm were implemented, including automated exclusion of non-valid primary estimate points and the use of a different approximation method to estimate the full scatter signal. To evaluate the effectiveness of the algorithm, evaluation of the resulting image quality was performed with a breast phantom and with nine patient images. The improvements in the algorithm resulted in the avoidance of introduction of artifacts, especially at the object borders, which was an issue in the previous implementation in some cases. Both contrast, in terms of signal difference and signal difference-to-noise ratio were improved with the proposed method, as opposed to with the correction algorithm incorporated in the system, which does not recover contrast. Patient image evaluation also showed enhanced contrast, better cupping correction, and more consistent voxel values for the different tissues. The algorithm also reduces artifacts present in reconstructions of non-regularly shaped breasts. With the implemented hardware and software improvements, the proposed method can be reliably used during patient breast CT imaging, resulting in improvement of image quality, no introduction of artifacts, and in some cases reduction of artifacts already present. The impact of the algorithm on actual clinical performance for detection, diagnosis and other clinical tasks in breast imaging remains to be evaluated. (paper)

  4. Detection of freeze-thaw weathering effect using X-ray micro computed tomography

    Science.gov (United States)

    Park, J.; Hyun, C.; Park, H.

    2011-12-01

    Physical weathering caused by repeated freeze-thaw action of water inside rock pores or cracks was artificially simulated in laboratory. The tests were conducted on three rock types, i.e. diorite, basalt, and tuff, which are the major rock types around King Sejong Station of Korea located in Barton Peninsula, King George Island, Antarctica. The temperature of freeze-thaw cycle was also set with simulated the air temperature of the station, i.e. the maximum temperature was + 10 °C and the minimum temperature was - 20 °C. Three cylindrical specimens composed of one for each rock type with 24.6 mm diameter and 14.5 ~ 17.7 mm length were prepared, and 2 mm diameter and 7 mm shallow depth hole was drilled on the center of the specimens. To exaggerate the effect of the freeze-thaw weathering, all tests were conducted under completely saturated condition. 50 cycles of the freeze-thaw test was carried, and X-ray micro computed tomography (CT) images of each rock specimen were obtained after every 10 cycles. Using X-ray micro CT images, 3D structure was rendered and pore and crack structures were extracted. The changes of porosity, absorption rate and pore and crack structure were detected. Porosity of all specimens was decreased linearly and absorption rate of all specimens was increased linearly as weathering processes; the pore connection and crack propagation was detected in 3D rendering pore and crack structure. The change of tuff specimen is the most remarkable among three rock types used in the research, because of its relatively high initial absorption rate and low strength. This work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MEST) (No. 2011-0027520).

  5. Image statistics and nonlinear artifacts in composed transmission x-ray tomography

    International Nuclear Information System (INIS)

    Duerinckx, A.J.G.

    1979-01-01

    Knowledge of the image quality and image statistics in Computed Tomography (CT) images obtained with transmission x-ray CT scanners can increase the amount of clinically useful information that can be retrieved. Artifacts caused by nonlinear shadows are strongly object-dependent and are visible over larger areas of the image. No simple technique exists for their complete elimination. One source of artifacts in the first order statistics is the nonlinearities in the measured shadow or projection data used to reconstruct the image. One of the leading causes is the polychromaticity of the x-ray beam used in transmission CT scanners. Ways to improve the resulting image quality and techniques to extract additional information using dual energy scanning are discussed. A unique formalism consisting of a vector representation of the material dependence of the photon-tissue interactions is generalized to allow an in depth analysis. Poly-correction algorithms are compared using this analytic approach. Both quantum and detector electronic noise decrease the quality or information content of first order statistics. Preliminary results are presented using an heuristic adaptive nonlinear noise filter system for projection data. This filter system can be improved and/or modified to remove artifacts in both first and second order image statistics. Artifacts in the second order image statistics arise from the contribution of quantum noise. This can be described with a nonlinear detection equivalent model, similar to the model used to study artifacts in first order statistics. When analyzing these artifacts in second order statistics, one can divide them into linear artifacts, which do not present any problem of interpretation, and nonlinear artifacts, referred to as noise artifacts. A study of noise artifacts is presented together with a discussion of their relative importance in diagnostic radiology

  6. Quantitative wood–adhesive penetration with X-ray computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Paris, Jesse L.; Kamke, Frederick A. (Oregon State U.); (Willamette Valley)

    2015-09-01

    Micro X-ray computed tomography (XCT) was used to analyze the 3D adhesive penetration behavior of different wood–adhesive bondlines. Three adhesives, a phenol formaldehyde (PF), a polymeric diphenylmethane diisocyanate (pMDI), and a hybrid polyvinyl acetate (PVA), all tagged with iodine for enhanced X-ray attenuation, were used to prepare single-bondline laminates in two softwoods, Douglas-fir and loblolly pine, and one hardwood, a hybrid polar. Adhesive penetration depth was measured with two separate calculations, and results were compared with 2D fluorescent micrographs. A total of 54 XCT scans were collected, representing six replicates of each treatment type; each replicate, however, consisted of approximately 1500 individual, cross-section slices stacked along the specimen length. As these adhesives were highly modified, the presented results do not indicate typical behavior for their broader adhesive classes. Still, clear penetration differences were observed between each adhesive type, and between wood species bonded with both the PF and pMDI adhesives. Furthermore, penetration results depended on the calculation method used. Two adhesive types with noticeably different resin distributions in the cured bondline, showed relatively similar penetration depths when calculated with a traditional effective penetration equation. However, when the same data was calculated with a weighted penetration calculation, which accounts for both adhesive area and depth, the results appeared to better represent the different distributions depicted in the photomicrographs and tomograms. Additionally, individual replicate comparisons showed variation due to specimen anatomy, not easily observed or interpreted from 2D images. Finally, 3D views of segmented 3D adhesive phases offered unique, in-situ views of the cured adhesive structures. In particular, voids formed by CO2 bubbles generated during pMDI cure were clearly visible in penetrated columns of the solidified

  7. Multifunctional BSA-Au nanostars for photoacoustic imaging and X-ray computed tomography.

    Science.gov (United States)

    Zu, Lihui; Liu, Lin; Qin, Yeshan; Liu, Hongguang; Yang, Haishan

    2016-10-01

    We report the synthesis and characterization of bovine serum albumin-capped Au nanostars (BSA-AuNSs) for dual-modal computed tomography (CT)/photoacoustic (PA) imaging application. The BSA-AuNSs have an average size of 85nm, and a surface plasmon resonance (SPR) peak at approximately 770nm. They have excellent biocompatibility, good X-ray attenuation, and great PA contrast enhancement properties. When injected intravenously, liver signal markedly increases in both CT and PA modalities. The in vivo biodistribution studies and pathology results showed that the BSA-AuNSs were mainly excreted through the liver and intestines with no obvious biotoxicity. These results indicate that BSA-AuNSs have high potential to be used as dual-modal CT/PA imaging contrast agents or further used to develop targeted probes. This preliminary study suggests that PA tomography may be used to non-invasively trace the kinetics and biodistribution of the nanoparticles. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. A minute fossil phoretic mite recovered by phase-contrast X-ray computed tomography

    Science.gov (United States)

    Dunlop, Jason A.; Wirth, Stefan; Penney, David; McNeil, Andrew; Bradley, Robert S.; Withers, Philip J.; Preziosi, Richard F.

