Science.gov

Sample records for real-time phase-contrast x-ray

  1. Real-time measurement of alveolar size and population using phase contrast x-ray imaging

    PubMed Central

    Leong, Andrew F.T.; Buckley, Genevieve A.; Paganin, David M.; Hooper, Stuart B.; Wallace, Megan J.; Kitchen, Marcus J.

    2014-01-01

    Herein a propagation-based phase contrast x-ray imaging technique for measuring particle size and number is presented. This is achieved with an algorithm that utilizes the Fourier space signature of the speckle pattern associated with the images of particles. We validate this algorithm using soda-lime glass particles, demonstrating its effectiveness on random and non-randomly packed particles. This technique is then applied to characterise lung alveoli, which are difficult to measure dynamically in vivo with current imaging modalities due to inadequate temporal resolution and/or depth of penetration and field-of-view. We obtain an important result in that our algorithm is able to measure changes in alveolar size on the micron scale during ventilation and shows the presence of alveolar recruitment/de-recruitment in newborn rabbit kittens. This technique will be useful for ventilation management and lung diagnostic procedures. PMID:25426328

  2. Factors influencing real time internal structural visualization and dynamic process monitoring in plants using synchrotron-based phase contrast X-ray imaging

    PubMed Central

    Karunakaran, Chithra; Lahlali, Rachid; Zhu, Ning; Webb, Adam M.; Schmidt, Marina; Fransishyn, Kyle; Belev, George; Wysokinski, Tomasz; Olson, Jeremy; Cooper, David M. L.; Hallin, Emil

    2015-01-01

    Minimally invasive investigation of plant parts (root, stem, leaves, and flower) has good potential to elucidate the dynamics of plant growth, morphology, physiology, and root-rhizosphere interactions. Laboratory based absorption X-ray imaging and computed tomography (CT) systems are extensively used for in situ feasibility studies of plants grown in natural and artificial soil. These techniques have challenges such as low contrast between soil pore space and roots, long X-ray imaging time, and low spatial resolution. In this study, the use of synchrotron (SR) based phase contrast X-ray imaging (PCI) has been demonstrated as a minimally invasive technique for imaging plants. Above ground plant parts and roots of 10 day old canola and wheat seedlings grown in sandy clay loam soil were successfully scanned and reconstructed. Results confirmed that SR-PCI can deliver good quality images to study dynamic and real time processes such as cavitation and water-refilling in plants. The advantages of SR-PCI, effect of X-ray energy, and effective pixel size to study plant samples have been demonstrated. The use of contrast agents to monitor physiological processes in plants was also investigated and discussed. PMID:26183486

  3. Factors influencing real time internal structural visualization and dynamic process monitoring in plants using synchrotron-based phase contrast X-ray imaging.

    PubMed

    Karunakaran, Chithra; Lahlali, Rachid; Zhu, Ning; Webb, Adam M; Schmidt, Marina; Fransishyn, Kyle; Belev, George; Wysokinski, Tomasz; Olson, Jeremy; Cooper, David M L; Hallin, Emil

    2015-07-17

    Minimally invasive investigation of plant parts (root, stem, leaves, and flower) has good potential to elucidate the dynamics of plant growth, morphology, physiology, and root-rhizosphere interactions. Laboratory based absorption X-ray imaging and computed tomography (CT) systems are extensively used for in situ feasibility studies of plants grown in natural and artificial soil. These techniques have challenges such as low contrast between soil pore space and roots, long X-ray imaging time, and low spatial resolution. In this study, the use of synchrotron (SR) based phase contrast X-ray imaging (PCI) has been demonstrated as a minimally invasive technique for imaging plants. Above ground plant parts and roots of 10 day old canola and wheat seedlings grown in sandy clay loam soil were successfully scanned and reconstructed. Results confirmed that SR-PCI can deliver good quality images to study dynamic and real time processes such as cavitation and water-refilling in plants. The advantages of SR-PCI, effect of X-ray energy, and effective pixel size to study plant samples have been demonstrated. The use of contrast agents to monitor physiological processes in plants was also investigated and discussed.

  4. Factors influencing real time internal structural visualization and dynamic process monitoring in plants using synchrotron-based phase contrast X-ray imaging

    NASA Astrophysics Data System (ADS)

    Karunakaran, Chithra; Lahlali, Rachid; Zhu, Ning; Webb, Adam M.; Schmidt, Marina; Fransishyn, Kyle; Belev, George; Wysokinski, Tomasz; Olson, Jeremy; Cooper, David M. L.; Hallin, Emil

    2015-07-01

    Minimally invasive investigation of plant parts (root, stem, leaves, and flower) has good potential to elucidate the dynamics of plant growth, morphology, physiology, and root-rhizosphere interactions. Laboratory based absorption X-ray imaging and computed tomography (CT) systems are extensively used for in situ feasibility studies of plants grown in natural and artificial soil. These techniques have challenges such as low contrast between soil pore space and roots, long X-ray imaging time, and low spatial resolution. In this study, the use of synchrotron (SR) based phase contrast X-ray imaging (PCI) has been demonstrated as a minimally invasive technique for imaging plants. Above ground plant parts and roots of 10 day old canola and wheat seedlings grown in sandy clay loam soil were successfully scanned and reconstructed. Results confirmed that SR-PCI can deliver good quality images to study dynamic and real time processes such as cavitation and water-refilling in plants. The advantages of SR-PCI, effect of X-ray energy, and effective pixel size to study plant samples have been demonstrated. The use of contrast agents to monitor physiological processes in plants was also investigated and discussed.

  5. Phased Contrast X-Ray Imaging

    ScienceCinema

    Erin Miller

    2016-07-12

    The Pacific Northwest National Laboratory is developing a range of technologies to broaden the field of explosives detection. Phased contrast X-ray imaging, which uses silicon gratings to detect distortions in the X-ray wave front, may be applicable to mail or luggage scanning for explosives; it can also be used in detecting other contraband, small-parts inspection, or materials characterization.

  6. X-ray phase-contrast methods

    SciTech Connect

    Lider, V. V. Kovalchuk, M. V.

    2013-11-15

    This review is devoted to a comparative description of the methods for forming X-ray phase-contrast images of weakly absorbing (phase) objects. These include the crystal interferometer method, the Talbot interferometer method, diffraction-enhanced X-ray imaging, and the in-line method. The potential of their practical application in various fields of science and technology is discussed. The publications on the development and optimization of X-ray phase-contrast methods and the experimental study of phase objects are analyzed.

  7. Phase contrast hard x-ray microscopy with submicron resolution

    SciTech Connect

    Lagomarsino, S.; Cedola, A.; Cloetens, P.; Di Fonzo, S.; Jark, W.; Soullie, G.; Riekel, C.

    1997-11-01

    In this letter we present a hard x-ray phase contrast microscope based on the divergent and coherent beam exiting an x-ray waveguide. It uses lensless geometrical projection to magnify spatial variations in optical path length more than 700 times. Images of a nylon fiber and a gold test pattern were obtained with a resolution of 0.14 {mu}m in one direction. Exposure times as short as 0.1 s gave already visible contrast, opening the way to high resolution, real time studies. {copyright} {ital 1997 American Institute of Physics.}

  8. Differential phase contrast X-ray imaging system and components

    DOEpatents

    Stutman, Daniel; Finkenthal, Michael

    2014-07-01

    A differential phase contrast X-ray imaging system includes an X-ray illumination system, a beam splitter arranged in an optical path of the X-ray illumination system, and a detection system arranged in an optical path to detect X-rays after passing through the beam splitter.

  9. Differential phase contrast X-ray imaging system and components

    DOEpatents

    Stutman, Daniel; Finkenthal, Michael

    2017-01-31

    A differential phase contrast X-ray imaging system includes an X-ray illumination system, a beam splitter arranged in an optical path of the X-ray illumination system, and a detection system arranged in an optical path to detect X-rays after passing through the beam splitter.

  10. Real-Time X-Ray Inspection

    NASA Technical Reports Server (NTRS)

    Bulthuis, Ronald V.

    1988-01-01

    X-ray imaging instrument adapted to continuous scanning. Modern version of fluoroscope enables rapid x-ray inspection of parts. Developed for detection of buckling in insulated ducts. Uses radiation from radioactive gadolinium or thallium source. Instrument weighs only 6 1/2 lb. Quickly scanned by hand along duct surface, providing real-time image. Based on Lixiscope, developed at Goddard Space Flight Center.

  11. Acoustically modulated x-ray phase contrast imaging.

    PubMed

    Hamilton, Theron J; Bailat, Claude J; Rose-Petruck, Christoph; Diebold, Gerald J

    2004-11-07

    We report the use of ultrasonic radiation pressure with phase contrast x-ray imaging to give an image proportional to the space derivative of a conventional phase contrast image in the direction of propagation of an ultrasonic beam. Intense ultrasound is used to exert forces on objects within a body giving displacements of the order of tens to hundreds of microns. Subtraction of images made with and without the ultrasound field gives an image that removes low spatial frequency features and highlights high frequency features. The method acts as an acoustic 'contrast agent' for phase contrast x-ray imaging, which in soft tissue acts to highlight small density changes.

  12. Phase contrast imaging with coherent high energy X-rays

    SciTech Connect

    Snigireva, I.

    1997-02-01

    X-ray imaging concern high energy domain (>6 keV) like a contact radiography, projection microscopy and tomography is used for many years to discern the features of the internal structure non destructively in material science, medicine and biology. In so doing the main contrast formation is absorption that makes some limitations for imaging of the light density materials and what is more the resolution of these techniques is not better than 10-100 {mu}m. It was turned out that there is now way in which to overcome 1{mu}m or even sub-{mu}m resolution limit except phase contrast imaging. It is well known in optics that the phase contrast is realised when interference between reference wave front and transmitted through the sample take place. Examples of this imaging are: phase contrast microscopy suggested by Zernike and Gabor (in-line) holography. Both of this techniques: phase contrast x-ray microscopy and holography are successfully progressing now in soft x-ray region. For imaging in the hard X-rays to enhance the contrast and to be able to resolve phase variations across the beam the high degree of the time and more importantly spatial coherence is needed. Because of this it was reasonable that the perfect crystal optics was involved like Bonse-Hart interferometry, double-crystal and even triple-crystal set-up using Laue and Bragg geometry with asymmetrically cut crystals.

  13. Zernike phase contrast in scanning microscopy with X-rays.

    PubMed

    Holzner, Christian; Feser, Michael; Vogt, Stefan; Hornberger, Benjamin; Baines, Stephen B; Jacobsen, Chris

    2010-11-01

    Scanning X-ray microscopy focuses radiation to a small spot and probes the sample by raster scanning. It allows information to be obtained from secondary signals such as X-ray fluorescence, which yields an elemental mapping of the sample not available in full-field imaging. The analysis and interpretation from these secondary signals can be considerably enhanced if these data are coupled with structural information from transmission imaging. However, absorption often is negligible and phase contrast has not been easily available. Originally introduced with visible light, Zernike phase contrast(1) is a well-established technique in full-field X-ray microscopes for visualization of weakly absorbing samples(2-7). On the basis of reciprocity, we demonstrate the implementation of Zernike phase contrast in scanning X-ray microscopy, revealing structural detail simultaneously with hard-X-ray trace-element measurements. The method is straightforward to implement without significant influence on the resolution of the fluorescence images and delivers complementary information. We show images of biological specimens that clearly demonstrate the advantage of correlating morphology with elemental information.

  14. X-ray Phase Contrast analysis - Digital wavefront development

    SciTech Connect

    Idir, Mourad; Potier, Jonathan; Fricker, Sebastien; Snigirev, Anatoly; Snigireva, Irina; Modi, M. H.

    2010-06-23

    Optical schemes that enable imaging of the phase shift produced by an object have become popular in the x-ray region, where phase can be the dominant contrast mechanism. The propagation-based technique consists of recording the interference pattern produced by choosing one or several sample-to-detector distances. Pioneering studies, carried out making use of synchrotron radiation, demonstrated that this technique results in a dramatic increase of image contrast and detail visibility, allowing the detection of structures invisible with conventional techniques. An experimental and theoretical study of in-line hard x-ray phase-contrast imaging had been performed. The theoretical description of the technique is based on Fresnel diffraction. As an illustration of the potential of this quantitative imaging technique, high-resolution x-ray phase contrast images of simple objects will be presented.

  15. Various clinical application of phase contrast X-ray

    NASA Astrophysics Data System (ADS)

    Oh, Chilhwan; Park, Sangyong; Ha, Seunghan; Park, Gyuman; Lee, Gunwoo; Lee, Onseok; Je, Jungho

    2008-02-01

    In biomedical application study using phase contrast X-ray, both sample thickness or density and absorption difference are very important factors in aspects of contrast enhancement. We present experimental evidence that synchrotron hard X-ray are suitable for radiological imaging of biological samples down to the cellular level. We investigated the potential of refractive index radiology using un-monochromatized synchrotron hard X-rays for the imaging of cell and tissue in various diseases. Material had been adopted various medical field, such as apoE knockout mouse in cardiologic field, specimen from renal and prostatic carcinoma patient in urology, basal cell epithelioma in dermatology, brain tissue from autosy sample of pakinson's disease, artificially induced artilrtis tissue from rabbits and extracted tooth from patients of crack tooth syndrome. Formalin and paraffin fixed tissue blocks were cut in 3 mm thickness for the X-ray radiographic imaging. From adjacent areas, 4 μm thickness sections were also prepared for hematoxylin-eosin staining. Radiographic images of dissected tissues were obtained using the hard X-rays from the 7B2 beamline of the Pohang Light Source (PLS). The technique used for the study was the phase contrast images were compared with the optical microscopic images of corresponding histological slides. Radiographic images of various diseased tissues showed clear histological details of organelles in normal tissues. Most of cancerous lesions were well differentiated from adjacent normal tissues and detailed histological features of each tumor were clearly identified. Also normal microstructures were identifiable by the phase contrast imaging. Tissue in cancer or other disease showed clearly different findings from those of surrounding normal tissue. For the first time we successfully demonstrated that synchrotron hard X-rays can be used for radiological imaging of relatively thick tissue samples with great histological details.

  16. X-ray elastography: Modification of x-ray phase contrast images using ultrasonic radiation pressure

    SciTech Connect

    Hamilton, Theron J.; Bailat, Claude; Rose-Petruck, Christoph; Diebold, Gerald J.; Gehring, Stephan; Laperle, Christopher M.; Wands, Jack

    2009-05-15

    The high resolution characteristic of in-line x-ray phase contrast imaging can be used in conjunction with directed ultrasound to detect small displacements in soft tissue generated by differential acoustic radiation pressure. The imaging method is based on subtraction of two x-ray images, the first image taken with, and the second taken without the presence of ultrasound. The subtraction enhances phase contrast features and, to a large extent, removes absorption contrast so that differential movement of tissues with different acoustic impedances or relative ultrasonic absorption is highlighted in the image. Interfacial features of objects with differing densities are delineated in the image as a result of both the displacement introduced by the ultrasound and the inherent sensitivity of x-ray phase contrast imaging to density variations. Experiments with ex vivo murine tumors and human tumor phantoms point out a diagnostic capability of the method for identifying tumors.

  17. Phase Contrast X-ray Imaging of Shuttle Insulating Foam

    NASA Technical Reports Server (NTRS)

    Hu, Zhengwei

    2005-01-01

    X-ray radiation has been widely used for imaging applications since Rontgen first discovered X-rays over a century ago. Its large penetration depth makes it ideal for the nondestructive visualization of internal structure of materials or objects unobtainable otherwise. Currently widely used nondestructive evaluation (NDE) tools-X-ray radiography and tomography are absorption-based, and work well in highly absorbing materials where density or composition variations due to internal structure or defects are high enough to be spatially distinguished in terms of absorption contrast. However, in many cases where materials such as insulating foam are light-weight, the conventional absorption-based X-ray methods for NDE become less effective. Indeed, the low-density shuttle insulating foam used for flight mission poses a great challenge to the standard NDE tools in that the absorption contrast arising from internal defects of such a low- density material is either weak or indistinguishable. In this presentation, the latest progress in phase contrast X-ray imaging of internal defects of insulating foam will be presented and discussed, demonstrating new opportunities to solve challenging issues involved in advanced materials development and processing for space exploration.

  18. X-ray phase contrast for CO2 microangiography

    NASA Astrophysics Data System (ADS)

    Lundström, U.; Larsson, D. H.; Burvall, A.; Takman, P. A. C.; Scott, L.; Brismar, H.; Hertz, H. M.

    2012-05-01

    We demonstrate a laboratory method for imaging small blood vessels using x-ray propagation-based phase-contrast imaging and carbon dioxide (CO2) gas as a contrast agent. The limited radiation dose in combination with CO2 being clinically acceptable makes the method promising for small-diameter vascular visualization. We investigate the possibilities and limitations of the method for small-animal angiography and compare it with conventional absorption-based x-ray angiography. Photon noise in absorption-contrast imaging prevents visualization of blood vessels narrower than 50 µm at the highest radiation doses compatible with living animals, whereas our simulations and experiments indicate the possibility of visualizing 20 µm vessels at radiation doses as low as 100 mGy. Experimental computed tomography of excised rat kidney shows blood vessels of diameters down to 60 µm with improved image quality compared to absorption-based methods. With our present prototype x-ray source, the acquisition time for a tomographic dataset is approximately 1 h, which is long compared to the 1-20 min common for absorption-contrast micro-CT systems. Further development of the liquid-metal-jet microfocus x-ray sources used here and high-resolution x-ray detectors shows promise to reduce exposure times and make this high-resolution method practical for imaging of living animals.

  19. Hard X-ray Phase-Contrast Tomographic Nanoimaging

    NASA Astrophysics Data System (ADS)

    Stampanoni, M.; Marone, F.; Vila-Comamala, J.; Gorelick, S.; David, C.; Trtik, P.; Jefimovs, K.; Mokso, R.

    2011-09-01

    Synchrotron-based full-field tomographic microscopy established itself as a tool for noninvasive investigations. Many beamlines worldwide routinely achieve micrometer spatial resolution while the isotropic 100-nm barrier is reached and trespassed only by few instruments, mainly in the soft x-ray regime. We present an x-ray, full-field microscope with tomographic capabilities operating at 10 keV and with a 3D isotropic resolution of 144 nm recently installed at the TOMCAT beamline of the Swiss Light Source. Custom optical components, including a beam-shaping condenser and phase-shifting dot arrays, were used to obtain an ideal, aperture-matched sample illumination and very sensitive phase-contrast imaging. The instrument has been successfully used for the nondestructive, volumetric investigation of single, unstained cells.

  20. Simulation tools for analyzer-based x-ray phase contrast imaging system with a conventional x-ray source

    NASA Astrophysics Data System (ADS)

    Caudevilla, Oriol; Zhou, Wei; Stoupin, Stanislav; Verman, Boris; Brankov, J. G.

    2016-09-01

    Analyzer-based X-ray phase contrast imaging (ABI) belongs to a broader family of phase-contrast (PC) X-ray imaging modalities. Unlike the conventional X-ray radiography, which measures only X-ray absorption, in PC imaging one can also measures the X-rays deflection induced by the object refractive properties. It has been shown that refraction imaging provides better contrast when imaging the soft tissue, which is of great interest in medical imaging applications. In this paper, we introduce a simulation tool specifically designed to simulate the analyzer-based X-ray phase contrast imaging system with a conventional polychromatic X-ray source. By utilizing ray tracing and basic physical principles of diffraction theory our simulation tool can predicting the X-ray beam profile shape, the energy content, the total throughput (photon count) at the detector. In addition we can evaluate imaging system point-spread function for various system configurations.

  1. High Resolution X-Ray Phase Contrast Imaging with Acoustic Tissue-Selective Contrast Enhancement

    DTIC Science & Technology

    2005-06-01

    microfocus x - ray source. Rev. Sci. Instr. 68, 2774 (1997). 8. Krol, A. et al. Laser-based microfocused x - ray ...high spatial coherence, such as synchrotrons 46, microfocus x - ray tubes 7, or laser plasma x - ray sources 8,9are employed is the phase contrast component...imaging apparatus to determine the deflection of the bead as a function of acoustic pressure. The x - rays , generated by a microfocus x - ray tube

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

    NASA Astrophysics Data System (ADS)

    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.

  3. X-ray phase contrast imaging at MAMI

    NASA Astrophysics Data System (ADS)

    El-Ghazaly, M.; Backe, H.; Lauth, W.; Kube, G.; Kunz, P.; Sharafutdinov, A.; Weber, T.

    2006-05-01

    Experiments have been performed to explore the potential of the low emittance 855MeV electron beam of the Mainz Microtron MAMI for imaging with coherent X-rays. Transition radiation from a micro-focused electron beam traversing a foil stack served as X-ray source with good transverse coherence. Refraction contrast radiographs of low absorbing materials, in particular polymer strings with diameters between 30 and 450μm, were taken with a polychromatic transition radiation X-ray source with a spectral distribution in the energy range between 8 and about 40keV. The electron beam spot size had standard deviation σh = (8.6±0.1)μm in the horizontal and σv = (7.5±0.1)μm in the vertical direction. X-ray films were used as detectors. The source-to-detector distance amounted to 11.4m. The objects were placed in a distance of up to 6m from the X-ray film. Holograms of strings were taken with a beam spot size σv = (0.50±0.05)μm in vertical direction, and a monochromatic X-ray beam of 6keV energy. A good longitudinal coherence has been obtained by the (111) reflection of a flat silicon single crystal in Bragg geometry. It has been demonstrated that a direct exposure CCD chip with a pixel size of 13×13μm^2 provides a highly efficient on-line detector. Contrast images can easily be generated with a complete elimination of all parasitic background. The on-line capability allows a minimization of the beam spot size by observing the smallest visible interference fringe spacings or the number of visible fringes. It has been demonstrated that X-ray films are also very useful detectors. The main advantage in comparison with the direct exposure CCD chip is the resolution. For the Structurix D3 (Agfa) X-ray film the standard deviation of the resolution was measured to be σf = (1.2±0.4)μm, which is about a factor of 6 better than for the direct exposure CCD chip. With the small effective X-ray spot size in vertical direction of σv = (1.2±0.3)μm and a geometrical

  4. High Resolution X-Ray Phase Contrast Imaging With Acoustic Tissue-Selective Contrast Enhancement

    DTIC Science & Technology

    2006-06-01

    microfocus x - ray source. Rev. Sci. Instr. 68, 2774 (1997). 8. Krol, A. et al. Laser-based microfocused x - ray source for mammography: Feasibility study...W81XWH-04-1-0481 TITLE: High Resolution X - ray Phase Contrast Imaging With Acoustic Tissue-Selective Contrast Enhancement PRINCIPAL...REPORT TYPE Annual 3. DATES COVERED (From - To) 1 Jun 2005 – 31 May 2006 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER High Resolution X - ray

  5. 'Edge illumination' in X-ray Phase Contrast Imaging

    SciTech Connect

    Munro, Peter R. T.; Ignatyev, Konstantin; Diemoz, Paul C.; Szafraniec, Magdalena B.; Hagen, Charlotte K.; Millard, Thomas P.; Zapata, Cesar E.; Speller, Robert D.; Olivo, Alessandro

    2012-07-31

    In the late '90s, the concept of 'edge illumination' was developed at ELETTRA in Italy as an alternative method to increase the phase sensitivity of an imaging system. The main idea was to be able to reproduce the fine angular selection of 'analyzer' crystals without actually using a crystal, as this would allow employing the method with divergent and polychromatic (i.e. conventional) x-ray sources. It was observed that this could be achieved by illuminating only the edges of the detector pixels, and that the method's sensitivity could be progressively increased by illuminating smaller pixel fractions closer to its physical edge. A few years later the idea was adapted for use with a conventional source by means of two sets of x-ray masks ('coded aperture' masks), which enabled obtaining the same effect for each row (or column) of pixels of an area detector illuminated by a cone beam. This article reviews the method and presents recent examples of application.

  6. Motionless phase stepping in X-ray phase contrast imaging with a compact source

    PubMed Central

    Miao, Houxun; Chen, Lei; Bennett, Eric E.; Adamo, Nick M.; Gomella, Andrew A.; DeLuca, Alexa M.; Patel, Ajay; Morgan, Nicole Y.; Wen, Han

    2013-01-01

    X-ray phase contrast imaging offers a way to visualize the internal structures of an object without the need to deposit significant radiation, and thereby alleviate the main concern in X-ray diagnostic imaging procedures today. Grating-based differential phase contrast imaging techniques are compatible with compact X-ray sources, which is a key requirement for the majority of clinical X-ray modalities. However, these methods are substantially limited by the need for mechanical phase stepping. We describe an electromagnetic phase-stepping method that eliminates mechanical motion, thus removing the constraints in speed, accuracy, and flexibility. The method is broadly applicable to both projection and tomography imaging modes. The transition from mechanical to electromagnetic scanning should greatly facilitate the translation of X-ray phase contrast techniques into mainstream applications. PMID:24218599

  7. Optimization of phase contrast imaging using hard x rays

    SciTech Connect

    Zabler, S.; Cloetens, P.; Guigay, J.-P.; Baruchel, J.; Schlenker, M.

    2005-07-15

    X ray radiography and tomography are important tools in medicine as well as in life science and materials science. Not long ago an approach called in-line holography based on simple propagation became possible using partially coherent synchrotron beams like the ones available at the European Synchrotron Radiation Facility (ESRF). Theoretical and experimental work by Cloetens et al. [Appl. Phys. Lett 75, 2912 (1999)] have shown that quantitative retrieval of the optical phase, from a set of radiographs taken at different sample-to-detector distances, is feasible. Mathematically speaking we are dealing with a direct method based on linearization in order to solve an inverse nonlinear problem. The phase retrieval can be combined with classical tomography in order to obtain a three-dimensional representation of the object's electron density (holotomography). In order to optimize the image contrast for the numerical phase retrieval process, we have carried out calculations resulting in an optimized choice of value and number of the sample-to-detector distances as well as of the photon energy. These results were then confirmed by experiments on the ESRF long beamline ID19.

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

    PubMed

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

    2013-09-01

    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.

  9. Intact Imaging of Human Heart Structure Using X-ray Phase-Contrast Tomography.

    PubMed

    Kaneko, Yukihiro; Shinohara, Gen; Hoshino, Masato; Morishita, Hiroyuki; Morita, Kiyozo; Oshima, Yoshihiro; Takahashi, Masashi; Yagi, Naoto; Okita, Yutaka; Tsukube, Takuro

    2017-02-01

    Structural examination of human heart specimens at the microscopic level is a prerequisite for understanding congenital heart diseases. It is desirable not to destroy or alter the properties of such specimens because of their scarcity. However, many of the currently available imaging techniques either destroy the specimen through sectioning or alter the chemical and mechanical properties of the specimen through staining and contrast agent injection. As a result, subsequent studies may not be possible. X-ray phase-contrast tomography is an imaging modality for biological soft tissues that does not destroy or alter the properties of the specimen. The feasibility of X-ray phase-contrast tomography for the structural examination of heart specimens was tested using infantile and fetal heart specimens without congenital diseases. X-ray phase-contrast tomography was carried out at the SPring-8 synchrotron radiation facility using the Talbot grating interferometer at the bending magnet beamline BL20B2 to visualize the structure of five non-pretreated whole heart specimens obtained by autopsy. High-resolution, three-dimensional images were obtained for all specimens. The images clearly showed the myocardial structure, coronary vessels, and conduction bundle. X-ray phase-contrast tomography allows high-resolution, three-dimensional imaging of human heart specimens. Intact imaging using X-ray phase-contrast tomography can contribute to further structural investigation of heart specimens with congenital heart diseases.

  10. Image segmentation of nanoscale Zernike phase contrast X-ray computed tomography images

    SciTech Connect

    Kumar, Arjun S.; Mandal, Pratiti; Zhang, Yongjie; Litster, Shawn

    2015-05-14

    Zernike phase contrast is a useful technique for nanoscale X-ray computed tomography (CT) imaging of materials with a low X-ray absorption coefficient. It enhances the image contrast by phase shifting X-ray waves to create changes in amplitude. However, it creates artifacts that hinder the use of traditional image segmentation techniques. We propose an image restoration method that models the X-ray phase contrast optics and the three-dimensional image reconstruction method. We generate artifact-free images through an optimization problem that inverts this model. Though similar approaches have been used for Zernike phase contrast in visible light microscopy, this optimization employs an effective edge detection method tailored to handle Zernike phase contrast artifacts. We characterize this optics-based restoration method by removing the artifacts in and thresholding multiple Zernike phase contrast X-ray CT images to produce segmented results that are consistent with the physical specimens. We quantitatively evaluate and compare our method to other segmentation techniques to demonstrate its high accuracy.

  11. Interferometric hard x-ray phase contrast imaging at 204 nm grating period

    SciTech Connect

    Wen Han; Gomella, Andrew A.; Miao, Houxun; Lynch, Susanna K.; Wolfe, Douglas E.; Xiao Xianghui; Liu Chian; Morgan, Nicole

    2013-01-15

    We report on hard x-ray phase contrast imaging experiments using a grating interferometer of approximately 1/10th the grating period achieved in previous studies. We designed the gratings as a staircase array of multilayer stacks which are fabricated in a single thin film deposition process. We performed the experiments at 19 keV x-ray energy and 0.8 {mu}m pixel resolution. The small grating period resulted in clear separation of different diffraction orders and multiple images on the detector. A slitted beam was used to remove overlap of the images from the different diffraction orders. The phase contrast images showed detailed features as small as 10 {mu}m, and demonstrated the feasibility of high resolution x-ray phase contrast imaging with nanometer scale gratings.

  12. Recent advances in synchrotron-based hard x-ray phase contrast imaging

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Nelson, J.; Holzner, C.; Andrews, J. C.; Pianetta, P.

    2013-12-01

    Ever since the first demonstration of phase contrast imaging (PCI) in the 1930s by Frits Zernike, people have realized the significant advantage of phase contrast over conventional absorption-based imaging in terms of sensitivity to ‘transparent’ features within specimens. Thus, x-ray phase contrast imaging (XPCI) holds great potential in studies of soft biological tissues, typically containing low Z elements such as C, H, O and N. Particularly when synchrotron hard x-rays are employed, the favourable brightness, energy tunability, monochromatic characteristics and penetration depth have dramatically enhanced the quality and variety of XPCI methods, which permit detection of the phase shift associated with 3D geometry of relatively large samples in a non-destructive manner. In this paper, we review recent advances in several synchrotron-based hard x-ray XPCI methods. Challenges and key factors in methodological development are discussed, and biological and medical applications are presented.

  13. Clinical implementation of x-ray phase-contrast imaging: theoretical foundations and design considerations.

    PubMed

    Wu, Xizeng; Liu, Hong

    2003-08-01

    Theoretical foundation and design considerations of a clinical feasible x-ray phase contrast imaging technique were presented in this paper. Different from the analysis of imaging phase object with weak absorption in literature, we proposed a new formalism for in-line phase-contrast imaging to analyze the effects of four clinically important factors on the phase contrast. These are the body parts attenuation, the spatial coherence of spherical waves from a finite-size focal spot, and polychromatic x-ray and radiation doses to patients for clinical applications. The theory presented in this paper can be applied widely in diagnostic x-ray imaging procedures. As an example, computer simulations were conducted and optimal design parameters were derived for clinical mammography. The results of phantom experiments were also presented which validated the theoretical analysis and computer simulations.

  14. Interferometric hard x-ray phase contrast imaging at 204 nm grating period

    NASA Astrophysics Data System (ADS)

    Wen, Han; Wolfe, Douglas E.; Gomella, Andrew A.; Miao, Houxun; Xiao, Xianghui; Liu, Chian; Lynch, Susanna K.; Morgan, Nicole

    2013-01-01

    We report on hard x-ray phase contrast imaging experiments using a grating interferometer of approximately 1/10th the grating period achieved in previous studies. We designed the gratings as a staircase array of multilayer stacks which are fabricated in a single thin film deposition process. We performed the experiments at 19 keV x-ray energy and 0.8 μm pixel resolution. The small grating period resulted in clear separation of different diffraction orders and multiple images on the detector. A slitted beam was used to remove overlap of the images from the different diffraction orders. The phase contrast images showed detailed features as small as 10 μm, and demonstrated the feasibility of high resolution x-ray phase contrast imaging with nanometer scale gratings.

  15. [Application of brilliant x-rays in mammography. Development and perspectives of phase contrast techniques].

    PubMed

    Schneider, T; Coan, P; Habs, D; Reiser, M

    2008-04-01

    The early and reliable detection of breast cancer is often difficult with conventional mammography, especially within dense breast parenchyma. An alternative approach using x-rays are phase-sensitive imaging techniques, which are able to visualize the borders of tissues with different refraction indices with very high contrast. These phase contrast imaging techniques can generate projection images with much less glandular dose than conventional mammography. Even the acquisition of phase contrast CT data sets with an acceptable exposure dose is possible. As brilliant x-ray beams are required for phase contrast imaging, which up to now were only available at synchrotron facilities, these methods were restricted to only a few laboratories. However, with the advent of newly developed high intensity lasers which are also able to produce such radiation, a widespread and affordable use of this technique seems realistic. The further development of phase contrast imaging is funded by the excellence cluster MAP of the Munich universities.

  16. Single grating phase contrast imaging for x-ray microscopy and microtomography

    NASA Astrophysics Data System (ADS)

    Bruyndonckx, P.; Sasov, A.; Pauwels, B.

    2014-09-01

    The grating based approach to phase contrast imaging is rather inefficient in the use of the available x-ray flux due to the presence of two absorption gratings and it requires longer scan times compared to conventional CT because multiple images are needed at each projection angle. To avoid these drawbacks, a proof-of-principle experiment was developed to obtain absorption, phase contrast (DPC) and dark field images (DCI) in a single exposure using only a non-absorbing phase grating, a micro-focus source in cone-beam geometry and a highresolution x-ray detector.

  17. Phase contrast x-ray microscopy study of rabbit primo vessels

    NASA Astrophysics Data System (ADS)

    Kim, M.-S.; Oh, S.-W.; Lim, J.-H.; Han, S.-W.

    2010-11-01

    The microstructural properties of the primo-vascular systems of rabbits were examined by phase contrast x-ray microscopy. The primo-vascular systems with an average diameter of 32 μm were extracted from the surfaces of the rabbit internal organs. Phase contrast x-ray imaging showed that the primo-vascular systems were tubules with random holes on their lateral surfaces. The size of the holes on the vascular surface was 2-5 μm. The holes might act as size selective channels for microcells coming in and out and assist in the unidirectional flow of the primo-vascular systems.

  18. Benchmarking the x-ray phase contrast imaging for ICF DT ice characterization using roughened surrogates

    SciTech Connect

    Dewald, E; Kozioziemski, B; Moody, J; Koch, J; Mapoles, E; Montesanti, R; Youngblood, K; Letts, S; Nikroo, A; Sater, J; Atherton, J

    2008-06-26

    We use x-ray phase contrast imaging to characterize the inner surface roughness of DT ice layers in capsules planned for future ignition experiments. It is therefore important to quantify how well the x-ray data correlates with the actual ice roughness. We benchmarked the accuracy of our system using surrogates with fabricated roughness characterized with high precision standard techniques. Cylindrical artifacts with azimuthally uniform sinusoidal perturbations with 100 um period and 1 um amplitude demonstrated 0.02 um accuracy limited by the resolution of the imager and the source size of our phase contrast system. Spherical surrogates with random roughness close to that required for the DT ice for a successful ignition experiment were used to correlate the actual surface roughness to that obtained from the x-ray measurements. When comparing average power spectra of individual measurements, the accuracy mode number limits of the x-ray phase contrast system benchmarked against surface characterization performed by Atomic Force Microscopy are 60 and 90 for surrogates smoother and rougher than the required roughness for the ice. These agreement mode number limits are >100 when comparing matching individual measurements. We will discuss the implications for interpreting DT ice roughness data derived from phase-contrast x-ray imaging.

  19. Refracting Roentgen's rays: Propagation-based x-ray phase contrast for biomedical imaging

    SciTech Connect

    Gureyev, T. E.; Mayo, S. C.; Nesterets, Ya.; Pogany, A.; Stevenson, A. W.; Wilkins, S. W.; Myers, D. E.; Paganin, D. M.

    2009-05-15

    Absorption-contrast x-ray imaging serves to visualize the variation in x-ray attenuation within the volume of a given sample, whereas phase contrast allows one to visualize variations in x-ray refractive index. The former imaging mechanism has been well known and widely utilized since the time of Roentgen's Nobel prize winning work, whereas the latter mechanism--sought for, but not found, by Roentgen himself--has laid the foundation for a revolution in x-ray imaging which is the central topic of this review. We consider the physical imaging mechanisms underlying both absorption contrast and phase contrast, together with the associated inverse problem of how one may obtain quantitative two- or three-dimensional information regarding a sample, given one or more phase-contrast images of the same. Practical questions are considered, regarding optimized phase-contrast imaging geometries as a function of detector resolution, source size, x-ray spectrum, and dose. Experimental examples pertaining to biomedical applications are given, and prospects for the future outlined.

  20. High Resolution X-ray Phase Contrast Imaging with Acoustic Tissue-Selective Contrast Enhancement

    DTIC Science & Technology

    2008-06-01

    murine liver. 15. SUBJECT TERMS X-ray, ultrasound, phase contrast, imaging, elastography 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF...of the veins in a mouse liver that was excised from an euthanized mouse, fixed in paraformaldehyde and subsequently dried. The vascular tree is...clearly visible in the x-ray image. Contrast agent injections into the portal vein of another mouse liver verified that the veins are imaged and not

  1. Optimization of propagation-based x-ray phase-contrast tomography for breast cancer imaging

    NASA Astrophysics Data System (ADS)

    Baran, P.; Pacile, S.; Nesterets, Y. I.; Mayo, S. C.; Dullin, C.; Dreossi, D.; Arfelli, F.; Thompson, D.; Lockie, D.; McCormack, M.; Taba, S. T.; Brun, F.; Pinamonti, M.; Nickson, C.; Hall, C.; Dimmock, M.; Zanconati, F.; Cholewa, M.; Quiney, H.; Brennan, P. C.; Tromba, G.; Gureyev, T. E.

    2017-03-01

    The aim of this study was to optimise the experimental protocol and data analysis for in-vivo breast cancer x-ray imaging. Results are presented of the experiment at the SYRMEP beamline of Elettra Synchrotron using the propagation-based phase-contrast mammographic tomography method, which incorporates not only absorption, but also x-ray phase information. In this study the images of breast tissue samples, of a size corresponding to a full human breast, with radiologically acceptable x-ray doses were obtained, and the degree of improvement of the image quality (from the diagnostic point of view) achievable using propagation-based phase-contrast image acquisition protocols with proper incorporation of x-ray phase retrieval into the reconstruction pipeline was investigated. Parameters such as the x-ray energy, sample-to-detector distance and data processing methods were tested, evaluated and optimized with respect to the estimated diagnostic value using a mastectomy sample with a malignant lesion. The results of quantitative evaluation of images were obtained by means of radiological assessment carried out by 13 experienced specialists. A comparative analysis was performed between the x-ray and the histological images of the specimen. The results of the analysis indicate that, within the investigated range of parameters, both the objective image quality characteristics and the subjective radiological scores of propagation-based phase-contrast images of breast tissues monotonically increase with the strength of phase contrast which in turn is directly proportional to the product of the radiation wavelength and the sample-to-detector distance. The outcomes of this study serve to define the practical imaging conditions and the CT reconstruction procedures appropriate for low-dose phase-contrast mammographic imaging of live patients at specially designed synchrotron beamlines.

  2. Optimization of propagation-based x-ray phase-contrast tomography for breast cancer imaging.

    PubMed

    Baran, P; Pacile, S; Nesterets, Y I; Mayo, S C; Dullin, C; Dreossi, D; Arfelli, F; Thompson, D; Lockie, D; McCormack, M; Taba, S T; Brun, F; Pinamonti, M; Nickson, C; Hall, C; Dimmock, M; Zanconati, F; Cholewa, M; Quiney, H; Brennan, P C; Tromba, G; Gureyev, T E

    2017-03-21

    The aim of this study was to optimise the experimental protocol and data analysis for in-vivo breast cancer x-ray imaging. Results are presented of the experiment at the SYRMEP beamline of Elettra Synchrotron using the propagation-based phase-contrast mammographic tomography method, which incorporates not only absorption, but also x-ray phase information. In this study the images of breast tissue samples, of a size corresponding to a full human breast, with radiologically acceptable x-ray doses were obtained, and the degree of improvement of the image quality (from the diagnostic point of view) achievable using propagation-based phase-contrast image acquisition protocols with proper incorporation of x-ray phase retrieval into the reconstruction pipeline was investigated. Parameters such as the x-ray energy, sample-to-detector distance and data processing methods were tested, evaluated and optimized with respect to the estimated diagnostic value using a mastectomy sample with a malignant lesion. The results of quantitative evaluation of images were obtained by means of radiological assessment carried out by 13 experienced specialists. A comparative analysis was performed between the x-ray and the histological images of the specimen. The results of the analysis indicate that, within the investigated range of parameters, both the objective image quality characteristics and the subjective radiological scores of propagation-based phase-contrast images of breast tissues monotonically increase with the strength of phase contrast which in turn is directly proportional to the product of the radiation wavelength and the sample-to-detector distance. The outcomes of this study serve to define the practical imaging conditions and the CT reconstruction procedures appropriate for low-dose phase-contrast mammographic imaging of live patients at specially designed synchrotron beamlines.

  3. Quantitative X-ray phase-contrast microtomography from a compact laser-driven betatron source

    PubMed Central

    Wenz, J.; Schleede, S.; Khrennikov, K.; Bech, M.; Thibault, P.; Heigoldt, M.; Pfeiffer, F.; Karsch, S.

    2015-01-01

    X-ray phase-contrast imaging has recently led to a revolution in resolving power and tissue contrast in biomedical imaging, microscopy and materials science. The necessary high spatial coherence is currently provided by either large-scale synchrotron facilities with limited beamtime access or by microfocus X-ray tubes with rather limited flux. X-rays radiated by relativistic electrons driven by well-controlled high-power lasers offer a promising route to a proliferation of this powerful imaging technology. A laser-driven plasma wave accelerates and wiggles electrons, giving rise to a brilliant keV X-ray emission. This so-called betatron radiation is emitted in a collimated beam with excellent spatial coherence and remarkable spectral stability. Here we present a phase-contrast microtomogram of a biological sample using betatron X-rays. Comprehensive source characterization enables the reconstruction of absolute electron densities. Our results suggest that laser-based X-ray technology offers the potential for filling the large performance gap between synchrotron- and current X-ray tube-based sources. PMID:26189811

  4. Evaluation of microbubble contrast agents for dynamic imaging with x-ray phase contrast.

    PubMed

    Millard, T P; Endrizzi, M; Everdell, N; Rigon, L; Arfelli, F; Menk, R H; Stride, E; Olivo, A

    2015-07-29

    X-rays are commonly used as a means to image the inside of objects opaque to visible light, as their short wavelength allows penetration through matter and the formation of high spatial resolution images. This physical effect has found particular importance in medicine where x-ray based imaging is routinely used as a diagnostic tool. Increasingly, however, imaging modalities that provide functional as well as morphological information are required. In this study the potential to use x-ray phase based imaging as a functional modality through the use of microbubbles that can be targeted to specific biological processes is explored. We show that the concentration of a microbubble suspension can be monitored quantitatively whilst in flow using x-ray phase contrast imaging. This could provide the basis for a dynamic imaging technique that combines the tissue penetration, spatial resolution, and high contrast of x-ray phase based imaging with the functional information offered by targeted imaging modalities.

  5. Observation of a Soft Tissue by a Zernike Phase Contrast Hard X-ray Microscope

    NASA Astrophysics Data System (ADS)

    Aoki, Sadao; Namikawa, Tadahiro; Hoshino, Masato; Watanabe, Norio

    2007-01-01

    A Zernike-type phase contrast hard X-ray microscope was constructed at the Photon Factory BL3C2 (KEK). A white beam from a bending magnet was monochromatized by a silicon double crystal monochromator. Monochromatic parallel X-ray beam illuminated a sample, and transmitted and diffracted X-ray beams were imaged by a Fresnel zone plate (FZP) which had the outer zone width of 100 nm. A phase plate made of a thin aluminum foil with a pinhole was set at the back focal plane of the FZP. The phase plate modulated the diffraction beam from the FZP, whereas a direct beam passed through the pinhole. The resolution of the microscope was measured by observing a tantalum test pattern at an X-ray energy of 9 keV. A 100nm line-and-space pattern could be resolved. X-ray montage pictures of growing eggs of artemia (plankton) were obtained.

  6. Phase-contrast microscopy at high x-ray energy with a laboratory setup.

    PubMed

    Endrizzi, Marco; Vittoria, Fabio A; Diemoz, Paul C; Lorenzo, Rodolfo; Speller, Robert D; Wagner, Ulrich H; Rau, Christoph; Robinson, Ian K; Olivo, Alessandro

    2014-06-01

    We report on the design and realization of an x-ray imaging system for quantitative phase-contrast microscopy at high x-ray energy with laboratory-scale instrumentation. Phase and amplitude were separated quantitatively at x-ray energies up to 80 keV with micrometric spatial resolution. The accuracy of the results was tested against numerical simulations, and the spatial resolution was experimentally quantified by measuring a Siemens star phase object. This simple setup should find broad application in those areas of x-ray imaging where high energy and spatial resolution are simultaneously required and in those difficult cases where the sample contains materials with similar x-ray absorption.

  7. Observation of a Soft Tissue by a Zernike Phase Contrast Hard X-ray Microscope

    SciTech Connect

    Aoki, Sadao; Namikawa, Tadahiro; Hoshino, Masato; Watanabe, Norio

    2007-01-19

    A Zernike-type phase contrast hard X-ray microscope was constructed at the Photon Factory BL3C2 (KEK). A white beam from a bending magnet was monochromatized by a silicon double crystal monochromator. Monochromatic parallel X-ray beam illuminated a sample, and transmitted and diffracted X-ray beams were imaged by a Fresnel zone plate (FZP) which had the outer zone width of 100 nm. A phase plate made of a thin aluminum foil with a pinhole was set at the back focal plane of the FZP. The phase plate modulated the diffraction beam from the FZP, whereas a direct beam passed through the pinhole. The resolution of the microscope was measured by observing a tantalum test pattern at an X-ray energy of 9 keV. A 100nm line-and-space pattern could be resolved. X-ray montage pictures of growing eggs of artemia (plankton) were obtained.

  8. Hard X-Ray Phase-Contrast Imaging for Medical Applications - Physicist's Dream or Radiologist's Mainstream?

    SciTech Connect

    Wilkins, S. W.; Gureyev, T. E.; Mayo, S. C.; Nesterets, Ya. I.; Pogany, A.; Stevenson, A. W.; Paganin, D. M.

    2007-03-30

    We briefly review currently practiced methods of X-ray phase contrast imaging and consider some of their relative features, especially in regard to applicability to clinical medical studies. Various related technological issues and promising future areas of development are also briefly discussed.

  9. Phase contrast imaging using a micro focus x-ray source

    NASA Astrophysics Data System (ADS)

    Zhou, Wei; Majidi, Keivan; Brankov, Jovan G.

    2014-09-01

    Phase contrast x-ray imaging, a new technique to increase the imaging contrast for the tissues with close attenuation coefficients, has been studied since mid 1990s. This technique reveals the possibility to show the clear details of the soft tissues and tumors in small scale resolution. A compact and low cost phase contrast imaging system using a conventional x-ray source is described in this paper. Using the conventional x-ray source is of great importance, because it provides the possibility to use the method in hospitals and clinical offices. Simple materials and components are used in the setup to keep the cost in a reasonable and affordable range.Tungsten Kα1 line with the photon energy 59.3 keV was used for imaging. Some of the system design details are discussed. The method that was used to stabilize the system is introduced. A chicken thigh bone tissue sample was used for imaging followed by the image quality, image acquisition time and the potential clinical application discussion. High energy x-ray beam can be used in phase contrast imaging. Therefore the radiation dose to the patients can be greatly decreased compared to the traditional x-ray radiography.