    2012-01-01

    High-resolution phase-contrast X-ray computed tomography (CT) reveals the phoretic deutonymph of a fossil astigmatid mite (Acariformes: Astigmata) attached to a spider's carapace (Araneae: Dysderidae) in Eocene (44–49 Myr ago) Baltic amber. Details of appendages and a sucker plate were resolved, and the resulting three-dimensional model demonstrates the potential of tomography to recover morphological characters of systematic significance from even the tiniest amber inclusions without the need for a synchrotron. Astigmatids have an extremely sparse palaeontological record. We confirm one of the few convincing fossils, potentially the oldest record of Histiostomatidae. At 176 µm long, we believe this to be the smallest arthropod in amber to be CT-scanned as a complete body fossil, extending the boundaries for what can be recovered using this technique. We also demonstrate a minimum age for the evolution of phoretic behaviour among their deutonymphs, an ecological trait used by extant species to disperse into favourable environments. The occurrence of the fossil on a spider is noteworthy, as modern histiostomatids tend to favour other arthropods as carriers. PMID:22072283

  9. Quantitative X-ray computed tomography peritoneography in malignant peritoneal mesothelioma patients receiving intraperitoneal chemotherapy.

    Science.gov (United States)

    Leinwand, Joshua C; Zhao, Binsheng; Guo, Xiaotao; Krishnamoorthy, Saravanan; Qi, Jing; Graziano, Joseph H; Slavkovic, Vesna N; Bates, Gleneara E; Lewin, Sharyn N; Allendorf, John D; Chabot, John A; Schwartz, Lawrence H; Taub, Robert N

    2013-12-01

    Intraperitoneal chemotherapy is used to treat peritoneal surface-spreading malignancies. We sought to determine whether volume and surface area of the intraperitoneal chemotherapy compartments are associated with overall survival and posttreatment glomerular filtration rate (GFR) in malignant peritoneal mesothelioma (MPM) patients. Thirty-eight MPM patients underwent X-ray computed tomography peritoneograms during outpatient intraperitoneal chemotherapy. We calculated volume and surface area of contrast-filled compartments by semiautomated computer algorithm. We tested whether these were associated with overall survival and posttreatment GFR. Decreased likelihood of mortality was associated with larger surface areas (p = 0.0201) and smaller contrast-filled compartment volumes (p = 0.0341), controlling for age, sex, histologic subtype, and presence of residual disease >0.5 cm postoperatively. Larger volumes were associated with higher posttreatment GFR, controlling for pretreatment GFR, body surface area, surface area, and the interaction between body surface area and volume (p = 0.0167). Computed tomography peritoneography is an appropriate modality to assess for maldistribution of intraperitoneal chemotherapy. In addition to identifying catheter failure and frank loculation, quantitative analysis of the contrast-filled compartment's surface area and volume may predict overall survival and cisplatin-induced nephrotoxicity. Prospective studies should be undertaken to confirm and extend these findings to other diseases, including advanced ovarian carcinoma.

  10. A minute fossil phoretic mite recovered by phase-contrast X-ray computed tomography.

    Science.gov (United States)

    Dunlop, Jason A; Wirth, Stefan; Penney, David; McNeil, Andrew; Bradley, Robert S; Withers, Philip J; Preziosi, Richard F

    2012-06-23

    High-resolution phase-contrast X-ray computed tomography (CT) reveals the phoretic deutonymph of a fossil astigmatid mite (Acariformes: Astigmata) attached to a spider's carapace (Araneae: Dysderidae) in Eocene (44-49 Myr ago) Baltic amber. Details of appendages and a sucker plate were resolved, and the resulting three-dimensional model demonstrates the potential of tomography to recover morphological characters of systematic significance from even the tiniest amber inclusions without the need for a synchrotron. Astigmatids have an extremely sparse palaeontological record. We confirm one of the few convincing fossils, potentially the oldest record of Histiostomatidae. At 176 µm long, we believe this to be the smallest arthropod in amber to be CT-scanned as a complete body fossil, extending the boundaries for what can be recovered using this technique. We also demonstrate a minimum age for the evolution of phoretic behaviour among their deutonymphs, an ecological trait used by extant species to disperse into favourable environments. The occurrence of the fossil on a spider is noteworthy, as modern histiostomatids tend to favour other arthropods as carriers.

  11. Three-Dimensional Printing of X-Ray Computed Tomography Datasets with Multiple Materials Using Open-Source Data Processing

    Science.gov (United States)

    Sander, Ian M.; McGoldrick, Matthew T.; Helms, My N.; Betts, Aislinn; van Avermaete, Anthony; Owers, Elizabeth; Doney, Evan; Liepert, Taimi; Niebur, Glen; Liepert, Douglas; Leevy, W. Matthew

    2017-01-01

    Advances in three-dimensional (3D) printing allow for digital files to be turned into a "printed" physical product. For example, complex anatomical models derived from clinical or pre-clinical X-ray computed tomography (CT) data of patients or research specimens can be constructed using various printable materials. Although 3D printing…

  12. Fatigue damage assessment of uni-directional non-crimp fabric reinforced polyester composite using X-ray computed tomography

    DEFF Research Database (Denmark)

    Jespersen, Kristine Munk; Zangenberg Hansen, Jens; Lowe, Tristan

    2016-01-01

    In this study, the progression of tension-tension fatigue (R=0.1) damage in a unidirectional (UD) composite made from a non-crimp glass fibre fabric used for wind turbine blades is investigated using multi-scale 3D X-ray computed tomography (CT). Initially, a representative volume is examined at ...

  13. Computerized tomography and conventional radiography: A comparison from the standpoint of X-ray physics and technology

    Energy Technology Data Exchange (ETDEWEB)

    Pfeiler, M; Linke, G [Siemens A.G., Erlangen (Germany, F.R.). Unternehmensbereich Medizinische Technik

    1979-08-01

    After a short explantation of the technical foundations of computerized tomography (CT) from terms used in conventional X-ray technique and CT the differences (dose distribution, image character) and similarities (quantum noise, beam quality) of both methods are discussed. Finally possible methods of quantitative evaluation of CT images and computation of longitudinal layers from a series of computerized tomograms are described. (author).

  14. Evaluation of bone response to titanium-coated polymethyl methacrylate resin (PMMA) implants by X-ray tomography.

    NARCIS (Netherlands)

    Shalabi, M.M.; Wolke, J.G.C.; Cuijpers, V.M.J.I.; Jansen, J.A.

    2007-01-01

    High-resolution three-dimensional data about the bone response to oral implants can be obtained by using microfocus computer tomography. However, a disadvantage is that metallic implants cause streaking artifacts due to scattering of X-rays, which prevents an accurate evaluation of the interfacial

  15. Three-dimensional grain structure of sintered bulk strontium titanate from X-ray diffraction contrast tomography

    DEFF Research Database (Denmark)

    Syha, M.; Rheinheimer, W.; Bäurer, M.

    2012-01-01

    The three-dimensional grain boundary network of sintered bulk strontium titanate is reconstructed using X-ray diffraction contrast tomography, a non-destructive technique for determining the grain shape and crystallographic orientation in polycrystals that is ideally suited for detailed studies...

  16. A general methodology for full-field plastic strain measurements using X-ray absorption tomography and internal markers

    DEFF Research Database (Denmark)

    Haldrup, Martin Kristoffer; Nielsen, Søren Fæster; Wert, John A.

    2008-01-01

    on a homogenous distribution of marker particles throughout the bulk of a sample, markers which are detected through the application of synchrotron X-ray tomography. Making use of the morphology of individual markers, motion of individual markers is tracked during deformation allowing the local displacement field...

  17. Comparative analysis of brain X-ray computed tomography in patients with acromegaly before and after gamma-ray teletherapy

    International Nuclear Information System (INIS)

    Balkanov, A.S.; Stashuk, G.A.; Polyakov, P.Yu.; Sherman, L.A.; Bychenkov, O.A.

    1999-01-01

    Results are analysed of the application of X-ray computerized tomography (KT) of brain in acromegaly patients before and after remote gamma therapy (RGT). Efficiency is shown of the KT method permitting both to reveal pituitary adenomas in case of acromegaly and to be applicable in the combination with other methods to assessment of the RGT efficiency when treating acromegaly [ru

  18. Soft x-ray tomography for real-time applications: present status at Tore Supra and possible future developments

    Czech Academy of Sciences Publication Activity Database

    Mazon, D.; Vezinet, D.; Pacella, D.; Moreau, D.; Gabelieri, L.; Romano, A.; Malard, P.; Mlynář, Jan; Masset, R.; Lotte, P.

    2012-01-01

    Roč. 83, č. 6 (2012), 063505-063505 ISSN 0034-6748 Institutional research plan: CEZ:AV0Z20430508 Keywords : Tokamak * tomography X-ray * diagnostics Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.602, year: 2012 http://rsi.aip.org/resource/1/rsinak/v83/i6/p063505_s1

  19. In situ observation of syntactic foams under hydrostatic pressure using X-ray tomography

    International Nuclear Information System (INIS)

    Lachambre, J.; Maire, E.; Adrien, J.; Choqueuse, D.

    2013-01-01

    Syntactic foams (hollow glass microspheres embedded in a polymeric matrix) are being used increasingly for the purpose of thermal insulation in ultradeep water. A better understanding of the damage mechanisms of these materials at the microsphere scale under such a hydrostatic loading condition is of prior importance in determining actual material limits, improving phenomenological modelling and developing novel formulations in the future. To achieve this goal, a study based on X-ray microtomography was performed on two syntactic foam materials (polypropylene and polyurethane matrix) and a standard foamed PP. A special set up has been designed in order to allow the X-ray microtomographic observation of the material during hydrostatic pressure loading using ethanol as the pressure fluid. Spatial resolution of (3.5 μm) 3 and in situ non-destructive scanning allowed a unique qualitative and quantitative analysis of the composite microstructure during stepwise isotropic compression by hydrostatic pressure up to 50 MPa. The collapse of weaker microspheres were observed during pressure increase and the damage parameters could be estimated. It is shown that the microspheres which are broken or the porosities which are close to the surface in the foamed PP are filled by a fluid (either the ethanol or the polymeric matrix itself). The hydrostatic pressure decreases the volume of the foam only slightly. In the PU matrix, ethanol diffusion is seen to induce swelling of the matrix, which is an unexpected phenomenon but reveals the high potential of X-ray microtomographic observation to improve diffusion analysis in complex media

  20. Development and characterization of a laser-based hard x-ray source

    International Nuclear Information System (INIS)

    Tillman, C.

    1996-11-01

    A laser-produced plasma was generated by focusing 100 fs laser pulses, with an energy of 150 mJ, onto metal targets. The laser intensity was expected to reach 10 17 W/cm -2 . Radiation was emitted from the created plasma, with photon energies up to the MeV region. The laser-based X-ray source was optimized, with the purpose of making it a realistic source of hard X-rays (>10 keV). Dedicated equipment was developed for efficient generation and utilization of the hard X-rays. The X-ray source was characterized with respect to its spatial extent and the X-ray yield. Measurements were made of the spectral distribution, by the use of single-photon-counting detectors in different geometries, crystal spectrometers and dose measurements in combination with absorption filters. Ablation of the target material in the laser produced plasma was investigated. Imaging applications have been demonstrated, including ultrafast (picosecond) X-ray imaging, magnification imaging of up to x80, differential imaging in the spectral domain, and imaging of various biological and technical objects. The biological response of ultra-intense X-ray pulses was assessed in cell-culture exposures. The results indicate that the biological response from ultra-intense X-ray exposures is similar to the response with conventional X-ray tubes. 82 refs., 14 figs

  1. Development and characterization of a laser-based hard x-ray source

    Energy Technology Data Exchange (ETDEWEB)

    Tillman, C.