  10. X-ray phase-contrast imaging: transmission functions separable in Cartesian coordinates.

    PubMed

    Cao, Guohua; Hamilton, Theron J; Rose-Petruck, Christoph; Diebold, Gerald J

    2007-04-01

    In-line, x-ray phase-contrast imaging is responsive to both phase changes and absorption as the x radiation traverses a body. Expressions are derived for phase-contrast imaging of objects having transmission functions separable in Cartesian coordinates. Starting from the Fresnel-Kirchhoff integral formula for image formation, an expression is found for the phase-contrast image produced by an x-ray source with nonvanishing dimensions. This expression is evaluated in limiting cases where the source-to-object distance is large, where the source acts as a point source, and where the weak phase approximation is valid. The integral expression for the image is evaluated for objects with simple geometrical shapes, showing the influence of the source dimensions on the visibility of phase-contrast features. The expressions derived here are evaluated for cases where the magnification is substantially greater than one as would be employed in biological imaging. Experiments are reported using the in-line phase-contrast imaging method with a microfocus x-ray source and a CCD camera.

  11. Artifact characterization and reduction in scanning X-ray Zernike phase contrast microscopy.

    PubMed

    Vartiainen, Ismo; Holzner, Christian; Mohacsi, Istvan; Karvinen, Petri; Diaz, Ana; Pigino, Gaia; David, Christian

    2015-05-18

    Zernike phase contrast microscopy is a well-established method for imaging specimens with low absorption contrast. It has been successfully implemented in full-field microscopy using visible light and X-rays. In microscopy Cowley's reciprocity principle connects scanning and full-field imaging. Even though the reciprocity in Zernike phase contrast has been discussed by several authors over the past thirty years, only recently it was experimentally verified using scanning X-ray microscopy. In this paper, we investigate the image and contrast formation in scanning Zernike phase contrast microscopy with a particular and detailed focus on the origin of imaging artifacts that are typically associated with Zernike phase contrast. We demonstrate experimentally with X-rays the effect of the phase mask design on the contrast and halo artifacts and present an optimized design of the phase mask with respect to photon efficiency and artifact reduction. Similarly, due to the principle of reciprocity the observations and conclusions of this work have direct applicability to Zernike phase contrast in full-field microscopy as well.

  12. Inclusion of coherence in Monte Carlo models for simulation of x-ray phase contrast imaging.

    PubMed

    Cipiccia, Silvia; Vittoria, Fabio A; Weikum, Maria; Olivo, Alessandro; Jaroszynski, Dino A

    2014-09-22

    Interest in phase contrast imaging methods based on electromagnetic wave coherence has increased significantly recently, particularly at X-ray energies. This is giving rise to a demand for effective simulation methods. Coherent imaging approaches are usually based on wave optics, which require significant computational resources, particularly for producing 2D images. Monte Carlo (MC) methods, used to track individual particles/photons for particle physics, are not considered appropriate for describing coherence effects. Previous preliminary work has evaluated the possibility of incorporating coherence in Monte Carlo codes. However, in this paper, we present the implementation of refraction in a model that is based on time of flight calculations and the Huygens-Fresnel principle, which allow reproducing the formation of phase contrast images in partially and fully coherent experimental conditions. The model is implemented in the FLUKA Monte Carlo code and X-ray phase contrast imaging simulations are compared with experiments and wave optics calculations.

  13. X-ray phase contrast tomography by tracking near field speckle

    PubMed Central

    Wang, Hongchang; Berujon, Sebastien; Herzen, Julia; Atwood, Robert; Laundy, David; Hipp, Alexander; Sawhney, Kawal

    2015-01-01

    X-ray imaging techniques that capture variations in the x-ray phase can yield higher contrast images with lower x-ray dose than is possible with conventional absorption radiography. However, the extraction of phase information is often more difficult than the extraction of absorption information and requires a more sophisticated experimental arrangement. We here report a method for three-dimensional (3D) X-ray phase contrast computed tomography (CT) which gives quantitative volumetric information on the real part of the refractive index. The method is based on the recently developed X-ray speckle tracking technique in which the displacement of near field speckle is tracked using a digital image correlation algorithm. In addition to differential phase contrast projection images, the method allows the dark-field images to be simultaneously extracted. After reconstruction, compared to conventional absorption CT images, the 3D phase CT images show greatly enhanced contrast. This new imaging method has advantages compared to other X-ray imaging methods in simplicity of experimental arrangement, speed of measurement and relative insensitivity to beam movements. These features make the technique an attractive candidate for material imaging such as in-vivo imaging of biological systems containing soft tissue. PMID:25735237

  14. X-ray phase contrast tomography by tracking near field speckle

    NASA Astrophysics Data System (ADS)

    Wang, Hongchang; Berujon, Sebastien; Herzen, Julia; Atwood, Robert; Laundy, David; Hipp, Alexander; Sawhney, Kawal

    2015-03-01

    X-ray imaging techniques that capture variations in the x-ray phase can yield higher contrast images with lower x-ray dose than is possible with conventional absorption radiography. However, the extraction of phase information is often more difficult than the extraction of absorption information and requires a more sophisticated experimental arrangement. We here report a method for three-dimensional (3D) X-ray phase contrast computed tomography (CT) which gives quantitative volumetric information on the real part of the refractive index. The method is based on the recently developed X-ray speckle tracking technique in which the displacement of near field speckle is tracked using a digital image correlation algorithm. In addition to differential phase contrast projection images, the method allows the dark-field images to be simultaneously extracted. After reconstruction, compared to conventional absorption CT images, the 3D phase CT images show greatly enhanced contrast. This new imaging method has advantages compared to other X-ray imaging methods in simplicity of experimental arrangement, speed of measurement and relative insensitivity to beam movements. These features make the technique an attractive candidate for material imaging such as in-vivo imaging of biological systems containing soft tissue.

  15. Quantitative breast tissue characterization using grating-based x-ray phase-contrast imaging

    NASA Astrophysics Data System (ADS)

    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.

  16. Requirements for dynamical differential phase contrast x-ray imaging with a laboratory source

    NASA Astrophysics Data System (ADS)

    Macindoe, David; Kitchen, Marcus J.; Irvine, Sarah C.; Fouras, Andreas; Morgan, Kaye S.

    2016-12-01

    X-ray phase contrast enables weakly-attenuating structures to be imaged, with bright synchrotron sources adding the ability to capture time sequences and analyse sample dynamics. Here, we describe the translation of dynamical differential phase contrast imaging from the synchrotron to a compact x-ray source, in order to achieve this kind of time sequence imaging in the laboratory. We formulate broadly-applicable set-up guidelines for the single-grid, single-exposure imaging technique using a divergent source, exploring the experimental factors that restrict set-up size, imaging sensitivity and sample size. Experimental images are presented using the single-grid phase contrast technique with a steel attenuation grid and a liquid-metal-jet x-ray source, enabling exposure times as short as 0.5 s for dynamic imaging. Differential phase contrast images were retrieved from phantoms, incorporating noise filtering to improve the low-count images encountered when imaging dynamics using short exposures.

  17. Theoretical analysis of x-ray CT phase-contrast imaging

    NASA Astrophysics Data System (ADS)

    Feng, Sheng; Liu, Song; Zhang, Xuelong

    2008-12-01

    Recently phase contrast imaging has attracted much attention. An obvious advantage of using X-rays for imaging the internal structure of relatively thick samples lies in its high degree of penetration of solid objects. However, often leads to poor image contrast for soft tissue. Phase contrast imaging can be very useful in such situation, as the phase of the transmitted beam may often be more sensitive indicator of density of sample than convention contrast. On the other hand, Computed Tomography is the best technology in the aspect of X-rays detection. Using the technology, the detected object can be imaged to three-dimensional image, so as to observe the inner structure of object, and be convenient to the disease examination. If the phase contrast imaging can be used to the technology of Computed Tomography, the high resolution image can be gained. The technology will become the development orientation of medical image. The aim of this article was to apply the theory of X-rays phase contrast imaging to the traditional X-CT technique. For this purpose, the formula deduced from the imaging theory with parallel monochromatic X-rays illuminating the object based on the Fresnel-Kircohhof theory had been completed and a formula similar to that of the traditional X-CT reconstruction had been gained, which was Radon transform formula. At last, X-rays reconstruction simulation had been carried out according to the formula, and proved that the method could be used in clinical medical imaging. The method discussed in this paper had a very bright prospect for application.

  18. Hard X-ray phase-contrast imaging with the Compact Light Source based on inverse Compton X-rays

    PubMed Central

    Bech, Martin; Bunk, Oliver; David, Christian; Ruth, Ronald; Rifkin, Jeff; Loewen, Rod; Feidenhans’l, Robert; Pfeiffer, Franz

    2009-01-01

    The first imaging results obtained from a small-size synchrotron are reported. The newly developed Compact Light Source produces inverse Compton X-rays at the intersection point of the counter propagating laser and electron beam. The small size of the intersection point gives a highly coherent cone beam with a few milliradian angular divergence and a few percent energy spread. These specifications make the Compact Light Source ideal for a recently developed grating-based differential phase-contrast imaging method. PMID:19096173

  19. Source effects in analyzer-based X-ray phase contrast imaging with conventional sources

    SciTech Connect

    Hoennicke, M. G.; Manica, J.; Mazzaro, I.; Cusatis, C.; Huang, X.-R.

    2012-11-15

    Several recent papers have shown the implementation of analyzer based X-ray phase contrast imaging (ABI) with conventional X-ray sources. The high flux is always a requirement to make the technique useful for bio-medical applications. Here, we present and discuss three important parameters, which need to be taken into account, when searching for the high flux ABI: anisotropic magnification, double image, and source size spread due to intrinsic dispersive diffraction by asymmetrically cut crystals. These parameters, if not well optimized, may cause important features in the acquired images which can mislead the interpretation. A few ways to minimize these effects are implemented and discussed, including some experimental results.

  20. Source effects in analyzer-based X-ray phase contrast imaging with conventional sources

    NASA Astrophysics Data System (ADS)

    Hönnicke, M. G.; Manica, J.; Mazzaro, I.; Cusatis, C.; Huang, X.-R.

    2012-11-01

    Several recent papers have shown the implementation of analyzer based X-ray phase contrast imaging (ABI) with conventional X-ray sources. The high flux is always a requirement to make the technique useful for bio-medical applications. Here, we present and discuss three important parameters, which need to be taken into account, when searching for the high flux ABI: anisotropic magnification, double image, and source size spread due to intrinsic dispersive diffraction by asymmetrically cut crystals. These parameters, if not well optimized, may cause important features in the acquired images which can mislead the interpretation. A few ways to minimize these effects are implemented and discussed, including some experimental results.

  1. Phase-contrast tomography at the nanoscale using hard x rays

    NASA Astrophysics Data System (ADS)

    Stampanoni, Marco; Mokso, Rajmund; Marone, Federica; Vila-Comamala, Joan; Gorelick, Sergey; Trtik, Pavel; Jefimovs, Konstantin; David, Christian

    2010-04-01

    Synchrotron-based full-field tomographic microscopy established itself as a tool for noninvasive investigations. Many beamlines worldwide routinely achieve micrometer spatial resolution while the isotropic 100-nm barrier is reached and trespassed only by few instruments, mainly in the soft x-ray regime. We present an x-ray, full-field microscope with tomographic capabilities operating at 10 keV and with an isotropic resolution of 144 nm. Custom-designed optical components allow for ideal, aperture-matched sample illumination and very sensitive phase contrast imaging. We show here that the instrument has been successfully used for the nondestructive, volumetric investigation of single cells.

  2. Hard x-ray phase contrast imaging of black lipid membranes

    SciTech Connect

    Beerlink, A.; Mell, M.; Tolkiehn, M.; Salditt, T.

    2009-11-16

    We report hard x-ray phase contrast imaging of black lipid membranes, freely suspended over a micromachined aperture in an aqueous solution. Biomolecular and organic substances can thus be probed in hydrated environments by parallel beam propagation imaging, using coherent multi-kilo-electronvolt x-ray radiation. The width of the thinning film can be resolved from analysis of the intensity fringes in the Fresnel diffraction regime down to about 200 nm. The thinning process, in which solvent is expelled from the space in between two opposing monolayers, is monitored, and the domain walls between coexisting domains of swollen and thinned membrane patches are characterized.

  3. Tomographic Hard X-ray Phase Contrast Micro- and Nano-imaging at TOMCAT

    NASA Astrophysics Data System (ADS)

    Stampanoni, M.; Marone, F.; Modregger, P.; Pinzer, B.; Thüring, T.; Vila-Comamala, J.; David, C.; Mokso, R.

    2010-07-01

    This article illustrates the phase contrast instrumentation installed at the Tomographic Microscopy and Coherent Radiology beamline (TOMCAT) of the Swiss Light Source. Our experimental framework has been designed to extract phase information at spatial resolutions covering three orders of magnitude. For moderate (5-10 microns) resolutions we implemented a two-gratings interferometer, operated at energies between 14 and 40 keV. For high resolution (1-5 microns) we obtain phase information thanks to a modified transport of intensity approach. For very high-resolutions (0.1-0.5 microns) we developed a broadband hard X-ray full-field microscope operated in Zernike-phase contrast.

  4. X-ray phase-contrast imaging with an Inverse Compton Scattering source

    SciTech Connect

    Endrizzi, M.; Carpinelli, M.; Oliva, P.; Golosio, B.; Delogu, P.; Stefanini, A.; Gureyev, T. E.; Bottigli, U.

    2010-07-23

    Single-shot in-line phase-contrast imaging with the Inverse Compton Scattering X-ray source available at ATF (Accelerator Test Facility) at Brookhaven National Laboratory is experimentally demonstrated. Phase-contrast images of polymer wires are obtained with a single X-ray pulse whose time length is about 1 picosecond. The edge-enhancement effect is clearly visible in the images and simulations show a quantitative agreement with experimental data. A phase-retrieval step in the image processing leads to a accurate estimation of the projected thickness of our samples. Finally, a single-shot image of a wasp is presented as an example of a biological sample.

  5. Myelinated mouse nerves studied by X-ray phase contrast zoom tomography.

    PubMed

    Bartels, M; Krenkel, M; Cloetens, P; Möbius, W; Salditt, T

    2015-12-01

    We have used X-ray phase contrast tomography to resolve the structure of uncut, entire myelinated optic, saphenous and sciatic mouse nerves. Intrinsic electron density contrast suffices to identify axonal structures. Specific myelin labeling by an osmium tetroxide stain enables distinction between axon and surrounding myelin sheath. Utilization of spherical wave illumination enables zooming capabilities which enable imaging of entire sciatic internodes as well as identification of sub-structures such as nodes of Ranvier and Schmidt-Lanterman incisures.

  6. Simulation of single grid-based phase-contrast x-ray imaging (g-PCXI)

    NASA Astrophysics Data System (ADS)

    Lim, H. W.; Lee, H. W.; Cho, H. S.; Je, U. K.; Park, C. K.; Kim, K. S.; Kim, G. A.; Park, S. Y.; Lee, D. Y.; Park, Y. O.; Woo, T. H.; Lee, S. H.; Chung, W. H.; Kim, J. W.; Kim, J. G.

    2017-04-01

    Single grid-based phase-contrast x-ray imaging (g-PCXI) technique, which was recently proposed by Wen et al. to retrieve absorption, scattering, and phase-gradient images from the raw image of the examined object, seems a practical method for phase-contrast imaging with great simplicity and minimal requirements on the setup alignment. In this work, we developed a useful simulation platform for g-PCXI and performed a simulation to demonstrate its viability. We also established a table-top setup for g-PCXI which consists of a focused-linear grid (200-lines/in strip density), an x-ray tube (100-μm focal spot size), and a flat-panel detector (48-μm pixel size) and performed a preliminary experiment with some samples to show the performance of the simulation platform. We successfully obtained phase-contrast x-ray images of much enhanced contrast from both the simulation and experiment and the simulated contract seemed similar to the experimental contrast, which shows the performance of the developed simulation platform. We expect that the simulation platform will be useful for designing an optimal g-PCXI system.

  7. Reverse projection retrieval in edge illumination x-ray phase contrast computed tomography

    NASA Astrophysics Data System (ADS)

    Hagen, Charlotte K.; Endrizzi, Marco; Diemoz, Paul C.; Olivo, Alessandro

    2016-06-01

    Edge illumination (EI) x-ray phase contrast computed tomography (CT) can provide three-dimensional distributions of the real and imaginary parts of the complex refractive index (n=1-δ +\\text{i}β ) of the sample. Phase retrieval, i.e. the separation of attenuation and refraction data from projections that contain a combination of both, is a key step in the image reconstruction process. In EI-based x-ray phase contrast CT, this is conventionally performed on the basis of two projections acquired in opposite illumination configurations (i.e. with different positions of the pre-sample mask) at each CT angle. Displacing the pre-sample mask at each projection makes the scan susceptible to motor-induced misalignment and prevents a continuous sample rotation. We present an alternative method for the retrieval of attenuation and refraction data that does not require repositioning the pre-sample mask. The method is based on the reverse projection relation published by Zhu et al (2010 Proc. Natl Acad. Sci. USA 107 13576-81) for grating interferometry-based x-ray phase contrast CT. We use this relation to derive a simplified acquisition strategy that allows acquiring data with a continuous sample rotation, which can reduce scan time when combined with a fast read-out detector. Besides discussing the theory and the necessary alignment of the experimental setup, we present tomograms obtained with reverse projection retrieval and demonstrate their agreement with those obtained with the conventional EI retrieval.

  8. X-ray computed tomography of wood-adhesive bondlines: Attenuation and phase-contrast effects

    DOE PAGES

    Paris, Jesse L.; Kamke, Frederick A.; Xiao, Xianghui

    2015-07-29

    Microscale X-ray computed tomography (XCT) is discussed as a technique for identifying 3D adhesive distribution in wood-adhesive bondlines. Visualization and material segmentation of the adhesives from the surrounding cellular structures require sufficient gray-scale contrast in the reconstructed XCT data. Commercial wood-adhesive polymers have similar chemical characteristics and density to wood cell wall polymers and therefore do not provide good XCT attenuation contrast in their native form. Here, three different adhesive types, namely phenol formaldehyde, polymeric diphenylmethane diisocyanate, and a hybrid polyvinyl acetate, are tagged with iodine such that they yield sufficient X-ray attenuation contrast. However, phase-contrast effects at material edgesmore » complicate image quality and segmentation in XCT data reconstructed with conventional filtered backprojection absorption contrast algorithms. A quantitative phase retrieval algorithm, which isolates and removes the phase-contrast effect, was demonstrated. The paper discusses and illustrates the balance between material X-ray attenuation and phase-contrast effects in all quantitative XCT analyses of wood-adhesive bondlines.« less

  9. X-ray computed tomography of wood-adhesive bondlines: Attenuation and phase-contrast effects

    SciTech Connect

    Paris, Jesse L.; Kamke, Frederick A.; Xiao, Xianghui

    2015-07-29

    Microscale X-ray computed tomography (XCT) is discussed as a technique for identifying 3D adhesive distribution in wood-adhesive bondlines. Visualization and material segmentation of the adhesives from the surrounding cellular structures require sufficient gray-scale contrast in the reconstructed XCT data. Commercial wood-adhesive polymers have similar chemical characteristics and density to wood cell wall polymers and therefore do not provide good XCT attenuation contrast in their native form. Here, three different adhesive types, namely phenol formaldehyde, polymeric diphenylmethane diisocyanate, and a hybrid polyvinyl acetate, are tagged with iodine such that they yield sufficient X-ray attenuation contrast. However, phase-contrast effects at material edges complicate image quality and segmentation in XCT data reconstructed with conventional filtered backprojection absorption contrast algorithms. A quantitative phase retrieval algorithm, which isolates and removes the phase-contrast effect, was demonstrated. The paper discusses and illustrates the balance between material X-ray attenuation and phase-contrast effects in all quantitative XCT analyses of wood-adhesive bondlines.

  10. High-energy x-ray grating-based phase-contrast radiography of human anatomy

    NASA Astrophysics Data System (ADS)

    Horn, Florian; Hauke, Christian; Lachner, Sebastian; Ludwig, Veronika; Pelzer, Georg; Rieger, Jens; Schuster, Max; Seifert, Maria; Wandner, Johannes; Wolf, Andreas; Michel, Thilo; Anton, Gisela

    2016-03-01

    X-ray grating-based phase-contrast Talbot-Lau interferometry is a promising imaging technology that has the potential to raise soft tissue contrast in comparison to conventional attenuation-based imaging. Additionally, it is sensitive to attenuation, refraction and scattering of the radiation and thus provides complementary and otherwise inaccessible information due to the dark-field image, which shows the sub-pixel size granularity of the measured object. Until recent progress the method has been mainly limited to photon energies below 40 keV. Scaling the method to photon energies that are sufficient to pass large and spacious objects represents a challenging task. This is caused by increasing demands regarding the fabrication process of the gratings and the broad spectra that come along with the use of polychromatic X-ray sources operated at high acceleration voltages. We designed a setup that is capable to reach high visibilities in the range from 50 to 120 kV. Therefore, spacious and dense parts of the human body with high attenuation can be measured, such as a human knee. The authors will show investigations on the resulting attenuation, differential phase-contrast and dark-field images. The images experimentally show that X-ray grating-based phase-contrast radiography is feasible with highly absorbing parts of the human body containing massive bones.

  11. Phase contrast x-ray velocimetry of small animal lungs: optimising imaging rates

    PubMed Central

    Murrie, R. P.; Paganin, D. M.; Fouras, A.; Morgan, K. S.

    2015-01-01

    Chronic lung diseases affect a vast portion of the world’s population. One of the key difficulties in accurately diagnosing and treating chronic lung disease is our inability to measure dynamic motion of the lungs in vivo. Phase contrast x-ray imaging (PCXI) allows us to image the lungs in high resolution by exploiting the difference in refractive indices between tissue and air. Combining PCXI with x-ray velocimetry (XV) allows us to track the local motion of the lungs, improving our ability to locate small regions of disease under natural ventilation conditions. Via simulation, we investigate the optimal imaging speed and sequence to capture lung motion in vivo in small animals using XV on both synchrotron and laboratory x-ray sources, balancing the noise inherent in a short exposure with motion blur that results from a long exposure. PMID:26819819

  12. Note: Gratings on low absorbing substrates for x-ray phase contrast imaging

    SciTech Connect

    Koch, F. J. Schröter, T. J.; Kunka, D.; Meyer, P.; Meiser, J.; Faisal, A.; Khalil, M. I.; Mohr, J.; Birnbacher, L.; Viermetz, M.; Pfeiffer, F.; Walter, M.; Schulz, J.

    2015-12-15

    Grating based X-ray phase contrast imaging is on the verge of being applied in clinical settings. To achieve this goal, compact setups with high sensitivity and dose efficiency are necessary. Both can be increased by eliminating unwanted absorption in the beam path, which is mainly due to the grating substrates. Fabrication of gratings via deep X-ray lithography can address this issue by replacing the commonly used silicon substrate with materials with lower X-ray absorption that fulfill certain boundary conditions. Gratings were produced on both graphite and polymer substrates without compromising on structure quality. These gratings were tested in a three-grating setup with a source operated at 40 kVp and lead to an increase in the detector photon count rate of almost a factor of 4 compared to a set of gratings on silicon substrates. As the visibility was hardly affected, this corresponds to a significant increase in sensitivity and therefore dose efficiency.

  13. Compact laser accelerators for X-ray phase-contrast imaging.

    PubMed

    Najmudin, Z; Kneip, S; Bloom, M S; Mangles, S P D; Chekhlov, O; Dangor, A E; Döpp, A; Ertel, K; Hawkes, S J; Holloway, J; Hooker, C J; Jiang, J; Lopes, N C; Nakamura, H; Norreys, P A; Rajeev, P P; Russo, C; Streeter, M J V; Symes, D R; Wing, M

    2014-03-06

    Advances in X-ray imaging techniques have been driven by advances in novel X-ray sources. The latest fourth-generation X-ray sources can boast large photon fluxes at unprecedented brightness. However, the large size of these facilities means that these sources are not available for everyday applications. With advances in laser plasma acceleration, electron beams can now be generated at energies comparable to those used in light sources, but in university-sized laboratories. By making use of the strong transverse focusing of plasma accelerators, bright sources of betatron radiation have been produced. Here, we demonstrate phase-contrast imaging of a biological sample for the first time by radiation generated by GeV electron beams produced by a laser accelerator. The work was performed using a greater than 300 TW laser, which allowed the energy of the synchrotron source to be extended to the 10-100 keV range.

  14. Fourier domain image fusion for differential X-ray phase-contrast breast imaging.

    PubMed

    Coello, Eduardo; Sperl, Jonathan I; Bequé, Dirk; Benz, Tobias; Scherer, Kai; Herzen, Julia; Sztrókay-Gaul, Anikó; Hellerhoff, Karin; Pfeiffer, Franz; Cozzini, Cristina; Grandl, Susanne

    2017-04-01

    X-Ray Phase-Contrast (XPC) imaging is a novel technology with a great potential for applications in clinical practice, with breast imaging being of special interest. This work introduces an intuitive methodology to combine and visualize relevant diagnostic features, present in the X-ray attenuation, phase shift and scattering information retrieved in XPC imaging, using a Fourier domain fusion algorithm. The method allows to present complementary information from the three acquired signals in one single image, minimizing the noise component and maintaining visual similarity to a conventional X-ray image, but with noticeable enhancement in diagnostic features, details and resolution. Radiologists experienced in mammography applied the image fusion method to XPC measurements of mastectomy samples and evaluated the feature content of each input and the fused image. This assessment validated that the combination of all the relevant diagnostic features, contained in the XPC images, was present in the fused image as well.

  15. CRITIR: model-based reconstruction for x-ray phase contrast tomography (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Xiao, Xianghui; Mohan, Aditya; Bouman, Charles A.

    2016-10-01

    X-ray phase contrast imaging provides greater contrast compared to conventional absorption contrast imaging. It has higher sensitivity in discriminating mass density difference in a sample. Therefore phase contrast imaging has broad applications in dynamic tomography in which signal-to-noise ratio is usually traded off to the desired temporal resolution. Single-distance propagation phase contrast tomography is the most popular approach at many synchrotron facilities. The simple and flexible setup facilitates complicated in situ experiments. There are few phase retrieval algorithms available for phase-contrast image data processing. All the algorithms rely on certain models. In this talk we present a phase retrieval algorithm for phase-contrast tomography that is suitable for large propagation distance under phase-attenuation duality assumption. The validity of the algorithm is proved with both simulated and experimental data. The reconstruction results with the new algorithm show improved accuracy compared to other model based algorithms. The framework of this algorithm may be extended to the scenario in which phase-attenuation assumption is not satisfied, therefore a general model-free phase retrieval approach for single-distance phase contrast tomography.

  16. A general theoretical formalism for X-ray phase contrast imaging.

    PubMed

    Wu, Xizeng; Liu, Hong

    2003-01-01

    The in-line phase-contrast imaging has great potential for clinical imaging applications. This work presents a general theoretical formalism for the in-line phase-contrast imaging. The theoretical formalism developed in this work is derived by taking a new strategy to calculate the Fourier transform of image intensity directly. Different from the transport of intensity equation (TIE) formalism for phase-contrast imaging in literature [6], this general formalism covers both the near field regime and the holography regime of phase-contrast imaging. The image intensity formulas have been derived in both the image space and frequency space. Especially our results show that the Fresnel diffraction image intensity is a sum of convolutions of the cosine- and sine-Fresnel filters with the object attenuation A20(x) and attenuated phase A20(x)φ(x), respectively. The Pogany-Gao-Wilkins (PGW) formalism is recovered as a special case of our general formalism. In addition, in the low-resolution approximation, the general formula is reduced a spherical wave-generalization of the TIE-based formula for phase-contrast imaging. This spherical wave-generalization will be useful for phase-contrast imaging with a micro-focus x-ray tube. The transition of the formalism from 1-D to 2-D cases has been provided as well.

  17. Development of optics for x-ray phase-contrast imaging of high energy density plasmas

    SciTech Connect

    Stutman, D.; Finkenthal, M.; Moldovan, N.

    2010-10-15

    Phase-contrast or refraction-enhanced x-ray radiography can be useful for the diagnostic of low-Z high energy density plasmas, such as imploding inertial confinement fusion (ICF) pellets, due to its sensitivity to density gradients. To separate and quantify the absorption and refraction contributions to x-ray images, methods based on microperiodic optics, such as shearing interferometry, can be used. To enable applying such methods with the energetic x rays needed for ICF radiography, we investigate a new type of optics consisting of grazing incidence microperiodic mirrors. Using such mirrors, efficient phase-contrast imaging systems could be built for energies up to {approx}100 keV. In addition, a simple lithographic method is proposed for the production of the microperiodic x-ray mirrors based on the difference in the total reflection between a low-Z substrate and a high-Z film. Prototype mirrors fabricated with this method show promising characteristics in laboratory tests.

  18. Preliminary research on dual-energy X-ray phase-contrast imaging

    NASA Astrophysics Data System (ADS)

    Han, Hua-Jie; Wang, Sheng-Hao; Gao, Kun; Wang, Zhi-Li; Zhang, Can; Yang, Meng; Zhang, Kai; Zhu, Pei-Ping

    2016-04-01

    Dual-energy X-ray absorptiometry (DEXA) has been widely applied to measure the bone mineral density (BMD) and soft-tissue composition of the human body. However, the use of DEXA is greatly limited for low-Z materials such as soft tissues due to their weak absorption, while X-ray phase-contrast imaging (XPCI) shows significantly improved contrast in comparison with the conventional standard absorption-based X-ray imaging for soft tissues. In this paper, we propose a novel X-ray phase-contrast method to measure the area density of low-Z materials, including a single-energy method and a dual-energy method. The single-energy method is for the area density calculation of one low-Z material, while the dual-energy method aims to calculate the area densities of two low-Z materials simultaneously. Comparing the experimental and simulation results with the theoretical ones, the new method proves to have the potential to replace DEXA in area density measurement. The new method sets the prerequisites for a future precise and low-dose area density calculation method for low-Z materials. Supported by Major State Basic Research Development Program (2012CB825800), Science Fund for Creative Research Groups (11321503) and National Natural Science Foundation of China (11179004, 10979055, 11205189, 11205157)

  19. Beam hardening effects in grating-based x-ray phase-contrast imaging

    SciTech Connect

    Chabior, Michael; Donath, Tilman; David, Christian; Bunk, Oliver; Schuster, Manfred; Schroer, Christian; Pfeiffer, Franz

    2011-03-15

    Purpose: In this work, the authors investigate how beam hardening affects the image formation in x-ray phase-contrast imaging and consecutively develop a correction algorithm based on the results of the analysis. Methods: The authors' approach utilizes a recently developed x-ray imaging technique using a grating interferometer capable of visualizing the differential phase shift of a wave front traversing an object. An analytical description of beam hardening is given, highlighting differences between attenuation and phase-contrast imaging. The authors present exemplary beam hardening artifacts for a number of well-defined samples in measurements at a compact laboratory setup using a polychromatic source. Results: Despite the differences in image formation, the authors show that beam hardening leads to a similar reduction of image quality in phase-contrast imaging as in conventional attenuation-contrast imaging. Additionally, the authors demonstrate that for homogeneous objects, beam hardening artifacts can be corrected by a linearization technique, applicable to all kinds of phase-contrast methods using polychromatic sources. Conclusions: The evaluated correction algorithm is shown to yield good results for a number of simple test objects and can thus be advocated in medical imaging and nondestructive testing.

  20. Development of a prototype gantry system for preclinical x-ray phase-contrast computed tomography

    SciTech Connect

    Tapfer, Arne; Bech, Martin; Pauwels, Bart; Liu Xuan; Bruyndonckx, Peter; Sasov, Alexander; Kenntner, Johannes; Mohr, Juergen; Walter, Marco; Schulz, Joachim; Pfeiffer, Franz

    2011-11-15

    Purpose: To explore the potential of grating-based x-ray phase-contrast imaging for clinical applications, a first compact gantry system was developed. It is designed such that it can be implemented into an in-vivo small-animal phase-contrast computed tomography (PC-CT) scanner. The purpose of the present study is to assess the accuracy and quantitativeness of the described gantry in both absorption and phase-contrast. Methods: A phantom, containing six chemically well-defined liquids, was constructed. A tomography scan with cone-beam reconstruction of this phantom was performed yielding the spatial distribution of the linear attenuation coefficient {mu} and decrement {delta} of the complex refractive index. Theoretical values of {mu} and {delta} were calculated for each liquid from tabulated data and compared with the experimentally measured values. Additionally, a color-fused image representation is proposed to display the complementary absorption and phase-contrast information in a single image. Results: Experimental and calculated data of the phantom agree well confirming the quantitativeness and accuracy of the reconstructed spatial distributions of {mu} and {delta}. The proposed color-fused image representation, which combines the complementary absorption and phase information, considerably helps in distinguishing the individual substances. Conclusions: The concept of grating-based phase-contrast computed tomography (CT) can be implemented into a compact, cone-beam geometry gantry setup. The authors believe that this work represents an important milestone in translating phase-contrast x-ray imaging from previous proof-of-principle experiments to first preclinical biomedical imaging applications on small-animal models.

  1. Hard x-ray phase contrast imaging using a tabletop Talbot-Lau interferometer with multiline embedded x-ray targets.

    PubMed

    Shimura, Takayoshi; Morimoto, Naoki; Fujino, Sho; Nagatomi, Takaharu; Oshima, Keni-chi; Harada, Jimpei; Omote, Kazuhiko; Osaka, Naohisa; Hosoi, Takuji; Watanabe, Heiji

    2013-01-15

    We demonstrate hard x-ray phase contrast imaging (XPCI) using a tabletop Talbot-Lau interferometer in which the x-ray source and source grating are replaced with an x-ray source with multiline metal targets embedded in a diamond substrate. This source realizes an array of linear x-ray sources of a few micrometers width without fabrication difficulty because of the shallow penetration depth of electrons irradiated to the metal targets. This enhances the coherence of x rays from each linear source and allows XPCI within 45 cm source-detector distance under 1.2 W input power for 8 keV x rays.

  2. 4D x-ray phase contrast tomography for repeatable motion of biological samples

    NASA Astrophysics Data System (ADS)

    Hoshino, Masato; Uesugi, Kentaro; Yagi, Naoto

    2016-09-01

    X-ray phase contrast tomography based on a grating interferometer was applied to fast and dynamic measurements of biological samples. To achieve this, the scanning procedure in the tomographic scan was improved. A triangle-shaped voltage signal from a waveform generator to a Piezo stage was used for the fast phase stepping in the grating interferometer. In addition, an optical fiber coupled x-ray scientific CMOS camera was used to achieve fast and highly efficient image acquisitions. These optimizations made it possible to perform an x-ray phase contrast tomographic measurement within an 8 min scan with density resolution of 2.4 mg/cm3. A maximum volume size of 13 × 13 × 6 mm3 was obtained with a single tomographic measurement with a voxel size of 6.5 μm. The scanning procedure using the triangle wave was applied to four-dimensional measurements in which highly sensitive three-dimensional x-ray imaging and a time-resolved dynamic measurement of biological samples were combined. A fresh tendon in the tail of a rat was measured under a uniaxial stretching and releasing condition. To maintain the freshness of the sample during four-dimensional phase contrast tomography, the temperature of the bathing liquid of the sample was kept below 10° using a simple cooling system. The time-resolved deformation of the tendon and each fascicle was measured with a temporal resolution of 5.7 Hz. Evaluations of cross-sectional area size, length of the axis, and mass density in the fascicle during a stretching process provided a basis for quantitative analysis of the deformation of tendon fascicle.

  3. Second order x-ray in-line phase-contrast imaging

    NASA Astrophysics Data System (ADS)

    Cong, Wenxiang; Wang, Ge

    2014-09-01

    X-ray phase imaging is sensitive to structural variation of soft tissue, and offers excellent contrast resolution for characterization of cancerous tissues. Also, the cross-section of x-ray phase shift is a thousand times greater than that of x-ray attenuation in soft tissue over the diagnostic energy range, allowing a much higher signal-to-noise ratio at a substantially lower radiation dose than attenuation-based x-ray imaging. In this paper, we present a second order approximation model with respect to phase shift based on the paraxial Fresnel-Kirchhoff diffraction theory, and also discuss in-line dark-field imaging based on the second order model. This proposed model accurately establishes a quantitative correspondence between phases and recorded intensity images, outperforming the linear phase approximation model widely used in the conventional methods of x-ray in-line phase-contrast imaging. This new model can be iteratively solved using the algebraic reconstruction technique (ART). The state of the art compressive sensing ingredients can be incorporated to achieve high quality image reconstruction. Our numerical simulation studies demonstrate the feasibility of the proposed approach that is more accurate and stable, and more robust against noise than the conventional approach.

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

    SciTech Connect

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

    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.

  5. Phase contrast digital mammography using molybdenum x-ray: clinical implications in detectability improvement

    NASA Astrophysics Data System (ADS)

    Freedman, Matthew T.; Lo, Shih-Chung B.; Honda, Chika; Makariou, Erini; Sisney, Gale; Pien, Edward; Ohara, Hiromu; Ishisaka, Akira; Shimada, Fumio

    2003-06-01

    We have applied phase imaging on digital mammography to investigate adequate contrast of printed images for digital phase contrast mammography using a practical molybdenum X-ray tube. Phase contrast mammography procedures were performed with defined air gap (e.g., 0.6 m) configuration using customized mammography equipment and a computed radiography (CR) system. Magnified (x2) phase contrast images acquired with 0.0875mm per pixel were mapped onto the laser imager resolution at 0.04375mm per pixel for printing life-size object on wet processing silver halide recording film. For contact mammography of screen-film system, we used MinR2000 system as a baseline method. ACR 156 phantom printed images with contrasts of 2.8, 3.7, 4.9, 5.7 and 6.7 were evaluated by five radiologists. The ACR scores for the life-size image based on the 2 times magnified phase contrast image acquired by the computed radiography were higher than the scores of MinR2000 image, when the contrast of printed images for both methods was 3.7. The ACR scores were lower in the low contrast images (i.e., 2.8) than its higher contrast counterparts (i.e., >= 3.7) for all techniques used. The detectability improvement should be due to higher spatial resolution and lower noise in the phase contrast images.

  6. Evaluation of a new reconstruction algorithm for x-ray phase-contrast imaging

    NASA Astrophysics Data System (ADS)

    Seifert, Maria; Hauke, Christian; Horn, Florian; Lachner, Sebastian; Ludwig, Veronika; Pelzer, Georg; Rieger, Jens; Schuster, Max; Wandner, Johannes; Wolf, Andreas; Michel, Thilo; Anton, Gisela

    2016-04-01

    X-ray grating-based phase-contrast imaging might open up entirely new opportunities in medical imaging. However, transferring the interferometer technique from laboratory setups to conventional imaging systems the necessary rigidity of the system is difficult to achieve. Therefore, vibrations or distortions of the system lead to inaccuracies within the phase-stepping procedure. Given insufficient stability of the phase-step positions, up to now, artifacts in phase-contrast images occur, which lower the image quality. This is a problem with regard to the intended use of phase-contrast imaging in clinical routine as for example tiny structures of the human anatomy cannot be observed. In this contribution we evaluate an algorithm proposed by Vargas et.al.1 and applied to X-ray imaging by Pelzer et.al. that enables us to reconstruct a differential phase-contrast image without the knowledge of the specific phase-step positions. This method was tested in comparison to the standard reconstruction by Fourier analysis. The quality of phase-contrast images remains stable, even if the phase-step positions are completely unknown and not uniformly distributed. To also achieve attenuation and dark-field images the proposed algorithm has been combined with a further algorithm of Vargas et al.3 Using this algorithm, the phase-step positions can be reconstructed. With the help of the proper phase-step positions it is possible to get information about the phase, the amplitude and the offset of the measured data. We evaluated this algorithm concerning the measurement of thick objects which show a high absorbency.

  7. Phase contrast: the frontier of x-ray and electron imaging

    NASA Astrophysics Data System (ADS)

    Hwu, Y.; Margaritondo, G.

    2013-12-01

    Phase contrast has been a fundamental component of microscopy since the early 1940s. In broad terms, it refers to the formation of images using not the combination of wave intensities but their amplitudes with the corresponding phase factors. The impact on visible microscopy of biological specimens has been major. This contrast mechanism is now playing an increasingly important role in other kinds of microscopy, notably those based on electrons or x-rays. It notably solves the background problem of weak absorption contrast. New breakthroughs and new techniques are continuously produced, unfortunately unknown to most of the scientists that could exploit them. The present special cluster issue of reviews was inspired by this situation. The case of x-rays is very interesting. Phase contrast requires a high degree of longitudinal and lateral coherence. But conventional x-ray sources are not coherent. The progress of synchrotron sources yielded high coherence as a key byproduct—and started a rapid expansion of phase contrast radiology. No review—or cluster of reviews—can possibly cover all the facets of the recent progress. Without trying to be absolutely comprehensive, the present special cluster issue touches a variety of issues, giving a very broad picture. Liu et al review in general terms the different phase-based hard-x-ray techniques, with an interesting variety of examples. Then, Suortti et al and Wang et al present more specialized overviews of crystal and grating based x-ray imaging techniques, very powerful in the analysis of biological specimens. Mokso et al discuss the many facets of tomography using phase effects, expanding the picture of tomographic reconstruction of the three previous reviews. Wu et al treat the rapid progress in hard-x-ray focusing and its impact on radiology and tomography for materials science and biomedical research. The next two reviews deal with special and very interesting classes of applications. Specifically, Lee et al

  8. Noise properties of grating-based x-ray phase contrast computed tomography

    SciTech Connect

    Koehler, Thomas; Juergen Engel, Klaus; Roessl, Ewald

    2011-05-15

    Purpose: To investigate the properties of tomographic grating-based phase contrast imaging with respect to its noise power spectrum and the energy dependence of the achievable contrast to noise ratio. Methods: Tomographic simulations of an object with 11 cm diameter constituted of materials of biological interest were conducted at different energies ranging from 25 to 85 keV by using a wave propagation approach. Using a Monte Carlo simulation of the x-ray attenuation within the object, it is verified that the simulated measurement deposits the same dose within the object at each energy. Results: The noise in reconstructed phase contrast computed tomography images shows a maximum at low spatial frequencies. The contrast to noise ratio reaches a maximum around 45 keV for the simulated object. The general dependence of the contrast to noise on the energy appears to be independent of the material. Compared with reconstructed absorption contrast images, the reconstructed phase contrast images show sometimes better, sometimes worse, and sometimes similar contrast to noise, depending on the material and the energy. Conclusions: Phase contrast images provide additional information to the conventional absorption contrast images and might thus be useful for medical applications. However, the observed noise power spectrum in reconstructed phase contrast images implies that the usual trade-off between noise and resolution is less efficient for phase contrast imaging compared with absorption contrast imaging. Therefore, high-resolution imaging is a strength of phase contrast imaging, but low-resolution imaging is not. This might hamper the clinical application of the method, in cases where a low spatial resolution is sufficient for diagnosis.

  9. Complex dark-field contrast in grating-based x-ray phase contrast imaging

    NASA Astrophysics Data System (ADS)

    Yang, Yi; Tang, Xiangyang

    2015-03-01

    Without assuming that the sub-pixel microstructures of an object to be imaged distribute in space randomly, we investigate the influence of the object's microstructures on grating-based x-ray phase contrast imaging. Our theoretical analysis and 3D computer simulation study based on the paraxial Fresnel-Kirchhoff theory show that the existing dark-field contrast can be generalized into a complex dark-field contrast in a way such that its imaginary part quantifies the effect of the object's sub-pixel microstructures on the phase of intensity oscillations. A method based on the phase-attenuation duality that holds for soft tissues to be imaged at high x-ray energies is proposed to retrieve the imaginary part of the complex dark-field contrast for imaging. In comparison to the existing dark-field contrast, the imaginary part of complex dark-field contrast exhibits significantly stronger selectivity on the shape of the object's sub-pixel microstructures. Thus the x-ray imaging corresponding to the imaginary part of complex dark-field contrast can provide additional and complementary information to that corresponding to the attenuation contrast, phase contrast and the existing dark-field contrast.

  10. Phase contrast X-ray synchrotron imaging: opening access to fossil inclusions in opaque amber.

    PubMed

    Lak, Malvina; Néraudeau, Didier; Nel, André; Cloetens, Peter; Perrichot, Vincent; Tafforeau, Paul

    2008-06-01

    A significant portion of Mesozoic amber is fully opaque. Biological inclusions in such amber are invisible even after polishing, leading to potential bias in paleoecological and phylogenetic studies. Until now, studies using conventional X-ray microtomography focused on translucent or semi-opaque amber. In these cases, organisms of interest were visualized prior to X-ray analyses. It was recently demonstrated that propagation phase contrast X-ray synchrotron imaging techniques are powerful tools to access invisible inclusions in fully opaque amber. Here we describe an optimized synchrotron microradiographic protocol that allowed us to investigate efficiently and rapidly large amounts of opaque amber pieces from Charentes (southwestern France). Amber pieces were imaged with microradiography after immersion in water, which optimizes the visibility of inclusions. Determination is not accurate enough to allow precise phylogenetic studies, but provides preliminary data on biodiversity and ecotypes distribution; phase contrast microtomography remains necessary for precise determination. Because the organisms are generally much smaller than the amber pieces, we optimized local microtomography by using a continuous acquisition mode (sample moving during projection integration). As tomographic investigation of all inclusions is not practical, we suggest the use of a synchrotron for a microradiographic survey of opaque amber, coupled with microtomographic investigations of the most valuable organisms.

  11. Absorption and Phase Contrast X-Ray Imaging in Paleontology Using Laboratory and Synchrotron Sources.

    PubMed

    Bidola, Pidassa; Stockmar, Marco; Achterhold, Klaus; Pfeiffer, Franz; Pacheco, Mírian L A F; Soriano, Carmen; Beckmann, Felix; Herzen, Julia

    2015-10-01

    X-ray micro-computed tomography (μCT) is commonly used for imaging of samples in biomedical or materials science research. Owing to the ability to visualize a sample in a nondestructive way, X-ray μCT is perfectly suited to inspect fossilized specimens, which are mostly unique or rare. In certain regions of the world where important sedimentation events occurred in the Precambrian geological time, several fossilized animals are studied to understand questions related to their origin, environment, and life evolution. This article demonstrates the advantages of applying absorption and phase-contrast CT on the enigmatic fossil Corumbella werneri, one of the oldest known animals capable of building hard parts, originally discovered in Corumbá (Brazil). Different tomographic setups were tested to visualize the fossilized inner structures: a commercial laboratory-based μCT device, two synchrotron-based imaging setups using conventional absorption and propagation-based phase contrast, and a commercial X-ray microscope with a lens-coupled detector system, dedicated for radiography and tomography. Based on our results we discuss the strengths and weaknesses of the different imaging setups for paleontological studies.

  12. Absorption and Phase Contrast X-Ray Imaging in Paleontology Using Laboratory and Synchrotron Sources

    SciTech Connect

    Bidola, Pidassa; Stockmar, Marco; Achterhold, Klaus; Pfeiffer, Franz; Pacheco, Mirian L.A.F.; Soriano, Carmen; Beckmann, Felix; Herzen, Julia

    2015-10-01

    X-ray micro-computed tomography (CT) is commonly used for imaging of samples in biomedical or materials science research. Owing to the ability to visualize a sample in a nondestructive way, X-ray CT is perfectly suited to inspect fossilized specimens, which are mostly unique or rare. In certain regions of the world where important sedimentation events occurred in the Precambrian geological time, several fossilized animals are studied to understand questions related to their origin, environment, and life evolution. This article demonstrates the advantages of applying absorption and phase-contrast CT on the enigmatic fossil Corumbella werneri, one of the oldest known animals capable of building hard parts, originally discovered in Corumba (Brazil). Different tomographic setups were tested to visualize the fossilized inner structures: a commercial laboratory-based CT device, two synchrotron-based imaging setups using conventional absorption and propagation-based phase contrast, and a commercial X-ray microscope with a lens-coupled detector system, dedicated for radiography and tomography. Based on our results we discuss the strengths and weaknesses of the different imaging setups for paleontological studies.

  13. The application of phase contrast X-ray techniques for imaging Li-ion battery electrodes

    NASA Astrophysics Data System (ADS)

    Eastwood, D. S.; Bradley, R. S.; Tariq, F.; Cooper, S. J.; Taiwo, O. O.; Gelb, J.; Merkle, A.; Brett, D. J. L.; Brandon, N. P.; Withers, P. J.; Lee, P. D.; Shearing, P. R.

    2014-04-01

    In order to accelerate the commercialization of fuel cells and batteries across a range of applications, an understanding of the mechanisms by which they age and degrade at the microstructural level is required. Here, the most widely commercialized Li-ion batteries based on porous graphite based electrodes which de/intercalate Li+ ions during charge/discharge are studied by two phase contrast enhanced X-ray imaging modes, namely in-line phase contrast and Zernike phase contrast at the micro (synchrotron) and nano (laboratory X-ray microscope) level, respectively. The rate of charge cycling is directly dependent on the nature of the electrode microstructure, which are typically complex multi-scale 3D geometries with significant microstructural heterogeneities. We have been able to characterise the porosity and the tortuosity by micro-CT as well as the morphology of 5 individual graphite particles by nano-tomography finding that while their volume varied significantly their sphericity was surprisingly similar. The volume specific surface areas of the individual grains measured by nano-CT are significantly larger than the total volume specific surface area of the electrode from the micro-CT imaging, which can be attributed to the greater particle surface area visible at higher resolution.

  14. High-Resolution and Quantitative X-Ray Phase-Contrast Tomography for Mouse Brain Research.

    PubMed

    Xi, Yan; Lin, Xiaojie; Yuan, Falei; Yang, Guo-Yuan; Zhao, Jun

    2015-01-01

    Imaging techniques for visualizing cerebral vasculature and distinguishing functional areas are essential and critical to the study of various brain diseases. In this paper, with the X-ray phase-contrast imaging technique, we proposed an experiment scheme for the ex vivo mouse brain study, achieving both high spatial resolution and improved soft-tissue contrast. This scheme includes two steps: sample preparation and volume reconstruction. In the first step, we use heparinized saline to displace the blood inside cerebral vessels and then replace it with air making air-filled mouse brain. After sample preparation, X-ray phase-contrast tomography is performed to collect the data for volume reconstruction. Here, we adopt a phase-retrieval combined filtered backprojection method to reconstruct its three-dimensional structure and redesigned the reconstruction kernel. To evaluate its performance, we carried out experiments at Shanghai Synchrotron Radiation Facility. The results show that the air-tissue structured cerebral vasculatures are highly visible with propagation-based phase-contrast imaging and can be clearly resolved in reconstructed cross-images. Besides, functional areas, such as the corpus callosum, corpus striatum, and nuclei, are also clearly resolved. The proposed method is comparable with hematoxylin and eosin staining method but represents the studied mouse brain in three dimensions, offering a potential powerful tool for the research of brain disorders.

  15. Three-dimensional phase-contrast X-ray microtomography with scanning-imaging X-ray microscope optics.

    PubMed

    Takeuchi, Akihisa; Uesugi, Kentaro; Suzuki, Yoshio

    2013-09-01

    A three-dimensional (3D) X-ray tomographic micro-imaging system has been developed. The optical system is based on a scanning-imaging X-ray microscope (SIXM) optics, which is a hybrid system consisting of a scanning microscope optics with a one-dimensional (1D) focusing (line-focusing) device and an imaging microscope optics with a 1D objective. In the SIXM system, each 1D dataset of a two-dimensional (2D) image is recorded independently. An object is illuminated with a line-focused beam. Positional information of the region illuminated by the line-focused beam is recorded with the 1D imaging microscope optics as line-profile data. By scanning the object with the line focus, 2D image data are obtained. In the same manner as for a scanning microscope optics with a multi-pixel detector, imaging modes such as phase contrast and absorption contrast can be arbitrarily configured after the image data acquisition. By combining a tomographic scan method and the SIXM system, quantitative 3D imaging is performed. Results of a feasibility study of the SIXM for 3D imaging are shown.

  16. A fast-converging iterative method for X-ray in-line phase contrast tomography

    NASA Astrophysics Data System (ADS)

    Vo, Nghia T.; Atwood, Robert C.; Moser, Herbert O.; Lee, Peter D.; Breese, Mark B. H.; Drakopoulos, Michael

    2012-11-01

    X-ray in-line phase contrast tomography holds great promise for the quantitative analysis of soft materials. However, its applications have been limited, so far, by the fact that direct methods based on the transport-of-intensity equation and the contrast transfer function are sensitive to noise and applicable only to limited types of samples. Here, we propose an iterative method based on the Gerchberg-Saxton algorithm (R. W. Gerchberg and W. O. Saxton, Optik 35, 237 (1972)), but overcoming its slow convergence by an acceleration technique, named random signed feedback, which shows an excellent performance, both in numerical simulation and tomographic experiment, of discriminating various polymers even when using 53 keV synchrotron X-rays.

  17. A fast-converging iterative method for X-ray in-line phase contrast tomography

    SciTech Connect

    Vo, Nghia T.; Breese, Mark B. H.; Atwood, Robert C.; Drakopoulos, Michael; Moser, Herbert O.; Lee, Peter D.

    2012-11-26

    X-ray in-line phase contrast tomography holds great promise for the quantitative analysis of soft materials. However, its applications have been limited, so far, by the fact that direct methods based on the transport-of-intensity equation and the contrast transfer function are sensitive to noise and applicable only to limited types of samples. Here, we propose an iterative method based on the Gerchberg-Saxton algorithm (R. W. Gerchberg and W. O. Saxton, Optik 35, 237 (1972)), but overcoming its slow convergence by an acceleration technique, named random signed feedback, which shows an excellent performance, both in numerical simulation and tomographic experiment, of discriminating various polymers even when using 53 keV synchrotron X-rays.

  18. X-ray micro-beam techniques and phase contrast tomography applied to biomaterials

    NASA Astrophysics Data System (ADS)

    Fratini, Michela; Campi, Gaetano; Bukreeva, Inna; Pelliccia, Daniele; Burghammer, Manfred; Tromba, Giuliana; Cancedda, Ranieri; Mastrogiacomo, Maddalena; Cedola, Alessia

    2015-12-01

    A deeper comprehension of the biomineralization (BM) process is at the basis of tissue engineering and regenerative medicine developments. Several in-vivo and in-vitro studies were dedicated to this purpose via the application of 2D and 3D diagnostic techniques. Here, we develop a new methodology, based on different complementary experimental techniques (X-ray phase contrast tomography, micro-X-ray diffraction and micro-X-ray fluorescence scanning technique) coupled to new analytical tools. A qualitative and quantitative structural investigation, from the atomic to the micrometric length scale, is obtained for engineered bone tissues. The high spatial resolution achieved by X-ray scanning techniques allows us to monitor the bone formation at the first-formed mineral deposit at the organic-mineral interface within a porous scaffold. This work aims at providing a full comprehension of the morphology and functionality of the biomineralization process, which is of key importance for developing new drugs for preventing and healing bone diseases and for the development of bio-inspired materials.

  19. Spline based iterative phase retrieval algorithm for X-ray differential phase contrast radiography.

    PubMed

    Nilchian, Masih; Wang, Zhentian; Thuering, Thomas; Unser, Michael; Stampanoni, Marco

    2015-04-20

    Differential phase contrast imaging using grating interferometer is a promising alternative to conventional X-ray radiographic methods. It provides the absorption, differential phase and scattering information of the underlying sample simultaneously. Phase retrieval from the differential phase signal is an essential problem for quantitative analysis in medical imaging. In this paper, we formalize the phase retrieval as a regularized inverse problem, and propose a novel discretization scheme for the derivative operator based on B-spline calculus. The inverse problem is then solved by a constrained regularized weighted-norm algorithm (CRWN) which adopts the properties of B-spline and ensures a fast implementation. The method is evaluated with a tomographic dataset and differential phase contrast mammography data. We demonstrate that the proposed method is able to produce phase image with enhanced and higher soft tissue contrast compared to conventional absorption-based approach, which can potentially provide useful information to mammographic investigations.

  20. Projection phase contrast microscopy with a hard x-ray nanofocused beam: Defocus and contrast transfer

    SciTech Connect

    Salditt, T.; Giewekemeyer, K.; Fuhse, C.; Krueger, S. P.; Tucoulou, R.; Cloetens, P.

    2009-05-01

    We report a projection phase contrast microscopy experiment using hard x-ray pink beam undulator radiation focused by an adaptive mirror system to 100-200 nm spot size. This source is used to illuminate a lithographic test pattern with a well-controlled range of spatial frequencies. The oscillatory nature of the contrast transfer function with source-to-sample distance in this holographic imaging scheme is quantified and the validity of the weak phase object approximation is confirmed for the experimental conditions.

  1. Diffraction enhance x-ray imaging for quantitative phase contrast studies

    NASA Astrophysics Data System (ADS)

    Agrawal, A. K.; Singh, B.; Kashyap, Y. S.; Shukla, Mayank; Sarkar, P. S.; Sinha, Amar

    2016-05-01

    Conventional X-ray imaging based on absorption contrast permits limited visibility of feature having small density and thickness variations. For imaging of weakly absorbing material or materials possessing similar densities, a novel phase contrast imaging techniques called diffraction enhanced imaging has been designed and developed at imaging beamline Indus-2 RRCAT Indore. The technique provides improved visibility of the interfaces and show high contrast in the image forsmall density or thickness gradients in the bulk. This paper presents basic principle, instrumentation and analysis methods for this technique. Initial results of quantitative phase retrieval carried out on various samples have also been presented.

  2. Phase contrast tomography of the mouse cochlea at microfocus x-ray sources

    NASA Astrophysics Data System (ADS)

    Bartels, Matthias; Hernandez, Victor H.; Krenkel, Martin; Moser, Tobias; Salditt, Tim

    2013-08-01

    We present phase contrast x-ray tomography of functional soft tissue within the bony cochlear capsule of mice, carried out at laboratory microfocus sources with well-matched source, detector, geometry, and reconstruction algorithms at spatial resolutions down to 2 μm. Contrast, data quality and resolution enable the visualization of thin membranes and nerve fibers as well as automated segmentation of surrounding bone. By complementing synchrotron radiation imaging techniques, a broad range of biomedical applications becomes possible as demonstrated for optogenetic cochlear implant research.

  3. Optimization Of Phase-Contrast Enhanced X-Ray Imaging Of D-T Layers

    SciTech Connect

    Kozioziemski, B

    2005-06-17

    Phase-contrast enhanced x-ray imaging has been demonstrated for characterization of D-T layers inside of beryllium shells. These first demonstrations used both scintillator and direct-detection imaging. This memo details tradeoffs between the two methods in order to optimize the imaging. The guiding principle for optimization is to minimize the exposure time while maximizing the signal-to-noise ratio at the D-T solid-vapor interface. Direct-detection and scintillator performance are comparable when imaging the full capsule. However, a scintillator allows for higher-resolution images necessary for studying local defects in the D-T layer.

  4. Phase contrast tomography of the mouse cochlea at microfocus x-ray sources

    SciTech Connect

    Bartels, Matthias; Krenkel, Martin; Hernandez, Victor H.; Moser, Tobias; Salditt, Tim

    2013-08-19

    We present phase contrast x-ray tomography of functional soft tissue within the bony cochlear capsule of mice, carried out at laboratory microfocus sources with well-matched source, detector, geometry, and reconstruction algorithms at spatial resolutions down to 2 μm. Contrast, data quality and resolution enable the visualization of thin membranes and nerve fibers as well as automated segmentation of surrounding bone. By complementing synchrotron radiation imaging techniques, a broad range of biomedical applications becomes possible as demonstrated for optogenetic cochlear implant research.

  5. Analyzer-based phase-contrast imaging system using a micro focus x-ray source

    SciTech Connect

    Zhou, Wei; Majidi, Keivan; Brankov, Jovan G.

    2014-08-15

    Here we describe a new in-laboratory analyzer based phase contrast-imaging (ABI) instrument using a conventional X-ray tube source (CXS) aimed at bio-medical imaging applications. Phase contrast-imaging allows visualization of soft tissue details usually obscured in conventional X-ray imaging. The ABI system design and major features are described in detail. The key advantage of the presented system, over the few existing CXS ABI systems, is that it does not require high precision components, i.e., CXS, X-ray detector, and electro-mechanical components. To overcome a main problem introduced by these components, identified as temperature stability, the system components are kept at a constant temperature inside of three enclosures, thus minimizing the electrical and mechanical thermal drifts. This is achieved by using thermoelectric (Peltier) cooling/heating modules that are easy to control precisely. For CXS we utilized a microfocus X-ray source with tungsten (W) anode material. In addition the proposed system eliminates tungsten's multiple spectral lines by selecting monochromator crystal size appropriately therefore eliminating need for the costly mismatched, two-crystal monochromator. The system imaging was fine-tuned for tungsten Kα{sub 1} line with the energy of 59.3 keV since it has been shown to be of great clinical significance by a number of researchers at synchrotron facilities. In this way a laboratory system that can be used for evaluating and quantifying tissue properties, initially explored at synchrotron facilities, would be of great interest to a larger research community. To demonstrate the imaging capability of our instrument we use a chicken thigh tissue sample.

  6. TU-G-207-02: Clinical Applications of X-Ray Phase Contrast Imaging: Where Do We Stand?

    SciTech Connect

    Li, K.

    2015-06-15

    Last few years has witnessed the development of novel of X-ray imaging modalities, such as spectral CT, phase contrast CT, and X-ray acoustic/fluorescence/luminescence imaging. This symposium will present the recent advances of these emerging X-ray imaging modalities and update the attendees with knowledge in various related topics, including X-ray photon-counting detectors, X-ray physics underlying the emerging applications beyond the traditional X-ray imaging, image reconstruction for the novel modalities, characterization and evaluation of the systems, and their practical implications. In addition, the concept and practical aspects of X-ray activatable targeted nanoparticles for molecular X-ray imaging will be discussed in the context of X-ray fluorescence and luminescence CT. Learning Objectives: Present background knowledge of various emerging X-ray imaging techniques, such as spectral CT, phase contrast CT and X-ray fluorescence/luminescence CT. Discuss the practical need, technical aspects and current status of the emerging X-ray imaging modalities. Describe utility and future impact of the new generation of X-ray imaging applications.

  7. Contrast and resolution in direct Fresnel diffraction phase-contrast imaging with partially coherent x-ray source

    SciTech Connect

    Han Shensheng; Yu Hong; Cheng Jing; Gao Chen; Luo Zhenlin

    2004-10-01

    A general treatment of x-ray image formation by direct Fresnel diffraction with partially coherent hard x rays is presented. Contrast and resolution are the criteria used to specify the visibility of an image, which depend primarily on the spatial coherence of the illumination and the distance from object to the image, with chromatic coherence of lesser importance. The dependence of the quality of phase-contrast images on the parameters of in-line imaging configuration is described quantitatively. The influence of spatial coherence of hard x-ray source on the imaging quality is also discussed based on the partially coherent direct Fresnel diffraction phase-contrast imaging theory. Experimental results are also presented for phase-contrast x-ray images with partially coherent hard x rays.

  8. Diagnostics of 3D Scaffolds by the Method of X-Ray Phase Contrast Visualization

    NASA Astrophysics Data System (ADS)

    Al'tapova, V. R.; Khlusov, I. A.; Karpov, D. A.; Chen, F.; Baumbach, T.; Pichugin, V. F.

    2014-02-01

    Polymers are one of the most interesting classes of materials for bioengineering due to their high biocompatibility and the possibility of regulating their strength and degradation. In bioengineering, the design of a polymer scaffold determines the functional possibilities of the scaffold and its possible medical applications. Traditionally, the design of polymer scaffolds is analyzed with the help of two-dimensional visualization methods, such as optical and electron microscopy, and computer tomography. However, the x-ray region of the electromagnetic spectrum is only insignificantly absorbed by polymers and soft tissue, which means that it does not support computer tomography with sufficient contrast. The present work investigates visualization with the help of an interferometer based on the Talbot effect for three-dimensional visualization of a polymer scaffold in absorption, phase, and dark-field contrasts. A comparison of images obtained by x-ray visualization with histological sections of the scaffold is made. Phase contrast has made it possible to visualize the polymer structure and growth of soft tissues in the volume of the scaffold. In the future, it will be possible to use phase contrast for three-dimensional visualization of polymer scaffolds and soft tissues in vivo as well as in vitro.

  9. Noise in x-ray grating-based phase-contrast imaging

    SciTech Connect

    Weber, Thomas; Bartl, Peter; Bayer, Florian; Durst, Juergen; Haas, Wilhelm; Michel, Thilo; Ritter, Andre; Anton, Gisela

    2011-07-15

    Purpose: Grating-based x-ray phase-contrast imaging is a fast developing new modality not only for medical imaging, but as well for other fields such as material sciences. While these many possible applications arise, the knowledge of the noise behavior is essential. Methods: In this work, the authors used a least squares fitting algorithm to calculate the noise behavior of the three quantities absorption, differential phase, and dark-field image. Further, the calculated error formula of the differential phase image was verified by measurements. Therefore, a Talbot interferometer was setup, using a microfocus x-ray tube as source and a Timepix detector for photon counting. Additionally, simulations regarding this topic were performed. Results: It turned out that the variance of the reconstructed phase is only dependent of the total number of photons used to generate the phase image and the visibility of the experimental setup. These results could be evaluated in measurements as well as in simulations. Furthermore, the correlation between absorption and dark-field image was calculated. Conclusions: These results provide the understanding of the noise characteristics of grating-based phase-contrast imaging and will help to improve image quality.

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

    NASA Astrophysics Data System (ADS)

    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.

  11. Quantitative analysis of contrast to noise ratio using a phase contrast x-ray imaging prototype

    NASA Astrophysics Data System (ADS)

    Ghani, Muhammad U.; Wu, Di; Li, Yuhua; Kang, Minhua; Chen, Wei R.; Wu, Xizeng; Liu, Hong

    2013-02-01

    The purpose of this study was to determine the Contrast to Noise Ratio (CNR) of the x-ray images taken with the phase contrast imaging mode and compare them with the CNR of the images taken under the conventional mode. For each mode, three images were taken under three exposure conditions of 100 kVp (2.8mAs), 120 kVp (1.9mAs) and 140kVp (1.42mAs). A 1.61cm thick contrast detail phantom was used as an imaging object. For phase contrast, the source to image detector distance (SID) was 182.88 cm and the source to object (SOD) distance was 73.15 cm. The SOD was the same as SID in the conventional imaging mode. A computed radiography (CR) plate was used as a detector and the output CR images were converted to linear form in relation with the incident x-ray exposure. To calculate CNR, an image processing software was used to determine the mean pixel value and the standard deviation of the pixels in the region of interest (ROI) and in the nearby background around ROI. At any given exposure condition investigated in this study, the CNR values for the phase contrast images were better as compared to the corresponding conventional mode images. The superior image quality in terms of CNR is contributed by the phase-shifts resulted contrast, as well as the reduced scatters due to the air gap between the object and the detector.

  12. X-ray Phase Contrast Imaging of Calcified Tissue and Biomaterial Structure in Bioreactor Engineered Tissues

    SciTech Connect

    Appel, Alyssa A.; Larson, Jeffery C.; Garson, III, Alfred B.; Guan, Huifeng; Zhong, Zhong; Nguyen, Bao-Ngoc; Fisher, John P.; Anastasio, Mark A.; Brey, Eric M.

    2014-11-04

    Tissues engineered in bioreactor systems have been used clinically to replace damaged tissues and organs. In addition, these systems are under continued development for many tissue engineering applications. The ability to quantitatively assess material structure and tissue formation is critical for evaluating bioreactor efficacy and for preimplantation assessment of tissue quality. These techniques allow for the nondestructive and longitudinal monitoring of large engineered tissues within the bioreactor systems and will be essential for the translation of these strategies to viable clinical therapies. X-ray Phase Contrast (XPC) imaging techniques have shown tremendous promise for a number of biomedical applications owing to their ability to provide image contrast based on multiple X-ray properties, including absorption, refraction, and scatter. In this research, mesenchymal stem cell-seeded alginate hydrogels were prepared and cultured under osteogenic conditions in a perfusion bioreactor. The constructs were imaged at various time points using XPC microcomputed tomography (µCT). Imaging was performed with systems using both synchrotron- and tube-based X-ray sources. XPC µCT allowed for simultaneous three-dimensional (3D) quantification of hydrogel size and mineralization, as well as spatial information on hydrogel structure and mineralization. Samples were processed for histological evaluation and XPC showed similar features to histology and quantitative analysis consistent with the histomorphometry. Furthermore, these results provide evidence of the significant potential of techniques based on XPC for noninvasive 3D imaging engineered tissues grown in bioreactors.

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

    SciTech Connect

    Hagen, C. K. Endrizzi, M.; Diemoz, P. C.; Olivo, A.; Munro, P. R. T.

    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.

  14. Helical X-ray phase-contrast computed tomography without phase stepping

    NASA Astrophysics Data System (ADS)

    Marschner, M.; Willner, M.; Potdevin, G.; Fehringer, A.; Noël, P. B.; Pfeiffer, F.; Herzen, J.

    2016-04-01

    X-ray phase-contrast computed tomography (PCCT) using grating interferometry provides enhanced soft-tissue contrast. The possibility to use standard polychromatic laboratory sources enables an implementation into a clinical setting. Thus, PCCT has gained significant attention in recent years. However, phase-contrast CT scans still require significantly increased measurement times in comparison to conventional attenuation-based CT imaging. This is mainly due to a time-consuming stepping of a grating, which is necessary for an accurate retrieval of the phase information. In this paper, we demonstrate a novel scan technique, which directly allows the determination of the phase signal without a phase-stepping procedure. The presented work is based on moiré fringe scanning, which allows fast data acquisition in radiographic applications such as mammography or in-line product analysis. Here, we demonstrate its extension to tomography enabling a continuous helical sample rotation as routinely performed in clinical CT systems. Compared to standard phase-stepping techniques, the proposed helical fringe-scanning procedure enables faster measurements, an extended field of view and relaxes the stability requirements of the system, since the gratings remain stationary. Finally, our approach exceeds previously introduced methods by not relying on spatial interpolation to acquire the phase-contrast signal.

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

    PubMed

    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.

  16. K-alpha x-ray source using high energy and high repetition rate laser system for phase contrast imaging

    NASA Astrophysics Data System (ADS)

    Serbanescu, Cristina; Fourmaux, Sylvain; Kieffer, Jean-Claude; Kincaid, Russell; Krol, Andrzej

    2009-08-01

    K-alpha x-ray sources from laser produced plasmas provide completely new possibilities for x-ray phase-contrast imaging applications. By tightly focusing intense femtosecond laser pulses onto a solid target, K-alpha x-ray pulses are generated through the interaction of energetic electrons created in the plasma with the bulk target. In this paper, we present a continuous and efficient Mo K-alpha x-ray source produced by a femtosecond laser system operating at 100 Hz repetition rate with maximum pulse energy of 110 mJ before compression. The source has x-ray conversion efficiency greater than 10-5 into K-alpha line emission. In preparation for phase contrast imaging applications, the size of the resultant K-alpha x-ray emission spot has been also characterized. The source exhibits sufficient spatial coherence to observe phase contrast. We observe a relatively small broadening of the K-alpha source size compared to the size of the laser beam itself. Detailed characterization of the source including the x-ray spectrum and the x-ray average yield along with phase contrast images of test objects will be presented.

  17. Real-Time Radiography for CDI Castings X-ray Inspection System, SBIR Phase I

    DTIC Science & Technology

    2007-11-02

    project was demonstrated by real time radiographic experiments on a smaller object at 150 kV x-ray energy and by tangential x-ray imaging of an actual 3...CDI projectile at 280 kV x-ray energy . The greater sensitivity of the new detector technology introduced in this development project makes it...possible to use significantly lower x-ray energy than would normally be required for the inspection of such castings. This is an important achievement

  18. Single-shot x-ray differential phase-contrast and diffraction imaging using two-dimensional transmission gratings.

    PubMed

    Wen, Harold H; Bennett, Eric E; Kopace, Rael; Stein, Ashley F; Pai, Vinay

    2010-06-15

    We describe an x-ray differential phase-contrast imaging method based on two-dimensional transmission gratings that are directly resolved by an x-ray camera. X-ray refraction and diffraction in the sample lead to variations of the positions and amplitudes of the grating fringes on the camera. These effects can be quantified through spatial harmonic analysis. The use of 2D gratings allows differential phase contrast in several directions to be obtained from a single image. When compared to previous grating-based interferometry methods, this approach obviates the need for multiple exposures and separate measurements for different directions and thereby accelerates imaging speed.

  19. Advanced contrast modalities for X-ray radiology: Phase-contrast and dark-field imaging using a grating interferometer.

    PubMed

    Bech, Martin; Jensen, Torben H; Bunk, Oliver; Donath, Tilman; David, Christian; Weitkamp, Timm; Le Duc, Geraldine; Bravin, Alberto; Cloetens, Peter; Pfeiffer, Franz

    2010-01-01

    Here we review our recent progress in the field of X-ray dark-field and phase-contrast imaging using a grating interferometer. We describe the basic imaging principles of grating-based phase-contrast and dark-field radiography and present some exemplary results obtained for simple test objects and biological specimens. Furthermore, we discuss how phase-contrast and dark-field radiography can be combined with the concept of computed tomography, and yield highly detailed three-dimensional insights into biomedical sample. Exemplary results obtained with standard X-ray tube sources and highly brilliant synchrotron sources are presented.

  20. Analyzer-based phase contrast imaging and phase retrieval using a rotating anode x-ray source

    SciTech Connect

    Vine, D. J.; Paganin, D. M.; Pavlov, K. M.; Kraeusslich, J.; Wehrhan, O.; Uschmann, I.; Foerster, E.

    2007-12-17

    We have performed an analyzer crystal based phase contrast imaging (ABI) experiment using a rotating anode x-ray source. The use of such an incoherent source demonstrates the potential of ABI as a quantitative characterization tool for the laboratory environment. A phase contrast image of a plastic phantom was recorded on high resolution x-ray film and the projected thickness was retrieved from a single image. The projected thickness recovered from the phase contrast image was shown to quantitatively agree with a reference optical microscope measurement.

  1. High energy x-ray phase contrast CT using glancing-angle grating interferometers

    SciTech Connect

    Sarapata, A.; Stayman, J. W.; Siewerdsen, J. H.; Finkenthal, M.; Stutman, D.; Pfeiffer, F.

    2014-02-15

    Purpose: The authors present initial progress toward a clinically compatible x-ray phase contrast CT system, using glancing-angle x-ray grating interferometry to provide high contrast soft tissue images at estimated by computer simulation dose levels comparable to conventional absorption based CT. Methods: DPC-CT scans of a joint phantom and of soft tissues were performed in order to answer several important questions from a clinical setup point of view. A comparison between high and low fringe visibility systems is presented. The standard phase stepping method was compared with sliding window interlaced scanning. Using estimated dose values obtained with a Monte-Carlo code the authors studied the dependence of the phase image contrast on exposure time and dose. Results: Using a glancing angle interferometer at high x-ray energy (∼45 keV mean value) in combination with a conventional x-ray tube the authors achieved fringe visibility values of nearly 50%, never reported before. High fringe visibility is shown to be an indispensable parameter for a potential clinical scanner. Sliding window interlaced scanning proved to have higher SNRs and CNRs in a region of interest and to also be a crucial part of a low dose CT system. DPC-CT images of a soft tissue phantom at exposures in the range typical for absorption based CT of musculoskeletal extremities were obtained. Assuming a human knee as the CT target, good soft tissue phase contrast could be obtained at an estimated absorbed dose level around 8 mGy, similar to conventional CT. Conclusions: DPC-CT with glancing-angle interferometers provides improved soft tissue contrast over absorption CT even at clinically compatible dose levels (estimated by a Monte-Carlo computer simulation). Further steps in image processing, data reconstruction, and spectral matching could make the technique fully clinically compatible. Nevertheless, due to its increased scan time and complexity the technique should be thought of not as

  2. Revealing letters in rolled Herculaneum papyri by X-ray phase-contrast imaging

    NASA Astrophysics Data System (ADS)

    Mocella, Vito; Brun, Emmanuel; Ferrero, Claudio; Delattre, Daniel

    2015-01-01

    Hundreds of papyrus rolls, buried by the eruption of Mount Vesuvius in 79 AD and belonging to the only library passed on from Antiquity, were discovered 260 years ago at Herculaneum. These carbonized papyri are extremely fragile and are inevitably damaged or destroyed in the process of trying to open them to read their contents. In recent years, new imaging techniques have been developed to read the texts without unwrapping the rolls. Until now, specialists have been unable to view the carbon-based ink of these papyri, even when they could penetrate the different layers of their spiral structure. Here for the first time, we show that X-ray phase-contrast tomography can reveal various letters hidden inside the precious papyri without unrolling them. This attempt opens up new opportunities to read many Herculaneum papyri, which are still rolled up, thus enhancing our knowledge of ancient Greek literature and philosophy.

  3. Revealing letters in rolled Herculaneum papyri by X-ray phase-contrast imaging.

    PubMed

    Mocella, Vito; Brun, Emmanuel; Ferrero, Claudio; Delattre, Daniel

    2015-01-20

    Hundreds of papyrus rolls, buried by the eruption of Mount Vesuvius in 79 AD and belonging to the only library passed on from Antiquity, were discovered 260 years ago at Herculaneum. These carbonized papyri are extremely fragile and are inevitably damaged or destroyed in the process of trying to open them to read their contents. In recent years, new imaging techniques have been developed to read the texts without unwrapping the rolls. Until now, specialists have been unable to view the carbon-based ink of these papyri, even when they could penetrate the different layers of their spiral structure. Here for the first time, we show that X-ray phase-contrast tomography can reveal various letters hidden inside the precious papyri without unrolling them. This attempt opens up new opportunities to read many Herculaneum papyri, which are still rolled up, thus enhancing our knowledge of ancient Greek literature and philosophy.

  4. Big-data x-ray phase contrast imaging simulation challenges

    NASA Astrophysics Data System (ADS)

    Jimenez, Edward S.; Dagel, Amber L.

    2015-08-01

    This position paper describes a potential implementation of a large-scale grating-based X-ray Phase Contrast Imaging System (XPCI) simulation tool along with the associated challenges in its implementation. This work proposes an implementation based off of an implementation by Peterzol et. al. where each grating is treated as an object imaged in the field-of-view. Two main challenges exist; the first, is the required sampling and information management in object space due to the micron-scale periods of each grating propagating over significant distances. The second is maintaining algorithmic numerical stability for imaging systems relevant to industrial applications. We present preliminary results for a numerical stability study using a simplified algorithm that performs Talbot imaging in a big-data context

  5. Virtual unrolling and deciphering of Herculaneum papyri by X-ray phase-contrast tomography.

    PubMed

    Bukreeva, I; Mittone, A; Bravin, A; Festa, G; Alessandrelli, M; Coan, P; Formoso, V; Agostino, R G; Giocondo, M; Ciuchi, F; Fratini, M; Massimi, L; Lamarra, A; Andreani, C; Bartolino, R; Gigli, G; Ranocchia, G; Cedola, A

    2016-06-06

    A collection of more than 1800 carbonized papyri, discovered in the Roman 'Villa dei Papiri' at Herculaneum is the unique classical library survived from antiquity. These papyri were charred during 79 A.D. Vesuvius eruption, a circumstance which providentially preserved them until now. This magnificent collection contains an impressive amount of treatises by Greek philosophers and, especially, Philodemus of Gadara, an Epicurean thinker of 1st century BC. We read many portions of text hidden inside carbonized Herculaneum papyri using enhanced X-ray phase-contrast tomography non-destructive technique and a new set of numerical algorithms for 'virtual-unrolling'. Our success lies in revealing the largest portion of Greek text ever detected so far inside unopened scrolls, with unprecedented spatial resolution and contrast, all without damaging these precious historical manuscripts. Parts of text have been decoded and the 'voice' of the Epicurean philosopher Philodemus is brought back again after 2000 years from Herculaneum papyri.

  6. Phase Contrast X-Ray Synchrotron Microtomography for Virtual Dissection of the Head of Rhodnius prolixus

    NASA Astrophysics Data System (ADS)

    Sena, G.; Almeida, A. P.; Braz, D.; Nogueira, L. P.; Colaço, M. V.; Soares, J.; Cardoso, S. C.; Garcia, E. S.; Azambuja, P.; Gonzalez, M. S.; Mohammadi, S.; Tromba, G.; Barroso, R. C.

    2014-04-01

    Phase Contrast X-Ray Synchroton Microtomography is a non-destructive technique that allows the microanatomical investigations of Rhodnius prolixus, one of the most important insect vectors of Trypanosoma cruzi. In this work complete series of virtual thin sections through the heads of selected Rhodnius prolixus were obtained. The sections of the head were important to compare the difference in use the spatial resolution of 2 μm or 4.5 μm and to see anatomical details that couldn't be seen with other technique. Three different groups of Rhodnius prolixus were used. One group was fed with defibrinated rabbit blood and after 10 days was sacrificed, other group was sacrificed 4 days after feeding and the last group remained unfed. The results show some differences for each kind of groups and for the different resolutions.

  7. A continuous sampling scheme for edge illumination x-ray phase contrast imaging

    NASA Astrophysics Data System (ADS)

    Hagen, C. K.; Coan, P.; Bravin, A.; Olivo, A.; Diemoz, P. C.

    2015-08-01

    We discuss an alternative acquisition scheme for edge illumination (EI) x-ray phase contrast imaging based on a continuous scan of the object and compare its performance to that of a previously used scheme, which involved scanning the object in discrete steps rather than continuously. By simulating signals for both continuous and discrete methods under realistic experimental conditions, the effect of the spatial sampling rate is analysed with respect to metrics such as image contrast and accuracy of the retrieved phase shift. Experimental results confirm the theoretical predictions. Despite being limited to a specific example, the results indicate that continuous schemes present advantageous features compared to discrete ones. Not only can they be used to speed up the acquisition but they also prove superior in terms of accurate phase retrieval. The theory and experimental results provided in this study will guide the design of future EI experiments through the implementation of optimized acquisition schemes and sampling rates.

  8. Quantitative X-ray phase contrast waveguide imaging of bacterial endospores1

    PubMed Central

    Wilke, R. N.; Hoppert, M.; Krenkel, M.; Bartels, M.; Salditt, T.

    2015-01-01

    Quantitative waveguide-based X-ray phase contrast imaging has been carried out on the level of single, unstained, unsliced and freeze-dried bacterial cells of Bacillus thuringiensis and Bacillus subtilis using hard X-rays of 7.9 keV photon energy. The cells have been prepared in the metabolically dormant state of an endospore. The quantitative phase maps obtained by iterative phase retrieval using a modified hybrid input–output algorithm allow for mass and mass density determinations on the level of single individual endospores but include also large field of view investigations. Additionally, a direct reconstruction based on the contrast transfer function is investigated, and the two approaches are compared. Depending on the field of view and method, a resolution down to 65 nm was achieved at a maximum applied dose of below 5 × 105 Gy. Masses in the range of about ∼110–190 (20) fg for isolated endospores have been obtained. PMID:25844079

  9. X-ray Phase Contrast Allows Three Dimensional, Quantitative Imaging of Hydrogel Implants

    DOE PAGES

    Appel, Alyssa A.; Larson, Jeffrey C.; Jiang, Bin; ...

    2015-10-20

    Three dimensional imaging techniques are needed for the evaluation and assessment of biomaterials used for tissue engineering and drug delivery applications. Hydrogels are a particularly popular class of materials for medical applications but are difficult to image in tissue using most available imaging modalities. Imaging techniques based on X-ray Phase Contrast (XPC) have shown promise for tissue engineering applications due to their ability to provide image contrast based on multiple X-ray properties. In this manuscript we describe results using XPC to image a model hydrogel and soft tissue structure. Porous fibrin loaded poly(ethylene glycol) hydrogels were synthesized and implanted inmore » a rodent subcutaneous model. Samples were explanted and imaged with an analyzer-based XPC technique and processed and stained for histology for comparison. Both hydrogel and soft tissues structures could be identified in XPC images. Structure in skeletal muscle adjacent could be visualized and invading fibrovascular tissue could be quantified. In quantitative results, there were no differences between XPC and the gold-standard histological measurements. These results provide evidence of the significant potential of techniques based on XPC for 3D imaging of hydrogel structure and local tissue response.« less

  10. X-ray Phase Contrast Allows Three Dimensional, Quantitative Imaging of Hydrogel Implants

    SciTech Connect

    Appel, Alyssa A.; Larson, Jeffrey C.; Jiang, Bin; Zhong, Zhong; Anastasio, Mark A.; Brey, Eric M.

    2015-10-20

    Three dimensional imaging techniques are needed for the evaluation and assessment of biomaterials used for tissue engineering and drug delivery applications. Hydrogels are a particularly popular class of materials for medical applications but are difficult to image in tissue using most available imaging modalities. Imaging techniques based on X-ray Phase Contrast (XPC) have shown promise for tissue engineering applications due to their ability to provide image contrast based on multiple X-ray properties. In this manuscript we describe results using XPC to image a model hydrogel and soft tissue structure. Porous fibrin loaded poly(ethylene glycol) hydrogels were synthesized and implanted in a rodent subcutaneous model. Samples were explanted and imaged with an analyzer-based XPC technique and processed and stained for histology for comparison. Both hydrogel and soft tissues structures could be identified in XPC images. Structure in skeletal muscle adjacent could be visualized and invading fibrovascular tissue could be quantified. In quantitative results, there were no differences between XPC and the gold-standard histological measurements. These results provide evidence of the significant potential of techniques based on XPC for 3D imaging of hydrogel structure and local tissue response.

  11. Real-time X-ray Diffraction: Applications to Materials Characterization

    NASA Technical Reports Server (NTRS)

    Rosemeier, R. G.

    1984-01-01

    With the high speed growth of materials it becomes necessary to develop measuring systems which also have the capabilities of characterizing these materials at high speeds. One of the conventional techniques of characterizing materials was X-ray diffraction. Film, which is the oldest method of recording the X-ray diffraction phenomenon, is not quite adequate in most circumstances to record fast changing events. Even though conventional proportional counters and scintillation counters can provide the speed necessary to record these changing events, they lack the ability to provide image information which may be important in some types of experiment or production arrangements. A selected number of novel applications of using X-ray diffraction to characterize materials in real-time are discussed. Also, device characteristics of some X-ray intensifiers useful in instantaneous X-ray diffraction applications briefly presented. Real-time X-ray diffraction experiments with the incorporation of image X-ray intensification add a new dimension in the characterization of materials. The uses of real-time image intensification in laboratory and production arrangements are quite unlimited and their application depends more upon the ingenuity of the scientist or engineer.

  12. Phase-contrast and magnification radiography at diagnostic X-ray energies using a pseudo-microfocus X-ray source

    PubMed Central

    Robson, K J

    2014-01-01

    Objective: To investigate the use of conventional diagnostic X-ray tubes for applications in which specialist microfocus sources are normally required. Methods: A conventional diagnostic X-ray tube was used in conjunction with a range of apertures to investigate improvements in spatial resolution using a line-pairs test object. Phase-contrast effects were investigated by varying source-to-object and object-to-receptor distances using a 2-French catheter as a clinically realistic test object. Results: For magnification radiography using a computed radiography receptor and conventional X-ray tube with a 1-mm nominal focus size, the limiting spatial resolution was improved from 3.55 line-pairs per millimetre, for a conventional contact image, to 5.6 line-pairs per millimetre, for a ×2 magnified view with a 250-µm aperture. For inline phase-contrast radiography, phase contrast enhancement of a 2-French catheter was demonstrated, and the expected trends with variations in source-to-object and object-to-receptor distances were found. Images of a neonatal phantom demonstrated a subtle improvement in visibility of a superimposed 1-French catheter simulating a percutaneously inserted central catheter for no increase in patient radiation dose. Conclusion: Spatial resolution improvement and visible phase contrast can be produced in clinically relevant objects using a pseudo-microfocus geometry at X-ray energies in the normal diagnostic range, using conventional diagnostic X-ray tubes and image receptors. The disadvantages of the proposal are the large distances required to produce phase contrast and limitations imposed by the resulting tube loading. Advances in knowledge: It is possible to use conventional diagnostic X-ray equipment in applications that normally require microfocus X-ray sources. This presents some possibilities for clinical applications. PMID:24779409

  13. Quantitative hard x-ray phase contrast imaging of micropipes in SiC

    SciTech Connect

    Kohn, V. G.; Argunova, T. S.; Je, J. H.

    2013-12-15

    Peculiarities of quantitative hard x-ray phase contrast imaging of micropipes in SiC are discussed. The micropipe is assumed as a hollow cylinder with an elliptical cross section. The major and minor diameters can be restored using the least square fitting procedure by comparing the experimental data, i.e. the profile across the micropipe axis, with those calculated based on phase contrast theory. It is shown that one projection image gives an information which does not allow a complete determination of the elliptical cross section, if an orientation of micropipe is not known. Another problem is a weak accuracy in estimating the diameters, partly because of using pink synchrotron radiation, which is necessary because a monochromatic beam intensity is not sufficient to reveal the weak contrast from a very small object. The general problems of accuracy in estimating the two diameters using the least square procedure are discussed. Two experimental examples are considered to demonstrate small as well as modest accuracies in estimating the diameters.

  14. High sensitivity phase retrieval method in grating-based x-ray phase contrast imaging

    SciTech Connect

    Wu, Zhao; Gao, Kun; Chen, Jian; Wang, Dajiang; Wang, Shenghao; Chen, Heng; Bao, Yuan; Shao, Qigang; Wang, Zhili; Zhang, Kai; Zhu, Peiping; Wu, Ziyu

    2015-02-15

    Purpose: Grating-based x-ray phase contrast imaging is considered as one of the most promising techniques for future medical imaging. Many different methods have been developed to retrieve phase signal, among which the phase stepping (PS) method is widely used. However, further practical implementations are hindered, due to its complex scanning mode and high radiation dose. In contrast, the reverse projection (RP) method is a novel fast and low dose extraction approach. In this contribution, the authors present a quantitative analysis of the noise properties of the refraction signals retrieved by the two methods and compare their sensitivities. Methods: Using the error propagation formula, the authors analyze theoretically the signal-to-noise ratios (SNRs) of the refraction images retrieved by the two methods. Then, the sensitivities of the two extraction methods are compared under an identical exposure dose. Numerical experiments are performed to validate the theoretical results and provide some quantitative insight. Results: The SNRs of the two methods are both dependent on the system parameters, but in different ways. Comparison between their sensitivities reveals that for the refraction signal, the RP method possesses a higher sensitivity, especially in the case of high visibility and/or at the edge of the object. Conclusions: Compared with the PS method, the RP method has a superior sensitivity and provides refraction images with a higher SNR. Therefore, one can obtain highly sensitive refraction images in grating-based phase contrast imaging. This is very important for future preclinical and clinical implementations.

  15. Early Tumor Development Captured Through Nondestructive, High Resolution Differential Phase Contrast X-ray Imaging

    PubMed Central

    Beheshti, A.; Pinzer, B. R.; McDonald, J. T.; Stampanoni, M.; Hlatky, L.

    2014-01-01

    Although a considerable amount is known about molecular dysregulations in later stages of tumor progression, much less is known about the regulated processes supporting initial tumor growth. Insight into such processes can provide a fuller understanding of carcinogenesis, with implications for cancer treatment and risk assessment. Work from our laboratory suggests that organized substructure emerges during tumor formation. The goal here was to examine the feasibility of using state-of-the-art differential phase contrast X-ray imaging to investigate density differentials that evolve during early tumor development. To this end the beamline for TOmographic Microscopy and Coherent rAdiology experimenTs (TOMCAT) at the Swiss Light Source was used to examine the time-dependent assembly of substructure in developing tumors. Differential phase contrast (DPC) imaging based on grating interferometry as implemented with TOMCAT, offers sensitivity to density differentials within soft tissues and a unique combination of high resolution coupled with a large field of view that permits the accommodation of larger tissue sizes (1 cm in diameter), difficult with other imaging modalities. PMID:24125488

  16. High speed X-ray phase contrast imaging of energetic composites under dynamic compression

    NASA Astrophysics Data System (ADS)

    Parab, Niranjan D.; Roberts, Zane A.; Harr, Michael H.; Mares, Jesus O.; Casey, Alex D.; Gunduz, I. Emre; Hudspeth, Matthew; Claus, Benjamin; Sun, Tao; Fezzaa, Kamel; Son, Steven F.; Chen, Weinong W.

    2016-09-01

    Fracture of crystals and frictional heating are associated with the formation of "hot spots" (localized heating) in energetic composites such as polymer bonded explosives (PBXs). Traditional high speed optical imaging methods cannot be used to study the dynamic sub-surface deformation and the fracture behavior of such materials due to their opaque nature. In this study, high speed synchrotron X-ray experiments are conducted to visualize the in situ deformation and the fracture mechanisms in PBXs composed of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) crystals and hydroxyl-terminated polybutadiene binder doped with iron (III) oxide. A modified Kolsky bar apparatus was used to apply controlled dynamic compression on the PBX specimens, and a high speed synchrotron X-ray phase contrast imaging (PCI) setup was used to record the in situ deformation and failure in the specimens. The experiments show that synchrotron X-ray PCI provides a sufficient contrast between the HMX crystals and the doped binder, even at ultrafast recording rates. Under dynamic compression, most of the cracking in the crystals was observed to be due to the tensile stress generated by the diametral compression applied from the contacts between the crystals. Tensile stress driven cracking was also observed for some of the crystals due to the transverse deformation of the binder and superior bonding between the crystal and the binder. The obtained results are vital to develop improved understanding and to validate the macroscopic and mesoscopic numerical models for energetic composites so that eventually hot spot formation can be predicted.

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

    SciTech Connect

    Chou, Cheng-Ying; Anastasio, Mark A.

    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

  18. X-ray microscopy using two phase contrast imaging techniques: two dimensional grating interferometry and speckle tracking

    NASA Astrophysics Data System (ADS)

    Wang, Hongchang; Berujon, Sebastien; Pape, Ian; Sawhney, Kawal

    2013-10-01

    Two phase contrast imaging techniques, namely two dimensional grating interferometry and X-ray speckle tracking (XST), have been combined with the use of a Fresnel Zone Plate (FZP) for application to X-ray microscopy. Both techniques allows the phase shift introduced by a sample on a hard X-ray beam in two dimensions, to be recovered with a high sensitivity and low requirements on transverse and longitudinal coherence. Sub-micron phase imaging of carbon fibres was achieved using the two methods thanks to the high magnification ratio of the FZP. Advantages, drawbacks and differences between these two techniques for X-ray microscopy are discussed.