    1996-11-01

    A laser-produced plasma was generated by focusing 100 fs laser pulses, with an energy of 150 mJ, onto metal targets. The laser intensity was expected to reach 10{sup 17} W/cm{sup -2}. Radiation was emitted from the created plasma, with photon energies up to the MeV region. The laser-based X-ray source was optimized, with the purpose of making it a realistic source of hard X-rays (>10 keV). Dedicated equipment was developed for efficient generation and utilization of the hard X-rays. The X-ray source was characterized with respect to its spatial extent and the X-ray yield. Measurements were made of the spectral distribution, by the use of single-photon-counting detectors in different geometries, crystal spectrometers and dose measurements in combination with absorption filters. Ablation of the target material in the laser produced plasma was investigated. Imaging applications have been demonstrated, including ultrafast (picosecond) X-ray imaging, magnification imaging of up to x80, differential imaging in the spectral domain, and imaging of various biological and technical objects. The biological response of ultra-intense X-ray pulses was assessed in cell-culture exposures. The results indicate that the biological response from ultra-intense X-ray exposures is similar to the response with conventional X-ray tubes. 82 refs., 14 figs.

  2. A Compact 5 MeV S-Band Electron Linac Based X-Ray Source for Industrial Radiography

    CERN Document Server

    Auditore, Lucrezia; De Pasquale, Domenico; Emanuele, Umberto; Italiano, Antonio; Trifirò, Antonio; Trimarchi, Marina

    2005-01-01

    A compact and reliable X-ray source, based on a 5 MeV, 1 kW, S-band electron linac, has been set up at the Dipartimento di Fisica, Universit\\'a di Messina. This source, coupled with a GOS scintillator screen and a CCD camera, represents an innovative transportable system for industrial radiography and X-ray tomography. Optimization of the parameters influencing the e-gamma conversion and the X-ray beam characteristics have been studied by means of the MCNP-4C2 code. The converter choice is the result of the study of the e-gamma conversion performances for different materials and materials thicknesses. Also the converter position with respect to the linac exit window was studied. The chosen converter consists in a Ta-Cu target inserted close to the linac window. The Cu layer acts as a filter both on the electrons from the source and on the low energy X-rays. The X-ray beam angular profile was studied by means of GafChromic films with and without collimation. In the final source project, a collimation system pr...

  3. On the problem of possibilities of X-ray computer tomography in the diagnosis of endophitic tumors of the stomach

    International Nuclear Information System (INIS)

    Gorshkov, A.N.; Akberov, R.F.

    1996-01-01

    The possibilities of X-ray computer tomography in the diagnosis of endophitic tumors of the stomach including tumors of small size are considered using the examinations of 100 patients with stomach diseases. The computer-tomographic semiotics of small endophitic tumors of the stomach is presented, the place of computer tomography in the diagnosis of tumors of the stomach as well as its potential possibilities in revealing small tumors of the stomach with principally endophitic spreading. 10 refs.; 3 figs

  4. Application of X-ray phase-contrast tomography in quantative studies of heat induced structural changes in meat

    DEFF Research Database (Denmark)

    Miklos, R.; Nielsen, M. S.; Einarsdottir, Hildur

    2013-01-01

    X-ray computed tomography is increasingly used in the studies of food structure. This paper describes the perspectives of use of phase contrast computed tomography in studies of heat induced structural changes in meat. From the data it was possible to obtain reconstructed images of the sample...... structure for visualization and qualitative studies of the sample structure. Further data segmentation allowed structural changes to be quantified....

  5. Dynamic X-ray computed tomography; Tomographie dynamique a rayons X

    Energy Technology Data Exchange (ETDEWEB)

    Grangeat, P

    2003-07-01

    Paper Dynamic computed tomography (CT) imaging aims at reconstructing image sequences where the dynamic nature of the living human body is of primary interest. Main concerned applications are image-guided interventional procedures, functional studies and cardiac imaging. The introduction of ultra-fast rotating gantries along with multi-row detectors and in near future area detectors allows a huge progress toward the imaging of moving organs with low-contrast resolution. This paper gives an overview of the different concepts used in dynamic CT. A new reconstruction algorithm based on a voxel-specific dynamic evolution compensation is also presented. It provides four-dimensional image sequences with accurate spatio-temporal information, where each frame is reconstructed using a long-scan acquisition mode on several half-turns. In the same time, this technique permits to reduce the dose delivered per rotation while keeping the same signal to noise ratio for every frame using an adaptive motion-compensated temporal averaging. Results are illustrated on simulated data. (authors)

  6. X-ray Tomography and Chemical Imaging within Butterfly Wing Scales

    International Nuclear Information System (INIS)

    Chen Jianhua; Lee Yaochang; Tang, M.-T.; Song Yenfang

    2007-01-01

    The rainbow like color of butterfly wings is associated with the internal and surface structures of the wing scales. While the photonic structure of the scales is believed to diffract specific lights at different angle, there is no adequate probe directly answering the 3-D structures with sufficient spatial resolution. The NSRRC nano-transmission x-ray microscope (nTXM) with tens nanometers spatial resolution is able to image biological specimens without artifacts usually introduced in sophisticated sample staining processes. With the intrinsic deep penetration of x-rays, the nTXM is capable of nondestructively investigating the internal structures of fragile and soft samples. In this study, we imaged the structure of butterfly wing scales in 3-D view with 60 nm spatial resolution. In addition, synchrotron-radiation-based Fourier transform Infrared (FT-IR) microspectroscopy was employed to analyze the chemical components with spatial information of the butterfly wing scales. Based on the infrared spectral images, we suggest that the major components of scale structure were rich in protein and polysaccharide

  7. X-ray micro-tomography system for small-animal imaging with zoom-in imaging capability

    International Nuclear Information System (INIS)

    Chun, In Kon; Cho, Myung Hye; Lee, Sang Chul; Cho, Min Hyoung; Lee, Soo Yeol

    2004-01-01

    Since a micro-tomography system capable of μm-resolution imaging cannot be used for whole-body imaging of a small laboratory animal without sacrificing its spatial resolution, it is desirable for a micro-tomography system to have local imaging capability. In this paper, we introduce an x-ray micro-tomography system capable of high-resolution imaging of a local region inside a small animal. By combining two kinds of projection data, one from a full field-of-view (FOV) scan of the whole body and the other from a limited FOV scan of the region of interest (ROI), we have obtained zoomed-in images of the ROI without any contrast anomalies commonly appearing in conventional local tomography. For experimental verification of the zoom-in imaging capability, we have integrated a micro-tomography system using a micro-focus x-ray source, a 1248 x 1248 flat-panel x-ray detector, and a precision scan mechanism. The mismatches between the two projection data caused by misalignments of the scan mechanism have been estimated with a calibration phantom, and the mismatch effects have been compensated in the image reconstruction procedure. Zoom-in imaging results of bony tissues with a spatial resolution of 10 lp mm -1 suggest that zoom-in micro-tomography can be greatly used for high-resolution imaging of a local region in small-animal studies

  8. Linking Intra-Aggregate Pore Size Distribution with Organic Matter Decomposition Status, Evidence from FTIR and X-Ray Tomography

    Science.gov (United States)

    Toosi, E. R.; Quigley, M.; Kravchenko, A. N.