  19. Improving visibility of X-ray phase-contrast imaging with Wiener filtering.

    PubMed

    Gong, Shaorun; Gao, Feng; Zhou, Zhongxing

    2010-01-01

    To investigate the degrading effects of the physical parameters on the in-line X-ray phase-contrast imaging (XPCi), a simulation tool based on the Fresnel/Kirchhoff diffraction integral was firstly developed with comprehensively considering effects of the source-to-sample (S-S) and sample-to-detector (S-D) distances, the practical characteristics of a polychromatic and finite size source, the point spread function (PSF) of the fluorescent screen and the spatial resolution of the detector on the theoretical phase-contrast pattern. By a comparison between the simulative profile and the experimental one under the commonly-used parameters, an acceptable consistency has been demonstrated in despite of the deviation between the theoretically-predicted contrast (0.188) and the original experimental one (0.12). From the simulations, it is apparently observed that the fine interference pattern has been severely degraded by the finite spatial resolution, and will inevitably be further deteriorated by the system noise in practice. Since the image quality of the X-ray phase-contrast imaging is strongly dependent on the physical parameters of the system, a model-based deblurring procedure to upgrade the image visibility is preferably desired. As a simple restoration way, a Wiener filter was then introduced to offer an optimal tradeoff between the contrast preservation and the noise suppression. Finally, to minimize the deviation resulting from the finite spatial resolution, one-dimensional interpolation was performed by positioning the set square at a tiny angle to the vertical direction. The result after the Wiener-filtering-based deblurring has shown a considerably improved profile visibility: the processed experimental contrast (0.156) increased by 30% as compared to the original one (0.12) in company with the increase in the signal-to-noise ratio (SNR) by 0.9dB. With the trend of the post-filtered experimental contrast to the theoretical one, it could be motivated that

  20. Remote real time x-ray examination of fuel elements in a hot cell environment

    SciTech Connect

    Yapuncich, F.L.

    1993-03-01

    This report discusses the Remote Real Time X-ray System which will allow for detailed examination of fuel elements. This task will be accomplished in a highly radioactive hot cell environment. Two remote handling systems win be utilized at the examination station. One handling system will transfer the fuel element to and from the shielded x-ray system. A second handling system will allow for vertical and rotational inspection of the fuel elements. The process win include removing a single nuclear fuel element from a element fabrication magazine(EFM), positioning the fuel element within the shielding envelope of the x-ray system and transferring the fuel element from the station manipulator to the x-ray system manipulator, performing the x-ray inspection, and then transferring the fuel element to either the element storage magazine(ESM) or a reject bin.

  1. Remote real time x-ray examination of fuel elements in a hot cell environment

    SciTech Connect

    Yapuncich, F.L.

    1993-01-01

    This report discusses the Remote Real Time X-ray System which will allow for detailed examination of fuel elements. This task will be accomplished in a highly radioactive hot cell environment. Two remote handling systems win be utilized at the examination station. One handling system will transfer the fuel element to and from the shielded x-ray system. A second handling system will allow for vertical and rotational inspection of the fuel elements. The process win include removing a single nuclear fuel element from a element fabrication magazine(EFM), positioning the fuel element within the shielding envelope of the x-ray system and transferring the fuel element from the station manipulator to the x-ray system manipulator, performing the x-ray inspection, and then transferring the fuel element to either the element storage magazine(ESM) or a reject bin.

  2. X-ray phase-contrast tomosynthesis of a human ex vivo breast slice with an inverse Compton x-ray source

    NASA Astrophysics Data System (ADS)

    Eggl, E.; Schleede, S.; Bech, M.; Achterhold, K.; Grandl, S.; Sztrókay, A.; Hellerhoff, K.; Mayr, D.; Loewen, R.; Ruth, R. D.; Reiser, M. F.; Pfeiffer, F.

    2016-12-01

    While the performance of conventional x-ray tube sources often suffers from the broad polychromatic spectrum, synchrotrons that could provide highly brilliant x-rays are restricted to large research facilities and impose high investment and maintenance costs. Lately, a new type of compact synchrotron sources has been investigated. These compact light sources (CLS) based on inverse Compton scattering provide quasi-monochromatic hard x-rays. The flux and brilliance yielded by a CLS currently lie between x-ray tube sources and third-generation synchrotrons. The relatively large partially coherent x-ray beam is well suited for the investigation of preclinical applications of grating-based phase-contrast and dark-field imaging. Here we present the first grating-based multimodal tomosynthesis images of a human breast slice acquired at a CLS to investigate the possibilities of improved breast cancer diagnostics.

  3. Subnanoradian X-ray phase-contrast imaging using a far-field interferometer of nanometric phase gratings

    PubMed Central

    Wen, Han; Gomella, Andrew A.; Patel, Ajay; Lynch, Susanna K.; Morgan, Nicole Y.; Anderson, Stasia A.; Bennett, Eric E.; Xiao, Xianghui; Liu, Chian; Wolfe, Douglas E.

    2013-01-01

    Hard X-ray phase-contrast imaging characterizes the electron density distribution in an object without the need for radiation absorption. The power of phase contrast to resolve subtle changes, such as those in soft tissue structures, lies in its ability to detect minute refractive bending of X-rays. Here we report a far-field, two-arm interferometer based on the new nanometric phase gratings, which can detect X-ray refraction with subnanoradian sensitivity, and at the same time overcomes the fundamental limitation of ultra-narrow bandwidths (Δλ/λ~10−4) of the current, most sensitive methods based on crystal interferometers. On a 1.5% bandwidth synchrotron source, we demonstrate clear visualization of blood vessels in unstained mouse organs in simple projection views, with over an order-of-magnitude higher phase contrast than current near-field grating interferometers. PMID:24189696

  4. Subnanoradian X-ray phase-contrast imaging using a far-field interferometer of nanometric phase gratings.

    PubMed

    Wen, Han; Gomella, Andrew A; Patel, Ajay; Lynch, Susanna K; Morgan, Nicole Y; Anderson, Stasia A; Bennett, Eric E; Xiao, Xianghui; Liu, Chian; Wolfe, Douglas E

    2013-01-01

    Hard X-ray phase-contrast imaging characterizes the electron density distribution in an object without the need for radiation absorption. The power of phase contrast to resolve subtle changes, such as those in soft tissue structures, lies in its ability to detect minute refractive bending of X-rays. Here we report a far-field, two-arm interferometer based on the new nanometric phase gratings, which can detect X-ray refraction with subnanoradian sensitivity, and at the same time overcomes the fundamental limitation of ultra-narrow bandwidths (Δλ/λ~10⁻⁴) of the current, most sensitive methods based on crystal interferometers. On a 1.5% bandwidth synchrotron source, we demonstrate clear visualization of blood vessels in unstained mouse organs in simple projection views, with over an order-of-magnitude higher phase contrast than current near-field grating interferometers.

  5. Fast X-ray micro-CT for real-time 4D observation

    NASA Astrophysics Data System (ADS)

    Takano, H.; Yoshida, K.; Tsuji, T.; Koyama, T.; Tsusaka, Y.; Kagoshima, Y.

    2009-09-01

    Fast X-ray computed tomography (CT) system with sub-second order measurement for single CT acquisition has been developed. The system, consisting of a high-speed sample rotation stage and a high-speed X-ray camera, is constructed at synchrotron radiation beamline in order to utilize fully intense X-rays. A time-resolving CT movie (i.e. 4D CT) can be available by operating the fast CT system continuously. Real-time observation of water absorbing process of super-absorbent polymer (SAP) has been successfully performed with the 4D CT operation.

  6. Analyzer-based x-ray phase-contrast microscopy combining channel-cut and asymmetrically cut crystals

    SciTech Connect

    Hoennicke, M. G.; Cusatis, C.

    2007-11-15

    An analyzer-based x-ray phase-contrast microscopy (ABM) setup combining a standard analyzer-based x-ray phase-contrast imaging (ABI) setup [nondispersive 4-crystal setup (Bonse-Hart setup)] and diffraction by asymmetrically cut crystals is presented here. An attenuation-contrast microscopy setup with conventional x-ray source and asymmetrically cut crystals is first analyzed. Edge-enhanced effects attributed to phase jumps or refraction/total external reflection on the fiber borders were detected. However, the long exposure times and the possibility to achieve high contrast microscopies by using extremely low attenuation-contrast samples motivated us to assemble the ABM setup using a synchrotron source. This setup was found to be useful for low contrast attenuation samples due to the low exposure time, high contrast, and spatial resolution found. Moreover, thanks to the combination with the nondispersive ABI setup, the diffraction-enhanced x-ray imaging algorithm could be applied.

  7. Investigating biofilm structure using x-ray microtomography and gratings-based phase contrast

    SciTech Connect

    Miller, Erin A.; Xiao, Xianghui; Miller, Micah D.; Keller, Paul E.; White, Timothy A.; Marshall, Matthew J.

    2012-10-17

    Direct examination of natural and engineered environments has revealed that the majority of microorganisms in these systems live in structured communities termed biofilms. To gain a better understanding for how biofilms function and interact with their local environment, fundamental capabilities for enhanced visualization, compositional analysis, and functional characterization of biofilms are needed. For pore-scale and community-scale analysis (100’s of nm to 10’s of microns), a variety of surface tools are available. However, understanding biofilm structure in complex three-dimensional (3-D) environments is considerably more difficult. X-ray microtomography can reveal a biofilm’s internal structure, but the obtaining sufficient contrast to image low-Z biological material against a higher-Z substrate makes detecting biofilms difficult. Here we present results imaging Shewanella oneidensis biofilms on a Hollow-fiber Membrane Biofilm Reactor (HfMBR), using the x-ray microtomography system at sector 2-BM of the Advanced Photon Source (APS), at energies ranging from 13-15.4 keV and pixel sizes of 0.7 and 1.3 μm/pixel. We examine the use of osmium (Os) as a contrast agent to enhance biofilm visibility and demonstrate that staining improves imaging of hydrated biofilms. We also present results using a Talbot interferometer to provide phase and scatter contrast information in addition to absorption. Talbot interferometry allows imaging of unstained hydrated biofilms with phase contrast, while absorption contrast primarily highlights edges and scatter contrast provides little information. However, the gratings used here limit the spatial resolution to no finer than 2 μm, which hinders the ability to detect small features. Future studies at higher resolution or higher Talbot order for greater sensitivity to density variations may improve imaging.

  8. Talbot phase-contrast x-ray imaging for the small joints of the hand

    NASA Astrophysics Data System (ADS)

    Stutman, Dan; Beck, Thomas J.; Carrino, John A.; Bingham, Clifton O.

    2011-09-01

    A high-resolution radiographic method for soft tissues in the small joints of the hand would aid in the study and treatment of rheumatoid arthritis (RA) and osteoarthritis (OA), which often attacks these joints. Of particular interest would be imaging with <100 µm resolution the joint cartilage, whose integrity is a main indicator of disease. Differential phase-contrast (DPC) or refraction-based x-ray imaging with Talbot grating interferometers could provide such a method, since it enhances soft tissue contrast and can be implemented with conventional x-ray tubes. A numerical joint phantom was first developed to assess the angular sensitivity and spectrum needed for a hand DPC system. The model predicts that, due to quite similar refraction indexes for joint soft tissues, the refraction effects are very small, requiring high angular resolution. To compare our model to experiment we built a high-resolution bench-top interferometer using 10 µm period gratings, a W anode tube and a CCD-based detector. Imaging experiments on animal cartilage and on a human finger support the model predictions. For instance, the estimated difference between the index of refraction of cartilage and water is of only several percent at ~25 keV mean energy, comparable to that between the linear attenuation coefficients. The potential advantage of DPC imaging thus comes mainly from the edge enhancement at the soft tissue interfaces. Experiments using a cadaveric human finger are also qualitatively consistent with the joint model, showing that refraction contrast is dominated by tendon embedded in muscle, with the cartilage layer difficult to observe in our conditions. Nevertheless, the model predicts that a DPC radiographic system for the small hand joints of the hand could be feasible using a low energy quasi-monochromatic source, such as a K-edge filtered Rh or Mo tube, in conjunction with a ~2 m long 'symmetric' interferometer operated in a high Talbot order.

  9. Investigating biofilm structure using x-ray microtomography and gratings-based phase contrast

    NASA Astrophysics Data System (ADS)

    Miller, Erin A.; Xiao, Xianghui; Miller, Micah; Keller, Paul; White, Timothy A.; Marshall, Matthew

    2012-10-01

    Direct examination of natural and engineered environments has revealed that the majority of microorganisms in these systems live in structured communities termed biofilms. To gain a better understanding for how biofilms function and interact with their local environment, fundamental capabilities for enhanced visualization, compositional analysis, and functional characterization of biofilms are needed. For pore-scale and community-scale analysis (100's of nm to 10's of microns), a variety of surface tools are available. However, understanding biofilm structure in complex three-dimensional (3-D) environments is considerably more difficult. X-ray microtomography can reveal a biofilm's internal structure, but obtaining sufficient contrast to image low atomic number (Z) biological material against a higher-Z substrate makes detecting biofilms difficult. Here we present results imaging Shewanella oneidensis biofilms on a Hollow-fiber Membrane Biofilm Reactor (HfMBR), using the x-ray microtomography system at sector 2-BM of the Advanced Photon Source (APS), at energies ranging from 12.9-15.4 keV and pixel sizes of 0.7 and 1.3 μm/pixel. We examine the use of osmium (Os) as a contrast agent to enhance biofilm visibility and demonstrate that staining improves imaging of hydrated biofilms. We also present results using a Talbot interferometer to provide phase and scatter contrast information in addition to absorption. Talbot interferometry allows imaging of unstained hydrated biofilms with phase contrast, while absorption contrast primarily highlights edges and scatter contrast provides little information. However, the gratings used here limit the spatial resolution to no finer than 2 μm, which hinders the ability to detect small features. Future studies at higher resolution or higher Talbot order for greater sensitivity to density variations may improve imaging.

  10. Influence of imaging geometry on noise texture in quantitative in-line X-ray phase-contrast imaging.

    PubMed

    Chou, Cheng-Ying; Anastasio, Mark A

    2009-08-17

    Quantitative in-line X-ray phase-contrast imaging methods seek to reconstruct separate images that depict an object's projected absorption and refractive properties. An understanding of the statistical properties of the reconstructed images can facilitate the identification of optimal imaging parameters for specific diagnostic tasks. However, the statistical properties of quantitative X-ray phase-contrast imaging remain largely unexplored. In this work, we derive analytic expressions that describe the second-order statistics of the reconstructed absorption and phase images. Concepts from statistical decision theory are applied to demonstrate how the statistical properties of images corresponding to distinct imaging geometries can influence signal detectability.

  11. Small-animal microangiography using phase-contrast X-ray imaging and gas as contrast agent

    NASA Astrophysics Data System (ADS)

    Lundström, Ulf; Larsson, Daniel H.; Westermark, Ulrica K.; Burvall, Anna; Hertz, Hans M.

    2014-03-01

    We use propagation-based phase-contrast X-ray imaging with gas as contrast agent to visualize the microvasculature in small animals like mice and rats. The radiation dose required for absorption X-ray imaging is proportional to the minus fourth power of the structure size to be detected. This makes small vessels impossible to image at reasonable radiation doses using the absorption of conventional iodinated contrast agents. Propagation-based phase contrast gives enhanced contrast for high spatial frequencies by moving the detector away from the sample to let phase variations in the transmitted X-rays develop into intensity variations at the detector. Blood vessels are normally difficult to observe in phase contrast even with iodinated contrast agents as the density difference between blood and most tissues is relatively small. By injecting gas into the blood stream this density difference can be greatly enhanced giving strong phase contrast. One possible gas to use is carbon dioxide, which is a clinically accepted X-ray contrast agent. The gas is injected into the blood stream of patients to temporarily displace the blood in a region and thereby reduce the X-ray absorption in the blood vessels. We have shown that this method can be used to image blood vessels down to 8 μm in diameter in mouse ears. The low dose requirements of this method indicate a potential for live small-animal imaging and longitudinal studies of angiogenesis.

  12. Phase contrast medical imaging with compact X-ray sources at the Munich-Centre for Advance Photonics (MAP)

    NASA Astrophysics Data System (ADS)

    Coan, P.; Gruener, F.; Glaser, C.; Schneider, T.; Bravin, A.; Reiser, M.; Habs, D.

    2009-09-01

    In this paper, the excellence cluster "Munich-Centre for Advance Photonics" (MAP) is presented. One of the aims of the project is the development of innovative X-ray-based diagnostics imaging techniques to be implemented at an ultra-compact high-energy and high-brilliance X-ray source. The basis of the project and the developments towards the clinical application of phase contrast imaging applied to mammography and cartilage studies will be presented and discussed.

  13. Volumetric characterization of human patellar cartilage matrix on phase contrast x-ray computed tomography

    NASA Astrophysics Data System (ADS)

    Abidin, Anas Z.; Nagarajan, Mahesh B.; Checefsky, Walter A.; Coan, Paola; Diemoz, Paul C.; Hobbs, Susan K.; Huber, Markus B.; Wismüller, Axel

    2015-03-01

    Phase contrast X-ray computed tomography (PCI-CT) has recently emerged as a novel imaging technique that allows visualization of cartilage soft tissue, subsequent examination of chondrocyte patterns, and their correlation to osteoarthritis. Previous studies have shown that 2D texture features are effective at distinguishing between healthy and osteoarthritic regions of interest annotated in the radial zone of cartilage matrix on PCI-CT images. In this study, we further extend the texture analysis to 3D and investigate the ability of volumetric texture features at characterizing chondrocyte patterns in the cartilage matrix for purposes of classification. Here, we extracted volumetric texture features derived from Minkowski Functionals and gray-level co-occurrence matrices (GLCM) from 496 volumes of interest (VOI) annotated on PCI-CT images of human patellar cartilage specimens. The extracted features were then used in a machine-learning task involving support vector regression to classify ROIs as healthy or osteoarthritic. Classification performance was evaluated using the area under the receiver operating characteristic (ROC) curve (AUC). The best classification performance was observed with GLCM features correlation (AUC = 0.83 +/- 0.06) and homogeneity (AUC = 0.82 +/- 0.07), which significantly outperformed all Minkowski Functionals (p < 0.05). These results suggest that such quantitative analysis of chondrocyte patterns in human patellar cartilage matrix involving GLCM-derived statistical features can distinguish between healthy and osteoarthritic tissue with high accuracy.

  14. Virtual unrolling and deciphering of Herculaneum papyri by X-ray phase-contrast tomography

    PubMed Central

    Bukreeva, I.; Mittone, A.; Bravin, A.; Festa, G.; Alessandrelli, M.; Coan, P.; Formoso, V.; Agostino, R. G.; Giocondo, M.; Ciuchi, F.; Fratini, M.; Massimi, L.; Lamarra, A.; Andreani, C.; Bartolino, R.; Gigli, G.; Ranocchia, G.; Cedola, A.

    2016-01-01

    A collection of more than 1800 carbonized papyri, discovered in the Roman ‘Villa dei Papiri’ at Herculaneum is the unique classical library survived from antiquity. These papyri were charred during 79 A.D. Vesuvius eruption, a circumstance which providentially preserved them until now. This magnificent collection contains an impressive amount of treatises by Greek philosophers and, especially, Philodemus of Gadara, an Epicurean thinker of 1st century BC. We read many portions of text hidden inside carbonized Herculaneum papyri using enhanced X-ray phase-contrast tomography non-destructive technique and a new set of numerical algorithms for ‘virtual-unrolling’. Our success lies in revealing the largest portion of Greek text ever detected so far inside unopened scrolls, with unprecedented spatial resolution and contrast, all without damaging these precious historical manuscripts. Parts of text have been decoded and the ‘voice’ of the Epicurean philosopher Philodemus is brought back again after 2000 years from Herculaneum papyri. PMID:27265417

  15. Large field-of-view tiled grating structures for X-ray phase-contrast imaging

    NASA Astrophysics Data System (ADS)

    Schröter, Tobias J.; Koch, Frieder J.; Meyer, Pascal; Kunka, Danays; Meiser, Jan; Willer, Konstantin; Gromann, Lukas; De Marco, Fabio; Herzen, Julia; Noel, Peter; Yaroshenko, Andre; Hofmann, Andreas; Pfeiffer, Franz; Mohr, Jürgen

    2017-01-01

    X-ray grating-based interferometry promises unique new diagnostic possibilities in medical imaging and materials analysis. To transfer this method from scientific laboratories or small-animal applications to clinical radiography applications, compact setups with a large field of view (FoV) are required. Currently the FoV is limited by the grating area, which is restricted due to the complex manufacturing process. One possibility to increase the FoV is tiling individual grating tiles to create one large area grating mounted on a carrier substrate. We investigate theoretically the accuracy needed for a tiling process in all degrees of freedom by applying a simulation approach. We show how the resulting precision requirements can be met using a custom-built frame for exact positioning. Precise alignment is achieved by comparing the fringe patterns of two neighboring grating tiles in a grating interferometer. With this method, the FoV can be extended to practically any desired length in one dimension. First results of a phase-contrast scanning setup with a full FoV of 384 mm × 24 mm show the suitability of this method.

  16. Phase-contrast X-ray microtomography links Cretaceous seeds with Gnetales and Bennettitales.

    PubMed

    Friis, Else Marie; Crane, Peter R; Pedersen, Kaj Raunsgaard; Bengtson, Stefan; Donoghue, Philip C J; Grimm, Guido W; Stampanoni, Marco

    2007-11-22

    Over the past 25 years the discovery and study of Cretaceous plant mesofossils has yielded diverse and exquisitely preserved fossil flowers that have revolutionized our knowledge of early angiosperms, but remains of other seed plants in the same mesofossil assemblages have so far received little attention. These fossils, typically only a few millimetres long, have often been charred in natural fires and preserve both three-dimensional morphology and cellular detail. Here we use phase-contrast-enhanced synchrotron-radiation X-ray tomographic microscopy to clarify the structure of small charcoalified gymnosperm seeds from the Early Cretaceous of Portugal and North America. The new information links these seeds to Gnetales (including Erdtmanithecales, a putatively closely related fossil group), and to Bennettitales--important extinct Mesozoic seed plants with cycad-like leaves and flower-like reproductive structures. The results suggest that the distinctive seed architecture of Gnetales, Erdtmanithecales and Bennettitales defines a clade containing these taxa. This has significant consequences for hypotheses of seed plant phylogeny by providing support for key elements of the controversial anthophyte hypothesis, which links angiosperms, Bennettitales and Gnetales.

  17. Laboratory-based x-ray phase-contrast tomography enables 3D virtual histology

    NASA Astrophysics Data System (ADS)

    Töpperwien, Mareike; Krenkel, Martin; Quade, Felix; Salditt, Tim

    2016-09-01

    Due to the large penetration depth and small wavelength hard x-rays offer a unique potential for 3D biomedical and biological imaging, combining capabilities of high resolution and large sample volume. However, in classical absorption-based computed tomography, soft tissue only shows a weak contrast, limiting the actual resolution. With the advent of phase-contrast methods, the much stronger phase shift induced by the sample can now be exploited. For high resolution, free space propagation behind the sample is particularly well suited to make the phase shift visible. Contrast formation is based on the self-interference of the transmitted beam, resulting in object-induced intensity modulations in the detector plane. As this method requires a sufficiently high degree of spatial coherence, it was since long perceived as a synchrotron-based imaging technique. In this contribution we show that by combination of high brightness liquid-metal jet microfocus sources and suitable sample preparation techniques, as well as optimized geometry, detection and phase retrieval, excellent three-dimensional image quality can be obtained, revealing the anatomy of a cobweb spider in high detail. This opens up new opportunities for 3D virtual histology of small organisms. Importantly, the image quality is finally augmented to a level accessible to automatic 3D segmentation.

  18. X-ray phase contrast imaging of the breast: Analysis of tissue simulating materials

    SciTech Connect

    Vedantham, Srinivasan; Karellas, Andrew

    2013-04-15

    Purpose: Phase contrast imaging, particularly of the breast, is being actively investigated. The purpose of this work is to investigate the x-ray phase contrast properties of breast tissues and commonly used breast tissue substitutes or phantom materials with an aim of determining the phantom materials best representative of breast tissues. Methods: Elemental compositions of breast tissues including adipose, fibroglandular, and skin were used to determine the refractive index, n= 1 -{delta}+i {beta}. The real part of the refractive index, specifically the refractive index decrement ({delta}), over the energy range of 5-50 keV were determined using XOP software (version 2.3, European Synchrotron Radiation Facility, France). Calcium oxalate and calcium hydroxyapatite were considered to represent the material compositions of microcalcifications in vivo. Nineteen tissue substitutes were considered as possible candidates to represent adipose tissue, fibroglandular tissue and skin, and four phantom materials were considered as possible candidates to represent microcalcifications. For each material, either the molecular formula, if available, or the elemental composition based on weight fraction, was used to determine {delta}. At each x-ray photon energy, the absolute percent difference in {delta} between the breast tissue and the substitute material was determined, from which three candidates were selected. From these candidate tissue substitutes, the material that minimized the absolute percent difference in linear attenuation coefficient {mu}, and hence {beta}, was considered to be best representative of that breast tissue. Results: Over the energy range of 5-50 keV, while the {delta} of CB3 and fibroglandular tissue-equivalent material were within 1% of that of fibroglandular tissue, the {mu} of fibroglandular tissue-equivalent material better approximated the fibroglandular tissue. While the {delta} of BR10 and adipose tissue-equivalent material were within 1% of

  19. X-ray phase contrast imaging of the breast: Analysis of tissue simulating materials1

    PubMed Central

    Vedantham, Srinivasan; Karellas, Andrew

    2013-01-01

    Purpose: Phase contrast imaging, particularly of the breast, is being actively investigated. The purpose of this work is to investigate the x-ray phase contrast properties of breast tissues and commonly used breast tissue substitutes or phantom materials with an aim of determining the phantom materials best representative of breast tissues. Methods: Elemental compositions of breast tissues including adipose, fibroglandular, and skin were used to determine the refractive index, n = 1 − δ + i β. The real part of the refractive index, specifically the refractive index decrement (δ), over the energy range of 5–50 keV were determined using XOP software (version 2.3, European Synchrotron Radiation Facility, France). Calcium oxalate and calcium hydroxyapatite were considered to represent the material compositions of microcalcifications in vivo. Nineteen tissue substitutes were considered as possible candidates to represent adipose tissue, fibroglandular tissue and skin, and four phantom materials were considered as possible candidates to represent microcalcifications. For each material, either the molecular formula, if available, or the elemental composition based on weight fraction, was used to determine δ. At each x-ray photon energy, the absolute percent difference in δ between the breast tissue and the substitute material was determined, from which three candidates were selected. From these candidate tissue substitutes, the material that minimized the absolute percent difference in linear attenuation coefficient μ, and hence β, was considered to be best representative of that breast tissue. Results: Over the energy range of 5–50 keV, while the δ of CB3 and fibroglandular tissue-equivalent material were within 1% of that of fibroglandular tissue, the μ of fibroglandular tissue-equivalent material better approximated the fibroglandular tissue. While the δ of BR10 and adipose tissue-equivalent material were within 1% of that of adipose tissue, the tissue

  20. Experimental Realisation of High-sensitivity Laboratory X-ray Grating-based Phase-contrast Computed Tomography

    NASA Astrophysics Data System (ADS)

    Birnbacher, Lorenz; Willner, Marian; Velroyen, Astrid; Marschner, Mathias; Hipp, Alexander; Meiser, Jan; Koch, Frieder; Schröter, Tobias; Kunka, Danays; Mohr, Jürgen; Pfeiffer, Franz; Herzen, Julia

    2016-04-01

    The possibility to perform high-sensitivity X-ray phase-contrast imaging with laboratory grating-based phase-contrast computed tomography (gbPC-CT) setups is of great interest for a broad range of high-resolution biomedical applications. However, achieving high sensitivity with laboratory gbPC-CT setups still poses a challenge because several factors such as the reduced flux, the polychromaticity of the spectrum, and the limited coherence of the X-ray source reduce the performance of laboratory gbPC-CT in comparison to gbPC-CT at synchrotron facilities. In this work, we present our laboratory X-ray Talbot-Lau interferometry setup operating at 40 kVp and describe how we achieve the high sensitivity yet unrivalled by any other laboratory X-ray phase-contrast technique. We provide the angular sensitivity expressed via the minimum resolvable refraction angle both in theory and experiment, and compare our data with other differential phase-contrast setups. Furthermore, we show that the good stability of our high-sensitivity setup allows for tomographic scans, by which even the electron density can be retrieved quantitatively as has been demonstrated in several preclinical studies.

  1. In-line phase-contrast stereoscopic X-ray imaging for radiological purposes: An initial experimental study

    NASA Astrophysics Data System (ADS)

    Siegbahn, E. A.; Coan, P.; Zhou, S.-A.; Bravin, A.; Brahme, A.

    2011-02-01

    We report results from a pilot study in which the in-line propagation-based phase-contrast imaging technique is combined with the stereoscopic method. Two phantoms were imaged at several sample-detector distances using monochromatic, 30 keV, X-rays. High contrast- and spatial-resolution phase-contrast stereoscopic pairs of X-ray images were constructed using the anaglyph approach and a vivid stereoscopic effect was demonstrated. On the other hand, images of the same phantoms obtained with a shorter sample-to-detector distance, but otherwise the same experimental conditions (i.e. the same X-ray energy and absorbed radiation dose), corresponding to the conventional attenuation-based imaging mode, hardly revealed stereoscopic effects because of the lower image contrast produced. These results have confirmed our hypothesis that stereoscopic X-ray images of samples with objects composed of low-atomic-number elements are considerably improved if phase-contrast imaging is used. It is our belief that the high-resolution phase-contrast stereoscopic method will be a valuable new medical imaging tool for radiologists and that it will be of help to enhance the diagnostic capability in the examination of patients in future clinical practice, even though further efforts will be needed to optimize the system performance.

  2. Experimental Realisation of High-sensitivity Laboratory X-ray Grating-based Phase-contrast Computed Tomography

    PubMed Central

    Birnbacher, Lorenz; Willner, Marian; Velroyen, Astrid; Marschner, Mathias; Hipp, Alexander; Meiser, Jan; Koch, Frieder; Schröter, Tobias; Kunka, Danays; Mohr, Jürgen; Pfeiffer, Franz; Herzen, Julia

    2016-01-01

    The possibility to perform high-sensitivity X-ray phase-contrast imaging with laboratory grating-based phase-contrast computed tomography (gbPC-CT) setups is of great interest for a broad range of high-resolution biomedical applications. However, achieving high sensitivity with laboratory gbPC-CT setups still poses a challenge because several factors such as the reduced flux, the polychromaticity of the spectrum, and the limited coherence of the X-ray source reduce the performance of laboratory gbPC-CT in comparison to gbPC-CT at synchrotron facilities. In this work, we present our laboratory X-ray Talbot-Lau interferometry setup operating at 40 kVp and describe how we achieve the high sensitivity yet unrivalled by any other laboratory X-ray phase-contrast technique. We provide the angular sensitivity expressed via the minimum resolvable refraction angle both in theory and experiment, and compare our data with other differential phase-contrast setups. Furthermore, we show that the good stability of our high-sensitivity setup allows for tomographic scans, by which even the electron density can be retrieved quantitatively as has been demonstrated in several preclinical studies. PMID:27040492

  3. Characterization of an x-ray phase contrast imaging system based on the miniature synchrotron MIRRORCLE-6X

    SciTech Connect

    Heekeren, Joop van; Kostenko, Alexander; Hanashima, Takayasu; Yamada, Hironari; Stallinga, Sjoerd; Offerman, S. Erik; Vliet, Lucas J. van

    2011-09-15

    Purpose: The implementation of in-line x-ray phase contrast imaging (PCI) for soft-tissue patient imaging is hampered by the lack of a bright and spatially coherent x-ray source that fits into the hospital environment. This article provides a quantitative characterization of the phase-contrast enhancement of a PCI system based on the miniature synchrotron technology MIRRORCLE-6X. Methods: The phase-contrast effect was measured using an edge response of a plexiglass plate as a function of the incident angle of radiation. We have developed a comprehensive x-ray propagation model based on the system's components, properties, and geometry in order to interpret the measurement data. Monte-Carlo simulations are used to estimate the system's spectral properties and resolution. Results: The measured ratio of the detected phase-contrast to the absorption contrast is currently in the range 100% to 200%. Experiments show that with the current implementation of the MIRRORCLE-6X, a target smaller than 30-40 {mu}m does not lead to a larger phase-contrast. The reason for this is that the fraction of x-rays produced by the material (carbon filament and glue) that is used for mounting the target in the electron beam is more than 25% of the total amount of x-rays produced. This increases the apparent source size. The measured phase-contrast is at maximum two times larger than the absorption contrast with the current set-up. Conclusions: Calculations based on our model of the present imaging system predict that the phase-contrast can be up to an order of magnitude larger than the absorption contrast in case the materials used for mounting the target in the electron beam do not (or hardly) produce x-rays. The methods described in this paper provide vital feedback for guiding future modifications to the design of the x-ray target of MIRRORCLE-type system and configuration of the in-line PCI systems in general.

  4. Robustness of phase retrieval methods in x-ray phase contrast imaging: A comparison

    SciTech Connect

    Yan, Aimin; Wu, Xizeng; Liu, Hong

    2011-09-15

    Purpose: The robustness of the phase retrieval methods is of critical importance for limiting and reducing radiation doses involved in x-ray phase contrast imaging. This work is to compare the robustness of two phase retrieval methods by analyzing the phase maps retrieved from the experimental images of a phantom. Methods: Two phase retrieval methods were compared. One method is based on the transport of intensity equation (TIE) for phase contrast projections, and the TIE-based method is the most commonly used method for phase retrieval in the literature. The other is the recently developed attenuation-partition based (AP-based) phase retrieval method. The authors applied these two methods to experimental projection images of an air-bubble wrap phantom for retrieving the phase map of the bubble wrap. The retrieved phase maps obtained by using the two methods are compared. Results: In the wrap's phase map retrieved by using the TIE-based method, no bubble is recognizable, hence, this method failed completely for phase retrieval from these bubble wrap images. Even with the help of the Tikhonov regularization, the bubbles are still hardly visible and buried in the cluttered background in the retrieved phase map. The retrieved phase values with this method are grossly erroneous. In contrast, in the wrap's phase map retrieved by using the AP-based method, the bubbles are clearly recovered. The retrieved phase values with the AP-based method are reasonably close to the estimate based on the thickness-based measurement. The authors traced these stark performance differences of the two methods to their different techniques employed to deal with the singularity problem involved in the phase retrievals. Conclusions: This comparison shows that the conventional TIE-based phase retrieval method, regardless if Tikhonov regularization is used or not, is unstable against the noise in the wrap's projection images, while the AP-based phase retrieval method is shown in these

  5. Zernike-type phase contrast X-ray microscopy at 4 keV photon energy with 60 nm resolution

    NASA Astrophysics Data System (ADS)

    Neuhäusler, Ulrich; Schneider, Gerd

    2004-05-01

    X-ray microscopy in the multi-keV photon energy range offers unique possibilities to study thick dense samples with high spatial resolution. When employing a high numerical aperture (N.A.) condenser zone plate sample illumination in combination with a high resolution micro zone plate objective lens, a spatial resolution of currently 60 nm is achieved. Since the absorption becomes smaller with increasing photon energy, phase contrast imaging overcomes the limitation for imaging weakly absorbing structures in amplitude contrast mode. We report here on X-ray microscopy of advanced microelectronic devices imaged in Zernike phase contrast mode. While the amplitude contrast between copper and silicon dioxide in these samples is only 7 %, negative as well as positive phase contrast were demonstrated with a contrast of 40 % and 45 %, respectively.

  6. Experimental setup and the system performance for single-grid-based phase-contrast x-ray imaging (PCXI) with a microfocus x-ray tube

    NASA Astrophysics Data System (ADS)

    Lim, Hyunwoo; Park, Yeonok; Cho, Hyosung; Je, Uikyu; Hong, Daeki; Park, Chulkyu; Woo, Taeho; Lee, Minsik; Kim, Jinsoo; Chung, Nagkun; Kim, Jinwon; Kim, Jinguk

    2015-08-01

    In this work, we investigated a simplified approach to phase-contrast x-ray imaging (PCXI) by using a single antiscatter grid and a microfocus x-ray tube, which has potential to open the way to further widespread use of PCXI into the related application areas. We established a table-top setup for PCXI studies of biological and non-biological samples and investigated the system performance. The PCXI system consists of a focused-linear grid having a strip density of 200 lines/in. (JPI Healthcare Corp.), a microfocus x-ray tube having a focal spot size of about 5 μm (Hamamatsu, L7910), and a high-resolution CMOS imaging detector having a pixel size of 48 μm (Rad-icon Imaging Corp., Shad-o-Box 2048). By using our prototype system, we successfully obtained attenuation, scattering, and differential phase-contrast x-ray images of improved visibility from the raw images of several samples at x-ray tube conditions of 50 kVp and 6 mAs. Our initial results indicate that the single-grid-based approach seems a useful method for PCXI with great simplicity and minimal requirements on the setup alignment.

  7. In vivo x-ray phase contrast analyzer-based imaging for longitudinal osteoarthritis studies in guinea pigs

    NASA Astrophysics Data System (ADS)

    Coan, Paola; Wagner, Andreas; Bravin, Alberto; Diemoz, Paul C.; Keyriläinen, Jani; Mollenhauer, Juergen

    2010-12-01

    Over the last two decades phase contrast x-ray imaging techniques have been extensively studied for applications in the biomedical field. Published results demonstrate the high capability of these imaging modalities of improving the image contrast of biological samples with respect to standard absorption-based radiography and routinely used clinical imaging techniques. A clear depiction of the anatomic structures and a more accurate disease diagnosis may be provided by using radiation doses comparable to or lower than those used in current clinical methods. In the literature many works show images of phantoms and excised biological samples proving the high sensitivity of the phase contrast imaging methods for in vitro investigations. In this scenario, the applications of the so-called analyzer-based x-ray imaging (ABI) phase contrast technique are particularly noteworthy. The objective of this work is to demonstrate the feasibility of in vivo x-ray ABI phase contrast imaging for biomedical applications and in particular with respect to joint anatomic depiction and osteoarthritis detection. ABI in planar and tomographic modes was performed in vivo on articular joints of guinea pigs in order to investigate the animals with respect to osteoarthritis by using highly monochromatic x-rays of 52 keV and a low noise detector with a pixel size of 47 × 47 µm2. Images give strong evidence of the ability of ABI in depicting both anatomic structures in complex systems as living organisms and all known signs of osteoarthritis with high contrast, high spatial resolution and with an acceptable radiation dose. This paper presents the first proof of principle study of in vivo application of ABI. The technical challenges encountered when imaging an animal in vivo are discussed. This experimental study is an important step toward the study of clinical applications of phase contrast x-ray imaging techniques.

  8. High Resolution X-Ray Phase Contrast Imaging with Acoustic Tissue-Selective Contrast Enhancement

    DTIC Science & Technology

    2007-06-01

    Contrast and resolution in imaging with microfocus x - ray source. Rev. Sci. Instr. 68, 2774 (1997). 8. Krol, A. et al. Laser-based microfocused x - ray ...water jet of carbon suspension and imaged using a microfocus x - ray source coupled in-line with a synchronously gated intensified optically coupled...

  9. Observations of breakup processes of liquid jets using real-time X-ray radiography

    NASA Technical Reports Server (NTRS)

    Char, J. M.; Kuo, K. K.; Hsieh, K. C.

    1988-01-01

    To unravel the liquid-jet breakup process in the nondilute region, a newly developed system of real-time X-ray radiography, an advanced digital image processor, and a high-speed video camera were used. Based upon recorded X-ray images, the inner structure of a liquid jet during breakup was observed. The jet divergence angle, jet breakup length, and fraction distributions along the axial and transverse directions of the liquid jets were determined in the near-injector region. Both wall- and free-jet tests were conducted to study the effect of wall friction on the jet breakup process.

  10. Real-time x-ray microbeam characterization of electromigration effects in Al(Cu) wires

    SciTech Connect

    Wang, P.-C.; Noyan, I. C.; Kaldor, S. K.; Jordan-Sweet, J. L.; Liniger, E. G.; Hu, C.-K.

    2001-04-30

    We report real-time, in situ x-ray microbeam measurements of electromigration-induced Cu redistribution, and the concurrent local stress variation in Al(Cu) wires. The data, which were obtained by combining x-ray microtopography with energy-dispersive fluorescence analysis, encompass both the early and late stages of electromigration as well as the postrelaxation stage at high temperature with the current turned off. We observe that both Cu concentration and stress values show unexpected local variations that may reflect the effect of local configuration such as film--substrate interface integrity or microstructure.

  11. Towards tender X-rays with Zernike phase-contrast imaging of biological samples at 50 nm resolution.

    PubMed

    Vartiainen, Ismo; Warmer, Martin; Goeries, Dennis; Herker, Eva; Reimer, Rudolph; David, Christian; Meents, Alke

    2014-07-01

    X-ray microscopy is a commonly used method especially in material science application, where the large penetration depth of X-rays is necessary for three-dimensional structural studies of thick specimens with high-Z elements. In this paper it is shown that full-field X-ray microscopy at 6.2 keV can be utilized for imaging of biological specimens with high resolution. A full-field Zernike phase-contrast microscope based on diffractive optics is used to study lipid droplet formation in hepatoma cells. It is shown that the contrast of the images is comparable with that of electron microscopy, and even better contrast at tender X-ray energies between 2.5 keV and 4 keV is expected.

  12. Development of a Laser-Produced Plasma X-ray source for Phase-Contrast Radiography of DT Ice layers

    SciTech Connect

    Izumi, N; Dewald, E; Kozioziemski, B; Landen, O L; Koch, J A

    2008-07-21

    Refraction enhanced x-ray phase contrast imaging is crucial for characterization of deuterium-tritium (DT) ice layer roughness in optically opaque inertial confinement fusion capsules. To observe the time development of DT ice roughness over {approx} second timescales, we need a bright x-ray source that can produce an image faster than the evolution of the ice surface roughness. A laser produced plasma x-ray source is one of the candidates that can meet this requirement. We performed experiments at the Janus laser facility at Lawrence Livermore National Laboratory and assessed the characteristics of the laser produced plasma x-ray source as a potential backlight for in situ target characterization.

  13. X-ray phase contrast imaging by compact Talbot-Lau interferometer with a single transmission grating.

    PubMed

    Morimoto, Naoki; Fujino, Sho; Ohshima, Ken-Ichi; Harada, Jimpei; Hosoi, Takuji; Watanabe, Heiji; Shimura, Takayoshi

    2014-08-01

    We performed x-ray phase contrast imaging (XPCI) by Talbot-Lau interferometer using only a single transmission grating. Multiline metal targets embedded in a diamond substrate were irradiated with electrons to generate an array of x-ray lines of 1 μm width, which allowed XPCI within a 1 m source-detector distance in a configuration without a source or absorption grating. We directly resolved the self-image of the phase grating of 3 μm pitch using an x-ray image detector of 24 μm pixel size and successfully obtained absorption, differential phase, and dark-field images for 8 keV x rays.

  14. A user-friendly LabVIEW software platform for grating based X-ray phase-contrast imaging.

    PubMed

    Wang, Shenghao; Han, Huajie; Gao, Kun; Wang, Zhili; Zhang, Can; Yang, Meng; Wu, Zhao; Wu, Ziyu

    2015-01-01

    X-ray phase-contrast imaging can provide greatly improved contrast over conventional absorption-based imaging for weakly absorbing samples, such as biological soft tissues and fibre composites. In this study, we introduced an easy and fast way to develop a user-friendly software platform dedicated to the new grating-based X-ray phase-contrast imaging setup at the National Synchrotron Radiation Laboratory of the University of Science and Technology of China. The control of 21 motorized stages, of a piezoelectric stage and of an X-ray tube are achieved with this software, it also covers image acquisition with a flat panel detector for automatic phase stepping scan. Moreover, a data post-processing module for signals retrieval and other custom features are in principle available. With a seamless integration of all the necessary functions in one software package, this platform greatly facilitate users' activities during experimental runs with this grating based X-ray phase contrast imaging setup.

  15. Interferometric phase-contrast X-ray CT imaging of VX2 rabbit cancer at 35keV X-ray energy

    SciTech Connect

    Takeda, Tohoru; Wu Jin; Tsuchiya, Yoshinori; Lwin, Thet-Thet; Itai, Yuji; Yoneyama, Akio; Hyodo, Kazuyuki

    2004-05-12

    Imaging of large objects at 17.7-keV low x-ray energy causes huge x-ray exposure to the objects even using interferometric phase-contrast x-ray CT (PCCT). Thus, we tried to obtain PCCT images at high x-ray energy of 35keV and examined the image quality using a formalin-fixed VX2 rabbit cancer specimen with 15-mm in diameter. The PCCT system consisted of an asymmetrically cut silicon (220) crystal, a monolithic x-ray interferometer, a phase-shifter, an object cell and an x-ray CCD camera. The PCCT at 35 keV clearly visualized various inner structures of VX2 rabbit cancer such as necrosis, cancer, the surrounding tumor vessels, and normal liver tissue. Besides, image-contrast was not degraded significantly. These results suggest that the PCCT at 35 KeV is sufficient to clearly depict the histopathological morphology of VX2 rabbit cancer specimen.

  16. Regularized iterative integration combined with non-linear diffusion filtering for phase-contrast x-ray computed tomography.

    PubMed

    Burger, Karin; Koehler, Thomas; Chabior, Michael; Allner, Sebastian; Marschner, Mathias; Fehringer, Andreas; Willner, Marian; Pfeiffer, Franz; Noël, Peter

    2014-12-29

    Phase-contrast x-ray computed tomography has a high potential to become clinically implemented because of its complementarity to conventional absorption-contrast.In this study, we investigate noise-reducing but resolution-preserving analytical reconstruction methods to improve differential phase-contrast imaging. We apply the non-linear Perona-Malik filter on phase-contrast data prior or post filtered backprojected reconstruction. Secondly, the Hilbert kernel is replaced by regularized iterative integration followed by ramp filtered backprojection as used for absorption-contrast imaging. Combining the Perona-Malik filter with this integration algorithm allows to successfully reveal relevant sample features, quantitatively confirmed by significantly increased structural similarity indices and contrast-to-noise ratios. With this concept, phase-contrast imaging can be performed at considerably lower dose.

  17. High-resolution visualization of airspace structures in intact mice via synchrotron phase-contrast X-ray imaging (PCXI)

    PubMed Central

    Parsons, David W; Morgan, Kaye; Donnelley, Martin; Fouras, Andreas; Crosbie, Jeffrey; Williams, Ivan; Boucher, Richard C; Uesugi, Kentaro; Yagi, Naoto; Siu, Karen K W

    2008-01-01

    Anatomical visualization of airspace-containing organs in intact small animals has been limited by the resolution and contrast available from current imaging methods such as X-ray, micro-computed tomography and magnetic resonance imaging. Determining structural relationships and detailed anatomy has therefore relied on suitable fixation, sectioning and histological processing. More complex and informative analyses such as orthogonal views of an organ and three-dimensional structure visualizations have required different animals and image sets, laboriously processed to gather this complementary structural information. Precise three-dimensional anatomical views have always been difficult to achieve in small animals. Here we report the ability of phase-contrast synchrotron X-ray imaging to provide detailed two- and three-dimensional visualization of airspace organ structures in intact animals. Using sub-micrometre square pixel charge-coupled device array detectors, the structure and anatomy of hard and soft tissues, and of airspaces, is readily available using phase-contrast synchrotron X-ray imaging. Moreover, software-controlled volume-reconstructions of tomographic images not only provide unsurpassed image clarity and detail, but also selectable anatomical views that cannot be obtained with established histological techniques. The morphology and structure of nasal and lung airways and the middle ear are illustrated in intact mice, using two- and three-dimensional representations. The utility of phase-contrast synchrotron X-ray imaging for non-invasively localizing objects implanted within airspaces, and the detection of gas bubbles transiting live airways, are other novel features of this visualization methodology. The coupling of phase-contrast synchrotron X-ray imaging technology with software-based reconstruction techniques holds promise for novel and high-resolution non-invasive examination of airspace anatomy in small animal models. PMID:19172736

  18. Increasing the field of view of x-ray phase contrast imaging using stitched gratings on low absorbent carriers

    NASA Astrophysics Data System (ADS)

    Meiser, J.; Amberger, M.; Willner, M.; Kunka, D.; Meyer, P.; Koch, F.; Hipp, A.; Walter, M.; Pfeiffer, F.; Mohr, J.

    2014-03-01

    X-ray phase contrast imaging has become a promising biomedical imaging technique for enhancing soft-tissue contrast. In addition to an absorption contrast image it provides two more types of image, a phase contrast and a small-angle scattering contrast image recorded at the same time. In biomedical imaging their combination allows for the conventional investigation of e.g. bone fractures on the one hand and for soft-tissue investigation like cancer detection on the other hand. Among the different methods of X-ray phase contrast imaging the grating based approach, the Talbot-Lau interferometry, has the highest potential for commercial use in biomedical imaging at the moment, because commercially available X-ray sources can be used in a compact setup. In Talbot-Lau interferometers, core elements are phase and absorption gratings with challenging specifications because of their high aspect ratios (structure height over width). For the long grating lamellas structural heights of more than 100 μm together with structural width in the micron range are requested. We are developing a fabrication process based on deep x-ray lithography and electroforming (LIGA) to fabricate these challenging structures. In case of LIGA gratings the structural area is currently limited to several centimeters by several centimeters which limit the field of view in grating based X-ray phase contrast imaging. In order to increase the grating area significantly we are developing a stitching method for gratings using a 625 μm thick silicon wafer as a carrier substrate. In this work we compare the silicon carrier with an alternative one, polyimide, for patient dose reduction and for the use at lower energies in terms of transmission and image reconstruction problems.

  19. Imaging of Poly(α-hydroxy-ester) Scaffolds with X-ray Phase-Contrast Microcomputed Tomography

    PubMed Central

    Appel, Alyssa A.; Larson, Jeffery C.; Somo, Sami; Zhong, Zhong; Spicer, Patrick P.; Kasper, F. Kurtis; Garson, Alfred B.; Zysk, Adam M.; Mikos, Antonios G.; Anastasio, Mark A.

    2012-01-01

    Porous scaffolds based on poly(α-hydroxy-esters) are under investigation in many tissue engineering applications. A biological response to these materials is driven, in part, by their three-dimensional (3D) structure. The ability to evaluate quantitatively the material structure in tissue-engineering applications is important for the continued development of these polymer-based approaches. X-ray imaging techniques based on phase contrast (PC) have shown a tremendous promise for a number of biomedical applications owing to their ability to provide a contrast based on alternative X-ray properties (refraction and scatter) in addition to X-ray absorption. In this research, poly(α-hydroxy-ester) scaffolds were synthesized and imaged by X-ray PC microcomputed tomography. The 3D images depicting the X-ray attenuation and phase-shifting properties were reconstructed from the measurement data. The scaffold structure could be imaged by X-ray PC in both cell culture conditions and within the tissue. The 3D images allowed for quantification of scaffold properties and automatic segmentation of scaffolds from the surrounding hard and soft tissues. These results provide evidence of the significant potential of techniques based on X-ray PC for imaging polymer scaffolds. PMID:22607529

  20. Imaging of poly(α-hydroxy-ester) scaffolds with X-ray phase-contrast microcomputed tomography.

    PubMed

    Appel, Alyssa A; Larson, Jeffery C; Somo, Sami; Zhong, Zhong; Spicer, Patrick P; Kasper, F Kurtis; Garson, Alfred B; Zysk, Adam M; Mikos, Antonios G; Anastasio, Mark A; Brey, Eric M

    2012-11-01

    Porous scaffolds based on poly(α-hydroxy-esters) are under investigation in many tissue engineering applications. A biological response to these materials is driven, in part, by their three-dimensional (3D) structure. The ability to evaluate quantitatively the material structure in tissue-engineering applications is important for the continued development of these polymer-based approaches. X-ray imaging techniques based on phase contrast (PC) have shown a tremendous promise for a number of biomedical applications owing to their ability to provide a contrast based on alternative X-ray properties (refraction and scatter) in addition to X-ray absorption. In this research, poly(α-hydroxy-ester) scaffolds were synthesized and imaged by X-ray PC microcomputed tomography. The 3D images depicting the X-ray attenuation and phase-shifting properties were reconstructed from the measurement data. The scaffold structure could be imaged by X-ray PC in both cell culture conditions and within the tissue. The 3D images allowed for quantification of scaffold properties and automatic segmentation of scaffolds from the surrounding hard and soft tissues. These results provide evidence of the significant potential of techniques based on X-ray PC for imaging polymer scaffolds.

  1. Fundamental Studies of Solidification in Microgravity Using Real-Time X-Ray Microscopy

    NASA Technical Reports Server (NTRS)

    Curreri, Peter A.; Kaukler, William; Sen, Subhayu; Bhat, Biliyar N.

    1999-01-01

    This research applies a state of the art X-ray Transmission Microscope, XTM, to image (with resolutions up to 3 micrometers) the solidification of metallic or semiconductor alloys in real-time. We have successfully imaged in real-time: interfacial morphologies, phase growth, coalescence, incorporation of phases into the growing interface, and the solute boundary layer in the liquid at the solid-liquid interface. We have also measured true local growth rates and can evaluate segregation structures in the solid; a form of in-situ metallography. During this study, the growth of secondary phase fibers and lamellae from eutectic and monotectic alloys have been imaged during solidification, in real-time, for the first time in bulk metal alloys. Current high resolution X-ray sources and high contrast X-ray detectors have advanced to allow systematic study of solidification dynamics and the resulting microstructure. We have employed a state-of-the-art sub-micron source with acceleration voltages of 10-100 kV to image solidification of metals. One useful strength of the XTM stems from the manner an image is formed. The radiographic image is a shadow formed by x-ray photons that are not absorbed as they pass through the specimen. Composition gradients within the specimen cause variations in absorption of the flux such that the final image represents a spatial integral of composition (or thickness). The ability to image these features in real-time enables more fundamental and detailed understanding of solidification dynamics than has previously been possible. Hence, application of this technique towards microgravity experiments will allow rigorous testing of critical solidification models.

  2. Ultrafast x-ray phase-contrast imaging of the initial coalescence phase of two water droplets.

    SciTech Connect

    Fezzaa, K.; Wang, Y.; X-Ray Science Division

    2008-03-14

    We report an ultrafast x-ray phase-contrast imaging study of the early merging dynamics of two water drops in air. Owing to the edge-enhancement capability, the high penetrability, and the unprecedented temporal and spatial resolutions offered by this new x-ray technique, the coalescence singularity of two water drops was revisited. A finite initial contact radius was identified and the evolvement of the trapped toroidal air bubble was studied for the first time. Despite the existence of this finite initial contact radius, the subsequent meniscus radius followed power laws which agree with theoretical predictions for the inviscid regime.

  3. The second-order differential phase contrast and its retrieval for imaging with x-ray Talbot interferometry

    SciTech Connect

    Yang Yi; Tang Xiangyang

    2012-12-15

    Purpose: The x-ray differential phase contrast imaging implemented with the Talbot interferometry has recently been reported to be capable of providing tomographic images corresponding to attenuation-contrast, phase-contrast, and dark-field contrast, simultaneously, from a single set of projection data. The authors believe that, along with small-angle x-ray scattering, the second-order phase derivative {Phi}{sup Double-Prime }{sub s}(x) plays a role in the generation of dark-field contrast. In this paper, the authors derive the analytic formulae to characterize the contribution made by the second-order phase derivative to the dark-field contrast (namely, second-order differential phase contrast) and validate them via computer simulation study. By proposing a practical retrieval method, the authors investigate the potential of second-order differential phase contrast imaging for extensive applications. Methods: The theoretical derivation starts at assuming that the refractive index decrement of an object can be decomposed into {delta}={delta}{sub s}+{delta}{sub f}, where {delta}{sub f} corresponds to the object's fine structures and manifests itself in the dark-field contrast via small-angle scattering. Based on the paraxial Fresnel-Kirchhoff theory, the analytic formulae to characterize the contribution made by {delta}{sub s}, which corresponds to the object's smooth structures, to the dark-field contrast are derived. Through computer simulation with specially designed numerical phantoms, an x-ray differential phase contrast imaging system implemented with the Talbot interferometry is utilized to evaluate and validate the derived formulae. The same imaging system is also utilized to evaluate and verify the capability of the proposed method to retrieve the second-order differential phase contrast for imaging, as well as its robustness over the dimension of detector cell and the number of steps in grating shifting. Results: Both analytic formulae and computer

  4. Glancing angle Talbot-Lau grating interferometers for phase contrast imaging at high x-ray energy

    NASA Astrophysics Data System (ADS)

    Stutman, D.; Finkenthal, M.

    2012-08-01

    A Talbot-Lau interferometer is demonstrated using micro-periodic gratings inclined at a glancing angle along the light propagation direction. Due to the increase in the effective thickness of the absorption gratings, the device enables differential phase contrast imaging at high x-ray energy, with improved fringe visibility (contrast). For instance, at 28° glancing angle, we obtain up to ˜35% overall interferometer contrast with a spectrum having ˜43 keV mean energy, suitable for medical applications. In addition, glancing angle interferometers could provide high contrast at energies above 100 keV, enabling industrial and security applications of phase contrast imaging.

  5. Hummingbird: monitoring and analyzing flash X-ray imaging experiments in real time.

    PubMed

    Daurer, Benedikt J; Hantke, Max F; Nettelblad, Carl; Maia, Filipe R N C

    2016-06-01

    Advances in X-ray detectors and increases in the brightness of X-ray sources combined with more efficient sample delivery techniques have brought about tremendous increases in the speed of data collection in diffraction experiments. Using X-ray free-electron lasers such as the Linac Coherent Light Source (LCLS), more than 100 diffraction patterns can be collected in a second. These high data rates are invaluable for flash X-ray imaging (FXI), where aerosolized samples are exposed to the X-ray beam and the resulting diffraction patterns are used to reconstruct a three-dimensional image of the sample. Such experiments require immediate feedback on the quality of the data collected to adjust or validate experimental parameters, such as aerosol injector settings, beamline geometry or sample composition. The scarcity of available beamtime at the laser facilities makes any delay extremely costly. This paper presents Hummingbird, an open-source scalable Python-based software tool for real-time analysis of diffraction data with the purpose of giving users immediate feedback during their experiments. Hummingbird provides a fast, flexible and easy-to-use framework. It has already proven to be of great value in numerous FXI experiments at the LCLS.

  6. X-ray phase-contrast tomography with a compact laser-driven synchrotron source.

    PubMed

    Eggl, Elena; Schleede, Simone; Bech, Martin; Achterhold, Klaus; Loewen, Roderick; Ruth, Ronald D; Pfeiffer, Franz

    2015-05-05

    Between X-ray tubes and large-scale synchrotron sources, a large gap in performance exists with respect to the monochromaticity and brilliance of the X-ray beam. However, due to their size and cost, large-scale synchrotrons are not available for more routine applications in small and medium-sized academic or industrial laboratories. This gap could be closed by laser-driven compact synchrotron light sources (CLS), which use an infrared (IR) laser cavity in combination with a small electron storage ring. Hard X-rays are produced through the process of inverse Compton scattering upon the intersection of the electron bunch with the focused laser beam. The produced X-ray beam is intrinsically monochromatic and highly collimated. This makes a CLS well-suited for applications of more advanced--and more challenging--X-ray imaging approaches, such as X-ray multimodal tomography. Here we present, to our knowledge, the first results of a first successful demonstration experiment in which a monochromatic X-ray beam from a CLS was used for multimodal, i.e., phase-, dark-field, and attenuation-contrast, X-ray tomography. We show results from a fluid phantom with different liquids and a biomedical application example in the form of a multimodal CT scan of a small animal (mouse, ex vivo). The results highlight particularly that quantitative multimodal CT has become feasible with laser-driven CLS, and that the results outperform more conventional approaches.

  7. Realistic wave-optics simulation of X-ray phase-contrast imaging at a human scale.

    PubMed

    Sung, Yongjin; Segars, W Paul; Pan, Adam; Ando, Masami; Sheppard, Colin J R; Gupta, Rajiv

    2015-07-14

    X-ray phase-contrast imaging (XPCI) can dramatically improve soft tissue contrast in X-ray medical imaging. Despite worldwide efforts to develop novel XPCI systems, a numerical framework to rigorously predict the performance of a clinical XPCI system at a human scale is not yet available. We have developed such a tool by combining a numerical anthropomorphic phantom defined with non-uniform rational B-splines (NURBS) and a wave optics-based simulator that can accurately capture the phase-contrast signal from a human-scaled numerical phantom. Using a synchrotron-based, high-performance XPCI system, we provide qualitative comparison between simulated and experimental images. Our tool can be used to simulate the performance of XPCI on various disease entities and compare proposed XPCI systems in an unbiased manner.

  8. Realistic wave-optics simulation of X-ray phase-contrast imaging at a human scale

    NASA Astrophysics Data System (ADS)

    Sung, Yongjin; Segars, W. Paul; Pan, Adam; Ando, Masami; Sheppard, Colin J. R.; Gupta, Rajiv

    2015-07-01

    X-ray phase-contrast imaging (XPCI) can dramatically improve soft tissue contrast in X-ray medical imaging. Despite worldwide efforts to develop novel XPCI systems, a numerical framework to rigorously predict the performance of a clinical XPCI system at a human scale is not yet available. We have developed such a tool by combining a numerical anthropomorphic phantom defined with non-uniform rational B-splines (NURBS) and a wave optics-based simulator that can accurately capture the phase-contrast signal from a human-scaled numerical phantom. Using a synchrotron-based, high-performance XPCI system, we provide qualitative comparison between simulated and experimental images. Our tool can be used to simulate the performance of XPCI on various disease entities and compare proposed XPCI systems in an unbiased manner.

  9. Quantitative Three-Dimensional Imaging of Lipid, Protein, and Water Contents via X-Ray Phase-Contrast Tomography

    PubMed Central

    Willner, Marian; Viermetz, Manuel; Marschner, Mathias; Scherer, Kai; Braun, Christian; Fingerle, Alexander; Noël, Peter; Rummeny, Ernst; Pfeiffer, Franz; Herzen, Julia

    2016-01-01

    X-ray phase-contrast computed tomography is an emerging imaging technology with powerful capabilities for three-dimensional (3D) visualization of weakly absorbing objects such as biological soft tissues. This technique is an extension of existing X-ray applications because conventional attenuation-contrast images are simultaneously acquired. The complementary information provided by both the contrast modalities suggests that enhanced material characterization is possible when performing combined data analysis. In this study, we describe how protein, lipid, and water concentrations in each 3D voxel can be quantified by vector decomposition. Experimental results of dairy products, porcine fat and rind, and different human soft tissue types are presented. The results demonstrate the potential of phase-contrast imaging as a new analysis tool. The 3D representations of protein, lipid, and water contents open up new opportunities in the fields of biology, medicine, and food science. PMID:27003308

  10. Study of a macrodefect in a silicon carbid single crystal by means of X-ray phase contrast

    NASA Astrophysics Data System (ADS)

    Argunova, T. S.; Kohn, V. G.; Lim, J. H.; Je, J. H.

    2016-11-01

    The morphology of a macrodefect in a single-crystal silicon carbide wafer has been investigated by the computer simulation of an experimental X-ray phase-contrast image. A micropipe, i.e., a long cavity with a small (elliptical in the general case) cross section, in a single crystal has been considered as a macrodefect. A far-field image of micropipe has been measured with the aid of synchrotron radiation without a monochromator. The parameters of micropipe elliptical cross section are determined based on one projection in two directions: parallel and perpendicular to the X-ray beam propagation direction, when scanning along the pipe axis. The results demonstrate the efficiency of the phase contrast method supplemented with computer simulation for studying such macrodefects when the defect position in the sample volume is unknown beforehand.

  11. Microscopic identification of Chinese medicinal materials based on X-ray phase contrast imaging: from qualitative to quantitative

    NASA Astrophysics Data System (ADS)

    Xue, Y.; Liang, Z.; Tan, H.; Ni, L.; Zhao, Z.; Xiao, T.; Xu, H.

    2016-07-01

    Although a variety of methods, ranging from simple morphological examination to physical and chemical analysis, and DNA molecular biology, exist for authenticating Chinese medicinal materials(CMMs), no methods can achieve both the source species identification and quality evaluation of CMMs simultaneously. Furthermore, the methods that are currently available for the identification of CMMs, including both optical and electronic microscopy, usually entail strict requirements for sample preparation or testing environment, such as the slicing of super-thin sections, or processing with specific chemical reagents. These treatments not only damage the CMMs but may also cause some of the original microstructures to be missed. Additionally, they may even yield false results. Owing to the unique penetrating character of X-rays, X-ray phase contrast imaging(XPCI) can be used to realize the inner microstructures of CMMs through nondestructive imaging. With the higher flux and luminance of the third generation of synchrotron radiation facility, XPCI can provides clearer and finer microstructures of CMMs, which are mainly composed of C, H, O, and N elements, with better spatial and density resolutions. For more than ten years, the X-ray imaging group at the Shanghai Institute of Applied Physics has investigated the microstructures of CMMs by XPCI and they have established and developed a quantitative X-ray phase contrast micro-CT for investigating the characteristic microstructures of CMMs. During this period, a variety of typical CMMs have been investigated, from two-dimensional (2D) radiography to three-dimensional (3D) micro-CT, from qualitative to quantitative. Taken together, these results verify that quantitative X-ray phase contrast micro-CT is a practical tool for the microscopic investigation of CMMs. Additionally, further efforts are being made to find the relationship between the microstructures' quantitative factors and active chemical components. At present

  12. In-vivo dark-field and phase-contrast x-ray imaging.

    PubMed

    Bech, M; Tapfer, A; Velroyen, A; Yaroshenko, A; Pauwels, B; Hostens, J; Bruyndonckx, P; Sasov, A; Pfeiffer, F

    2013-11-13

    Novel radiography approaches based on the wave nature of x-rays when propagating through matter have a great potential for improved future x-ray diagnostics in the clinics. Here, we present a significant milestone in this imaging method: in-vivo multi-contrast x-ray imaging of a mouse using a compact scanner. Of particular interest is the enhanced contrast in regions related to the respiratory system, indicating a possible application in diagnosis of lung diseases (e.g. emphysema).

  13. In-vivo dark-field and phase-contrast x-ray imaging

    NASA Astrophysics Data System (ADS)

    Bech, M.; Tapfer, A.; Velroyen, A.; Yaroshenko, A.; Pauwels, B.; Hostens, J.; Bruyndonckx, P.; Sasov, A.; Pfeiffer, F.

    2013-11-01

    Novel radiography approaches based on the wave nature of x-rays when propagating through matter have a great potential for improved future x-ray diagnostics in the clinics. Here, we present a significant milestone in this imaging method: in-vivo multi-contrast x-ray imaging of a mouse using a compact scanner. Of particular interest is the enhanced contrast in regions related to the respiratory system, indicating a possible application in diagnosis of lung diseases (e.g. emphysema).

  14. Increasing the field of view in grating based X-ray phase contrast imaging using stitched gratings.

    PubMed

    Meiser, J; Willner, M; Schröter, T; Hofmann, A; Rieger, J; Koch, F; Birnbacher, L; Schüttler, M; Kunka, D; Meyer, P; Faisal, A; Amberger, M; Duttenhofer, T; Weber, T; Hipp, A; Ehn, S; Walter, M; Herzen, J; Schulz, J; Pfeiffer, F; Mohr, J

    2016-03-17

    Grating based X-ray differential phase contrast imaging (DPCI) allows for high contrast imaging of materials with similar absorption characteristics. In the last years' publications, small animals or parts of the human body like breast, hand, joints or blood vessels have been studied. Larger objects could not be investigated due to the restricted field of view limited by the available grating area. In this paper, we report on a new stitching method to increase the grating area significantly: individual gratings are merged on a carrier substrate. Whereas the grating fabrication process is based on the LIGA technology (X-ray lithography and electroplating) different cutting and joining methods have been evaluated. First imaging results using a 2×2 stitched analyzer grating in a Talbot-Lau interferometer have been generated using a conventional polychromatic X-ray source. The image quality and analysis confirm the high potential of the stitching method to increase the field of view considerably.

  15. X-ray phase-contrast imaging at 100 keV on a conventional source

    PubMed Central

    Thüring, T.; Abis, M.; Wang, Z.; David, C.; Stampanoni, M.

    2014-01-01

    X-ray grating interferometry is a promising imaging technique sensitive to attenuation, refraction and scattering of the radiation. Applications of this technique in the energy range between 80 and 150 keV pose severe technical challenges, and are still mostly unexplored. Phase-contrast X-ray imaging at such high energies is of relevant scientific and industrial interest, in particular for the investigation of strongly absorbing or thick materials as well as for medical imaging. Here we show the successful implementation of a Talbot-Lau interferometer operated at 100 keV using a conventional X-ray tube and a compact geometry, with a total length of 54 cm. We present the edge-on illumination of the gratings in order to overcome the current fabrication limits. Finally, the curved structures match the beam divergence and allow a large field of view on a short and efficient setup. PMID:24903579

  16. Flexible retrospective phase stepping in x-ray scatter correction and phase contrast imaging using structured illumination.

    PubMed

    Wen, Han; Miao, Houxun; Bennett, Eric E; Adamo, Nick M; Chen, Lei

    2013-01-01

    The development of phase contrast methods for diagnostic x-ray imaging is inspired by the potential of seeing the internal structures of the human body without the need to deposit any harmful radiation. An efficient class of x-ray phase contrast imaging and scatter correction methods share the idea of using structured illumination in the form of a periodic fringe pattern created with gratings or grids. They measure the scatter and distortion of the x-ray wavefront through the attenuation and deformation of the fringe pattern via a phase stepping process. Phase stepping describes image acquisition at regular phase intervals by shifting a grating in uniform steps. However, in practical conditions the actual phase intervals can vary from step to step and also spatially. Particularly with the advent of electromagnetic phase stepping without physical movement of a grating, the phase intervals are dependent upon the focal plane of interest. We describe a demodulation algorithm for phase stepping at arbitrary and position-dependent (APD) phase intervals without assuming a priori knowledge of the phase steps. The algorithm retrospectively determines the spatial distribution of the phase intervals by a Fourier transform method. With this ability, grating-based x-ray imaging becomes more adaptable and robust for broader applications.

  17. Flexible Retrospective Phase Stepping in X-Ray Scatter Correction and Phase Contrast Imaging Using Structured Illumination

    PubMed Central

    Wen, Han; Miao, Houxun; Bennett, Eric E.; Adamo, Nick M.; Chen, Lei

    2013-01-01

    The development of phase contrast methods for diagnostic x-ray imaging is inspired by the potential of seeing the internal structures of the human body without the need to deposit any harmful radiation. An efficient class of x-ray phase contrast imaging and scatter correction methods share the idea of using structured illumination in the form of a periodic fringe pattern created with gratings or grids. They measure the scatter and distortion of the x-ray wavefront through the attenuation and deformation of the fringe pattern via a phase stepping process. Phase stepping describes image acquisition at regular phase intervals by shifting a grating in uniform steps. However, in practical conditions the actual phase intervals can vary from step to step and also spatially. Particularly with the advent of electromagnetic phase stepping without physical movement of a grating, the phase intervals are dependent upon the focal plane of interest. We describe a demodulation algorithm for phase stepping at arbitrary and position-dependent (APD) phase intervals without assuming a priori knowledge of the phase steps. The algorithm retrospectively determines the spatial distribution of the phase intervals by a Fourier transform method. With this ability, grating-based x-ray imaging becomes more adaptable and robust for broader applications. PMID:24205177

  18. Quantitative studies on inner interfaces in conical metal joints using hard x-ray inline phase contrast radiography

    NASA Astrophysics Data System (ADS)

    Zabler, S.; Rack, T.; Rack, A.; Nelson, K.

    2010-10-01

    Quantitative investigation of micrometer and submicrometer gaps between joining metal surfaces is applied to conical plug-socket connections in dental titanium implants. Microgaps of widths well beyond the resolving power of industrial x-ray systems are imaged by synchrotron phase contrast radiography. Furthermore, by using an analytical model for the relatively simple sample geometry and applying it to numerical forward simulations of the optical Fresnel propagation, we show that quantitative measurements of the microgap width down to 0.1 μm are possible. Image data recorded at the BAMline (BESSY-II light source, Germany) are presented, with the resolving power of the imaging system being 4 μm in absorption mode and ˜14 μm in phase contrast mode (z2=0.74 m). Thus, phase contrast radiography, combined with numerical forward simulations, is capable of measuring the widths of gaps that are two orders of magnitude thinner than the conventional detection limit.

  19. Real-Time X-Ray Transmission Microscopy of Solidifying Al-In Alloys

    NASA Technical Reports Server (NTRS)

    Curreri, Peter A.; Kaukler, William F.

    1997-01-01

    Real-time observations of transparent analog materials have provided insight, yet the results of these observations are not necessarily representative of opaque metallic systems. In order to study the detailed dynamics of the solidification process, we develop the technologies needed for real-time X ray microscopy of solidifying metallic systems, which has not previously been feasible with the necessary resolution, speed, and contrast. In initial studies of Al-In monotectic alloys unidirectionally solidified in an X-ray transparent furnace, in situ records of the evolution of interface morphologies, interfacial solute accumulation, and formation of the monotectic droplets were obtained for the first time: A radiomicrograph of Al-30In grown during aircraft parabolic maneuvers is presented, showing the volumetric phase distribution in this specimen. The benefits of using X-ray microscopy for postsolidification metallography include ease of specimen preparation, increased sensitivity, and three-dimensional analysis of phase distribution. Imaging of the solute boundary layer revealed that the isoconcentration lines are not parallel (as is often assumed) to the growth interface. Striations in the solidified crystal did not accurately decorate the interface position and shape. The monotectic composition alloy under some conditions grew in an uncoupled manner.

  20. Development and validation of real-time simulation of X-ray imaging with respiratory motion.

    PubMed

    Vidal, Franck P; Villard, Pierre-Frédéric

    2016-04-01

    We present a framework that combines evolutionary optimisation, soft tissue modelling and ray tracing on GPU to simultaneously compute the respiratory motion and X-ray imaging in real-time. Our aim is to provide validated building blocks with high fidelity to closely match both the human physiology and the physics of X-rays. A CPU-based set of algorithms is presented to model organ behaviours during respiration. Soft tissue deformation is computed with an extension of the Chain Mail method. Rigid elements move according to kinematic laws. A GPU-based surface rendering method is proposed to compute the X-ray image using the Beer-Lambert law. It is provided as an open-source library. A quantitative validation study is provided to objectively assess the accuracy of both components: (i) the respiration against anatomical data, and (ii) the X-ray against the Beer-Lambert law and the results of Monte Carlo simulations. Our implementation can be used in various applications, such as interactive medical virtual environment to train percutaneous transhepatic cholangiography in interventional radiology, 2D/3D registration, computation of digitally reconstructed radiograph, simulation of 4D sinograms to test tomography reconstruction tools.

  1. Application of Fourier-wavelet regularized deconvolution for improving image quality of free space propagation x-ray phase contrast imaging.

    PubMed

    Zhou, Zhongxing; Gao, Feng; Zhao, Huijuan; Zhang, Lixin

    2012-11-21

    New x-ray phase contrast imaging techniques without using synchrotron radiation confront a common problem from the negative effects of finite source size and limited spatial resolution. These negative effects swamp the fine phase contrast fringes and make them almost undetectable. In order to alleviate this problem, deconvolution procedures should be applied to the blurred x-ray phase contrast images. In this study, three different deconvolution techniques, including Wiener filtering, Tikhonov regularization and Fourier-wavelet regularized deconvolution (ForWaRD), were applied to the simulated and experimental free space propagation x-ray phase contrast images of simple geometric phantoms. These algorithms were evaluated in terms of phase contrast improvement and signal-to-noise ratio. The results demonstrate that the ForWaRD algorithm is most appropriate for phase contrast image restoration among above-mentioned methods; it can effectively restore the lost information of phase contrast fringes while reduce the amplified noise during Fourier regularization.

  2. 'Taking X-ray phase contrast imaging into mainstream applications' and its satellite workshop 'Real and reciprocal space X-ray imaging'.

    PubMed

    Olivo, Alessandro; Robinson, Ian

    2014-03-06

    A double event, supported as part of the Royal Society scientific meetings, was organized in February 2013 in London and at Chicheley Hall in Buckinghamshire by Dr A. Olivo and Prof. I. Robinson. The theme that joined the two events was the use of X-ray phase in novel imaging approaches, as opposed to conventional methods based on X-ray attenuation. The event in London, led by Olivo, addressed the main roadblocks that X-ray phase contrast imaging (XPCI) is encountering in terms of commercial translation, for clinical and industrial applications. The main driver behind this is the development of new approaches that enable XPCI, traditionally a synchrotron method, to be performed with conventional laboratory sources, thus opening the way to its deployment in clinics and industrial settings. The satellite meeting at Chicheley Hall, led by Robinson, focused on the new scientific developments that have recently emerged at specialized facilities such as third-generation synchrotrons and free-electron lasers, which enable the direct measurement of the phase shift induced by a sample from intensity measurements, typically in the far field. The two events were therefore highly complementary, in terms of covering both the more applied/translational and the blue-sky aspects of the use of phase in X-ray research. 

  3. A grating-based single-shot x-ray phase contrast and diffraction method for in vivo imaging

    SciTech Connect

    Bennett, Eric E.; Kopace, Rael; Stein, Ashley F.; Wen Han

    2010-11-15

    Purpose: The purpose of this study is to develop a single-shot version of the grating-based phase contrast x-ray imaging method and demonstrate its capability of in vivo animal imaging. Here, the authors describe the principle and experimental results. They show the source of artifacts in the phase contrast signal and optimal designs that minimize them. They also discuss its current limitations and ways to overcome them. Methods: A single lead grid was inserted midway between an x-ray tube and an x-ray camera in the planar radiography setting. The grid acted as a transmission grating and cast periodic dark fringes on the camera. The camera had sufficient spatial resolution to resolve the fringes. Refraction and diffraction in the imaged object manifested as position shifts and amplitude attenuation of the fringes, respectively. In order to quantify these changes precisely without imposing a fixed geometric relationship between the camera pixel array and the fringes, a spatial harmonic method in the Fourier domain was developed. The level of the differential phase (refraction) contrast as a function of hardware specifications and device geometry was derived and used to guide the optimal placement of the grid and object. Both ex vivo and in vivo images of rodent extremities were collected to demonstrate the capability of the method. The exposure time using a 50 W tube was 28 s. Results: Differential phase contrast images of glass beads acquired at various grid and object positions confirmed theoretical predictions of how phase contrast and extraneous artifacts vary with the device geometry. In anesthetized rats, a single exposure yielded artifact-free images of absorption, differential phase contrast, and diffraction. Differential phase contrast was strongest at bone-soft tissue interfaces, while diffraction was strongest in bone. Conclusions: The spatial harmonic method allowed us to obtain absorption, differential phase contrast, and diffraction images, all from a

  4. Quantitative characterization of edge enhancement in phase contrast x-ray imaging.

    PubMed

    Monnin, P; Bulling, S; Hoszowska, J; Valley, J F; Meuli, R; Verdun, F R

    2004-06-01

    The aim of this study was to model the edge enhancement effect in in-line holography phase contrast imaging. A simple analytical approach was used to quantify refraction and interference contrasts in terms of beam energy and imaging geometry. The model was applied to predict the peak intensity and frequency of the edge enhancement for images of cylindrical fibers. The calculations were compared with measurements, and the relationship between the spatial resolution of the detector and the amplitude of the phase contrast signal was investigated. Calculations using the analytical model were in good agreement with experimental results for nylon, aluminum and copper wires of 50 to 240 microm diameter, and with numerical simulations based on Fresnel-Kirchhoff theory. A relationship between the defocusing distance and the pixel size of the image detector was established. This analytical model is a useful tool for optimizing imaging parameters in phase contrast in-line holography, including defocusing distance, detector resolution and beam energy.

  5. A system for high-resolution x-ray phase-contrast imaging and tomography of biological specimens

    NASA Astrophysics Data System (ADS)

    Poletto, Luca; Caldon, Matteo; Tondello, Giuseppe; Megighian, Aram

    2008-08-01

    A system for high-resolution X-ray diagnostics is presented. It consists of a microfocus X-ray source with spot size of 5 μm that is operated in the 10-90 kV range. The detector is a Ce:YAG crystal coupled to a CCD camera with 5μm pixel size and 1392x1040 format. The magnification of the optical coupling is chosen in the 1 to 4 range, giving a spatial resolving element of 5 to 20 μm. The sample to be acquired is mounted on a motorized rototranslation stage for the automatic acquisition of the X-tay views both for tomography and phase-contrast imaging. The sample is positioned half-way between the source and the detector. X-ray images show very high contrast due to phase effects in addition to absorption. Some images of biological specimens are presented to assess the capability of revealing very low differences in density due to the presence of phase contrast. A complete high-resolution tomography of a drosophila is presented.

  6. A Universal Moiré Effect and Application in X-Ray Phase-Contrast Imaging

    PubMed Central

    Miao, Houxun; Panna, Alireza; Gomella, Andrew A.; Bennett, Eric E.; Znati, Sami; Chen, Lei; Wen, Han

    2016-01-01

    A moiré pattern is created by superimposing two black-and-white or gray-scale patterns of regular geometry, such as two sets of evenly spaced lines. We observed an analogous effect between two transparent phase masks in a light beam which occurs at a distance. This phase moiré effect and the classic moiré effect are shown to be the two ends of a continuous spectrum. The phase moiré effect allows the detection of sub-resolution intensity or phase patterns with a transparent screen. When applied to x-ray imaging, it enables a polychromatic far-field interferometer (PFI) without absorption gratings. X-ray interferometry can non-invasively detect refractive index variations inside an object1–10. Current bench-top interferometers operate in the near field with limitations in sensitivity and x-ray dose efficiency2, 5, 7–10. The universal moiré effect helps overcome these limitations and obviates the need to make hard x-ray absorption gratings of sub-micron periods. PMID:27746823

  7. Single shot x-ray phase contrast imaging using a direct conversion microstrip detector with single photon sensitivity

    NASA Astrophysics Data System (ADS)

    Kagias, M.; Cartier, S.; Wang, Z.; Bergamaschi, A.; Dinapoli, R.; Mozzanica, A.; Schmitt, B.; Stampanoni, M.

    2016-06-01

    X-ray phase contrast imaging enables the measurement of the electron density of a sample with high sensitivity compared to the conventional absorption contrast. This is advantageous for the study of dose-sensitive samples, in particular, for biological and medical investigations. Recent developments relaxed the requirement for the beam coherence, such that conventional X-ray sources can be used for phase contrast imaging and thus clinical applications become possible. One of the prominent phase contrast imaging methods, Talbot-Lau grating interferometry, is limited by the manufacturing, alignment, and photon absorption of the analyzer grating, which is placed in the beam path in front of the detector. We propose an alternative improved method based on direct conversion charge integrating detectors, which enables a grating interferometer to be operated without an analyzer grating. Algorithms are introduced, which resolve interference fringes with a periodicity of 4.7 μm recorded with a 25 μm pitch Si microstrip detector (GOTTHARD). The feasibility of the proposed approach is demonstrated by an experiment at the TOMCAT beamline of the Swiss Light Source on a polyethylene sample.

  8. Visualisation by high resolution synchrotron X-ray phase contrast micro-tomography of gas films on submerged superhydrophobic leaves.

    PubMed

    Lauridsen, Torsten; Glavina, Kyriaki; Colmer, Timothy David; Winkel, Anders; Irvine, Sarah; Lefmann, Kim; Feidenhans'l, Robert; Pedersen, Ole

    2014-10-01

    Floods can completely submerge terrestrial plants but some wetland species can sustain O2 and CO2 exchange with the environment via gas films forming on superhydrophobic leaf surfaces. We used high resolution synchrotron X-ray phase contrast micro-tomography in a novel approach to visualise gas films on submerged leaves of common cordgrass (Spartina anglica). 3D tomograms enabled a hitherto unmatched level of detail regarding the micro-topography of leaf gas films. Gas films formed only on the superhydrophobic adaxial leaf side (water droplet contact angle, Φ=162°) but not on the abaxial side (Φ=135°). The adaxial side of the leaves of common cordgrass is plicate with a longitudinal system of parallel grooves and ridges and the vast majority of the gas film volume was found in large ∼180μm deep elongated triangular volumes in the grooves and these volumes were connected to each neighbouring groove via a fine network of gas tubules (∼1.7μm diameter) across the ridges. In addition to the gas film retained on the leaf exterior, the X-ray phase contrast micro-tomography also successfully distinguished gas spaces internally in the leaf tissues, and the tissue porosity (gas volume per unit tissue volume) ranged from 6.3% to 20.3% in tip and base leaf segments, respectively. We conclude that X-ray phase contrast micro-tomography is a powerful tool to obtain quantitative data of exterior gas features on biological samples because of the significant difference in electron density between air, biological tissues and water.

  9. System for phase-contrast x-ray radiography using X pinch radiation and a method thereof

    DOEpatents

    Chandler, Katherine; Chelkovenko, Tatiana; Hammer, David; Pikuz, Sergei; Sinars, Daniel; Song, Byungmoo

    2007-11-06

    A radiograph system with an anode plate, a cathode plate, and a power source coupled to said anode plate and the cathode plate. At least two wires coupled between the anode plate and the cathode plate provide a configuration to form an X-pinch having a photon source size of less than five microns at energies above 2.5 keV. Material at the configuration forming the X-pinch vaporizes upon application of a suitable current to the wires forming a dense hot plasma and emitting a single x-ray pulse with sufficient photons having energies in the range of from about 2.5 keV to about 20 keV to provide a phase contrast image of an object in the path of the photons. Multiple simultaneous images may be formed of a plurality of objects. Suitable filters and x-ray detectors are provided.

  10. Motionless electromagnetic phase stepping versus mechanical phase stepping in x-ray phase-contrast imaging with a compact source.

    PubMed

    Harmon, Katherine J; Miao, Houxun; Gomella, Andrew A; Bennett, Eric E; Foster, Barbara A; Bhandarkar, Priya; Wen, Han

    2015-04-21

    X-ray phase contrast imaging based on grating interferometers detects the refractive index distribution of an object without relying on radiation attenuation, thereby having the potential for reduced radiation absorption. These techniques belong to the broader category of optical wavefront measurement, which requires stepping the phase of the interference pattern to obtain a pixel-wise map of the phase distortion of the wavefront. While phase stepping traditionally involves mechanical scanning of a grating or mirror, we developed electromagnetic phase stepping (EPS) for imaging with compact sources to obviate the need for mechanical movement. In EPS a solenoid coil is placed outside the x-ray tube to shift its focal spot with a magnetic field, causing a relative movement between the projection of the sample and the interference pattern in the image. Here we present two embodiments of this method. We verified experimentally that electromagnetic and mechanical phase stepping give the same results and attain the same signal-to-noise ratios under the same radiation dose. We found that the relative changes of interference fringe visibility were within 3.0% when the x-ray focal spot was shifted by up to 1.0 mm in either direction. We conclude that when using x-ray tube sources, EPS is an effective means of phase stepping without the need for mechanical movement.

  11. X-ray differential phase contrast imaging using a grating interferometer and a single photon counting detector

    NASA Astrophysics Data System (ADS)

    Ge, Yongshuai; Zhang, Ran; Li, Ke; Chen, Guang-Hong

    2016-03-01

    For grating interferometer-based x-ray differential phase contrast (DPC) imaging systems, their noise performance is strongly dependent on both the visibility of the interference fringe pattern and the total number of photons used to acquire and extract the DPC signal. For a given interferometer, it is usually designed to work at a specific x-ray energy, therefore any deviation from the designed energy may result in certain visibility loss. In this work, a single photon counting detector (PCD) was incorporated into a DPC imaging system, which enabled photons with energies close to the designed operation energy of the interferometer to be selectively used for DPC signal extraction. This approach led to significant boost in the fringe visibility, but it also discarded x-ray photons with other energies incident on the detector and might result in degradations of the overall radiation dose efficiency of the DPC imaging systems. This work presents a novel singular value decomposition (SVD)-based method to leverage the entire spectrum of x-ray photons detected by the PCD, enabling both fringe visibility improvement and reduction in image noise. As evidenced by the results of experimental phantom studies, the contrast-to-noise ratio of the final DPC images could be effectively improved by the proposed method.

  12. High-resolution short-exposure small-animal laboratory x-ray phase-contrast tomography

    PubMed Central

    Larsson, Daniel H.; Vågberg, William; Yaroshenko, Andre; Yildirim, Ali Önder; Hertz, Hans M.

    2016-01-01

    X-ray computed tomography of small animals and their organs is an essential tool in basic and preclinical biomedical research. In both phase-contrast and absorption tomography high spatial resolution and short exposure times are of key importance. However, the observable spatial resolutions and achievable exposure times are presently limited by system parameters rather than more fundamental constraints like, e.g., dose. Here we demonstrate laboratory tomography with few-ten μm spatial resolution and few-minute exposure time at an acceptable dose for small-animal imaging, both with absorption contrast and phase contrast. The method relies on a magnifying imaging scheme in combination with a high-power small-spot liquid-metal-jet electron-impact source. The tomographic imaging is demonstrated on intact mouse, phantoms and excised lungs, both healthy and with pulmonary emphysema. PMID:27958376

  13. High-resolution short-exposure small-animal laboratory x-ray phase-contrast tomography

    NASA Astrophysics Data System (ADS)

    Larsson, Daniel H.; Vågberg, William; Yaroshenko, Andre; Yildirim, Ali Önder; Hertz, Hans M.

    2016-12-01

    X-ray computed tomography of small animals and their organs is an essential tool in basic and preclinical biomedical research. In both phase-contrast and absorption tomography high spatial resolution and short exposure times are of key importance. However, the observable spatial resolutions and achievable exposure times are presently limited by system parameters rather than more fundamental constraints like, e.g., dose. Here we demonstrate laboratory tomography with few-ten μm spatial resolution and few-minute exposure time at an acceptable dose for small-animal imaging, both with absorption contrast and phase contrast. The method relies on a magnifying imaging scheme in combination with a high-power small-spot liquid-metal-jet electron-impact source. The tomographic imaging is demonstrated on intact mouse, phantoms and excised lungs, both healthy and with pulmonary emphysema.

  14. Real Time Space Weather Support for Chandra X-Ray Observatory Operations

    NASA Technical Reports Server (NTRS)

    O'Dell, Stephen L.; Minow, Joseph I.; Miller, J. Scott; Wolk, Scott J.; Aldcroft, Thomas L.; Spitzbart, Bradley D.; Swartz. Douglas A.

    2012-01-01

    NASA launched the Chandra X-ray Observatory in July 1999. Soon after first light in August 1999, however, degradation in the energy resolution and charge transfer efficiency of the Advanced CCD Imaging Spectrometer (ACIS) x-ray detectors was observed. The source of the degradation was quickly identified as radiation damage in the charge-transfer channel of the front-illuminated CCDs, by weakly penetrating ( soft , 100 500 keV) protons as Chandra passed through the Earth s radiation belts and ring currents. As soft protons were not considered a risk to spacecraft health before launch, the only on-board radiation monitoring system is the Electron, Proton, and Helium Instrument (EPHIN) which was included on Chandra with the primary purpose of monitoring energetic solar particle events. Further damage to the ACIS detector has been successfully mitigated through a combination of careful mission planning, autonomous on-board radiation protection, and manual intervention based upon real-time monitoring of the soft-proton environment. The AE-8 and AP-8 trapped radiation models and Chandra Radiation Models are used to schedule science operations in regions of low proton flux. EPHIN has been used as the primary autonomous in-situ radiation trigger; but, it is not sensitive to the soft protons that damage the front-illuminated CCDs. Monitoring of near-real-time space weather data sources provides critical information on the proton environment outside the Earth s magnetosphere due to solar proton events and other phenomena. The operations team uses data from the Geostationary Operational Environmental Satellites (GOES) to provide near-real-time monitoring of the proton environment; however, these data do not give a representative measure of the soft-proton (< 1 MeV) flux in Chandra s high elliptical orbit. The only source of relevant measurements of sub-MeV protons is the Electron, Proton, and Alpha Monitor (EPAM) aboard the Advanced Composition Explorer (ACE) satellite at L1

  15. Real Time Space Weather Support for Chandra X-ray Observatory Operations

    NASA Technical Reports Server (NTRS)

    O'Dell, Stephen L.; Miller, J. Scott; Minow, Joseph I.; Wolk, Scott J.; Aldcroft, Thomas L.; Spitzbart, Bradley D.; Swartz, Douglas A.

    2012-01-01

    NASA launched the Chandra X-ray Observatory in July 1999. Soon after first light in August 1999, however, degradation in the energy resolution and charge transfer efficiency of the Advanced CCD Imaging Spectrometer (ACIS) x-ray detectors was observed. The source of the degradation was quickly identified as radiation damage in the charge-transfer channel of the front-illuminated CCDs, by weakly penetrating ("soft", 100-500 keV) protons as Chandra passed through the Earth s radiation belts and ring currents. As soft protons were not considered a risk to spacecraft health before launch, the only on-board radiation monitoring system is the Electron, Proton, and Helium Instrument (EPHIN) which was included on Chandra with the primary purpose of monitoring energetic solar particle events. Further damage to the ACIS detector has been successfully mitigated through a combination of careful mission planning, autonomous on-board radiation protection, and manual intervention based upon real-time monitoring of the soft-proton environment. The AE-8 and AP-8 trapped radiation models and Chandra Radiation Models are used to schedule science operations in regions of low proton flux. EPHIN has been used as the primary autonomous in-situ radiation trigger; but, it is not sensitive to the soft protons that damage the front-illuminated CCDs. Monitoring of near-real-time space weather data sources provides critical information on the proton environment outside the Earth's magnetosphere due to solar proton events and other phenomena. The operations team uses data from the Geostationary Operational Environmental Satellites (GOES) to provide near-real-time monitoring of the proton environment; however, these data do not give a representative measure of the soft-proton (less than 1 MeV) flux in Chandra s high elliptical orbit. The only source of relevant measurements of sub-MeV protons is the Electron, Proton, and Alpha Monitor (EPAM) aboard the Advanced Composition Explorer (ACE

  16. Real Time Space Weather Support for Chandra X-ray Observatory Operations

    NASA Astrophysics Data System (ADS)

    O'Dell, S. L.; Miller, S.; Minow, J. I.; Wolk, S.; Aldcroft, T. L.; Spitzbart, B. D.; Swartz, D. A.

    2012-12-01

    NASA launched the Chandra X-ray Observatory in July 1999. Soon after first light in August 1999, however, degradation in the energy resolution and charge transfer efficiency of the Advanced CCD Imaging Spectrometer (ACIS) x-ray detectors was observed. The source of the degradation was quickly identified as radiation damage in the charge-transfer channel of the front-illuminated CCDs, by weakly penetrating ("soft", 100-500 keV) protons as Chandra passed through the Earth's radiation belts and ring currents. As soft protons were not considered a risk to spacecraft health before launch, the only on-board radiation monitoring system is the Electron, Proton, and Helium Instrument (EPHIN) which was included on Chandra with the primary purpose of monitoring energetic solar particle events. Further damage to the ACIS detector has been successfully mitigated through a combination of careful mission planning, autonomous on-board radiation protection, and manual intervention based upon real-time monitoring of the soft-proton environment. The AE-8 and AP-8 trapped radiation models and Chandra Radiation Models are used to schedule science operations in regions of low proton flux. EPHIN has been used as the primary autonomous in-situ radiation trigger; but, it is not sensitive to the soft protons that damage the front-illuminated CCDs. Monitoring of near-real-time space weather data sources provides critical information on the proton environment outside the Earth's magnetosphere due to solar proton events and other phenomena. The operations team uses data from the Geostationary Operational Environmental Satellites (GOES) to provide near-real-time monitoring of the proton environment; however, these data do not give a representative measure of the soft-proton (< 1 MeV) flux in Chandra's high elliptical orbit. The only source of relevant measurements of sub-MeV protons is the Electron, Proton, and Alpha Monitor (EPAM) aboard the Advanced Composition Explorer (ACE) satellite at L1

  17. SOFT-X RAY DIAGNOSTICS AND TREATMENTS FOR FUTURE REAL TIME APPLICATIONS

    SciTech Connect

    Pacella, D.; Mazon, D.