    2014-12-01

    It has been reported that conversion of intensively cultivated lands to less disturbed systems enhances soil OM storage capacity, primarily through OM stabilization in macroaggregates. We hypothesized that the potential for OM stabilization inside macro-aggregates is influenced by presence and abundance of intra-aggregate pores. Pores determine microbial access to OM and regulate diffusion of solution/gases within aggregates which drives microbial functioning. We investigated the influence of longterm disturbance intensity on soil OM composition and its relation to pore size distribution within macroaggregates. We used quantitative FTIR to determine OM decomposition status and X-ray micro-tomography to assess pore size distribution in macroaggregates as affected by management and landuse. Macroaggregates 4-6 mm in size where selected from topsoil under long term conventional tillage (CT), cover-crop (CC), and native succession vegetation (NS) treatments at Kellogg Biological Station, Michigan. Comparison of main soil OM functional groups suggested that with increasing disturbance intensity, the proportion of aromatic and carboxylic/carbohydrates associated compounds increased and it was concomitant with a decrease in the proportion of aliphatic associated compounds and lignin derivatives. Further, FTIR-based decomposition indices revealed that overall decomposition status of macroaggregates followed the pattern of CT > CC ≈ NS. X-ray micro-tomography findings suggested that greater OM decomposition within the macroaggregates was associated with i) greater percent of pores >13 micron in size within the aggregates, as well as ii) greater proportion of small to medium pores (13-110 micron). The results develop previous findings, suggesting that shift in landuse or management indirectly affects soil OM stabilization through alteration of pore size distribution within macroaggregates that itself, is coupled with OM decomposition status.

  9. Incomplete-data image reconstructions in industrial x-ray computerized tomography

    International Nuclear Information System (INIS)

    Tam, K.C.; Eberhard, J.W.; Mitchell, K.W.

    1989-01-01

    In earlier works it was concluded that image reconstruction from incomplete data can be achieved through an iterative transform algorithm which utilizes the a priori information on the object to compensate for the missing data. The image is transformed back and forth between the object space and the projection space, being corrected by the a priori information on the object in the object space, and by the known projections in the projection space. The a priori information in the object space includes a boundary enclosing the object, and an upper bound and a lower bound of the object density. In this paper we report the results of testing the iterative transform algorithm on experimental data. X-ray sinogram data of the cross section of a F404 high-pressure turbine blade made of Ni-based superalloy were supplied to us by the Aircraft Engine Business Group of General Electric Company at Cincinnati, Ohio. From the data set we simulated two kinds of incomplete data situations, incomplete projection and limited-angle scanning, and applied the iterative transform algorithm to reconstruct the images. The results validated the practical value of the iterative transform algorithm in reconstructing images from incomplete x-ray data, both incomplete projections and limited-angle data. In all the cases tested there were significant improvements in the appearance of the images after iterations. The visual improvements are substantiated in a quantitative manner by the plots of errors in wall thickness measurements which in general decrease in magnitude with iterations

  10. Monte Carlo modeling of a conventional X-ray computed tomography scanner for gel dosimetry purposes.

    Science.gov (United States)

    Hayati, Homa; Mesbahi, Asghar; Nazarpoor, Mahmood

    2016-01-01

    Our purpose in the current study was to model an X-ray CT scanner with the Monte Carlo (MC) method for gel dosimetry. In this study, a conventional CT scanner with one array detector was modeled with use of the MCNPX MC code. The MC calculated photon fluence in detector arrays was used for image reconstruction of a simple water phantom as well as polyacrylamide polymer gel (PAG) used for radiation therapy. Image reconstruction was performed with the filtered back-projection method with a Hann filter and the Spline interpolation method. Using MC results, we obtained the dose-response curve for images of irradiated gel at different absorbed doses. A spatial resolution of about 2 mm was found for our simulated MC model. The MC-based CT images of the PAG gel showed a reliable increase in the CT number with increasing absorbed dose for the studied gel. Also, our results showed that the current MC model of a CT scanner can be used for further studies on the parameters that influence the usability and reliability of results, such as the photon energy spectra and exposure techniques in X-ray CT gel dosimetry.

  11. Beam hardening: Analytical considerations of the effective attenuation coefficient of x-ray tomography

    International Nuclear Information System (INIS)

    Alles, J.; Mudde, R. F.

    2007-01-01

    Polychromatic x-ray beams traveling though material are prone to beam hardening, i.e., the high energy part of the incident spectrum gets over represented when traveling farther into the material. This study discusses the concept of a mean attenuation coefficient in a formal way. The total energy fluence is one-to-one related to the traveled distance in case of a polychromatic beam moving through a given, inhomogeneous material. On the basis of this one-to-one relation, it is useful to define a mean attenuation coefficient and study its decrease with depth. Our results are based on a novel parametrization of the energy dependence of the attenuation coefficient that allows for closed form evaluation of certain spectral integrals. This approach underpins the ad hoc semianalytical expressions given in the literature. An analytical model for the average attenuation coefficient is proposed that uses a simple fit of the attenuation coefficient as a function of the photon energy as input. It is shown that a simple extension of this model gives a rather good description of beam hardening for x-rays traveling through water

  12. JAX: a micro-computer based X-ray diffractometer controller

    International Nuclear Information System (INIS)

    Naval, P.C. Jr.

    1987-05-01

    This paper describes a micro-computer based X-ray diffractometer controller and explores its possibilities in simplifying acquisition and analysis of X-ray powder diffraction data. The interrupt-driven controller can operate in both present time and present count data acquisition modes and allows a data analysis program to execute concurrently with data collection. (Auth.). 16 figs.; 2 tabs

  13. Status of Kharkov X-ray Generator based on Compton Scattering NESTOR

    NARCIS (Netherlands)

    Zelinsky, A.; Androsov, V.P.; Bulyak, E.V.; Drebot, I.; Gladkikh, P.I.; Grevtsev, V.; Botman, J.I.M.; Ivashchenko, V.; Karnaukhov, I.M.; Lapshin, V.I.; Markov, V.; Mocheshnikov, N.; Mytsykov, A.; Peev, F.A.; Rezaev, A.; Shcherbakov, A.; Skomorkohov, V.; Skyrda, V.; Telegin, Y.; Trotsenko, V.; Tatchyn, R.; Lebedev, B.; Agafonov, A.V.