    2008-03-12

    This paper offers a preliminary review of the present diagnostics and data analysis techniques in the domain of Soft X-ray (SXR) emissions of fusion magnetic plasmas, including a short description of the theoretical background as well. Particular attention is devoted to the wide use of SXR tomography and impurity transport simulation. In their actual form, these techniques are not adequate to future real time applications. For this goal a step forward in the diagnosing and analysis of SXR emissions is required. The following part of the paper is therefore dedicated to the discussion of these improvements. The first one is the SXR tomography optimized for real time applications, like that one developed at Tore Supra (Cadarache, France). Fast 2-D tomographic inversions using different techniques (regularisation of Minimum Fisher, Maximum entropy, Zernicke polynomial expansions), will be optimized to be performed in a few millisecond time scale, crucial for MHD analysis, mode detection and localisation. The other goal to be pursued is the energy resolved imaging, now possible with a gas Micro Pattern Gas Detector with pixel read-out, as recently demonstrated at FTU (Frascati, Italy) and at NSTX (Princeton NJ, US), together with an ad hoc modeling of SXR emissions, compatible with future real time applications.

  18. Non-linear regularized phase retrieval for unidirectional X-ray differential phase contrast radiography.

    PubMed

    Thüring, Thomas; Modregger, Peter; Pinzer, Bernd R; Wang, Zhentian; Stampanoni, Marco

    2011-12-05

    Phase retrieval from unidirectional radiographic differential phase contrast images requires integration of noisy data. A method is presented, which aims to suppress stripe artifacts arising from direct image integration. It is purely algorithmic and therefore, compared to alternative approaches, neither additional alignment nor an increased scan time is required. We report on the theory of this method and present results using numerical as well as experimental data. The method shows significant improvements on the phase retrieval accuracy and enhances contrast in the phase image. Due to its general applicability, the proposed method provides a valuable tool for various 2D imaging applications using differential data.

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

    NASA Astrophysics Data System (ADS)

    Melli, Seyed Ali; Wahid, Khan A.; Babyn, Paul; Montgomery, James; Snead, Elisabeth; El-Gayed, Ali; Pettitt, Murray; Wolkowski, Bailey; Wesolowski, Michal

    2016-01-01

    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.

  20. Real time cumulant approach for charge-transfer satellites in x-ray photoemission spectra

    SciTech Connect

    Kas, Joshua J.; Vila, Fernando D.; Rehr, John J.; Chambers, Scott A.

    2015-03-01

    X-ray photoemission spectra generally exhibit satellite features in addition to quasi-particle peaks due to many-body excitations which have been of considerable theoretical and experimental interest. However, the satellites attributed to charge-transfer (CT) excitations in correlated materials have proved difficult to calculate from first principles. Here we report a real-time, real-space approach for such calculations based on a cumulant representation of the core-hole Green’s function and time-dependent density functional theory. This approach also yields an interpretation of CT satellites in terms of a complex oscillatory, transient response to a suddenly created core hole. Illustrative results for TiO2 and NiO are in good agreement with experiment.

  1. Crystallization Dynamics of Organolead Halide Perovskite by Real-Time X-ray Diffraction.

    PubMed

    Miyadera, Tetsuhiko; Shibata, Yosei; Koganezawa, Tomoyuki; Murakami, Takurou N; Sugita, Takeshi; Tanigaki, Nobutaka; Chikamatsu, Masayuki

    2015-08-12

    We analyzed the crystallization process of the CH3NH3PbI3 perovskite by observing real-time X-ray diffraction immediately after combining a PbI2 thin film with a CH3NH3I solution. A detailed analysis of the transformation kinetics demonstrated the fractal diffusion of the CH3NH3I solution into the PbI2 film. Moreover, the perovskite crystal was found to be initially oriented based on the PbI2 crystal orientation but to gradually transition to a random orientation. The fluctuating characteristics of the crystallization process of perovskites, such as fractal penetration and orientational transformation, should be controlled to allow the fabrication of high-quality perovskite crystals. The characteristic reaction dynamics observed in this study should assist in establishing reproducible fabrication processes for perovskite solar cells.

  2. In-situ X-ray Synchrotron Microtomography: Real Time Pore Structure Evolution during Olivine Carbonation

    NASA Astrophysics Data System (ADS)

    Zhu, W.; Fusseis, F.; Lisabeth, H. P.; Xiao, X.

    2013-12-01

    Mineral carbonation has been proposed as a promising method for long-term, secure sequestration of carbon dioxide. In porous rocks, fluid-rock interactions can significantly alter the pore space and thus exert important controls over the rate and extent of carbonation. We constructed an x-ray transparent pressure cell [Fusseis et al., 2013] to investigate the real time pore structure evolution during mineral carbonation in porous olivine aggregates. In each experiment, a sintered olivine sample was subjected to a confining pressure of 13 MPa and a pore pressure of 10 MPa, with a sodium bicarbonate solution (NaHCO3 at 1.5 M) as pore fluid. At these pressure conditions, the cell was heated to 473 K. Constant pressure and temperature conditions were maintained during the length of the experiments, lasting 72-120 hours. Using a polychromatic beam in the 2-BM upstream hutch at the Advanced Photon Source, 3-dimensional (3-D) microtomography data were collected in 20 seconds with 30-minute interval. A novel phase retrieval reconstruction algorithm [Paganin et al., 2002] was used to reconstruct microtomographic datasets with a voxel size of ~1.1 micron. The microtomography images at different stages of the carbonation process reveal progressive growth of new crystals in the pore space. Integration of a x-ray transparent pressure vessel with flow through capacity and 3-D microtomography provides a novel research direction of studying the coupled chemo-hydro-thermal-mechanical processes in rocks.

  3. Advancement of Solidification Processing Technology Through Real Time X-Ray Transmission Microscopy: Sample Preparation

    NASA Technical Reports Server (NTRS)

    Stefanescu, D. M.; Curreri, P. A.

    1996-01-01

    Two types of samples were prepared for the real time X-ray transmission microscopy (XTM) characterization. In the first series directional solidification experiments were carried out to evaluate the critical velocity of engulfment of zirconia particles in the Al and Al-Ni eutectic matrix under ground (l-g) conditions. The particle distribution in the samples was recorded on video before and after the samples were directionally solidified. In the second series samples of the above two type of composites were prepared for directional solidification runs to be carried out on the Advanced Gradient Heating Facility (AGHF) aboard the space shuttle during the LMS mission in June 1996. X-ray microscopy proved to be an invaluable tool for characterizing the particle distribution in the metal matrix samples. This kind of analysis helped in determining accurately the critical velocity of engulfment of ceramic particles by the melt interface in the opaque metal matrix composites. The quality of the cast samples with respect to porosity and instrumented thermocouple sheath breakage or shift could be easily viewed and thus helped in selecting samples for the space shuttle experiments. Summarizing the merits of this technique it can be stated that this technique enabled the use of cast metal matrix composite samples since the particle location was known prior to the experiment.

  4. Quantitative studies on inner interfaces in conical metal joints using hard x-ray inline phase contrast radiography

    SciTech Connect

    Zabler, S.; Rack, T.; Nelson, K.; Rack, A.

    2010-10-15

    Quantitative investigation of micrometer and submicrometer gaps between joining metal surfaces is applied to conical plug-socket connections in dental titanium implants. Microgaps of widths well beyond the resolving power of industrial x-ray systems are imaged by synchrotron phase contrast radiography. Furthermore, by using an analytical model for the relatively simple sample geometry and applying it to numerical forward simulations of the optical Fresnel propagation, we show that quantitative measurements of the microgap width down to 0.1 {mu}m are possible. Image data recorded at the BAMline (BESSY-II light source, Germany) are presented, with the resolving power of the imaging system being 4 {mu}m in absorption mode and {approx}14 {mu}m in phase contrast mode (z{sub 2}=0.74 m). Thus, phase contrast radiography, combined with numerical forward simulations, is capable of measuring the widths of gaps that are two orders of magnitude thinner than the conventional detection limit.

  5. A K-alpha x-ray source using high energy and high repetition rate laser system for phase contrast imaging.

    PubMed

    Serbanescu, Cristina; Fourmaux, Sylvain; Kieffer, Jean-Claude; Kincaid, Russell; Krol, Andrzej

    2009-01-01

    K-alpha x-ray sources from laser produced plasmas provide completely new possibilities for x-ray phase-contrast imaging applications. By tightly focusing intense femtosecond laser pulses onto a solid target K-alpha x-ray pulses are generated through the interaction of energetic electrons created in the plasma with the bulk target. In this paper, we present a continuous and efficient Mo K-alpha x-ray source produced by a femtosecond laser system operating at 100 Hz repetition rate with maximum pulse energy of 110 mJ before compression. The source has an x-ray conversion efficiency of greater than 10(-5) into K-alpha line emission. In preparation for phase contrast imaging applications, the size of the resultant K-alpha x-ray emission spot has been also characterized. The source exhibits sufficient spatial coherence to observe phase contrast. We observe a relatively small broadening of the K-alpha source size compared to the size of the laser beam itself. Detailed characterization of the source including the x-ray spectrum and the x-ray average yield along with phase contrast images of test objects will be presented.

  6. Real-Time X-ray Radiography Diagnostics of Components in Solid Rocket Motors

    NASA Technical Reports Server (NTRS)

    Cortopassi, A. C.; Martin, H. T.; Boyer, E.; Kuo, K. K.

    2012-01-01

    the recession of the solid propellant grain can drastically alter the flow-field and effect the recession of internal insulation and nozzle materials. Simultaneous measurement of the overall erosion rate, the development of the char layer, and the recession of the char-virgin interface during the motor operation can be rather difficult. While invasive techniques have been used with limited success, they have serious drawbacks. Break wires or make wire sensors can be installed into a sufficient number of locations in the charring material from which a time history of the charring surface can be deduced. These sensors fundamentally alter the local structure of the material in which they are imbedded. Also, the location of these sensors within the material is not known precisely without the use of an X-ray. To determine instantaneous recession rates, real-time X-ray radiography (X-ray RTR) has been utilized in several SRM experiments at PSU. The X-ray RTR system discussed in this paper consists of an X-ray source, X-ray image intensifier, and CCD camera connected to a capture computer. The system has been used to examine the ablation process of internal insulation as well as nozzle material erosion in a subscale SRM. The X-ray source is rated to 320 kV at 10 mA and has both a large (5.5 mm) and small (3.0 mm) focal spot. The lead-lined cesium iodide X-ray image intensifier produces an image which is captured by a CCD camera with a 1,000 x 1,000 pixel resolution. To produce accurate imagery of the object of interest, the alignment of the X-ray source to the X-ray image intensifier is crucial. The image sequences captured during the operation of an SRM are then processed to enhance the quality of the images. This procedure allows for computer software to extract data on the total erosion rate and the char layer thickness. Figure 1 Error! Reference source not found.shows a sequence of images captured during the operation the subscale SRM with the X-ray RTR system. The X-ray

  7. Real-time direct and diffraction X-ray imaging of irregular silicon wafer breakage

    PubMed Central

    Rack, Alexander; Scheel, Mario; Danilewsky, Andreas N.

    2016-01-01

    Fracture and breakage of single crystals, particularly of silicon wafers, are multi-scale problems: the crack tip starts propagating on an atomic scale with the breaking of chemical bonds, forms crack fronts through the crystal on the micrometre scale and ends macroscopically in catastrophic wafer shattering. Total wafer breakage is a severe problem for the semiconductor industry, not only during handling but also during temperature treatments, leading to million-dollar costs per annum in a device production line. Knowledge of the relevant dynamics governing perfect cleavage along the {111} or {110} faces, and of the deflection into higher indexed {hkl} faces of higher energy, is scarce due to the high velocity of the process. Imaging techniques are commonly limited to depicting only the state of a wafer before the crack and in the final state. This paper presents, for the first time, in situ high-speed crack propagation under thermal stress, imaged simultaneously in direct transmission and diffraction X-ray imaging. It shows how the propagating crack tip and the related strain field can be tracked in the phase-contrast and diffracted images, respectively. Movies with a time resolution of microseconds per frame reveal that the strain and crack tip do not propagate continuously or at a constant speed. Jumps in the crack tip position indicate pinning of the crack tip for about 1–2 ms followed by jumps faster than 2–6 m s−1, leading to a macroscopically observed average velocity of 0.028–0.055 m s−1. The presented results also give a proof of concept that the described X-ray technique is compatible with studying ultra-fast cracks up to the speed of sound. PMID:27006774

  8. Construction and evaluation of a high-energy grating-based x-ray phase-contrast imaging setup

    NASA Astrophysics Data System (ADS)

    Hauke, Christian; Horn, Florian; Pelzer, Georg; Rieger, Jens; Lachner, Sebastian; Ludwig, Veronika; Seifert, Maria; Schuster, Max; Wandner, Johannes; Wolf, Andreas; Weber, Thomas; Michel, Thilo; Anton, Gisela

    2016-03-01

    Interferometric x-ray imaging becomes more and more attractive for applications such as medical imaging or non-destructive testing, because it provides the opportunity to obtain additional information on the internal structure of radiographed objects.12 Therefore, three types of images are acquired: An attenuation image like in conventional x-ray imaging, an image of the differential phase-shift generated by the object and the so called dark-field image, which contains information about the object's granularity even on sub-pixel scale.3 However, most experiments addressing grating-based x-ray phase-contrast imaging with polychromatic sources are restricted to energies up to about 40 keV. For the application of this imaging method to thicker objects like human specimens or dense components, higher tube voltages are required. This is why we designed and constructed a laboratory setup for high energies, which is able to image larger objects.4 To evaluate the performance of the setup, the mean visibility of the field of view was measured for several tube voltages. The result shows that the mean visibility has a peak value of 23% at a tube voltage of 60 kV and is constantly greater than 16% up to a tube voltage of 120 kV. Thus, good image quality is provided even for high energies. To further substantiate the performance of the setup at high energies, a human ex-vivo foot was examined at a tube voltage of 75 kV. The interferometric x-ray images show a good image quality and a promising diagnostic power.

  9. Amyloid-β plaque deposition measured using propagation-based X-ray phase contrast CT imaging

    PubMed Central

    Astolfo, Alberto; Lathuilière, Aurélien; Laversenne, Vanessa; Schneider, Bernard; Stampanoni, Marco

    2016-01-01

    Amyloid beta accumulation into insoluble plaques (Aβp) is known to play a significant role in the pathological process in Alzheimer’s disease (AD). The presence of Aβp is also one of the neuropathological hallmarks for the disease. AD final diagnosis is generally acknowledged after the evaluation of Aβp deposition in the brain. Insoluble Aβp accumulation may also concur to cause AD as postulated in the so-called amyloid hypothesis. Therefore, the visualization, evaluation and quantification of Aβp are nowadays the keys for a better understanding of the disease, which may point to a possible cure for AD in the near future. Synchrotron-based X-ray phase contrast (XPC) has been demonstrated as the only imaging method that can retrieve the Aβp signal with high spatial resolution (up to 10 µm), high sensitivity and three-dimensional information at the same time. Although at the moment XPC is suitable for ex vivo samples only, it may develop into an alternative to positron emission tomography and magnetic resonance imaging in Aβp imaging. In this contribution the possibility of using synchrotron-based X-ray phase propagation computed tomography to visualize and measure Aβp on mouse brains is presented. A careful setup optimization for this application leads to a significant improvement of spatial resolution (∼1 µm), data acquisition speed (five times faster), X-ray dose (five times lower) and setup complexity, without a substantial loss in sensitivity when compared with the classic implementation of grating-based X-ray interferometry. PMID:27140162

  10. High-throughput data acquisition and processing for real-time x-ray imaging

    NASA Astrophysics Data System (ADS)

    Vogelgesang, Matthias; Rota, Lorenzo; Ardila Perez, Luis E.; Caselle, Michele; Chilingaryan, Suren; Kopmann, Andreas

    2016-10-01

    With ever-increasing data rates due to stronger light sources and better detectors, X-ray imaging experiments conducted at synchrotron beamlines face bandwidth and processing limitations that inhibit efficient workflows and prevent real-time operations. We propose an experiment platform comprised of programmable hardware and optimized software to lift these limitations and make beamline setups future-proof. The hardware consists of an FPGA-based data acquisition system with custom logic for data pre-processing and a PCIe data connection for transmission of currently up to 6.6 GB/s. Moreover, the accompanying firmware supports pushing data directly into GPU memory using AMD's DirectGMA technology without crossing system memory first. The GPUs are used to pre-process projection data and reconstruct final volumetric data with OpenCL faster than possible with CPUs alone. Besides, more efficient use of resources this enables a real-time preview of a reconstruction for early quality assessment of both experiment setup and the investigated sample. The entire system is designed in a modular way and allows swapping all components, e.g. replacing our custom FPGA camera with a commercial system but keep reconstructing data with GPUs. Moreover, every component is accessible using a low-level C library or using a high-level Python interface in order to integrate these components in any legacy environment.

  11. Bilateral filtering using the full noise covariance matrix applied to x-ray phase-contrast computed tomography

    NASA Astrophysics Data System (ADS)

    Allner, S.; Koehler, T.; Fehringer, A.; Birnbacher, L.; Willner, M.; Pfeiffer, F.; Noël, P. B.

    2016-05-01

    The purpose of this work is to develop an image-based de-noising algorithm that exploits complementary information and noise statistics from multi-modal images, as they emerge in x-ray tomography techniques, for instance grating-based phase-contrast CT and spectral CT. Among the noise reduction methods, image-based de-noising is one popular approach and the so-called bilateral filter is a well known algorithm for edge-preserving filtering. We developed a generalization of the bilateral filter for the case where the imaging system provides two or more perfectly aligned images. The proposed generalization is statistically motivated and takes the full second order noise statistics of these images into account. In particular, it includes a noise correlation between the images and spatial noise correlation within the same image. The novel generalized three-dimensional bilateral filter is applied to the attenuation and phase images created with filtered backprojection reconstructions from grating-based phase-contrast tomography. In comparison to established bilateral filters, we obtain improved noise reduction and at the same time a better preservation of edges in the images on the examples of a simulated soft-tissue phantom, a human cerebellum and a human artery sample. The applied full noise covariance is determined via cross-correlation of the image noise. The filter results yield an improved feature recovery based on enhanced noise suppression and edge preservation as shown here on the example of attenuation and phase images captured with grating-based phase-contrast computed tomography. This is supported by quantitative image analysis. Without being bound to phase-contrast imaging, this generalized filter is applicable to any kind of noise-afflicted image data with or without noise correlation. Therefore, it can be utilized in various imaging applications and fields.

  12. Bilateral filtering using the full noise covariance matrix applied to x-ray phase-contrast computed tomography.

    PubMed

    Allner, S; Koehler, T; Fehringer, A; Birnbacher, L; Willner, M; Pfeiffer, F; Noël, P B

    2016-05-21

    The purpose of this work is to develop an image-based de-noising algorithm that exploits complementary information and noise statistics from multi-modal images, as they emerge in x-ray tomography techniques, for instance grating-based phase-contrast CT and spectral CT. Among the noise reduction methods, image-based de-noising is one popular approach and the so-called bilateral filter is a well known algorithm for edge-preserving filtering. We developed a generalization of the bilateral filter for the case where the imaging system provides two or more perfectly aligned images. The proposed generalization is statistically motivated and takes the full second order noise statistics of these images into account. In particular, it includes a noise correlation between the images and spatial noise correlation within the same image. The novel generalized three-dimensional bilateral filter is applied to the attenuation and phase images created with filtered backprojection reconstructions from grating-based phase-contrast tomography. In comparison to established bilateral filters, we obtain improved noise reduction and at the same time a better preservation of edges in the images on the examples of a simulated soft-tissue phantom, a human cerebellum and a human artery sample. The applied full noise covariance is determined via cross-correlation of the image noise. The filter results yield an improved feature recovery based on enhanced noise suppression and edge preservation as shown here on the example of attenuation and phase images captured with grating-based phase-contrast computed tomography. This is supported by quantitative image analysis. Without being bound to phase-contrast imaging, this generalized filter is applicable to any kind of noise-afflicted image data with or without noise correlation. Therefore, it can be utilized in various imaging applications and fields.

  13. Penalized maximum likelihood reconstruction for x-ray differential phase-contrast tomography

    SciTech Connect

    Brendel, Bernhard; Teuffenbach, Maximilian von; Noël, Peter B.; Pfeiffer, Franz; Koehler, Thomas

    2016-01-15

    Purpose: The purpose of this work is to propose a cost function with regularization to iteratively reconstruct attenuation, phase, and scatter images simultaneously from differential phase contrast (DPC) acquisitions, without the need of phase retrieval, and examine its properties. Furthermore this reconstruction method is applied to an acquisition pattern that is suitable for a DPC tomographic system with continuously rotating gantry (sliding window acquisition), overcoming the severe smearing in noniterative reconstruction. Methods: We derive a penalized maximum likelihood reconstruction algorithm to directly reconstruct attenuation, phase, and scatter image from the measured detector values of a DPC acquisition. The proposed penalty comprises, for each of the three images, an independent smoothing prior. Image quality of the proposed reconstruction is compared to images generated with FBP and iterative reconstruction after phase retrieval. Furthermore, the influence between the priors is analyzed. Finally, the proposed reconstruction algorithm is applied to experimental sliding window data acquired at a synchrotron and results are compared to reconstructions based on phase retrieval. Results: The results show that the proposed algorithm significantly increases image quality in comparison to reconstructions based on phase retrieval. No significant mutual influence between the proposed independent priors could be observed. Further it could be illustrated that the iterative reconstruction of a sliding window acquisition results in images with substantially reduced smearing artifacts. Conclusions: Although the proposed cost function is inherently nonconvex, it can be used to reconstruct images with less aliasing artifacts and less streak artifacts than reconstruction methods based on phase retrieval. Furthermore, the proposed method can be used to reconstruct images of sliding window acquisitions with negligible smearing artifacts.

  14. EVITA Project: Comparison Between Traditional Non-Destructive Techniques and Phase Contrast X-Ray Imaging Applied to Aerospace Carbon Fibre Reinforced Polymer

    NASA Astrophysics Data System (ADS)

    Gresil, Matthieu; Revol, Vincent; Kitsianos, Konstantinos; Kanderakis, Georges; Koulalis, Ilias; Sauer, Marc-Olivier; Trétout, Hervé; Madrigal, Ana-Maria

    2016-10-01

    The EU-project EVITA (Non-Destructive EValuation, Inspection and Testing of Primary Aeronautical Composite Structures Using Phase Contrast X-Ray Imaging) aims at bringing Grating-based Phase Contrast X-ray imaging technology to Non-Destructive Evaluation and Inspection of advanced primary and/or complex aerospace composite structures. Grating-based Phase Contrast X-Ray Imaging is based on the so-called Talbot-Lau interferometer, which is made of the combination of a standard X-ray apparatus with three transmission gratings as documented in the literature. This paper presents a comparison of two traditional non-destructive techniques (NDT): ultrasonic through transmission (immersed and water jet) and ultrasonic phased-array pulse echo, with the developed phase contrast X-Ray Imaging applied to advanced aerospace carbon fibre reinforced polymer. Typical defects produced during manufacture is examined as part of the testing and validation procedure. The following defects have been identified as being those most likely to be detected more effectively by the Grating-based Phase Contrast X-Ray Imaging process than other state of the art industrial NDT techniques: porosity, foreign objects, cracks, resin rich, cut fibres, and wavy fibres. The introduction of this innovative methodology is expected to provide the aeronautical industry with a reliable and detailed insight of the integrity of thin and thick composite structures as well as of complex geometry ones, such as integrated closed boxes and sandwiches.

  15. EVITA Project: Comparison Between Traditional Non-Destructive Techniques and Phase Contrast X-Ray Imaging Applied to Aerospace Carbon Fibre Reinforced Polymer

    NASA Astrophysics Data System (ADS)

    Gresil, Matthieu; Revol, Vincent; Kitsianos, Konstantinos; Kanderakis, Georges; Koulalis, Ilias; Sauer, Marc-Olivier; Trétout, Hervé; Madrigal, Ana-Maria

    2017-04-01

    The EU-project EVITA (Non-Destructive EValuation, Inspection and Testing of Primary Aeronautical Composite Structures Using Phase Contrast X-Ray Imaging) aims at bringing Grating-based Phase Contrast X-ray imaging technology to Non-Destructive Evaluation and Inspection of advanced primary and/or complex aerospace composite structures. Grating-based Phase Contrast X-Ray Imaging is based on the so-called Talbot-Lau interferometer, which is made of the combination of a standard X-ray apparatus with three transmission gratings as documented in the literature. This paper presents a comparison of two traditional non-destructive techniques (NDT): ultrasonic through transmission (immersed and water jet) and ultrasonic phased-array pulse echo, with the developed phase contrast X-Ray Imaging applied to advanced aerospace carbon fibre reinforced polymer. Typical defects produced during manufacture is examined as part of the testing and validation procedure. The following defects have been identified as being those most likely to be detected more effectively by the Grating-based Phase Contrast X-Ray Imaging process than other state of the art industrial NDT techniques: porosity, foreign objects, cracks, resin rich, cut fibres, and wavy fibres. The introduction of this innovative methodology is expected to provide the aeronautical industry with a reliable and detailed insight of the integrity of thin and thick composite structures as well as of complex geometry ones, such as integrated closed boxes and sandwiches.

  16. Real-time, high-resolution x-ray diffraction measurements on shocked crystals at a synchrotron facility.

    PubMed

    Gupta, Y M; Turneaure, Stefan J; Perkins, K; Zimmerman, K; Arganbright, N; Shen, G; Chow, P

    2012-12-01

    The Advanced Photon Source (APS) at Argonne National Laboratory was used to obtain real-time, high-resolution x-ray diffraction measurements to determine the microscopic response of shock-compressed single crystals. Disk shaped samples were subjected to plane shock wave compression by impacting them with half-inch diameter, flat-faced projectiles. The projectiles were accelerated to velocities ranging between 300 and 1200 m/s using a compact powder gun designed specifically for use at a synchrotron facility. The experiments were designed to keep the sample probed volume under uniaxial strain and constant stress for a duration longer than the 153.4 ns spacing between x-ray bunches. X-rays from a single pulse (<100 ps duration) out of the periodic x-ray pulses emitted by the synchrotron were used for the diffraction measurements. A synchronization and x-ray detection technique was developed to ensure that the measured signal was obtained unambiguously from the desired x-ray pulse incident on the sample while the sample was in a constant uniaxial strain state. The synchronization and x-ray detection techniques described can be used for a variety of x-ray measurements on shock compressed solids and liquids at the APS. Detailed procedures for applying the Bragg-Brentano parafocusing approach to single crystals at the APS are presented. Analytic developments to determine the effects of crystal substructure and non-ideal geometry on the diffraction pattern position and shape are presented. Representative real-time x-ray diffraction data, indicating shock-induced microstructural changes, are presented for a shock-compressed Al(111) sample. The experimental developments presented here provided, in part, the impetus for the Dynamic Compression Sector (DCS) currently under development at the APS. Both the synchronization∕x-ray detection methods and the analysis equations for high-resolution single crystal x-ray diffraction can be used at the DCS.

  17. Real-time, high-resolution x-ray diffraction measurements on shocked crystals at a synchrotron facility

    NASA Astrophysics Data System (ADS)

    Gupta, Y. M.; Turneaure, Stefan J.; Perkins, K.; Zimmerman, K.; Arganbright, N.; Shen, G.; Chow, P.

    2012-12-01

    The Advanced Photon Source (APS) at Argonne National Laboratory was used to obtain real-time, high-resolution x-ray diffraction measurements to determine the microscopic response of shock-compressed single crystals. Disk shaped samples were subjected to plane shock wave compression by impacting them with half-inch diameter, flat-faced projectiles. The projectiles were accelerated to velocities ranging between 300 and 1200 m/s using a compact powder gun designed specifically for use at a synchrotron facility. The experiments were designed to keep the sample probed volume under uniaxial strain and constant stress for a duration longer than the 153.4 ns spacing between x-ray bunches. X-rays from a single pulse (<100 ps duration) out of the periodic x-ray pulses emitted by the synchrotron were used for the diffraction measurements. A synchronization and x-ray detection technique was developed to ensure that the measured signal was obtained unambiguously from the desired x-ray pulse incident on the sample while the sample was in a constant uniaxial strain state. The synchronization and x-ray detection techniques described can be used for a variety of x-ray measurements on shock compressed solids and liquids at the APS. Detailed procedures for applying the Bragg-Brentano parafocusing approach to single crystals at the APS are presented. Analytic developments to determine the effects of crystal substructure and non-ideal geometry on the diffraction pattern position and shape are presented. Representative real-time x-ray diffraction data, indicating shock-induced microstructural changes, are presented for a shock-compressed Al(111) sample. The experimental developments presented here provided, in part, the impetus for the Dynamic Compression Sector (DCS) currently under development at the APS. Both the synchronization/x-ray detection methods and the analysis equations for high-resolution single crystal x-ray diffraction can be used at the DCS.

  18. Characterization of mouse spinal cord vascular network by means of synchrotron radiation X-ray phase contrast tomography.

    PubMed

    Massimi, Lorenzo; Fratini, Michela; Bukreeva, Inna; Brun, Francesco; Mittone, Alberto; Campi, Gaetano; Spanò, Raffaele; Mastrogiacomo, Milena; de Rosbo, Nicole Kerlero; Bravin, Alberto; Uccelli, Antonio; Cedola, Alessia

    2016-12-01

    High resolution Synchrotron-based X-ray Phase Contrast Tomography (XPCT) allows the simultaneous detection of three dimensional neuronal and vascular networks without using contrast agents or invasive casting preparation. We show and discuss the different features observed in reconstructed XPCT volumes of the ex vivo mouse spinal cord in the lumbo-sacral region, including motor neurons and blood vessels. We report the application of an intensity-based segmentation method to detect and quantitatively characterize the modification in the vascular networks in terms of reduction in experimental visibility. In particular, we apply our approach to the case of the experimental autoimmune encephalomyelitis (EAE), i.e. human multiple sclerosis animal model.

  19. Degradation of Li/S Battery Electrodes On 3D Current Collectors Studied Using X-ray Phase Contrast Tomography

    PubMed Central

    Zielke, L.; Barchasz, C.; Waluś, S.; Alloin, F.; Leprêtre, J.-C.; Spettl, A.; Schmidt, V.; Hilger, A.; Manke, I.; Banhart, J.; Zengerle, R.; Thiele, S.

    2015-01-01

    Lithium/sulphur batteries are promising candidates for future energy storage systems, mainly due to their high potential capacity. However low sulphur utilization and capacity fading hinder practical realizations. In order to improve understanding of the system, we investigate Li/S electrode morphology changes for different ageing steps, using X-ray phase contrast tomography. Thereby we find a strong decrease of sulphur loading after the first cycle, and a constant loading of about 15% of the initial loading afterwards. While cycling, the mean sulphur particle diameters decrease in a qualitatively similar fashion as the discharge capacity fades. The particles spread, migrate into the current collector and accumulate in the upper part again. Simultaneously sulphur particles lose contact area with the conducting network but regain it after ten cycles because their decreasing size results in higher surface areas. Since the capacity still decreases, this regain could be associated with effects such as surface area passivation and increasing charge transfer resistance. PMID:26043280

  20. Degradation of Li/S Battery Electrodes On 3D Current Collectors Studied Using X-ray Phase Contrast Tomography.

    PubMed

    Zielke, L; Barchasz, C; Waluś, S; Alloin, F; Leprêtre, J-C; Spettl, A; Schmidt, V; Hilger, A; Manke, I; Banhart, J; Zengerle, R; Thiele, S

    2015-06-04

    Lithium/sulphur batteries are promising candidates for future energy storage systems, mainly due to their high potential capacity. However low sulphur utilization and capacity fading hinder practical realizations. In order to improve understanding of the system, we investigate Li/S electrode morphology changes for different ageing steps, using X-ray phase contrast tomography. Thereby we find a strong decrease of sulphur loading after the first cycle, and a constant loading of about 15% of the initial loading afterwards. While cycling, the mean sulphur particle diameters decrease in a qualitatively similar fashion as the discharge capacity fades. The particles spread, migrate into the current collector and accumulate in the upper part again. Simultaneously sulphur particles lose contact area with the conducting network but regain it after ten cycles because their decreasing size results in higher surface areas. Since the capacity still decreases, this regain could be associated with effects such as surface area passivation and increasing charge transfer resistance.

  1. Using X-ray in-line phase-contrast imaging for the investigation of nude mouse hepatic tumors.

    PubMed

    Tao, Qiang; Li, Dongyue; Zhang, Lu; Luo, Shuqian

    2012-01-01

    The purpose of this paper is to report the noninvasive imaging of hepatic tumors without contrast agents. Both normal tissues and tumor tissues can be detected, and tumor tissues in different stages can be classified quantitatively. We implanted BEL-7402 human hepatocellular carcinoma cells into the livers of nude mice and then imaged the livers using X-ray in-line phase-contrast imaging (ILPCI). The projection images' texture feature based on gray level co-occurrence matrix (GLCM) and dual-tree complex wavelet transforms (DTCWT) were extracted to discriminate normal tissues and tumor tissues. Different stages of hepatic tumors were classified using support vector machines (SVM). Images of livers from nude mice sacrificed 6 days after inoculation with cancer cells show diffuse distribution of the tumor tissue, but images of livers from nude mice sacrificed 9, 12, or 15 days after inoculation with cancer cells show necrotic lumps in the tumor tissue. The results of the principal component analysis (PCA) of the texture features based on GLCM of normal regions were positive, but those of tumor regions were negative. The results of PCA of the texture features based on DTCWT of normal regions were greater than those of tumor regions. The values of the texture features in low-frequency coefficient images increased monotonically with the growth of the tumors. Different stages of liver tumors can be classified using SVM, and the accuracy is 83.33%. Noninvasive and micron-scale imaging can be achieved by X-ray ILPCI. We can observe hepatic tumors and small vessels from the phase-contrast images. This new imaging approach for hepatic cancer is effective and has potential use in the early detection and classification of hepatic tumors.

  2. 3D algebraic iterative reconstruction for cone-beam x-ray differential phase-contrast computed tomography.

    PubMed

    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.

  3. X-ray Diffraction and Multi-Frame Phase Contrast Imaging Diagnostics for IMPULSE at the Advanced Photon Source

    SciTech Connect

    Iverson, Adam; Carlson, Carl; Young, Jason; Curtis, Alden; Jensen, Brian; Ramos, Kyle; Yeager, John; Montgomery, David; Fezza, Kamel

    2013-07-08

    The diagnostic needs of any dynamic loading platform present unique technical challenges that must be addressed in order to accurately measure in situ material properties in an extreme environment. The IMPULSE platform (IMPact system for Ultrafast Synchrotron Experiments) at the Advanced Photon Source (APS) is no exception and, in fact, may be more challenging, as the imaging diagnostics must be synchronized to both the experiment and the 60 ps wide x-ray bunches produced at APS. The technical challenges of time-resolved x-ray diffraction imaging and high-resolution multi-frame phase contrast imaging (PCI) are described in this paper. Example data from recent IMPULSE experiments are shown to illustrate the advances and evolution of these diagnostics with a focus on comparing the performance of two intensified CCD cameras and their suitability for multi-frame PCI. The continued development of these diagnostics is fundamentally important to IMPULSE and many other loading platforms and will benefit future facilities such as the Dynamic Compression Sector at APS and MaRIE at Los Alamos National Laboratory.

  4. Simultaneous X-ray diffraction and phase-contrast imaging for investigating material deformation mechanisms during high-rate loading

    PubMed Central

    Hudspeth, M.; Sun, T.; Parab, N.; Guo, Z.; Fezzaa, K.; Luo, S.; Chen, W.

    2015-01-01

    Using a high-speed camera and an intensified charge-coupled device (ICCD), a simultaneous X-ray imaging and diffraction technique has been developed for studying dynamic material behaviors during high-rate tensile loading. A Kolsky tension bar has been used to pull samples at 1000 s−1 and 5000 s−1 strain-rates for super-elastic equiatomic NiTi and 1100-O series aluminium, respectively. By altering the ICCD gating time, temporal resolutions of 100 ps and 3.37 µs have been achieved in capturing the diffraction patterns of interest, thus equating to single-pulse and 22-pulse X-ray exposure. Furthermore, the sample through-thickness deformation process has been simultaneously imaged via phase-contrast imaging. It is also shown that adequate signal-to-noise ratios are achieved for the detected white-beam diffraction patterns, thereby allowing sufficient information to perform quantitative data analysis diffraction via in-house software (WBXRD_GUI). Of current interest is the ability to evaluate crystal d-spacing, texture evolution and material phase transitions, all of which will be established from experiments performed at the aforementioned elevated strain-rates. PMID:25537588

  5. Asymmetric masks for large field-of-view and high-energy X-ray phase contrast imaging

    NASA Astrophysics Data System (ADS)

    Endrizzi, M.; Astolfo, A.; Price, B.; Haig, I.; Olivo, A.

    2016-12-01

    We report on a large field of view, laboratory-based X-ray phase-contrast imaging setup. The method is based upon the asymmetric mask design that enables the retrieval of the absorption, refraction and scattering properties of the sample without the need to move any component of the imaging system. This can be thought of as a periodic repetition of a group of three (or more) apertures arranged in such a way that each laminar beam, defined by the apertures, produces a different illumination level when analysed with a standard periodic set of apertures. The sample is scanned through the imaging system, also removing possible aliasing problems that might arise from partial sample illumination when using the edge illumination technique. This approach preserves the incoherence and achromatic properties of edge illumination, removes the problems related to aliasing and it naturally adapts to those situations in clinical, industrial and security imaging where the image is acquired by scanning the sample relative to the imaging system. These concepts were implemented for a large field-of-view set of masks (20 cm × 1.5 cm and 15 cm × 1.2 cm), designed to work with a tungsten anode X-ray source operated up to 80-100 kVp, from which preliminary experimental results are presented.

  6. Simultaneous X-ray diffraction and phase-contrast imaging for investigating material deformation mechanisms during high-rate loading

    SciTech Connect

    Hudspeth, M.; Sun, T.; Parab, N.; Guo, Z.; Fezzaa, K.; Luo, S.; Chen, W.

    2015-01-01

    Using a high-speed camera and an intensified charge-coupled device (ICCD), a simultaneous X-ray imaging and diffraction technique has been developed for studying dynamic material behaviors during high-rate tensile loading. A Kolsky tension bar has been used to pull samples at 1000 s-1and 5000 s-1strain-rates for super-elastic equiatomic NiTi and 1100-O series aluminium, respectively. By altering the ICCD gating time, temporal resolutions of 100 ps and 3.37 µs have been achieved in capturing the diffraction patterns of interest, thus equating to single-pulse and 22-pulse X-ray exposure. Furthermore, the sample through-thickness deformation process has been simultaneously imagedviaphase-contrast imaging. It is also shown that adequate signal-to-noise ratios are achieved for the detected white-beam diffraction patterns, thereby allowing sufficient information to perform quantitative data analysis diffractionviain-house software (WBXRD_GUI). Of current interest is the ability to evaluate crystald-spacing, texture evolution and material phase transitions, all of which will be established from experiments performed at the aforementioned elevated strain-rates.

  7. Simultaneous X-ray diffraction and phase-contrast imaging for investigating material deformation mechanisms during high-rate loading.

    PubMed

    Hudspeth, M; Sun, T; Parab, N; Guo, Z; Fezzaa, K; Luo, S; Chen, W

    2015-01-01

    Using a high-speed camera and an intensified charge-coupled device (ICCD), a simultaneous X-ray imaging and diffraction technique has been developed for studying dynamic material behaviors during high-rate tensile loading. A Kolsky tension bar has been used to pull samples at 1000 s(-1) and 5000 s(-1) strain-rates for super-elastic equiatomic NiTi and 1100-O series aluminium, respectively. By altering the ICCD gating time, temporal resolutions of 100 ps and 3.37 µs have been achieved in capturing the diffraction patterns of interest, thus equating to single-pulse and 22-pulse X-ray exposure. Furthermore, the sample through-thickness deformation process has been simultaneously imaged via phase-contrast imaging. It is also shown that adequate signal-to-noise ratios are achieved for the detected white-beam diffraction patterns, thereby allowing sufficient information to perform quantitative data analysis diffraction via in-house software (WBXRD_GUI). Of current interest is the ability to evaluate crystal d-spacing, texture evolution and material phase transitions, all of which will be established from experiments performed at the aforementioned elevated strain-rates.

  8. Fusion imaging of fluorescent and phase-contrast x-ray computed tomography using synchrotron radiation in medical biology

    NASA Astrophysics Data System (ADS)

    Wu, Jin; Takeda, Tohoru; Lwin, Thet Thet; Sunaguchi, Naoki; Fukami, Tadanori; Yuasa, Tetsuya; Minami, Manabu; Akatsuka, Takao

    2006-08-01

    We integrated fluorescent X-ray computed tomography (FXCT) and phase-contrast X-ray computed tomography (PCCT), and the feasibility of this fusion imaging was assessed for small animals. Brain tumor model of mouse and cardiomyopathic model of hamsters were examined. The brain and heart were extracted after intravenous injection of cerebral perfusion agent 127I-IMP and myocardial fatty acid metabolic agent 127I-BMIPP, respectively. Each target organ was fixed by formalin for FXCT and PCCT. Images were obtained three-dimensionally (3D), and the surface contour of brain and heart were determined from 3D-image after re-sampling for the description with the same spatial resolution. These images were fused interactively on displayed images by 3D image manipulation software. In FXCT, cerebral perfusion image with IMP and fatty acid metabolic image with BMIPP were clearly demonstrated at 0.5 mm and 0.2 mm spatial resolution, respectively. PCCT image with 0.03 mm spatial resolution depicted clearly the morphological structures of brain such as cerebral cortex, hippocampus, lateral ventricle and cerebellum, and for heart such as cardiac lumen, papillary muscle, left and right ventricle. On fusion image, localization and degree of abnormality of cerebral perfusion and myocardial fatty acid metabolism were easily recognized. Our results suggested that the integration of FXCT and PCCT is very useful to understand biological state corresponding to its anatomical localization even in small animal.

  9. Simultaneous X-ray diffraction and phase-contrast imaging for investigating material deformation mechanisms during high-rate loading

    SciTech Connect

    Hudspeth, M.; Sun, T.; Parab, N.; Guo, Z.; Fezzaa, K.; Luo, S.; Chen, W.

    2015-01-01

    Using a high-speed camera and an intensified charge-coupled device (ICCD), a simultaneous X-ray imaging and diffraction technique has been developed for studying dynamic material behaviors during high-rate tensile loading. A Kolsky tension bar has been used to pull samples at 1000 s–1and 5000 s–1strain-rates for super-elastic equiatomic NiTi and 1100-O series aluminium, respectively. By altering the ICCD gating time, temporal resolutions of 100 ps and 3.37 µs have been achieved in capturing the diffraction patterns of interest, thus equating to single-pulse and 22-pulse X-ray exposure. Furthermore, the sample through-thickness deformation process has been simultaneously imagedviaphase-contrast imaging. It is also shown that adequate signal-to-noise ratios are achieved for the detected white-beam diffraction patterns, thereby allowing sufficient information to perform quantitative data analysis diffractionviain-house software (WBXRD_GUI). Finally, of current interest is the ability to evaluate crystald-spacing, texture evolution and material phase transitions, all of which will be established from experiments performed at the aforementioned elevated strain-rates.

  10. FMT-PCCT: hybrid fluorescence molecular tomography-x-ray phase-contrast CT imaging of mouse models.

    PubMed

    Mohajerani, Pouyan; Hipp, Alexander; Willner, Marian; Marschner, Mathias; Trajkovic-Arsic, Marija; Ma, Xiaopeng; Burton, Neal C; Klemm, Uwe; Radrich, Karin; Ermolayev, Vladimir; Tzoumas, Stratis; Siveke, Jens T; Bech, Martin; Pfeiffer, Franz; Ntziachristos, Vasilis

    2014-07-01

    The implementation of hybrid fluorescence molecular tomography (FMT) and X-ray computed tomography (CT) has been shown to be a necessary development, not only for combining anatomical with functional and molecular contrast, but also for generating optical images of high accuracy. FMT affords highly sensitive 3-D imaging of fluorescence bio-distribution, but in stand-alone form it offers images of low resolution. It was shown that FMT accuracy significantly improves by considering anatomical priors from CT. Conversely, CT generally suffers from low soft tissue contrast. Therefore utilization of CT data as prior information in FMT inversion is challenging when different internal organs are not clearly differentiated. Instead, we combined herein FMT with emerging X-ray phase-contrast CT (PCCT). PCCT relies on phase shift differences in tissue to achieve soft tissue contrast superior to conventional CT. We demonstrate for the first time FMT-PCCT imaging of different animal models, where FMT and PCCT scans were performed in vivo and ex vivo, respectively. The results show that FMT-PCCT expands the potential of FMT in imaging lesions with otherwise low or no CT contrast, while retaining the cost benefits of CT and simplicity of hybrid device realizations. The results point to the most accurate FMT performance to date.

  11. Optimisation of image reconstruction for phase-contrast x-ray Talbot-Lau imaging with regard to mechanical robustness

    NASA Astrophysics Data System (ADS)

    Seifert, M.; Kaeppler, S.; Hauke, C.; Horn, F.; Pelzer, G.; Rieger, J.; Michel, T.; Riess, C.; Anton, G.

    2016-09-01

    X-ray grating-based phase-contrast imaging opens new opportunities, inter alia, in medical imaging and non-destructive testing. Because, information about the attenuation properties and about the refractive properties of an object are gained simultaneously. Talbot-Lau imaging requires the knowledge of a reference or free-field image. The long-term stability of a Talbot-Lau interferometer is related to the time span of the validity of a measured reference image. It would be desirable to keep the validity of the reference image for a day or longer to improve feasibility of Talbot-Lau imaging. However, for example thermal and other long-term external influences result in drifting effects of the phase images. Therefore, phases are shifting over time and the reference image is not valid for long-term measurements. Thus, artifacts occur in differential phase-contrast images. We developed an algorithm to determine the differential phase-contrast image with the help of just one calibration image, which is valid for a long time-period. With the help of this algorithm, called phase-plane-fit method, it is possible to save measurement-time, as it is not necessary to take a reference image for each measurement. Additionally, transferring the interferometer technique from laboratory setups to conventional imaging systems the necessary rigidity of the system is difficult to achieve. Therefore, short-term effects like vibrations or distortions of the system lead to imperfections within the phase-stepping procedure. Consequently, artifacts occur in all three image modalities (differential phase-contrast image, attenuation image and dark-field image) of Talbot-Lau imaging. This is a problem with regard to the intended use of phase-contrast imaging for example in clinical routine or non-destructive testing. In this publication an algorithm of Vargas et al is applied and complemented to correct inaccurate phase-step positions with the help of a principal component analysis (PCA

  12. Three-dimensional mouse brain cytoarchitecture revealed by laboratory-based x-ray phase-contrast tomography

    NASA Astrophysics Data System (ADS)

    Töpperwien, Mareike; Krenkel, Martin; Vincenz, Daniel; Stöber, Franziska; Oelschlegel, Anja M.; Goldschmidt, Jürgen; Salditt, Tim

    2017-02-01

    Studies of brain cytoarchitecture in mammals are routinely performed by serial sectioning of the specimen and staining of the sections. The procedure is labor-intensive and the 3D architecture can only be determined after aligning individual 2D sections, leading to a reconstructed volume with non-isotropic resolution. Propagation-based x-ray phase-contrast tomography offers a unique potential for high-resolution 3D imaging of intact biological specimen due to the high penetration depth and potential resolution. We here show that even compact laboratory CT at an optimized liquid-metal jet microfocus source combined with suitable phase-retrieval algorithms and a novel tissue preparation can provide cellular and subcellular resolution in millimeter sized samples of mouse brain. We removed water and lipids from entire mouse brains and measured the remaining dry tissue matrix in air, lowering absorption but increasing phase contrast. We present single-cell resolution images of mouse brain cytoarchitecture and show that axons can be revealed in myelinated fiber bundles. In contrast to optical 3D techniques our approach does neither require staining of cells nor tissue clearing, procedures that are increasingly difficult to apply with increasing sample and brain sizes. The approach thus opens a novel route for high-resolution high-throughput studies of brain architecture in mammals.

  13. Three-dimensional mouse brain cytoarchitecture revealed by laboratory-based x-ray phase-contrast tomography

    PubMed Central

    Töpperwien, Mareike; Krenkel, Martin; Vincenz, Daniel; Stöber, Franziska; Oelschlegel, Anja M.; Goldschmidt, Jürgen; Salditt, Tim

    2017-01-01

    Studies of brain cytoarchitecture in mammals are routinely performed by serial sectioning of the specimen and staining of the sections. The procedure is labor-intensive and the 3D architecture can only be determined after aligning individual 2D sections, leading to a reconstructed volume with non-isotropic resolution. Propagation-based x-ray phase-contrast tomography offers a unique potential for high-resolution 3D imaging of intact biological specimen due to the high penetration depth and potential resolution. We here show that even compact laboratory CT at an optimized liquid-metal jet microfocus source combined with suitable phase-retrieval algorithms and a novel tissue preparation can provide cellular and subcellular resolution in millimeter sized samples of mouse brain. We removed water and lipids from entire mouse brains and measured the remaining dry tissue matrix in air, lowering absorption but increasing phase contrast. We present single-cell resolution images of mouse brain cytoarchitecture and show that axons can be revealed in myelinated fiber bundles. In contrast to optical 3D techniques our approach does neither require staining of cells nor tissue clearing, procedures that are increasingly difficult to apply with increasing sample and brain sizes. The approach thus opens a novel route for high-resolution high-throughput studies of brain architecture in mammals. PMID:28240235

  14. Alignment of low-dose X-ray fluorescence tomography images using differential phase contrast

    PubMed Central

    Hong, Young Pyo; Gleber, Sophie-Charlotte; O’Halloran, Thomas V.; Que, Emily L.; Bleher, Reiner; Vogt, Stefan; Woodruff, Teresa K.; Jacobsen, Chris

    2014-01-01

    X-ray fluorescence nanotomography provides unprecedented sensitivity for studies of trace metal distributions in whole biological cells. Dose fractionation, in which one acquires very low dose individual projections and then obtains high statistics reconstructions as signal from a voxel is brought together (Hegerl & Hoppe, 1976 ▶), requires accurate alignment of these individual projections so as to correct for rotation stage runout. It is shown here that differential phase contrast at 10.2 keV beam energy offers the potential for accurate cross-correlation alignment of successive projections, by demonstrating that successive low dose, 3 ms per pixel, images acquired at the same specimen position and rotation angle have a narrower and smoother cross-correlation function (1.5 pixels FWHM at 300 nm pixel size) than that obtained from zinc fluorescence images (25 pixels FWHM). The differential phase contrast alignment resolution is thus well below the 700 nm × 500 nm beam spot size used in this demonstration, so that dose fractionation should be possible for reduced-dose, more rapidly acquired, fluorescence nanotomography experiments. PMID:24365941

  15. Peak flow velocities in the ascending aorta-real-time phase-contrast magnetic resonance imaging vs. cine magnetic resonance imaging and echocardiography.

    PubMed

    Sohns, Jan M; Kowallick, Johannes T; Joseph, Arun A; Merboldt, K Dietmar; Voit, Dirk; Fasshauer, Martin; Staab, Wieland; Frahm, Jens; Lotz, Joachim; Unterberg-Buchwald, Christina

    2015-10-01

    This prospective study of eight healthy volunteers evaluates peak flow velocities (PFV) in the ascending aorta using real-time phase-contrast magnetic resonance imaging (MRI) in comparison to cine phase-contrast MRI and echocardiography. Flow measurements by echocardiography and cine phase-contrast MRI with breath-holding were performed according to clinical standards. Real-time phase-contrast MRI at 40 ms temporal resolution and 1.3 mm in-plane resolution was based on highly undersampled radial fast low-angle shot (FLASH) sequences with image reconstruction by regularized nonlinear inversion (NLINV). Evaluations focused on the determination of PFV. Linear regressions and Bland-Altman plots were used for comparisons of methods. When averaged across subjects, real-time phase-contrast MRI resulted in PFV of 120±20 cm s(-1) (mean ± SD) in comparison to 122±16 cm s(-1) for cine MRI and 124±20 cm s(-1) for echocardiography. The maximum deviations between real-time phase-contrast MRI and echocardiography ranged from -20 to +14 cm s(-1) (cine MRI: -10 to +12 cm s(-1)). Thus, in general, real-time phase-contrast MRI of cardiac outflow revealed quantitative agreement with cine MRI and echocardiography. The advantages of real-time MRI are measurements during free breathing and access to individual cardiac cycles.

  16. Real-Time, Light Weight, X-Ray Imager. Phase 2

    DTIC Science & Technology

    1994-06-06

    Lght Weight, X-Ray Imager"I Principle hwvesdgatow Eiren Kutlubay Miderm Report Table of Contents Front Cover Report Dcm taonpage Foreword 1...of the system to an X-ray exposure. Lanex screens will be used for the initial tests. Phantoms will be available to be used under X-ray exposure

  17. Real-time x-ray scattering study of the initial growth of organic crystals on polymer brushes

    SciTech Connect

    An, Sung Yup; Ahn, Kwangseok; Kim, Doris Yangsoo; Lee, Dong Ryeol; Lee, Hyun-Hwi; Cho, Jeong Ho

    2014-04-21

    We studied the early-stage growth structures of pentacene organic crystals grown on polymer brushes using real-time x-ray scattering techniques. In situ x-ray reflectivity and atomic force microscopy analyses revealed that at temperatures close to the glass transition temperature of polymer brush, the pentacene overlayer on a polymer brush film showed incomplete condensation and 3D island structures from the first monolayer. A growth model based on these observations was used to quantitatively analyze the real-time anti-Bragg x-ray scattering intensities measured during pentacene growth to obtain the time-dependent layer coverage of the individual pentacene monolayers. The extracted total coverage confirmed significant desorption and incomplete condensation in the pentacene films deposited on the polymer brushes. These effects are ascribed to the change in the surface viscoelasticity of the polymer brushes around the glass transition temperature.

  18. High spatiotemporal resolution measurement of regional lung air volumes from 2D phase contrast x-ray images

    SciTech Connect

    Leong, Andrew F. T.; Islam, M. Sirajul; Kitchen, Marcus J.; Fouras, Andreas; Wallace, Megan J.; Hooper, Stuart B.

    2013-04-15

    Purpose: Described herein is a new technique for measuring regional lung air volumes from two-dimensional propagation-based phase contrast x-ray (PBI) images at very high spatial and temporal resolution. Phase contrast dramatically increases lung visibility and the outlined volumetric reconstruction technique quantifies dynamic changes in respiratory function. These methods can be used for assessing pulmonary disease and injury and for optimizing mechanical ventilation techniques for preterm infants using animal models. Methods: The volumetric reconstruction combines the algorithms of temporal subtraction and single image phase retrieval (SIPR) to isolate the image of the lungs from the thoracic cage in order to measure regional lung air volumes. The SIPR algorithm was used to recover the change in projected thickness of the lungs on a pixel-by-pixel basis (pixel dimensions {approx}16.2 {mu}m). The technique has been validated using numerical simulation and compared results of measuring regional lung air volumes with and without the use of temporal subtraction for removing the thoracic cage. To test this approach, a series of PBI images of newborn rabbit pups mechanically ventilated at different frequencies was employed. Results: Regional lung air volumes measured from PBI images of newborn rabbit pups showed on average an improvement of at least 20% in 16% of pixels within the lungs in comparison to that measured without the use of temporal subtraction. The majority of pixels that showed an improvement was found to be in regions occupied by bone. Applying the volumetric technique to sequences of PBI images of newborn rabbit pups, it is shown that lung aeration at birth can be highly heterogeneous. Conclusions: This paper presents an image segmentation technique based on temporal subtraction that has successfully been used to isolate the lungs from PBI chest images, allowing the change in lung air volume to be measured over regions as small as the pixel size. Using

  19. 100 percent x-ray weld inspection: A real-time imaging system for large diameter steel pipe manufacturing

    SciTech Connect

    Stone, G.R.; Lehmann, D.; Gilblom, D.

    1996-02-01

    The new, real-time microfocus X-ray system described here not only paid for itself and saved $1 million on the first job, it provided 100% inspection 12--14 times faster than the previously used conventional radiographic technique. Compared to conventional radiography, real-time X-ray inspection offers benefits that translate into significant cost and time savings. One primary advantage is the real time reporting capability to manufacturing for process control allowing the operator to receive instantaneous feedback during production and to make adjustments immediately. For example, with conventional film based radiographic systems, the operator would have to predetermine energy levels, exposure time, and orientation of the sample to be inspected before beginning the actual inspection run. Only after developing the film and analyzing the images was it possible to determine if the desired results were obtained. If not, the settings would have to be adjusted and the manufacturing process repeated. In contrast, with real-time X-ray, the operator has the ability to visually observe the inspection process on a video monitor while adjusting the energy level and/or orientation of the sample using a five-axis (x, y, z, tilt, and rotate) sample manipulator for optimum results. In addition, real-time monitoring allows visual observation of any mechanical movement which is internal to the sample. The application of this technique to still pipe welding at the Northwest Pipe Company is discussed.

  20. Analysis of a deconvolution-based information retrieval algorithm in X-ray grating-based phase-contrast imaging

    NASA Astrophysics Data System (ADS)

    Horn, Florian; Bayer, Florian; Pelzer, Georg; Rieger, Jens; Ritter, André; Weber, Thomas; Zang, Andrea; Michel, Thilo; Anton, Gisela

    2014-03-01

    Grating-based X-ray phase-contrast imaging is a promising imaging modality to increase soft tissue contrast in comparison to conventional attenuation-based radiography. Complementary and otherwise inaccessible information is provided by the dark-field image, which shows the sub-pixel size granularity of the measured object. This could especially turn out to be useful in mammography, where tumourous tissue is connected with the presence of supertiny microcalcifications. In addition to the well-established image reconstruction process, an analysis method was introduced by Modregger, 1 which is based on deconvolution of the underlying scattering distribution within a single pixel revealing information about the sample. Subsequently, the different contrast modalities can be calculated with the scattering distribution. The method already proved to deliver additional information in the higher moments of the scattering distribution and possibly reaches better image quality with respect to an increased contrast-to-noise ratio. Several measurements were carried out using melamine foams as phantoms. We analysed the dependency of the deconvolution-based method with respect to the dark-field image on different parameters such as dose, number of iterations of the iterative deconvolution-algorithm and dark-field signal. A disagreement was found in the reconstructed dark-field values between the FFT method and the iterative method. Usage of the resulting characteristics might be helpful in future applications.

  1. Analysis and accurate reconstruction of incomplete data in X-ray differential phase-contrast computed tomography.

    PubMed

    Fu, Jian; Tan, Renbo; Chen, Liyuan

    2014-01-01

    X-ray differential phase-contrast computed tomography (DPC-CT) is a powerful physical and biochemical analysis tool. In practical applications, there are often challenges for DPC-CT due to insufficient data caused by few-view, bad or missing detector channels, or limited scanning angular range. They occur quite frequently because of experimental constraints from imaging hardware, scanning geometry, and the exposure dose delivered to living specimens. In this work, we analyze the influence of incomplete data on DPC-CT image reconstruction. Then, a reconstruction method is developed and investigated for incomplete data DPC-CT. It is based on an algebraic iteration reconstruction technique, which minimizes the image total variation and permits accurate tomographic imaging with less data. This work comprises a numerical study of the method and its experimental verification using a dataset measured at the W2 beamline of the storage ring DORIS III equipped with a Talbot-Lau interferometer. The numerical and experimental results demonstrate that the presented method can handle incomplete data. It will be of interest for a wide range of DPC-CT applications in medicine, biology, and nondestructive testing.

  2. Phase contrast imaging X-ray computed tomography: quantitative characterization of human patellar cartilage matrix with topological and geometrical features

    NASA Astrophysics Data System (ADS)

    Nagarajan, Mahesh B.; Coan, Paola; Huber, Markus B.; Diemoz, Paul C.; Wismüller, Axel

    2014-03-01

    Current assessment of cartilage is primarily based on identification of indirect markers such as joint space narrowing and increased subchondral bone density on x-ray images. In this context, phase contrast CT imaging (PCI-CT) has recently emerged as a novel imaging technique that allows a direct examination of chondrocyte patterns and their correlation to osteoarthritis through visualization of cartilage soft tissue. This study investigates the use of topological and geometrical approaches for characterizing chondrocyte patterns in the radial zone of the knee cartilage matrix in the presence and absence of osteoarthritic damage. For this purpose, topological features derived from Minkowski Functionals and geometric features derived from the Scaling Index Method (SIM) were extracted from 842 regions of interest (ROI) annotated on PCI-CT images of healthy and osteoarthritic specimens of human patellar cartilage. The extracted features were then used in a machine learning task involving support vector regression to classify ROIs as healthy or osteoarthritic. Classification performance was evaluated using the area under the receiver operating characteristic (ROC) curve (AUC). The best classification performance was observed with high-dimensional geometrical feature vectors derived from SIM (0.95 ± 0.06) which outperformed all Minkowski Functionals (p < 0.001). These results suggest that such quantitative analysis of chondrocyte patterns in human patellar cartilage matrix involving SIM-derived geometrical features can distinguish between healthy and osteoarthritic tissue with high accuracy.

  3. Laboratory implementation of edge illumination X-ray phase-contrast imaging with energy-resolved detectors

    NASA Astrophysics Data System (ADS)

    Diemoz, P. C.; Endrizzi, M.; Vittoria, F. A.; Hagen, C. K.; Kallon, G.; Basta, D.; Marenzana, M.; Delogu, P.; Vincenzi, A.; De Ruvo, L.; Spandre, G.; Brez, A.; Bellazzini, R.; Olivo, A.

    2015-03-01

    Edge illumination (EI) X-ray phase-contrast imaging (XPCI) has potential for applications in different fields of research, including materials science, non-destructive industrial testing, small-animal imaging, and medical imaging. One of its main advantages is the compatibility with laboratory equipment, in particular with conventional non-microfocal sources, which makes its exploitation in normal research laboratories possible. In this work, we demonstrate that the signal in laboratory implementations of EI can be correctly described with the use of the simplified geometrical optics. Besides enabling the derivation of simple expressions for the sensitivity and spatial resolution of a given EI setup, this model also highlights the EI's achromaticity. With the aim of improving image quality, as well as to take advantage of the fact that all energies in the spectrum contribute to the image contrast, we carried out EI acquisitions using a photon-counting energy-resolved detector. The obtained results demonstrate that this approach has great potential for future laboratory implementations of EI.

  4. Imaging of Hydrogel Microsphere Structure and Foreign Body Response Based on Endogenous X-Ray Phase Contrast

    DOE PAGES

    Appel, Alyssa A.; Ibarra, Veronica; Somo, Sami I.; ...

    2016-10-31

    Transplantation of functional islets encapsulated in stable biomaterials has the potential to cure Type I diabetes. However, the success of these materials requires the ability to understand their stability in vivo. Imaging techniques that enable monitoring of biomaterial performance are critical to further development in the field. In this study, we demonstrate for the first time that X-ray phase contrast (XPC) imaging techniques enable 3D imaging and evaluation of islet volume, alginate hydrogel structure and local soft tissue response. Islets were encapsulated in alginate systems prepared in methods used in clinical trials and implanted in a rodent omentum pouch modelmore » as a treatment for type I diabetes. Microbeads were imaged with XPC prior to implantation and following implantation into an omentum pouch. Islets could be identified within alginate beads and the islet volume quantified. Omental adipose tissue could be distinguished from inflammatory regions resulting from implanted beads. Individual beads and the local encapsulation response were visualized and quantifiable. Measurements were in agreement with histology. The 3D structure of the microbeads could be characterized with XPC and failed beads could also be identified. These results point to the substantial potential of XPC as a tool for imaging biomaterials in small animal models.« less

  5. Imaging of Hydrogel Microsphere Structure and Foreign Body Response Based on Endogenous X-Ray Phase Contrast

    SciTech Connect

    Appel, Alyssa A.; Ibarra, Veronica; Somo, Sami I.; Larson, Jeffery C.; Garson, Alfred B.; Guan, Huifeng; McQuilling, John Patrick; Zhong, Zhong; Anastasio, Mark A.; Opara, Emmanuel C.; Brey, Eric M.

    2016-10-31

    Transplantation of functional islets encapsulated in stable biomaterials has the potential to cure Type I diabetes. However, the success of these materials requires the ability to understand their stability in vivo. Imaging techniques that enable monitoring of biomaterial performance are critical to further development in the field. In this study, we demonstrate for the first time that X-ray phase contrast (XPC) imaging techniques enable 3D imaging and evaluation of islet volume, alginate hydrogel structure and local soft tissue response. Islets were encapsulated in alginate systems prepared in methods used in clinical trials and implanted in a rodent omentum pouch model as a treatment for type I diabetes. Microbeads were imaged with XPC prior to implantation and following implantation into an omentum pouch. Islets could be identified within alginate beads and the islet volume quantified. Omental adipose tissue could be distinguished from inflammatory regions resulting from implanted beads. Individual beads and the local encapsulation response were visualized and quantifiable. Measurements were in agreement with histology. The 3D structure of the microbeads could be characterized with XPC and failed beads could also be identified. These results point to the substantial potential of XPC as a tool for imaging biomaterials in small animal models.

  6. The first large area, high X-ray energy phase contrast prototype for enhanced detection of threat object in baggage screening

    NASA Astrophysics Data System (ADS)

    Astolfo, Alberto; Endrizzi, Marco; Price, Benjamin; Haig, Ian; Olivo, Alessandro

    2016-10-01

    X-ray imaging is the most commonly used method in baggage screening. Conventional x-ray attenuation (usually in dual-energy mode) is exploited to discriminate threat and non-threat materials: this is essentially, a method that has seen little changes in decades. Our goal is to demonstrate that x-rays can be used in a different way to achieve improved detection of weapons and explosives. Our approach involves the use of x-ray phase contrast and it a) allows much higher sensitivity in the detection of object edges and b) can be made sensitive to the sample's microstructure. We believe that these additional channels of information, alongside conventional attenuation which would still be available, have the potential to significantly increase both sensitivity and specificity in baggage scanning. We obtained preliminary data demonstrating the above enhanced detection, and we built a scanner (currently in commissioning) to scale the concept up and test it on real baggage. In particular, while previous X-ray phase contrast imaging systems were limited in terms of both field of view (FOV) and maximum x-ray energy, this scanner overcomes both those limitations and provides FOVs up to 20 to 50 cm2 with x-ray energies up to 100 keV.

  7. Volumetric quantitative characterization of human patellar cartilage with topological and geometrical features on phase contrast x-ray computed tomography

    PubMed Central

    Nagarajan, Mahesh B.; Coan, Paola; Huber, Markus B.; Diemoz, Paul C.; Wismüller, Axel

    2015-01-01

    Phase contrast X-ray computed tomography (PCI-CT) has attracted significant interest in recent years for its ability to provide significantly improved image contrast in low absorbing materials such as soft biological tissue. In the research context of cartilage imaging, previous studies have demonstrated the ability of PCI-CT to visualize structural details of human patellar cartilage matrix and capture changes to chondrocyte organization induced by osteoarthritis. This study evaluates the use of geometrical and topological features for volumetric characterization of such chondrocyte patterns in the presence (or absence) of osteoarthritic damage. Geometrical features derived from the scaling index method (SIM) and topological features derived from Minkowski Functionals were extracted from 1392 volumes of interest (VOI) annotated on PCI-CT images of ex vivo human patellar cartilage specimens. These features were subsequently used in a machine learning task with support vector regression to classify VOIs as healthy or osteoarthritic; classification performance was evaluated using the area under the receiver-operating characteristic (ROC) curve (AUC). Our results show that the classification performance of SIM-derived geometrical features (AUC: 0.90 ± 0.09) significantly outperform Minkowski Functionals volume (AUC: 0.54 ± 0.02), surface (AUC: 0.72 ± 0.06), mean breadth (AUC: 0.74 ± 0.06) and Euler characteristic (AUC: 0.78 ± 0.04) (p < 10−4). These results suggest that such geometrical features can provide a detailed characterization of the chondrocyte organization in the cartilage matrix in an automated manner, while also enabling classification of cartilage as healthy or osteoarthritic with high accuracy. Such features could potentially serve as diagnostic imaging markers for evaluating osteoarthritis progression and its response to different therapeutic intervention strategies. PMID:26142112

  8. Visualization of small lesions in rat cartilage by means of laboratory-based x-ray phase contrast imaging

    NASA Astrophysics Data System (ADS)

    Marenzana, Massimo; Hagen, Charlotte K.; Das Neves Borges, Patricia; Endrizzi, Marco; Szafraniec, Magdalena B.; Ignatyev, Konstantin; Olivo, Alessandro

    2012-12-01

    Being able to quantitatively assess articular cartilage in three-dimensions (3D) in small rodent animal models, with a simple laboratory set-up, would prove extremely important for the development of pre-clinical research focusing on cartilage pathologies such as osteoarthritis (OA). These models are becoming essential tools for the development of new drugs for OA, a disease affecting up to 1/3 of the population older than 50 years for which there is no cure except prosthetic surgery. However, due to limitations in imaging technology, high-throughput 3D structural imaging has not been achievable in small rodent models, thereby limiting their translational potential and their efficiency as research tools. We show that a simple laboratory system based on coded-aperture x-ray phase contrast imaging (CAXPCi) can correctly visualize the cartilage layer in slices of an excised rat tibia imaged both in air and in saline solution. Moreover, we show that small, surgically induced lesions are also correctly detected by the CAXPCi system, and we support this finding with histopathology examination. Following these successful proof-of-concept results in rat cartilage, we expect that an upgrade of the system to higher resolutions (currently underway) will enable extending the method to the imaging of mouse cartilage as well. From a technological standpoint, by showing the capability of the system to detect cartilage also in water, we demonstrate phase sensitivity comparable to other lab-based phase methods (e.g. grating interferometry). In conclusion, CAXPCi holds a strong potential for being adopted as a routine laboratory tool for non-destructive, high throughput assessment of 3D structural changes in murine articular cartilage, with a possible impact in the field similar to the revolution that conventional microCT brought into bone research.

  9. Detector, collimator and real-time reconstructor for a new scanning-beam digital x-ray (SBDX) prototype

    PubMed Central

    Speidel, Michael A.; Tomkowiak, Michael T.; Raval, Amish N.; Dunkerley, David A. P.; Slagowski, Jordan M.; Kahn, Paul; Ku, Jamie; Funk, Tobias

    2015-01-01

    Scanning-beam digital x-ray (SBDX) is an inverse geometry fluoroscopy system for low dose cardiac imaging. The use of a narrow scanned x-ray beam in SBDX reduces detected x-ray scatter and improves dose efficiency, however the tight beam collimation also limits the maximum achievable x-ray fluence. To increase the fluence available for imaging, we have constructed a new SBDX prototype with a wider x-ray beam, larger-area detector, and new real-time image reconstructor. Imaging is performed with a scanning source that generates 40,328 narrow overlapping projections from 71 × 71 focal spot positions for every 1/15 s scan period. A high speed 2-mm thick CdTe photon counting detector was constructed with 320×160 elements and 10.6 cm × 5.3 cm area (full readout every 1.28 μs), providing an 86% increase in area over the previous SBDX prototype. A matching multihole collimator was fabricated from layers of tungsten, brass, and lead, and a multi-GPU reconstructor was assembled to reconstruct the stream of captured detector images into full field-of-view images in real time. Thirty-two tomosynthetic planes spaced by 5 mm plus a multiplane composite image are produced for each scan frame. Noise equivalent quanta on the new SBDX prototype measured 63%–71% higher than the previous prototype. X-ray scatter fraction was 3.9–7.8% when imaging 23.3–32.6 cm acrylic phantoms, versus 2.3–4.2% with the previous prototype. Coronary angiographic imaging at 15 frame/s was successfully performed on the new SBDX prototype, with live display of either a multiplane composite or single plane image. PMID:26236071

  10. Observation of low-temperature object by phase-contrast x-ray imaging: Nondestructive imaging of air clathrate hydrates at 233 K

    SciTech Connect

    Takeya, Satoshi; Honda, Kazumasa; Yoneyama, Akio; Hirai, Yasuharu; Okuyama, Junichi; Hondoh, Takeo; Hyodo, Kazuyuki; Takeda, Tohoru

    2006-05-15

    A cryochamber and a liquid cell that are designed for nondestructive three dimensional observations and arranged in a two-crystal x-ray interferometer expand the use of phase-contrast x-ray imaging that could only be performed at room temperature in previous studies to a new temperature range of 190 K to room temperature. The methyl acetate in the liquid cell prevents undesirable sample outline contrasts and enables internal observations. Both a nondestructive observation and a highly accurate absolute density of the materials under low-temperature conditions can be obtained with a single measurement using this new technique. A three dimensional x-ray computed tomography (x-ray CT) of the air clathrate hydrate in the hexagonal ice drilled from Dome Fuji in Antarctica is shown, and the density of the air hydrate is estimated to be 0.937(3) g/cm{sup 3} at 233 K.

  11. Real-time Studies of Shocked Polycrystalline Materials with Single-Pulse X-ray Diffraction

    SciTech Connect

    Dane V. Morgan

    2011-05-25

    Characteristic K-α x-rays used for single-pulse XRD are conventionally produced by a 37-stage high-voltage Marx pulse generator coupled to a vacuum needle-and-washer x-ray diode via coaxial transmission line. A large field-of-view x-ray image plate detection system typically enables observation of several Debye-Scherrer rings. Recently, we have developed a fiber-optic reducer, coupled to a CCD camera, to obtain low-noise, large field-of-view images. The direct beam spot is produced by bremsstrahlung radiation attenuated by a twomillimeter tungsten beam stop. Determination of the direct beam position is necessary to perform the ring integration.

  12. A feasibility study of X-ray phase-contrast mammographic tomography at the Imaging and Medical beamline of the Australian Synchrotron.

    PubMed

    Nesterets, Yakov I; Gureyev, Timur E; Mayo, Sheridan C; Stevenson, Andrew W; Thompson, Darren; Brown, Jeremy M C; Kitchen, Marcus J; Pavlov, Konstantin M; Lockie, Darren; Brun, Francesco; Tromba, Giuliana

    2015-11-01

    Results are presented of a recent experiment at the Imaging and Medical beamline of the Australian Synchrotron intended to contribute to the implementation of low-dose high-sensitivity three-dimensional mammographic phase-contrast imaging, initially at synchrotrons and subsequently in hospitals and medical imaging clinics. The effect of such imaging parameters as X-ray energy, source size, detector resolution, sample-to-detector distance, scanning and data processing strategies in the case of propagation-based phase-contrast computed tomography (CT) have been tested, quantified, evaluated and optimized using a plastic phantom simulating relevant breast-tissue characteristics. Analysis of the data collected using a Hamamatsu CMOS Flat Panel Sensor, with a pixel size of 100 µm, revealed the presence of propagation-based phase contrast and demonstrated significant improvement of the quality of phase-contrast CT imaging compared with conventional (absorption-based) CT, at medically acceptable radiation doses.

  13. Real-Time Studies of Gallium Adsorption and Desorption Kinetics by Grazing-Incidence Small-Angle X-ray Scattering and X-ray Fluorescence

    SciTech Connect

    Wang, Y.; Ozcan, A; Ludwig, K; Bhattacharyya, A

    2008-01-01

    Gallium adsorption and desorption on c-plane sapphire has been studied by real-time grazing incidence small-angle x-ray scattering and x-ray fluorescence as a function of substrate temperature (680-740 C) and Ga flux. The x-ray techniques monitor the surface morphology evolution and amount of Ga on the surface. During deposition, nanodroplets of liquid Ga are observed to form on the surface and coarsen. The growth of droplet size during continuous deposition follows dynamical scaling, in agreement with expectations from theory and simulations which include deposition-induced droplet coalescence. However, observation of continued droplet distance scale coarsening during desorption points to the necessity of including further physical processes in the modeling. The desorption rate at different substrate temperatures gives the activation energy of Ga desorption as 2.7 eV, comparable to measured activation energies for desorption from Ga droplets on other substrates and to the Ga heat of vaporization.

  14. Development of ultrafast laser-based x-ray in-vivo phase-contrast micro-CT beamline for biomedical applications at Advanced Laser Light Source (ALLS).

    PubMed

    Kincaid, Russell; Krol, Andrzej; Fourmaux, Sylvain; Kieffer, Jean-Claude; Serbanescu, Cristina; Servol, Marina; Vogelsang, Levon; Wilkins, Steve; Stevenson, Andrew; Nesterets, Yakov; Lipson, Edward; Ye, Hongwei; Pogany, Andrew

    2008-01-01

    We are developing and exploring the imaging performance of, an in vivo, in-line holography, x-ray phase-contrast, micro-CT system with an ultrafast laser-based x-ray (ULX) source. By testing and refining our system, and by performing computer simulations, we plan to improve system performance in terms of contrast resolution and multi-energy imaging to a level beyond what can be obtained using a conventional microfocal x-ray tube. Initial CT projection sets at single energy (Mo K(alpha) and K(beta) lines) were acquired in the Fresnel regime and reconstructed for phantoms and a euthanized mouse. We also performed computer simulations of phase-contrast micro-CT scans for low-contrast, soft-tissue, tumor imaging. We determined that, in order to perform a phase-contrast, complete micro-CT scan using ULX, the following conditions must be met: (i) the x-ray source needs to be stable during the scan; (ii) the laser focal spot size needs to be less than 10 mum for source-to-object distance greater than 30 cm; (iii) the laser light intensity on the target needs to be in the range of 5 x 10(17) to 5 x 10(19) W/cm(2); (iv) the ablation protection system needs to allow uninterrupted scans; (v) the laser light focusing on the target needs to remain accurate during the entire scan; (vi) a fresh surface of the target must be exposed to consecutive laser shots during the entire scan; (vii) the effective detector element size must be less than 12 mum. Based on the results obtained in this research project, we anticipate that the new 10 Hz, 200 TW laser with 50 W average power that is being commissioned at ALLS will allow us practical implementation of in vivo x-ray phase-contrast micro-CT.

  15. Gas gun shock experiments with single-pulse x-ray phase contrast imaging and diffraction at the Advanced Photon Source

    NASA Astrophysics Data System (ADS)

    Luo, S. N.; Jensen, B. J.; Hooks, D. E.; Fezzaa, K.; Ramos, K. J.; Yeager, J. D.; Kwiatkowski, K.; Shimada, T.

    2012-07-01

    The highly transient nature of shock loading and pronounced microstructure effects on dynamic materials response call for in situ, temporally and spatially resolved, x-ray-based diagnostics. Third-generation synchrotron x-ray sources are advantageous for x-ray phase contrast imaging (PCI) and diffraction under dynamic loading, due to their high photon fluxes, high coherency, and high pulse repetition rates. The feasibility of bulk-scale gas gun shock experiments with dynamic x-ray PCI and diffraction measurements was investigated at the beamline 32ID-B of the Advanced Photon Source. The x-ray beam characteristics, experimental setup, x-ray diagnostics, and static and dynamic test results are described. We demonstrate ultrafast, multiframe, single-pulse PCI measurements with unprecedented temporal (<100 ps) and spatial (˜2 μm) resolutions for bulk-scale shock experiments, as well as single-pulse dynamic Laue diffraction. The results not only substantiate the potential of synchrotron-based experiments for addressing a variety of shock physics problems, but also allow us to identify the technical challenges related to image detection, x-ray source, and dynamic loading.

  16. Gas gun shock experiments with single-pulse x-ray phase contrast imaging and diffraction at the Advanced Photon Source.

    PubMed

    Luo, S N; Jensen, B J; Hooks, D E; Fezzaa, K; Ramos, K J; Yeager, J D; Kwiatkowski, K; Shimada, T

    2012-07-01

    The highly transient nature of shock loading and pronounced microstructure effects on dynamic materials response call for in situ, temporally and spatially resolved, x-ray-based diagnostics. Third-generation synchrotron x-ray sources are advantageous for x-ray phase contrast imaging (PCI) and diffraction under dynamic loading, due to their high photon fluxes, high coherency, and high pulse repetition rates. The feasibility of bulk-scale gas gun shock experiments with dynamic x-ray PCI and diffraction measurements was investigated at the beamline 32ID-B of the Advanced Photon Source. The x-ray beam characteristics, experimental setup, x-ray diagnostics, and static and dynamic test results are described. We demonstrate ultrafast, multiframe, single-pulse PCI measurements with unprecedented temporal (<100 ps) and spatial (∼2 μm) resolutions for bulk-scale shock experiments, as well as single-pulse dynamic Laue diffraction. The results not only substantiate the potential of synchrotron-based experiments for addressing a variety of shock physics problems, but also allow us to identify the technical challenges related to image detection, x-ray source, and dynamic loading.

  17. In vivo physiological saline-infused hepatic vessel imaging using a two-crystal-interferometer-based phase-contrast X-ray technique.

    PubMed

    Takeda, Tohoru; Yoneyama, Akio; Wu, Jin; Momose, Atsushi; Hyodo, Kazuyuki

    2012-03-01

    Using a two-crystal-interferometer-based phase-contrast X-ray imaging system, the portal vein, capillary vessel area and hepatic vein of live rats were revealed sequentially by injecting physiological saline via the portal vein. Vessels greater than 0.06 mm in diameter were clearly shown with low levels of X-rays (552 µGy). This suggests that in vivo vessel imaging of small animals can be performed as conventional angiography without the side effects of the presently used iodine contrast agents.

  18. Hybrid quantitative simulation on the in-line phase-contrast x-ray imaging of three dimensional samples under actual clinic imaging parameters

    SciTech Connect

    Yu Hong; Han Shensheng; Ding Jianhui; Jiang Zhaoxia; Peng Weijun

    2009-07-06

    A hybrid model combining Monte Carlo method with diffraction theory of wave optics has been developed and applied to quantitatively simulate the in-line diffractive phase-contrast x-ray imaging of three dimensional tissue samples under actual clinic imaging parameters. The primary microcosmic interactions of medical-energy x-ray within matter including photoabsorption, Compton scattering, and coherent scattering, have been taken into account in the Monte Carlo simulation. A diffraction processing based on Fresnel diffraction theory is carried out to simulate the macroscopic diffraction effect. A comparison with experiment results has also been performed.

  19. Development of a large-area CMOS-based detector for real-time x-ray imaging

    NASA Astrophysics Data System (ADS)

    Heo, Sung Kyn; Park, Sung Kyu; Hwang, Sung Ha; Im, Dong Ak; Kosonen, Jari; Kim, Tae Woo; Yun, Seungman; Kim, Ho Kyung

    2010-04-01

    Complementary metal-oxide-semiconductor (CMOS) active pixel sensors (APSs) with high electrical and optical performances are now being attractive for digital radiography (DR) and dental cone-beam computed tomography (CBCT). In this study, we report our prototype CMOS-based detectors capable of real-time imaging. The field-of-view of the detector is 12 × 14.4 cm. The detector employs a CsI:Tl scintillator as an x-ray-to-light converter. The electrical performance of the CMOS APS, such as readout noise and full-well capacity, was evaluated. The x-ray imaging characteristics of the detector were evaluated in terms of characteristic curve, pre-sampling modulation transfer function, noise power spectrum, detective quantum efficiency, and image lag. The overall performance of the detector is demonstrated with phantom images obtained for DR and CBCT applications. The detailed development description and measurement results are addressed. With the results, we suggest that the prototype CMOS-based detector has the potential for CBCT and real-time x-ray imaging applications.

  20. In-line phase-contrast imaging of a biological specimen using a compact laser-Compton scattering-based x-ray source

    NASA Astrophysics Data System (ADS)

    Ikeura-Sekiguchi, H.; Kuroda, R.; Yasumoto, M.; Toyokawa, H.; Koike, M.; Yamada, K.; Sakai, F.; Mori, K.; Maruyama, K.; Oka, H.; Kimata, T.

    2008-03-01

    Laser-Compton scattering (LCS) x-ray sources have recently attracted much attention for their potential use at local medical facilities because they can produce ultrashort pulsed, high-brilliance, and quasimonochromatic hard x rays with a small source size. The feasibility of in-line phase-contrast imaging for a "thick" biological specimens of rat lumbar vertebrae using the developed compact LCS-X in AIST was investigated for the promotion of clinical imaging. In the higher-quality images, anatomical details of the spinous processes of the vertebrae are more clearly observable than with conventional absorption radiography. The results demonstrate that phase-contrast radiography can be performed using LCS-X.

  1. Time-resolved x-ray photoelectron spectroscopy techniques for real-time studies of interfacial charge transfer dynamics

    NASA Astrophysics Data System (ADS)

    Shavorskiy, Andrey; Cordones, Amy; Vura-Weis, Josh; Siefermann, Katrin; Slaughter, Daniel; Sturm, Felix; Weise, Fabian; Bluhm, Hendrik; Strader, Matthew; Cho, Hana; Lin, Ming-Fu; Bacellar, Camila; Khurmi, Champak; Hertlein, Marcus; Guo, Jinghua; Tyliszczak, Tolek; Prendergast, David; Coslovich, Giacomo; Robinson, Joseph; Kaindl, Robert A.; Schoenlein, Robert W.; Belkacem, Ali; Weber, Thorsten; Neumark, Daniel M.; Leone, Stephen R.; Nordlund, Dennis; Ogasawara, Hirohito; Nilsson, Anders R.; Krupin, Oleg; Turner, Joshua J.; Schlotter, William F.; Holmes, Michael R.; Heimann, Philip A.; Messerschmidt, Marc; Minitti, Michael P.; Beye, Martin; Gul, Sheraz; Zhang, Jin Z.; Huse, Nils; Gessner, Oliver

    2013-04-01

    X-ray based spectroscopy techniques are particularly well suited to gain access to local oxidation states and electronic dynamics in complex systems with atomic pinpoint accuracy. Traditionally, these techniques are applied in a quasi-static fashion that usually highlights the steady-state properties of a system rather than the fast dynamics that often define the system function on a molecular level. Novel x-ray spectroscopy techniques enabled by free electron lasers (FELs) and synchrotron based pump-probe schemes provide the opportunity to monitor intramolecular and interfacial charge transfer processes in real-time and with element and chemical specificity. Two complementary time-domain xray photoelectron spectroscopy techniques are presented that are applied at the Linac Coherent Light Source (LCLS) and the Advanced Light Source (ALS) to study charge transfer processes in N3 dye-sensitized ZnO semiconductor nanocrystals, which are at the heart of emerging light-harvesting technologies.

  2. Time-resolved x-ray photoelectron spectroscopy techniques for real-time studies of interfacial charge transfer dynamics

    SciTech Connect

    Shavorskiy, Andrey; Hertlein, Marcus; Guo Jinghua; Tyliszczak, Tolek; Cordones, Amy; Vura-Weis, Josh; Siefermann, Katrin; Slaughter, Daniel; Sturm, Felix; Weise, Fabian; Khurmi, Champak; Belkacem, Ali; Weber, Thorsten; Gessner, Oliver; Bluhm, Hendrik; Strader, Matthew; Cho, Hana; Coslovich, Giacomo; Kaindl, Robert A.; Lin, Ming-Fu; and others

    2013-04-19

    X-ray based spectroscopy techniques are particularly well suited to gain access to local oxidation states and electronic dynamics in complex systems with atomic pinpoint accuracy. Traditionally, these techniques are applied in a quasi-static fashion that usually highlights the steady-state properties of a system rather than the fast dynamics that often define the system function on a molecular level. Novel x-ray spectroscopy techniques enabled by free electron lasers (FELs) and synchrotron based pump-probe schemes provide the opportunity to monitor intramolecular and interfacial charge transfer processes in real-time and with element and chemical specificity. Two complementary time-domain xray photoelectron spectroscopy techniques are presented that are applied at the Linac Coherent Light Source (LCLS) and the Advanced Light Source (ALS) to study charge transfer processes in N3 dye-sensitized ZnO semiconductor nanocrystals, which are at the heart of emerging light-harvesting technologies.

  3. Real-time X-ray Diffraction Measurements of Shocked Polycrystalline Tin and Aluminum

    SciTech Connect

    Dane V. Morgan, Don Macy, Gerald Stevens

    2008-11-22

    A new, fast, single-pulse x-ray diffraction (XRD) diagnostic for determining phase transitions in shocked polycrystalline materials has been developed. The diagnostic consists of a 37-stage Marx bank high-voltage pulse generator coupled to a needle-and-washer electron beam diode via coaxial cable, producing line and bremsstrahlung x-ray emission in a 35-ns pulse. The characteristic Kα lines from the selected anodes of silver and molybdenum are used to produce the diffraction patterns, with thin foil filters employed to remove the characteristic Kβ line emission. The x-ray beam passes through a pinhole collimator and is incident on the sample with an approximately 3-mm by 6-mm spot and 1° full-width-half-maximum (FWHM) angular divergence in a Bragg-reflecting geometry. For the experiments described in this report, the angle between the incident beam and the sample surface was 8.5°. A Debye-Scherrer diffraction image was produced on a phosphor located 76 mm from the polycrystalline sample surface. The phosphor image was coupled to a charge-coupled device (CCD) camera through a coherent fiberoptic bundle. Dynamic single-pulse XRD experiments were conducted with thin foil samples of tin, shock loaded with a 1-mm vitreous carbon back window. Detasheet high explosive with a 2-mm-thick aluminum buffer was used to shock the sample. Analysis of the dynamic shock-loaded tin XRD images revealed a phase transformation of the tin beta phase into an amorphous or liquid state. Identical experiments with shock-loaded aluminum indicated compression of the face-centered-cubic (fcc) aluminum lattice with no phase transformation.

  4. A Bayesian approach to real-time 3D tumor localization via monoscopic x-ray imaging during treatment delivery

    SciTech Connect

    Li, Ruijiang; Fahimian, Benjamin P.; Xing, Lei

    2011-07-15

    Purpose: Monoscopic x-ray imaging with on-board kV devices is an attractive approach for real-time image guidance in modern radiation therapy such as VMAT or IMRT, but it falls short in providing reliable information along the direction of imaging x-ray. By effectively taking consideration of projection data at prior times and/or angles through a Bayesian formalism, the authors develop an algorithm for real-time and full 3D tumor localization with a single x-ray imager during treatment delivery. Methods: First, a prior probability density function is constructed using the 2D tumor locations on the projection images acquired during patient setup. Whenever an x-ray image is acquired during the treatment delivery, the corresponding 2D tumor location on the imager is used to update the likelihood function. The unresolved third dimension is obtained by maximizing the posterior probability distribution. The algorithm can also be used in a retrospective fashion when all the projection images during the treatment delivery are used for 3D localization purposes. The algorithm does not involve complex optimization of any model parameter and therefore can be used in a ''plug-and-play'' fashion. The authors validated the algorithm using (1) simulated 3D linear and elliptic motion and (2) 3D tumor motion trajectories of a lung and a pancreas patient reproduced by a physical phantom. Continuous kV images were acquired over a full gantry rotation with the Varian TrueBeam on-board imaging system. Three scenarios were considered: fluoroscopic setup, cone beam CT setup, and retrospective analysis. Results: For the simulation study, the RMS 3D localization error is 1.2 and 2.4 mm for the linear and elliptic motions, respectively. For the phantom experiments, the 3D localization error is < 1 mm on average and < 1.5 mm at 95th percentile in the lung and pancreas cases for all three scenarios. The difference in 3D localization error for different scenarios is small and is not

  5. High-resolution and high-sensitivity phase-contrast imaging by focused hard x-ray ptychography with a spatial filter

    NASA Astrophysics Data System (ADS)

    Takahashi, Yukio; Suzuki, Akihiro; Furutaku, Shin; Yamauchi, Kazuto; Kohmura, Yoshiki; Ishikawa, Tetsuya

    2013-03-01

    We demonstrate high-resolution and high-sensitivity x-ray phase-contrast imaging of a weakly scattering extended object by scanning coherent diffractive imaging, i.e., ptychography, using a focused x-ray beam with a spatial filter. We develop the x-ray illumination optics installed with the spatial filter to collect coherent diffraction patterns with a high signal-to-noise ratio. We quantitatively visualize the object with a slight phase shift (˜λ/320) at spatial resolution better than 17 nm in a field of view larger than ˜2×2μm2. The present coherent method has a marked potential for high-resolution and wide-field-of-view observation of weakly scattering objects such as biological soft tissues.

  6. A method for high-energy, low-dose mammography using edge illumination x-ray phase-contrast imaging

    NASA Astrophysics Data System (ADS)

    Diemoz, Paul C.; Bravin, Alberto; Sztrókay-Gaul, Anikó; Ruat, Marie; Grandl, Susanne; Mayr, Doris; Auweter, Sigrid; Mittone, Alberto; Brun, Emmanuel; Ponchut, Cyril; Reiser, Maximilian F.; Coan, Paola; Olivo, Alessandro

    2016-12-01

    Since the breast is one of the most radiosensitive organs, mammography is arguably the area where lowering radiation dose is of the uttermost importance. Phase-based x-ray imaging methods can provide opportunities in this sense, since they do not require x-rays to be stopped in tissue for image contrast to be generated. Therefore, x-ray energy can be considerably increased compared to those usually exploited by conventional mammography. In this article we show how a novel, optimized approach can lead to considerable dose reductions. This was achieved by matching the edge-illumination phase method, which reaches very high angular sensitivity also at high x-ray energies, to an appropriate image processing algorithm and to a virtually noise-free detection technology capable of reaching almost 100% efficiency at the same energies. Importantly, while proof-of-concept was obtained at a synchrotron, the method has potential for a translation to conventional sources.

  7. X-ray phase contrast imaging of biological specimens with femtosecond pulses of betatron radiation from a compact laser plasma wakefield accelerator

    SciTech Connect

    Kneip, S.; McGuffey, C.; Dollar, F.; Chvykov, V.; Kalintchenko, G.; Krushelnick, K.; Maksimchuk, A.; Mangles, S. P. D.; Matsuoka, T.; Schumaker, W.; Thomas, A. G. R.; Yanovsky, V.; Bloom, M. S.; Najmudin, Z.; Palmer, C. A. J.; Schreiber, J.

    2011-08-29

    We show that x-rays from a recently demonstrated table top source of bright, ultrafast, coherent synchrotron radiation [Kneip et al., Nat. Phys. 6, 980 (2010)] can be applied to phase contrast imaging of biological specimens. Our scheme is based on focusing a high power short pulse laser in a tenuous gas jet, setting up a plasma wakefield accelerator that accelerates and wiggles electrons analogously to a conventional synchrotron, but on the centimeter rather than tens of meter scale. We use the scheme to record absorption and phase contrast images of a tetra fish, damselfly and yellow jacket, in particular highlighting the contrast enhancement achievable with the simple propagation technique of phase contrast imaging. Coherence and ultrafast pulse duration will allow for the study of various aspects of biomechanics.

  8. Near-isothermal furnace for in situ and real time X-ray radiography solidification experiments.

    PubMed

    Becker, M; Dreißigacker, C; Klein, S; Kargl, F

    2015-06-01

    In this paper, we present a newly developed near-isothermal X-ray transparent furnace for in situ imaging of solidification processes in thin metallic samples. We show that the furnace is ideally suited to study equiaxed microstructure evolution and grain interaction. To observe the growth dynamics of equiaxed dendritic structures, a minimal temperature gradient across the sample is required. A uniform thermal profile inside a circular sample is achieved by positioning the sample in the center of a cylindrical furnace body surrounded by a circular heater arrangement. Performance tests with the hypo-eutectic Al-15wt.%Cu and the near-eutectic Al-33wt.%Cu alloys validate the near-isothermal character of the sample environment. Controlled cooling rates of less than 0.5 K min(-1) up to 10 K min(-1) can be achieved in a temperature range of 720 K-1220 K. Integrated in our rotatable laboratory X-ray facility, X-RISE, the furnace provides a large field of view of 10.5 mm in diameter and a high spatial resolution of ∼4 μm. With the here presented furnace, equiaxed dendrite growth models can be rigorously tested against experiments on metal alloys by, e.g., enabling dendrite growth velocities to be determined as a function of undercooling or solutal fields in front of the growing dendrite to be measured.