    2004-01-01

    Nowadays the sources of the X-rays based on a storage ring with low beam energy and Compton scattering of intense laser beam are under development in several laboratories. In the paper the state-of-art in development and construction of cooperative project of a Kharkov advanced X-ray source NESTOR

  14. X-ray microbeams based on Kumakhov polycapillary optics and its

    Indian Academy of Sciences (India)

    Kumakhov polycapillary optics is based on the effective passage of X-ray radiation through bundles of monocapillaries of various configurations. The passage of radiation takes place because of the total external reflection of X-rays from the inner capillary walls. In this work,the basic characteristics of intense quasi-parallel ...

  15. Microprocessor-based system for automatic X-ray diffraction and fluorescence

    International Nuclear Information System (INIS)

    Souza, A.M. de; Carmo, L.C.S. do; Pereira, V.J.E.; Soares, E.A.

    1984-01-01

    A data acquisition and processing device appropriate for X-ray analysis and goniometer control was built. The Z-80 based system as well as the whole architeture is described. The advantages and new possibilities of the automated instrument as compared to the traditional ones are listed. The X-ray diffraction and fluorescence techniques can take advantage of the automation. (Author) [pt

  16. Quality assurance challenges in x-ray emission based analyses

    International Nuclear Information System (INIS)

    Papp, T.

    2005-01-01

    Complete text of publication follows. There is a large scatter in the results of X-ray analysis with solid-state detectors suggesting methodological origin. Although the PIXE (proton induced X-ray emission) analytical technique can work without relation to any physics, as was commented at the recent PIXE conference, one could argue that if the same technique is used for measuring physical quantities reveals problems, then perhaps potential methodological issues can not apriory be excluded. We present a simple example which could be interpreted as indications for methodological considerations. Recently an inter-comparison was made of analysis of the spectra measured at the laboratory of the International Atomic Energy Agency (IAEA). Four participating analytical software packages were used to evaluate the X-ray spectra. There are several thin metal samples spectra, for which common energy scale could not be established. The quality of the spectrum can be judged from the line shape. The line shape is parametrized by the full widths at half maximum (FWHM) of a peak and the so-called low energy tailing. Fitting the spectra individually we obtained FWHM squared values at different energies and determined the linear regression parameters. The parameters suggest a rather poor detector performance. It is generally assumed that the (FWHM) 2 values have a first order polynomial form as a function of X-ray energy. Having done a linear regression analysis, we can plot the standard residual, presented in Fig. 1, which clearly shows a three-sigma deviation. The probability to having a three-sigma deviation is 1%. In other words, the probability that these spectra are in accordance with the expected FWHM functional form is less than 1%. The main problem is that, although the composite spectra were analyzed using four different programs, the difficulty in interpreting the spectra was not commented upon by any of the participants in the inter-comparison. (author)

  17. X-ray Tomography and Impregnation Methods to Analyze Pore Space Hetrerogeneities at the Hydrated State

    International Nuclear Information System (INIS)

    Pret, D.; Ferrage, E.; Tertre, E.; Robinet, J.C.; Faurel, M.; Hubert, F.; Pelletier, M.; Bihannic, I.

    2013-01-01

    decimetre sample in constrained volume conditions and with a resin fixing the clay as in i ts hydrated state. Such preparation allows a down-scaling characterization of the pore space heterogeneities when using laboratory and synchrotron X-Ray μtomography (μCT) by facilitating sub-sampling. In order to reveal the interest/limitations of this 3D non-destructive imaging technique, a few comparisons will be done with other 2D techniques for the same samples. Finally, as X-Ray beams are well adapted to wet samples, we report a characterization of the pore space/water distribution upon hydration for pure swelling clay media at different scales

  18. Development of a Radiation Dose Reporting Software for X-ray Computed Tomography (CT)

    Science.gov (United States)

    Ding, Aiping

    X-ray computed tomography (CT) has experienced tremendous technological advances in recent years and has established itself as one of the most popular diagnostic imaging tools. While CT imaging clearly plays an invaluable role in modern medicine, its rapid adoption has resulted in a dramatic increase in the average medical radiation exposure to the worldwide and United States populations. Existing software tools for CT dose estimation and reporting are mostly based on patient phantoms that contain overly simplified anatomies insufficient in meeting the current and future needs. This dissertation describes the development of an easy-to-use software platform, “VirtualDose”, as a service to estimate and report the organ dose and effective dose values for patients undergoing the CT examinations. “VirtualDose” incorporates advanced models for the adult male and female, pregnant women, and children. To cover a large portion of the ignored obese patients that frequents the radiology clinics, a new set of obese male and female phantoms are also developed and applied to study the effects of the fat tissues on the CT radiation dose. Multi-detector CT scanners (MDCT) and clinical protocols, as well as the most recent effective dose algorithms from the International Commission on Radiological Protection (ICRP) Publication 103 are adopted in “VirtualDose” to keep pace with the MDCT development and regulatory requirements. A new MDCT scanner model with both body and head bowtie filter is developed to cover both the head and body scanning modes. This model was validated through the clinical measurements. A comprehensive slice-by-slice database is established by deriving the data from a larger number of single axial scans simulated on the patient phantoms using different CT bowtie filters, beam thicknesses, and different tube voltages in the Monte Carlo N-Particle Extended (MCNPX) code. When compared to the existing CT dose software packages, organ dose data in this

  19. Quantitative breast tissue characterization using grating-based x-ray phase-contrast imaging

    Science.gov (United States)

    Willner, M.; Herzen, J.; Grandl, S.; Auweter, S.; Mayr, D.; Hipp, A.; Chabior, M.; Sarapata, A.; Achterhold, K.; Zanette, I.; Weitkamp, T.; Sztrókay, A.; Hellerhoff, K.; Reiser, M.; Pfeiffer, F.

    2014-04-01

    X-ray phase-contrast imaging has received growing interest in recent years due to its high capability in visualizing soft tissue. Breast imaging became the focus of particular attention as it is considered the most promising candidate for a first clinical application of this contrast modality. In this study, we investigate quantitative breast tissue characterization using grating-based phase-contrast computed tomography (CT) at conventional polychromatic x-ray sources. Different breast specimens have been scanned at a laboratory phase-contrast imaging setup and were correlated to histopathology. Ascertained tumor types include phylloides tumor, fibroadenoma and infiltrating lobular carcinoma. Identified tissue types comprising adipose, fibroglandular and tumor tissue have been analyzed in terms of phase-contrast Hounsfield units and are compared to high-quality, high-resolution data obtained with monochromatic synchrotron radiation, as well as calculated values based on tabulated tissue properties. The results give a good impression of the method’s prospects and limitations for potential tumor detection and the associated demands on such a phase-contrast breast CT system. Furthermore, the evaluated quantitative tissue values serve as a reference for simulations and the design of dedicated phantoms for phase-contrast mammography.

  20. Imaging of pharmacokinetic rates of indocyanine green in mouse liver with a hybrid fluorescence molecular tomography/x-ray computed tomography system.

    Science.gov (United States)

    Zhang, Guanglei; Liu, Fei; Zhang, Bin; He, Yun; Luo, Jianwen; Bai, Jing

    2013-04-01

    Pharmacokinetic rates have the potential to provide quantitative physiological and pathological information for biological studies and drug development. Fluorescence molecular tomography (FMT) is an attractive imaging tool for three-dimensionally resolving fluorophore distribution in small animals. In this letter, pharmacokinetic rates of indocyanine green (ICG) in mouse liver are imaged with a hybrid FMT and x-ray computed tomography (XCT) system. A recently developed FMT method using structural priors from an XCT system is adopted to improve the quality of FMT reconstruction. In the in vivo experiments, images of uptake and excretion rates of ICG in mouse liver are obtained, which can be used to quantitatively evaluate liver function. The accuracy of the results is validated by a fiber-based fluorescence measurement system.

  1. Characterization of a confocal three-dimensional micro X-ray fluorescence facility based on polycapillary X-ray optics and Kirkpatrick-Baez mirrors

    International Nuclear Information System (INIS)

    Sun Tianxi; Ding Xunliang; Liu Zhiguo; Zhu Guanghua; Li Yude; Wei Xiangjun; Chen Dongliang; Xu Qing; Liu Quanru; Huang Yuying; Lin Xiaoyan; Sun Hongbo

    2008-01-01

    A new confocal three-dimensional micro X-ray fluorescence (3D micro-XRF) facility based on polycapillary X-ray optics in the detection channel and Kirkpatrick-Baez (KB) mirrors in the excitation channel is designed. The lateral resolution (l x , l y ) of this confocal three-dimensional micro-X-ray fluorescence facility is 76.3(l x ) and 53.4(l y ) μm respectively, and its depth resolution d z is 77.1 μm at θ = 90 o . A plant sample (twig of B. microphylla) and airborne particles are analyzed

  2. Application of natural basis functions to soft x-ray tomography

    International Nuclear Information System (INIS)

    Ingesson, L.

    2000-03-01

    Natural basis functions (NBFs), also known as natural pixels in the literature, have been applied in tomographic reconstructions of simulated measurements for the JET soft x-ray system, which has a total of about 200 detectors spread over 6 directions. Various types of NBFs, i.e. normal, generalized and orthonormal NBFs, are reviewed. The number of basis functions is roughly equal to the number of measurements. Therefore, little a priori information is required as regularization and truncated singular-value decomposition can be used for the tomographic inversion. The results of NBFs are compared with reconstructions by the same solution technique using local basis functions (LBFs), and with the reconstructions of a conventional constrained-optimization tomography method with many more LBFs that requires more a priori information. Although the results of the conventional method are superior due to the a priori information, the results of the NBF and other LBF methods are reasonable and show the main features. Therefore, NBFs are a promising way to assess whether features in reconstructions are real or artefacts resulting from the a priori information. Of the NBFs, regular triangular (generalized) NBFs give the most acceptable reconstructions, much better than traditional square pixels, although the reconstructions with pyramid-shaped LBFs are also reasonable and have slightly smaller reconstruction errors. A more-regular (virtual) viewing geometry improves the reconstructions. However, simulations with a viewing geometry with a total of 480 channels spread over 12 directions clearly show that a priori information still improves the reconstructions considerably. (author)

  3. Metal artifact reduction in x-ray computed tomography by using analytical DBP-type algorithm

    Science.gov (United States)

    Wang, Zhen; Kudo, Hiroyuki

    2012-03-01

    This paper investigates a common metal artifacts problem in X-ray computed tomography (CT). The artifacts in reconstructed image may render image non-diagnostic because of inaccuracy beam hardening correction from high attenuation objects, satisfactory image could not be reconstructed from projections with missing or distorted data. In traditionally analytical metal artifact reduction (MAR) method, firstly subtract the metallic object part of projection data from the original obtained projection, secondly complete the subtracted part in original projection by using various interpolating method, thirdly reconstruction from the interpolated projection by filtered back-projection (FBP) algorithm. The interpolation error occurred during the second step can make unrealistic assumptions about the missing data, leading to DC shift artifact in the reconstructed images. We proposed a differentiated back-projection (DBP) type MAR method by instead of FBP algorithm with DBP algorithm in third step. In FBP algorithm the interpolated projection will be filtered on each projection view angle before back-projection, as a result the interpolation error is propagated to whole projection. However, the property of DBP algorithm provide a chance to do filter after the back-projection in a Hilbert filter direction, as a result the interpolation error affection would be reduce and there is expectation on improving quality of reconstructed images. In other word, if we choose the DBP algorithm instead of the FBP algorithm, less contaminated projection data with interpolation error would be used in reconstruction. A simulation study was performed to evaluate the proposed method using a given phantom.

  4. Dynamics of barite growth in porous media quantified by in situ synchrotron X-ray tomography

    Science.gov (United States)

    Godinho, jose; Gerke, kirill

    2016-04-01

    Current models used to formulate mineral sequestration strategies of dissolved contaminants in the bedrock often neglect the effect of confinement and the variation of reactive surface area with time. In this work, in situ synchrotron X-ray micro-tomography is used to quantify barite growth rates in a micro-porous structure as a function of time during 13.5 hours with a resolution of 1 μm. Additionally, the 3D porous network at different time frames are used to simulate the flow velocities and calculate the permeability evolution during the experiment. The kinetics of barite growth under porous confinement is compared with the kinetics of barite growth on free surfaces in the same fluid composition. Results are discussed in terms of surface area normalization and the evolution of flow velocities as crystals fill the porous structure. During the initial hours the growth rate measured in porous media is similar to the growth rate on free surfaces. However, as the thinner flow paths clog the growth rate progressively decreases, which is correlated to a decrease of local flow velocity. The largest pores remain open, enabling growth to continue throughout the structure. Quantifying the dynamics of mineral precipitation kinetics in situ in 4D, has revealed the importance of using a time dependent reactive surface area and accounting for the local properties of the porous network, when formulating predictive models of mineral precipitation in porous media.

  5. Detective studies of soft X-ray tomography on controlled thermonuclear fusion device

    International Nuclear Information System (INIS)

    Li Linzhong; Su Fei

    2004-01-01

    In is necessary to design tomographic detective system with very high accuracy and high quality. It is such a detective system that its five resolutions are all very high quality. The five resolutions are: the radial resolution, the angular resolution, the spatial resolution of detector, the resolution of detector array, and the time resolution. The radial resolution is decided by the number of detectors in detector array. The angular resolutions depend on the number of detector arrays. According to the concrete condition of controlled device, through making special rectangular detector the optimum spatial resolution of detector and the optimum spatial resolution of detector array can be obtained. The high time resolution can be got by making wide-band ampli-filter circuit system. The tomographic system with high quality can use the multi-angle multi-array mode or perfect single array mode. The soft X-ray tomographic system with high sensitivity can measure the stable signal and perform the tomography under the conditions of Te ∼150 eV, ne ∼1013 cm-3 on the small Tokamak devices. (authors)

  6. An improved ring removal procedure for in-line x-ray phase contrast tomography

    Science.gov (United States)

    Massimi, Lorenzo; Brun, Francesco; Fratini, Michela; Bukreeva, Inna; Cedola, Alessia

    2018-02-01

    The suppression of ring artifacts in x-ray computed tomography (CT) is a required step in practical applications; it can be addressed by introducing refined digital low pass filters within the reconstruction process. However, these filters may introduce additional ringing artifacts when simultaneously imaging pure phase objects and elements having a non-negligible absorption coefficient. Ringing originates at sharp interfaces, due to the truncation of spatial high frequencies, and severely affects qualitative and quantitative analysis of the reconstructed slices. In this work, we discuss the causes of ringing artifacts, and present a general compensation procedure to account for it. The proposed procedure has been tested with CT datasets of the mouse central nervous system acquired at different synchrotron radiation facilities. The results demonstrate that the proposed method compensates for ringing artifacts induced by low pass ring removal filters. The effectiveness of the ring suppression filters is not altered; the proposed method can thus be considered as a framework to improve the ring removal step, regardless of the specific filter adopted or the imaged sample.

  7. X-ray tomography investigation of intensive sheared Al–SiC metal matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    De Giovanni, Mario; Warnett, Jason M.; Williams, Mark A. [WMG, University of Warwick, Coventry CV4 7AL (United Kingdom); Haribabu, Nadendla [BCAST, Brunel University London, Uxbridge UB8 3PH (United Kingdom); Srirangam, Prakash, E-mail: p.srirangam@warwick.ac.uk [WMG, University of Warwick, Coventry CV4 7AL (United Kingdom)

    2015-12-15

    X-ray computed tomography (XCT) was used to characterise three dimensional internal structure of Al–SiC metal matrix composites. The alloy composite was prepared by casting method with the application of intensive shearing to uniformly disperse SiC particles in the matrix. Visualisation of SiC clusters as well as porosity distribution were evaluated and compared with non-shearing samples. Results showed that the average particle size as well as agglomerate size is smaller in sheared sample compared to conventional cast samples. Further, it was observed that the volume fraction of porosity was reduced by 50% compared to conventional casting, confirming that the intensive shearing helps in deagglomeration of particle clusters and decrease in porosity of Al–SiC metal matrix composites. - Highlights: • XCT was used to visualise 3D internal structure of Al-SiC MMC. • Al-SiC MMC was prepared by casting with the application of intensive shearing. • SiC particles and porosity distribution were evaluated. • Results show shearing deagglomerates particle clusters and reduces porosity in MMC.

  8. Revealing Soil Structure and Functional Macroporosity along a Clay Gradient Using X-ray Computed Tomography

    DEFF Research Database (Denmark)

    Naveed, Muhammad; Møldrup, Per; Arthur, Emmanuel

    2013-01-01

    clay content, respectively) at a field site in Lerbjerg, Denmark. The water-holding capacity of soils markedly increased with increasing soil clay content, while significantly higher air permeability was observed for the L1 to L3 soils than for the L4 to L6 soils. Higher air permeability values......The influence of clay content in soil-pore structure development and the relative importance of macroporosity in governing convective fluid flow are two key challenges toward better understanding and quantifying soil ecosystem functions. In this study, soil physical measurements (soil-water...... retention and air permeability) and x-ray computed tomography (CT) scanning were combined and used from two scales on intact soil columns (100 and 580 cm3). The columns were sampled along a natural clay gradient at six locations (L1, L2, L3, L4, L5 and L6 with 0.11, 0.16, 0.21, 0.32, 0.38 and 0.46 kg kg−1...

  9. Relationship of brain imaging with radionuclides and with x-ray computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kuhl, D.E.

    1981-03-03

    Because of high sensitivity and specificity for altered local cerebral structure, x-ray computed tomography (CT) is the preferred initial diagnostic imaging study under most circumstances when cerebral disease is suspected. CT has no competitor for detecting fresh intracerebral hemorrhage. Radionuclide imaging (RN) scan is preferred when relative perfusion is to be assessed, in patients allergic to contrast media, and when an adequate CT study is not technically possible. (RN) plays an important complementary role to CT, especially for patients suspected of subacute or chronic subdura hematoma, cerebral infarction, arteriovenous malformations, meningitis, encephalitis, normal pressure hydrocephalus, or when CT findings are inconclusive. When CT is not available, RN serves as a good screening study for suspected cerebral tumor, infection, recent infarction, arteriovenous malformation, and chronic subdural hematoma. Future improvement in radionuclide imaging by means of emission composition potential. The compound plating approacl threshold for all the investigated transistors and fast neutron spectra lies within the raal. The value of the potential slightly changes with the coordinate change in this region, i.e. the charge on a collecting electrode is not practically guided up to a certain moment of time during the movement of nonequilibrium carriers.

  10. Visualization of the internal structure of Didymosphenia geminata frustules using nano X-ray tomography.

    Science.gov (United States)

    Zgłobicka, Izabela; Li, Qiong; Gluch, Jürgen; Płocińska, Magdalena; Noga, Teresa; Dobosz, Romuald; Szoszkiewicz, Robert; Witkowski, Andrzej; Zschech, Ehrenfried; Kurzydłowski, Krzysztof J

    2017-08-22

    For the first time, the three-dimensional (3D) internal structure of naturally produced Didymosphenia geminata frustules were nondestructively visualized at sub-1