  9. Near-isothermal furnace for in situ and real time X-ray radiography solidification experiments

    SciTech Connect

    Becker, M. Dreißigacker, C.; Klein, S.; Kargl, F.

    2015-06-15

    In this paper, we present a newly developed near-isothermal X-ray transparent furnace for in situ imaging of solidification processes in thin metallic samples. We show that the furnace is ideally suited to study equiaxed microstructure evolution and grain interaction. To observe the growth dynamics of equiaxed dendritic structures, a minimal temperature gradient across the sample is required. A uniform thermal profile inside a circular sample is achieved by positioning the sample in the center of a cylindrical furnace body surrounded by a circular heater arrangement. Performance tests with the hypo-eutectic Al-15wt.%Cu and the near-eutectic Al-33wt.%Cu alloys validate the near-isothermal character of the sample environment. Controlled cooling rates of less than 0.5 K min{sup −1} up to 10 K min{sup −1} can be achieved in a temperature range of 720 K–1220 K. Integrated in our rotatable laboratory X-ray facility, X-RISE, the furnace provides a large field of view of 10.5 mm in diameter and a high spatial resolution of ∼4 μm. With the here presented furnace, equiaxed dendrite growth models can be rigorously tested against experiments on metal alloys by, e.g., enabling dendrite growth velocities to be determined as a function of undercooling or solutal fields in front of the growing dendrite to be measured.

  10. "Real-time" core formation experiments using X-ray tomography at high pressure and temperature

    NASA Astrophysics Data System (ADS)

    Watson, H. C.; Anzures, B.; Yu, T.; Wang, Y.

    2015-12-01

    The process of differentiation is a defining moment in a planet's history. Direct observation of this process at work is impossible in our solar system because it was complete within the first few tens of millions of years. Geochemical and geophysical evidence points to magma ocean scenarios to explain differentiation of large planets such as Earth. Smaller planets and planetesimals likely never achieved the high temperatures necessary for wide scale melting. In these smaller bodies, silicates may have only partially melted, or not melted at all. Furthermore, isotopic signatures in meteorites suggest that some planetesimals differentiated within just a few million years. Achieving efficient core segregation on this rapid timescale is difficult, particularly in a solid or semi-solid silicate matrix. Direct measurements of metallic melt migration velocities have been difficult due to experimental limitations and most previous work has relied on geometric models based on 2-D observations in quenched samples. We have employed a relatively new technique of in-situ, high pressure, high temperature, X-ray micro-tomography coupled with 3-D numerical simulations to evaluate the efficiency of melt percolation in metal/silicate systems. From this, we can place constraints on the timing of core formation in early solar system bodies. Mixtures of olivine and KLB-1 peridotite and up to 12 vol% FeS were pre-synthesized to achieve an initial equilibrium microstructure of silicate and sulfide. The samples were then were then pressed again to ~2GPa, and heated to ~1300°C to collect X-ray tomography images as the partially molten samples were undergoing shear deformation. The reconstructed 3-D images of melt distribution were used as the input for lattice Boltzmann simulations of fluid flow through the melt network and calculations of permeability and melt migration velocity. Our in-situ x-ray tomography results are complemented by traditional 2-D image analysis and high

  11. Real-time 3-D X-ray and gamma-ray viewer

    NASA Technical Reports Server (NTRS)

    Yin, L. I. (Inventor)

    1983-01-01

    A multi-pinhole aperture lead screen forms an equal plurality of invisible mini-images having dissimilar perspectives of an X-ray and gamma-ray emitting object (ABC) onto a near-earth phosphor layer. This layer provides visible light mini-images directly into a visible light image intensifier. A viewing screen having an equal number of dissimilar perspective apertures distributed across its face in a geometric pattern identical to the lead screen, provides a viewer with a real, pseudoscopic image (A'B'C') of the object with full horizontal and vertical parallax. Alternatively, a third screen identical to viewing screen and spaced apart from a second visible light image intensifier, may be positioned between the first image intensifier and the viewing screen, thereby providing the viewer with a virtual, orthoscopic image (A"B"C") of the object (ABC) with full horizontal and vertical parallax.

  12. High-throughput real-time x-ray microtomography at the Advanced Photon Source

    NASA Astrophysics Data System (ADS)

    De Carlo, Francesco; Albee, Paul B.; Chu, Yong S.; Mancini, Derrick C.; Tieman, Brian; Wang, Steve Y.

    2002-01-01

    It is now possible for large volumes of synchrotron- radiation-generated micro-tomography data to be produced at gigabyte-per-minute rates, especially when using currently available CCD cameras at a high-brightness source, such as the Advanced Photon Source (APS). Recent improvements in the speed of our detectors and stages, combined with increased photon flux supplied by a newly installed double multilayer monochromator, allow us to achieve these data rates on a bending magnet beamline. Previously, most x-ray microtomography experiments have produced data at comparatively lower rates, and often the data were analyzed after the experiment. The time needed to generate complete data sets meant putting off analysis to the completion of a run, thus preventing the user from evaluating the usefulness of a data set and consequently impairing decision making during data acquisition as to how to proceed. Thus, the ability to provide to a tomography user a fully reconstructed data set in few minutes is one of the major problems to be solved when dealing with high-throughput x- ray tomography. This is due to the complexity of the data analysis that involves data preprocessing, sinogram generation, 3D reconstruction, and rendering. At the APS, we have developed systems and techniques to address this issue. We present a method that uses a cluster-based, parallel- computing system based on the Message Passing Interface (MPI) standard. Among the advantages of this approach are the portability, ease-of-use, and low cost of the system. The combination of high-speed, online analysis with high- throughput acquisition allows us to acquire and reconstruct a 512x512x512-voxel sample with a few microns resolution in less than ten minutes.

  13. Real time synchrotron x-ray diffraction measurements to determine material strength of shocked single crystals following compression and release

    SciTech Connect

    Turneaure, Stefan J.; Gupta, Y.M.

    2009-09-15

    We present a method to use real time, synchrotron x-ray diffraction measurements to determine the strength of shocked single crystals following compression and release during uniaxial strain loading. Aluminum and copper single crystals shocked along [111] were examined to peak stresses ranging from 2 to 6 GPa. Synchrotron x rays were used to probe the longitudinal lattice strains near the rear free surface (16 and 5 {micro}m depths for Al and Cu, respectively) of the metal crystals following shock compression and release. The 111 diffraction peaks showed broadening indicating a heterogeneous microstructure in the released state. The diffraction peaks also shifted to lower Bragg angles relative to the ambient Bragg angle; the magnitude of the shift increased with increasing impact stress. The Bragg angle shifts and appropriate averaging procedures were used to determine the macroscopic or continuum strength following compression and release. For both crystals, the strengths upon release increased with increasing impact stress and provide a quantitative measure of the strain hardening that occurs in Al(111) and Cu(111) during the shock and release process. Our results for Al(111) are in reasonable agreement with a previous determination based solely on continuum measurements. Two points are noteworthy about the developments presented here: Synchrotron x rays are needed because they provide the resolution required for analyzing the data in the released state; the method presented here can be extended to the shocked state but will require additional measurements.

  14. Fiber-optic detector for real time dosimetry of a micro-planar x-ray beam

    PubMed Central

    Belley, Matthew D.; Stanton, Ian N.; Hadsell, Mike; Ger, Rachel; Langloss, Brian W.; Lu, Jianping; Zhou, Otto; Chang, Sha X.; Therien, Michael J.; Yoshizumi, Terry T.

    2015-01-01

    Purpose: Here, the authors describe a dosimetry measurement technique for microbeam radiation therapy using a nanoparticle-terminated fiber-optic dosimeter (nano-FOD). Methods: The nano-FOD was placed in the center of a 2 cm diameter mouse phantom to measure the deep tissue dose and lateral beam profile of a planar x-ray microbeam. Results: The continuous dose rate at the x-ray microbeam peak measured with the nano-FOD was 1.91 ± 0.06 cGy s−1, a value 2.7% higher than that determined via radiochromic film measurements (1.86 ± 0.15 cGy s−1). The nano-FOD-determined lateral beam full-width half max value of 420 μm exceeded that measured using radiochromic film (320 μm). Due to the 8° angle of the collimated microbeam and resulting volumetric effects within the scintillator, the profile measurements reported here are estimated to achieve a resolution of ∼0.1 mm; however, for a beam angle of 0°, the theoretical resolution would approach the thickness of the scintillator (∼0.01 mm). Conclusions: This work provides proof-of-concept data and demonstrates that the novel nano-FOD device can be used to perform real-time dosimetry in microbeam radiation therapy to measure the continuous dose rate at the x-ray microbeam peak as well as the lateral beam shape. PMID:25832087

  15. Development of a Real-Time Pulse Processing Algorithm for TES-Based X-Ray Microcalorimeters

    NASA Technical Reports Server (NTRS)

    Tan, Hui; Hennig, Wolfgang; Warburton, William K.; Doriese, W. Bertrand; Kilbourne, Caroline A.

    2011-01-01

    We report here a real-time pulse processing algorithm for superconducting transition-edge sensor (TES) based x-ray microcalorimeters. TES-based. microca1orimeters offer ultra-high energy resolutions, but the small volume of each pixel requires that large arrays of identical microcalorimeter pixe1s be built to achieve sufficient detection efficiency. That in turn requires as much pulse processing as possible must be performed at the front end of readout electronics to avoid transferring large amounts of data to a host computer for post-processing. Therefore, a real-time pulse processing algorithm that not only can be implemented in the readout electronics but also achieve satisfactory energy resolutions is desired. We have developed an algorithm that can be easily implemented. in hardware. We then tested the algorithm offline using several data sets acquired with an 8 x 8 Goddard TES x-ray calorimeter array and 2x16 NIST time-division SQUID multiplexer. We obtained an average energy resolution of close to 3.0 eV at 6 keV for the multiplexed pixels while preserving over 99% of the events in the data sets.

  16. Real-time x-ray fluoroscopy-based catheter detection and tracking for cardiac electrophysiology interventions

    SciTech Connect

    Ma Yingliang; Housden, R. James; Razavi, Reza; Rhode, Kawal S.; Gogin, Nicolas; Cathier, Pascal; Gijsbers, Geert; Cooklin, Michael; O'Neill, Mark; Gill, Jaswinder; Rinaldi, C. Aldo

    2013-07-15

    Purpose: X-ray fluoroscopically guided cardiac electrophysiology (EP) procedures are commonly carried out to treat patients with arrhythmias. X-ray images have poor soft tissue contrast and, for this reason, overlay of a three-dimensional (3D) roadmap derived from preprocedural volumetric images can be used to add anatomical information. It is useful to know the position of the catheter electrodes relative to the cardiac anatomy, for example, to record ablation therapy locations during atrial fibrillation therapy. Also, the electrode positions of the coronary sinus (CS) catheter or lasso catheter can be used for road map motion correction.Methods: In this paper, the authors present a novel unified computational framework for image-based catheter detection and tracking without any user interaction. The proposed framework includes fast blob detection, shape-constrained searching and model-based detection. In addition, catheter tracking methods were designed based on the customized catheter models input from the detection method. Three real-time detection and tracking methods are derived from the computational framework to detect or track the three most common types of catheters in EP procedures: the ablation catheter, the CS catheter, and the lasso catheter. Since the proposed methods use the same blob detection method to extract key information from x-ray images, the ablation, CS, and lasso catheters can be detected and tracked simultaneously in real-time.Results: The catheter detection methods were tested on 105 different clinical fluoroscopy sequences taken from 31 clinical procedures. Two-dimensional (2D) detection errors of 0.50 {+-} 0.29, 0.92 {+-} 0.61, and 0.63 {+-} 0.45 mm as well as success rates of 99.4%, 97.2%, and 88.9% were achieved for the CS catheter, ablation catheter, and lasso catheter, respectively. With the tracking method, accuracies were increased to 0.45 {+-} 0.28, 0.64 {+-} 0.37, and 0.53 {+-} 0.38 mm and success rates increased to 100%, 99

  17. X-ray beam modulation, image acquisition and real-time processing in region-of-interest fluoroscopy

    NASA Astrophysics Data System (ADS)

    Yang, Chang-Ying Joseph

    2000-07-01

    Region of interest (ROI) fluoroscopy is a technique whereby a partially attenuating filter with an aperture in the center is placed in the x-ray beam between the source and the patient The part of the x-ray beam going through the filter aperture un-attenuated is used to project the main features of interest in the patient to form the ROI in each fluoroscopic image. The periphery of the image is formed by the projection of the features needed only for reference using the part of the attenuated x-ray beam passing through the filter. This technique can substantially reduce patient and staff dose and improve the image quality in the ROI of the image. By using Gd for the filter material, it is even possible to improve the x-ray attenuation contrast in the periphery. However, real-time image processing is needed to compensate for the x-ray intensity attenuation in the periphery so that the brightness in the two parts of the fluoroscopic image is linearity is restored. Based on the method of binary masks, a system was developed to perform the real-time image processing with the flexibility to accommodate both the horizontal and vertical movement of the imaging chain relative to the patient. A binary mask is a binary image used to define those regions in the fluoroscopic image which should be processed and those which should not. A method of binary mask generation was proposed so the region defined as not to be processed in the binary mask maintains as close a resemblance as possible to the ROI of the fluoroscopic image. The construction method for the look-up table used for the processing of the periphery and its dependence on physical quantities were described and studied. An algorithm for constantly tracking the change of the ROI in the fluoroscopic images and selecting the proper corresponding binary mask was developed. The quality of the processed ROI fluoroscopic images such as brightness, contrast and noise were evaluated and compared using test phantoms. The test

  18. Simulations of x-ray speckle-based dark-field and phase-contrast imaging with a polychromatic beam

    SciTech Connect

    Zdora, Marie-Christine; Thibault, Pierre; Pfeiffer, Franz; Zanette, Irene

    2015-09-21

    Following the first experimental demonstration of x-ray speckle-based multimodal imaging using a polychromatic beam [I. Zanette et al., Phys. Rev. Lett. 112(25), 253903 (2014)], we present a simulation study on the effects of a polychromatic x-ray spectrum on the performance of this technique. We observe that the contrast of the near-field speckles is only mildly influenced by the bandwidth of the energy spectrum. Moreover, using a homogeneous object with simple geometry, we characterize the beam hardening artifacts in the reconstructed transmission and refraction angle images, and we describe how the beam hardening also affects the dark-field signal provided by speckle tracking. This study is particularly important for further implementations and developments of coherent speckle-based techniques at laboratory x-ray sources.

  19. Simulations of x-ray speckle-based dark-field and phase-contrast imaging with a polychromatic beam

    NASA Astrophysics Data System (ADS)

    Zdora, Marie-Christine; Thibault, Pierre; Pfeiffer, Franz; Zanette, Irene

    2015-09-01

    Following the first experimental demonstration of x-ray speckle-based multimodal imaging using a polychromatic beam [I. Zanette et al., Phys. Rev. Lett. 112(25), 253903 (2014)], we present a simulation study on the effects of a polychromatic x-ray spectrum on the performance of this technique. We observe that the contrast of the near-field speckles is only mildly influenced by the bandwidth of the energy spectrum. Moreover, using a homogeneous object with simple geometry, we characterize the beam hardening artifacts in the reconstructed transmission and refraction angle images, and we describe how the beam hardening also affects the dark-field signal provided by speckle tracking. This study is particularly important for further implementations and developments of coherent speckle-based techniques at laboratory x-ray sources.

  20. Real-time image-processing algorithm for markerless tumour tracking using X-ray fluoroscopic imaging

    PubMed Central

    2014-01-01

    Objective: To ensure accuracy in respiratory-gating treatment, X-ray fluoroscopic imaging is used to detect tumour position in real time. Detection accuracy is strongly dependent on image quality, particularly positional differences between the patient and treatment couch. We developed a new algorithm to improve the quality of images obtained in X-ray fluoroscopic imaging and report the preliminary results. Methods: Two oblique X-ray fluoroscopic images were acquired using a dynamic flat panel detector (DFPD) for two patients with lung cancer. The weighting factor was applied to the DFPD image in respective columns, because most anatomical structures, as well as the treatment couch and port cover edge, were aligned in the superior–inferior direction when the patient lay on the treatment couch. The weighting factors for the respective columns were varied until the standard deviation of the pixel values within the image region was minimized. Once the weighting factors were calculated, the quality of the DFPD image was improved by applying the factors to multiframe images. Results: Applying the image-processing algorithm produced substantial improvement in the quality of images, and the image contrast was increased. The treatment couch and irradiation port edge, which were not related to a patient's position, were removed. The average image-processing time was 1.1 ms, showing that this fast image processing can be applied to real-time tumour-tracking systems. Conclusion: These findings indicate that this image-processing algorithm improves the image quality in patients with lung cancer and successfully removes objects not related to the patient. Advances in knowledge: Our image-processing algorithm might be useful in improving gated-treatment accuracy. PMID:24661056

  1. Real-time segmentation of multiple implanted cylindrical liver markers in kilovoltage and megavoltage x-ray images

    NASA Astrophysics Data System (ADS)

    Fledelius, W.; Worm, E.; Høyer, M.; Grau, C.; Poulsen, P. R.

    2014-06-01

    Gold markers implanted in or near a tumor can be used as x-ray visible landmarks for image based tumor localization. The aim of this study was to develop and demonstrate fast and reliable real-time segmentation of multiple liver tumor markers in intra-treatment kV and MV images and in cone-beam CT (CBCT) projections, for real-time motion management. Thirteen patients treated with conformal stereotactic body radiation therapy in three fractions had 2-3 cylindrical gold markers implanted in the liver prior to treatment. At each fraction, the projection images of a pre-treatment CBCT scan were used for automatic generation of a 3D marker model that consisted of the size, orientation, and estimated 3D trajectory of each marker during the CBCT scan. The 3D marker model was used for real-time template based segmentation in subsequent x-ray images by projecting each marker's 3D shape and likely 3D motion range onto the imager plane. The segmentation was performed in intra-treatment kV images (526 marker traces, 92 097 marker projections) and MV images (88 marker traces, 22 382 marker projections), and in post-treatment CBCT projections (42 CBCT scans, 71 381 marker projections). 227 kV marker traces with low mean contrast-to-noise ratio were excluded as markers were not visible due to MV scatter. Online segmentation times measured for a limited dataset were used for estimating real-time segmentation times for all images. The percentage of detected markers was 94.8% (kV), 96.1% (MV), and 98.6% (CBCT). For the detected markers, the real-time segmentation was erroneous in 0.2-0.31% of the cases. The mean segmentation time per marker was 5.6 ms [2.1-12 ms] (kV), 5.5 ms [1.6-13 ms] (MV), and 6.5 ms [1.8-15 ms] (CBCT). Fast and reliable real-time segmentation of multiple liver tumor markers in intra-treatment kV and MV images and in CBCT projections was demonstrated for a large dataset.

  2. Speckle-Based X-Ray Phase-Contrast and Dark-Field Imaging with a Laboratory Source

    NASA Astrophysics Data System (ADS)

    Zanette, I.; Zhou, T.; Burvall, A.; Lundström, U.; Larsson, D. H.; Zdora, M.; Thibault, P.; Pfeiffer, F.; Hertz, H. M.

    2014-06-01

    We report on the observation and application of near-field speckles with a laboratory x-ray source. The detection of speckles is possible thanks to the enhanced brilliance properties of the used liquid-metal-jet source, and opens the way to a range of new applications in laboratory-based coherent x-ray imaging. Here, we use the speckle pattern for multimodal imaging of demonstrator objects. Moreover, we introduce algorithms for phase and dark-field imaging using speckle tracking, and we show that they yield superior results with respect to existing methods.

  3. Propagator based formalism for optimizing in-line phase contrast imaging in laboratory X-ray setups.

    PubMed

    Balles, Andreas; Zabler, Simon; Ebensperger, Thomas; Fella, Christian; Hanke, Randolf

    2016-09-01

    We derive a propagator based formalism for optimizing phase contrast imaging in laboratory setups as well as in synchrotron setups. We confirm based on five different setups the well known existence of an optimum position for the sample in terms of phase contrast by measuring two types of fibers and evaluating the fringe contrast. Furthermore, we demonstrate for these setups a correlation of our formula and the fringe contrast. Hence, an estimate of this optimum position is given by our formalism which only depends on the source size, the detector blurring, and the total distance between source and detector.

  4. The behavior of single-crystal silicon to dynamic loading using in-situ X-ray diffraction and phase contrast imaging

    NASA Astrophysics Data System (ADS)

    Lee, Hae Ja; Xing, Zhou; Galtier, Eric; Arnold, Brice; Granados, Eduardo; Brown, Shaughnessy B.; Tavella, Franz; McBride, Emma; Fry, Alan; Nagler, Bob; Schropp, Andreas; Seiboth, Frank; Samberg, Dirk; Schroer, Christian; Gleason, Arianna E.; Higginbotham, Andrew

    Hydrostatic and uniaxial compression studies have revealed that crystalline silicon undergoes phase transitions from a cubic diamond structure to a variety of phases including orthorhombic Imma phase, body-centered tetragonal phase, and a hexagonal primitive phase. The dynamic response of silicon at high pressure, however, is not well understood. Phase contrast imaging has proven to be a powerful tool for probing density changes caused by the shock propagation into a material. In order to characterize the elastic and phase transitions, we image shock waves in Si with high spatial resolution using the LCLS X-ray free electron laser and Matter in Extreme Conditions instrument. In this study, the long pulse optical laser with pseudo-flat top shape creates high pressures up to 60 GPa. We measure the crystal structure by observing X-ray diffraction orthogonal to the shock propagation direction over a range of pressures. We describe the capability of simultaneously performing phase contrast imaging and in situ X-ray diffraction during shock loading and discuss the dynamic response of Si in high-pressure phases Use of the Linac Coherent Light Source (LCLS), SLAC National Accelerator Laboratory, is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-76SF00515. The MEC instrument is supported by.

  5. Upgrade of High-Energy X-Ray real-time radioscopy for KROTOS experiment

    SciTech Connect

    Estre, N.; Payan, E.; Cassiaut-Louis, N.; Compagnon, F.; Valerian, M.; Mallet, R.

    2015-07-01

    As part of its R and D programs on severe accidents, in particular on understanding of corium-water interaction, CEA is commissioning an update of the KROTOS experiment at Cadarache. The Xray imaging setup (high energy real-time radioscopy) is upgraded to provide the best performances for the new experimental program. In order to fit the performance needs (faster acquisition, smaller detection limit and higher field of view), two radioscopy setups, with two linear accelerators (linacs 9 MV and 6 MV), are placed in the irradiation cell. Having discussed the expected performances in terms of frequency, detection limit and field-of-view, this article details each stage of both radioscopy chains: principles and technical characteristics. Then, linacs and cameras synchronization (at few hundred Hertz), data flows and storage setups are detailed. Finally, experimental characterizations and performance validations on phantom are presented. (authors)

  6. Metrology of Wide Field of View Nano-Thickness Foils’ Homogeneity by Conventional and Phase Contrast Soft X-ray Imaging

    NASA Astrophysics Data System (ADS)

    Anatoly Faenov,; Tatiana Pikuz,; Yuji Fukuda,; Masaki Kando,; Hideyuki Kotaki,; Takayuki Homma,; Keigo Kawase,; Igor Skobelev,; Sergei Gasilov,; Tetsuya Kawachi,; Hiroyuki Daido,; Toshiki Tajima,; Yoshiaki Kato,; Sergei Bulanov,

    2010-06-01

    A tabletop ultra-bright, debris-free femtosecond-laser-driven cluster-based plasma soft X-ray source, which emits more than 1012 photons/(sr\\cdotpulse) in the spectral range 1-10 nm within a 4π sr solid angle was developed. Using such source in combination with a high dynamic range LiF crystal soft X-ray detector allows obtaining contact and propagation-based phase-contrast images of nanostructures with 700 nm spatial resolutions in a wide field of view. It was demonstrated that the high precision of used techniques enable distinguishing inhomogeneity of measured intensities of ultrathin foils in the order of ± 3%. All of this opens a new approach for PBPC imaging and metrology of full areas of free-standing or mesh-supported nano-thickness foils, or other nanostructures.

  7. Metrology of Wide Field of View Nano-Thickness Foils' Homogeneity by Conventional and Phase Contrast Soft X-ray Imaging

    NASA Astrophysics Data System (ADS)

    Faenov, Anatoly; Pikuz, Tatiana; Fukuda, Yuji; Kando, Masaki; Kotaki, Hideyuki; Homma, Takayuki; Kawase, Keigo; Skobelev, Igor; Gasilov, Sergei; Kawachi, Tetsuya; Daido, Hiroyuki; Tajima, Toshiki; Kato, Yoshiaki; Bulanov, Sergei

    2010-06-01

    A tabletop ultra-bright, debris-free femtosecond-laser-driven cluster-based plasma soft X-ray source, which emits more than 1012 photons/(sr·pulse) in the spectral range 1-10 nm within a 4π sr solid angle was developed. Using such source in combination with a high dynamic range LiF crystal soft X-ray detector allows obtaining contact and propagation-based phase-contrast images of nanostructures with 700 nm spatial resolutions in a wide field of view. It was demonstrated that the high precision of used techniques enable distinguishing inhomogeneity of measured intensities of ultrathin foils in the order of ±3%. All of this opens a new approach for PBPC imaging and metrology of full areas of free-standing or mesh-supported nano-thickness foils, or other nanostructures.

  8. Demonstration of synchrotron x-ray phase contrast imaging computed tomography of infiltrative transitional cell carcinoma of the prostatic urethra in a dog

    PubMed Central

    Montgomery, James E.; Wesolowski, Michal J.; Wolkowski, Bailey; Chibbar, Rajni; Snead, Elisabeth C. R.; Singh, Jaswant; Pettitt, Murray; Malhi, Pritpal S.; Barboza, Trinita; Adams, Gregg

    2016-01-01

    Abstract. Prostatic urethral transitional cell carcinoma with prostatic invasion in a dog was imaged with abdominal radiography and abdominal ultrasonography antemortem. Synchrotron in-line x-ray phase contrast imaging computed tomography (XPCI-CT) was performed on the prostate ex vivo at the Canadian Light Source Synchrotron and compared to histology. XPCI-CT imaging provides greater soft tissue contrast than conventional absorption-based x-ray imaging modalities, permitting visualization of regions of inflammatory cell infiltration, differentiation of invasive versus noninvasive tumor regions, and areas of necrosis and mineralization. This represents the first report of XPCI-CT images of an invasive prostatic urothelial neoplasm in a dog. PMID:27014719

  9. Preliminary comparison of grating-based and in-line phase contrast X-ray imaging with synchrotron radiation for mouse kidney at TOMCAT

    NASA Astrophysics Data System (ADS)

    Sun, J.; Liu, P.; Irvine, S.; Pinzer, B.; Stampanoni, M.; Xu, L. X.

    2013-06-01

    Phase contrast imaging has been demonstrated to be advantageous in revealing detailed structures inside biological specimens without contrast agents. Grating-based differential phase contrast (DPC) and in-line phase contrast (ILPC) X-ray imaging are the two modalities frequently used at the beamline of TOmographic Microscopy and Coherent rAdiology experimenTs (TOMCAT) at the Swiss Light Source (SLS). In this paper, we preliminarily compared the abilities of two types of phase contrast imaging in distinguishing micro structures in mouse kidneys. The 3D reconstructions showed that the microstructures in kidney, such as micro vessels and renal tubules, were displayed clearly with both imaging modalities. The two techniques may be viewed as complementary. For larger features with very small density variations DPC is the desirable method. In cases where dose and time limits may prohibit the multiple steps required for DPC, and when the focus is on finer features, the ILPC method may be considered as a more viable alternative. Moreover, high resolution ILPC images are comparable with histological results.

  10. A monoscopic method for real-time tumour tracking using combined occasional x-ray imaging and continuous respiratory monitoring

    NASA Astrophysics Data System (ADS)

    Cho, Byungchul; Suh, Yelin; Dieterich, Sonja; Keall, Paul J.

    2008-06-01

    Three major linear accelerator vendors offer gantry-mounted single (monoscopic) x-ray imagers. The use of monoscopic imaging to estimate three-dimensional (3D) target positions has not been fully explored. The purpose of this work is to develop and investigate a robust monoscopic method for real-time tumour tracking, combining occasional x-ray imaging and continuous external respiratory monitoring, and compare this with an established stereoscopic method. Monoscopic estimation of 3D target positions is a two-step procedure. Step (1) is similar to the stereoscopic approach using combined occasional x-ray imaging and real-time external respiratory monitoring, i.e. to establish the correlation between the target coordinates T(x, y, z) and the external respiratory signal (R) (sECM: stereoscopic external correlation model). However, in monoscopic estimation, the correlation between the two coordinates (xp, yp) projected on the imager plane and the external respiratory signal (mECM: monoscopic external correlation model) is established. With only a single projection, the component of the 3D target position, which is along the x-ray imaging direction, is unresolved. Therefore, step (2) is used to estimate the unresolved component (zpar) by building a correlation model between the unresolved component and the two other components projected on the imager (ICM: internal correlation model) with a prior 3D target trajectory that may be obtained by 4DCT, MV/kV imaging or 4DCBCT. At the time of prediction, (xp, yp) are estimated from (R) using the correlation model in step (1), and then zpar is estimated from the estimated (xp, yp) using the correlation model in step (2). The performance of the proposed method was evaluated under various model update intervals and compared with the stereoscopic estimation method using 160 tumour trajectory and external respiratory motion data recorded at 25 Hz from 46 thoracic and abdominal cancer patients who underwent hypofractionated

  11. Fiber-optic detector for real time dosimetry of a micro-planar x-ray beam

    SciTech Connect

    Belley, Matthew D.; Stanton, Ian N.; Langloss, Brian W.; Therien, Michael J.; Hadsell, Mike; Ger, Rachel; Lu, Jianping; Zhou, Otto; Chang, Sha X.; Yoshizumi, Terry T.

    2015-04-15

    Purpose: Here, the authors describe a dosimetry measurement technique for microbeam radiation therapy using a nanoparticle-terminated fiber-optic dosimeter (nano-FOD). Methods: The nano-FOD was placed in the center of a 2 cm diameter mouse phantom to measure the deep tissue dose and lateral beam profile of a planar x-ray microbeam. Results: The continuous dose rate at the x-ray microbeam peak measured with the nano-FOD was 1.91 ± 0.06 cGy s{sup −1}, a value 2.7% higher than that determined via radiochromic film measurements (1.86 ± 0.15 cGy s{sup −1}). The nano-FOD-determined lateral beam full-width half max value of 420 μm exceeded that measured using radiochromic film (320 μm). Due to the 8° angle of the collimated microbeam and resulting volumetric effects within the scintillator, the profile measurements reported here are estimated to achieve a resolution of ∼0.1 mm; however, for a beam angle of 0°, the theoretical resolution would approach the thickness of the scintillator (∼0.01 mm). Conclusions: This work provides proof-of-concept data and demonstrates that the novel nano-FOD device can be used to perform real-time dosimetry in microbeam radiation therapy to measure the continuous dose rate at the x-ray microbeam peak as well as the lateral beam shape.

  12. Numerical simulations for diamond sensors as real-time X-ray skin dosemeters; comparison to silicon

    NASA Astrophysics Data System (ADS)

    Jung, M.; Morel, J.; Siffert, P.

    2008-03-01

    Simulation results from Monte Carlo codes developed in our laboratory are used to analyze and improve detector responses against unknown high flux X-ray spectra exposures, as encountered in medicine. The algorithms are applied to diamond and silicon based dosemeters studies. The simulations are focused on real-time skin dosimetry for X-ray energies between 10 and 200 keV. The detector response is simulated as an induced collected charge under high fluence irradiation, to control patient injury. The dose equivalent response at 0.07 mm skin depth is calculated for a large set of diamond sensors. Their sensitivity, accuracy and angular response dispersion are presented. The quasi-tissue equivalent property of the diamond material allows maximum response uncertainties lower than 10% at least up to 75∘ opening incidences. For such monitors the amount of collected charges shows an asymptotic maximum limit near 80 nC Sv-1 per mm 3 sensor interaction volume. These performances are discussed, and compared to those of silicon diodes.

  13. In situ and real-time monitoring of mechanochemical milling reactions using synchrotron X-ray diffraction.

    PubMed

    Halasz, Ivan; Kimber, Simon A J; Beldon, Patrick J; Belenguer, Ana M; Adams, Frank; Honkimäki, Veijo; Nightingale, Richard C; Dinnebier, Robert E; Friščić, Tomislav

    2013-09-01

    We describe the only currently available protocol for in situ, real-time monitoring of mechanochemical reactions and intermediates by X-ray powder diffraction. Although mechanochemical reactions (inducing transformations by mechanical forces such as grinding and milling) are normally performed in commercially available milling assemblies, such equipment does not permit direct reaction monitoring. We now describe the design and in-house modification of milling equipment that allows the reaction jars of the operating mill to be placed in the path of a high-energy (∼90 keV) synchrotron X-ray beam while the reaction is taking place. Resulting data are analyzed using conventional software, such as TOPAS. Reaction intermediates and products are identified using the Cambridge Structural Database or Inorganic Crystal Structure Database. Reactions are analyzed by fitting the time-resolved diffractograms using structureless Pawley refinement for crystalline phases that are not fully structurally characterized (such as porous frameworks with disordered guests), or the Rietveld method for solids with fully determined crystal structures (metal oxides, coordination polymers).

  14. Simultaneous X-ray diffraction and phase-contrast imaging for investigating material deformation mechanisms during high-rate loading

    DOE PAGES

    Hudspeth, M.; Sun, T.; Parab, N.; ...

    2015-01-01

    Using a high-speed camera and an intensified charge-coupled device (ICCD), a simultaneous X-ray imaging and diffraction technique has been developed for studying dynamic material behaviors during high-rate tensile loading. A Kolsky tension bar has been used to pull samples at 1000 s–1and 5000 s–1strain-rates for super-elastic equiatomic NiTi and 1100-O series aluminium, respectively. By altering the ICCD gating time, temporal resolutions of 100 ps and 3.37 µs have been achieved in capturing the diffraction patterns of interest, thus equating to single-pulse and 22-pulse X-ray exposure. Furthermore, the sample through-thickness deformation process has been simultaneously imagedviaphase-contrast imaging. It is also shownmore » that adequate signal-to-noise ratios are achieved for the detected white-beam diffraction patterns, thereby allowing sufficient information to perform quantitative data analysis diffractionviain-house software (WBXRD_GUI). Finally, of current interest is the ability to evaluate crystald-spacing, texture evolution and material phase transitions, all of which will be established from experiments performed at the aforementioned elevated strain-rates.« less

  15. Polyglycolic acid-polylactic acid scaffold response to different progenitor cell in vitro cultures: a demonstrative and comparative X-ray synchrotron radiation phase-contrast microtomography study.

    PubMed

    Giuliani, Alessandra; Moroncini, Francesca; Mazzoni, Serena; Belicchi, Marzia Laura Chiara; Villa, Chiara; Erratico, Silvia; Colombo, Elena; Calcaterra, Francesca; Brambilla, Lucia; Torrente, Yvan; Albertini, Gianni; Della Bella, Silvia

    2014-04-01

    Spatiotemporal interactions play important roles in tissue development and function, especially in stem cell-seeded bioscaffolds. Cells interact with the surface of bioscaffold polymers and influence material-driven control of cell differentiation. In vitro cultures of different human progenitor cells, that is, endothelial colony-forming cells (ECFCs) from a healthy control and a patient with Kaposi sarcoma (an angioproliferative disease) and human CD133+ muscle-derived stem cells (MSH 133+ cells), were seeded onto polyglycolic acid-polylactic acid scaffolds. Three-dimensional (3D) images were obtained by X-ray phase-contrast microtomography (micro-CT) and processed with the Modified Bronnikov Algorithm. The method enabled high spatial resolution detection of the 3D structural organization of cells on the bioscaffold and evaluation of the way and rate at which cells modified the construct at different time points from seeding. The different cell types displayed significant differences in the proliferation rate. In conclusion, X-ray synchrotron radiation phase-contrast micro-CT analysis proved to be a useful and sensitive tool to investigate the spatiotemporal pattern of progenitor cell organization on a bioscaffold.

  16. Phase unwrapping in spectral X-ray differential phase-contrast imaging with an energy-resolving photon-counting pixel detector.

    PubMed

    Epple, Franz M; Ehn, Sebastian; Thibault, Pierre; Koehler, Thomas; Potdevin, Guillaume; Herzen, Julia; Pennicard, David; Graafsma, Heinz; Noël, Peter B; Pfeiffer, Franz

    2015-03-01

    Grating-based differential phase-contrast imaging has proven to be feasible with conventional X-ray sources. The polychromatic spectrum generally limits the performance of the interferometer but benefit can be gained with an energy-sensitive detector. In the presented work, we employ the energy-discrimination capability to correct for phase-wrapping artefacts. We propose to use the phase shifts, which are measured in distinct energy bins, to estimate the optimal phase shift in the sense of maximum likelihood. We demonstrate that our method is able to correct for phase-wrapping artefacts, to improve the contrast-to-noise ratio and to reduce beam hardening due to the modelled energy dependency. The method is evaluated on experimental data which are measured with a laboratory Talbot-Lau interferometer equipped with a conventional polychromatic X-ray source and an energy-sensitive photon-counting pixel detector. Our work shows, that spectral imaging is an important step to move differential phase-contrast imaging closer to pre-clinical and clinical applications, where phase wrapping is particularly problematic.

  17. Computational cell quantification in the human brain tissues based on hard x-ray phase-contrast tomograms

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

    Cell visualization and counting plays a crucial role in biological and medical research including the study of neurodegenerative diseases. The neuronal cell loss is typically determined to measure the extent of the disease. Its characterization is challenging because the cell density and size already differs by more than three orders of magnitude in a healthy cerebellum. Cell visualization is commonly performed by histology and fluorescence microscopy. These techniques are limited to resolve complex microstructures in the third dimension. Phase- contrast tomography has been proven to provide sufficient contrast in the three-dimensional imaging of soft tissue down to the cell level and, therefore, offers the basis for the three-dimensional segmentation. Within this context, a human cerebellum sample was embedded in paraffin and measured in local phase-contrast mode at the beamline ID19 (ESRF, Grenoble, France) and the Diamond Manchester Imaging Branchline I13-2 (Diamond Light Source, Didcot, UK). After the application of Frangi-based filtering the data showed sufficient contrast to automatically identify the Purkinje cells and to quantify their density to 177 cells per mm3 within the volume of interest. Moreover, brain layers were segmented in a region of interest based on edge detection. Subsequently performed histological analysis validated the presence of the cells, which required a mapping from the two- dimensional histological slices to the three-dimensional tomogram. The methodology can also be applied to further tissue types and shows potential for the computational tissue analysis in health and disease.

  18. Analysis of Flame Retardancy in Polymer Blends by Synchrotron X-ray K-edge Tomography and Interferometric Phase Contrast Movies.

    PubMed

    Olatinwo, Mutairu B; Ham, Kyungmin; McCarney, Jonathan; Marathe, Shashidhara; Ge, Jinghua; Knapp, Gerry; Butler, Leslie G

    2016-03-10

    Underwriters Laboratories 94 test bars have been imaged with X-ray K-edge tomography between 12 and 32 keV to assess the bromine and antimony concentration gradient across char layers of partially burnt samples. Phase contrast tomography on partially burnt samples showed gas bubbles and dark-field scattering ascribed to residual blend inhomogeneity. In addition, single-shot grating interferometry was used to record X-ray movies of test samples during heating (IR and flame) intended to mimic the UL 94 plastics flammability test. The UL 94 test bars were formulated with varying concentrations of a brominated flame retardant, Saytex 8010, and a synergist, Sb2O3, blended into high-impact polystyrene (HIPS). Depending on the sample composition, samples will pass or fail the UL 94 plastics flammability test. Tomography and interferometry imaging show differences that correlate with UL 94 performance. Key features such as char layer, gas bubble formation, microcracks, and dissolution of the flame retardant in the char layer regions are used in understanding the efficiency of the flame retardant and synergist. The samples that pass the UL 94 test have a thick, highly visible char layer as well as an interior rich in gas bubbles. Growth of gas bubbles from flame-retardant thermal decomposition is noted in the X-ray phase contrast movies. Also noteworthy is an absence of bubbles near the burning surface of the polymer; dark-field images after burning suggest a microcrack structure between interior bubbles and the surface. The accepted mechanism for flame retardant activity includes free radical quenching in the flame by bromine and antimony species. The imaging supports this as well as provides a fast inspection of other parameters, such as viscosity and surface tension.

  19. Real-time pose estimation of devices from x-ray images: Application to x-ray/echo registration for cardiac interventions.

    PubMed

    Hatt, Charles R; Speidel, Michael A; Raval, Amish N

    2016-12-01

    In recent years, registration between x-ray fluoroscopy (XRF) and transesophageal echocardiography (TEE) has been rapidly developed, validated, and translated to the clinic as a tool for advanced image guidance of structural heart interventions. This technology relies on accurate pose-estimation of the TEE probe via standard 2D/3D registration methods. It has been shown that latencies caused by slow registrations can result in errors during untracked frames, and a real-time ( > 15 hz) tracking algorithm is needed to minimize these errors. This paper presents two novel similarity metrics designed for accurate, robust, and extremely fast pose-estimation of devices from XRF images: Direct Splat Correlation (DSC) and Patch Gradient Correlation (PGC). Both metrics were implemented in CUDA C, and validated on simulated and clinical datasets against prior methods presented in the literature. It was shown that by combining DSC and PGC in a hybrid method (HYB), target registration errors comparable to previously reported methods were achieved, but at much higher speeds and lower failure rates. In simulated datasets, the proposed HYB method achieved a median projected target registration error (pTRE) of 0.33 mm and a mean registration frame-rate of 12.1 hz, while previously published methods produced median pTREs greater than 1.5 mm and mean registration frame-rates less than 4 hz. In clinical datasets, the HYB method achieved a median pTRE of 1.1 mm and a mean registration frame-rate of 20.5 hz, while previously published methods produced median pTREs greater than 1.3 mm and mean registration frame-rates less than 12 hz. The proposed hybrid method also had much lower failure rates than previously published methods.

  20. Real-time pose estimation of devices from x-ray images: Application to x-ray/echo registration for cardiac interventions

    PubMed Central

    Hatt, Charles R.; Speidel, Michael A.; Raval, Amish N.

    2016-01-01

    In recent years, registration between x-ray fluoroscopy (XRF) and transesophageal echocardiography (TEE) has been rapidly developed, validated, and translated to the clinic as a tool for advanced image guidance of structural heart interventions. This technology relies on accurate pose-estimation of the TEE probe via standard 2D/3D registration methods. It has been shown that latencies caused by slow registrations can result in errors during untracked frames, and a real-time (> 15 hz) tracking algorithm is needed to minimize these errors. This paper presents two novel similarity metrics designed for accurate, robust, and extremely fast pose-estimation of devices from XRF images: Direct Splat Correlation (DSC) and Patch Gradient Correlation (PGC). Both metrics were implemented in CUDA C, and validated on simulated and clinical datasets against prior methods presented in the literature. It was shown that by combining DSC and PGC in a hybrid method (HYB), target registration errors comparable to previously reported methods were achieved, but at much higher speeds and lower failure rates. In simulated datasets, the proposed HYB method achieved a median projected target registration error (pTRE) of 0.33 mm and a mean registration frame-rate of 12.1 hz, while previously published methods produced median pTREs greater than 1.5 mm and mean registration frame-rates less than 4 hz. In clinical datasets, the HYB method achieved a median pTRE of 1.1 mm and a mean registration frame-rate of 20.5 hz, while previously published methods produced median pTREs greater than 1.3 mm and mean registration frame-rates less than 12 hz. The proposed hybrid method also had much lower failure rates than previously published methods. PMID:27179366

  1. Translation of Atherosclerotic Plaque Phase-Contrast CT Imaging from Synchrotron Radiation to a Conventional Lab-Based X-Ray Source

    PubMed Central

    Saam, Tobias; Herzen, Julia; Hetterich, Holger; Fill, Sandra; Willner, Marian; Stockmar, Marco; Achterhold, Klaus; Zanette, Irene; Weitkamp, Timm; Schüller, Ulrich; Auweter, Sigrid; Adam-Neumair, Silvia; Nikolaou, Konstantin; Reiser, Maximilian F.; Pfeiffer, Franz; Bamberg, Fabian

    2013-01-01

    Objectives Phase-contrast imaging is a novel X-ray based technique that provides enhanced soft tissue contrast. The aim of this study was to evaluate the feasibility of visualizing human carotid arteries by grating-based phase-contrast tomography (PC-CT) at two different experimental set-ups: (i) applying synchrotron radiation and (ii) using a conventional X-ray tube. Materials and Methods Five ex-vivo carotid artery specimens were examined with PC-CT either at the European Synchrotron Radiation Facility using a monochromatic X-ray beam (2 specimens; 23 keV; pixel size 5.4 µm), or at a laboratory set-up on a conventional X-ray tube (3 specimens; 35-40 kVp; 70 mA; pixel size 100 µm). Tomographic images were reconstructed and compared to histopathology. Two independent readers determined vessel dimensions and one reader determined signal-to-noise ratios (SNR) between PC-CT and absorption images. Results In total, 51 sections were included in the analysis. Images from both set-ups provided sufficient contrast to differentiate individual vessel layers. All PCI-based measurements strongly predicted but significantly overestimated lumen, intima and vessel wall area for both the synchrotron and the laboratory-based measurements as compared with histology (all p<0.001 with slope >0.53 per mm2, 95%-CI: 0.35 to 0.70). Although synchrotron-based images were characterized by higher SNRs than laboratory-based images; both PC-CT set-ups had superior SNRs compared to corresponding conventional absorption-based images (p<0.001). Inter-reader reproducibility was excellent (ICCs >0.98 and >0.84 for synchrotron and for laboratory-based measurements; respectively). Conclusion Experimental PC-CT of carotid specimens is feasible with both synchrotron and conventional X-ray sources, producing high-resolution images suitable for vessel characterization and atherosclerosis research. PMID:24039969

  2. Three dimensional visualization of engineered bone and soft tissue by combined x-ray micro-diffraction and phase contrast tomography

    NASA Astrophysics Data System (ADS)

    Cedola, Alessia; Campi, Gaetano; Pelliccia, Daniele; Bukreeva, Inna; Fratini, Michela; Burghammer, Manfred; Rigon, Luigi; Arfelli, Fulvia; Chen, Rong Chang; Dreossi, Diego; Sodini, Nicola; Mohammadi, Sara; Tromba, Giuliana; Cancedda, Ranieri; Mastrogiacomo, Maddalena

    2014-01-01

    Computed x-ray phase contrast micro-tomography is the most valuable tool for a three dimensional (3D) and non destructive analysis of the tissue engineered bone morphology. We used a Talbot interferometer installed at SYRMEP beamline of the ELETTRA synchrotron (Trieste, Italy) for a precise 3D reconstruction of both bone and soft connective tissue, regenerated in vivo within a porous scaffold. For the first time the x-ray tomographic reconstructions have been combined with x-ray scanning micro-diffraction measurement on the same sample, in order to give an exhaustive identification of the different tissues participating to the biomineralization process. As a result, we were able to investigate in detail the different densities in the tissues, distinguishing the 3D organization of the amorphous calcium phosphate from the collagen matrix. Our experimental approach allows for a deeper understanding of the role of collagen matrix in the organic-mineral transition, which is a crucial issue for the development of new bio-inspired composites.

  3. Non-destructive phase contrast hard x-ray imaging to reveal the three-dimensional microstructure of soft and hard tissues

    NASA Astrophysics Data System (ADS)

    Khimchenko, Anna; Schulz, Georg; Deyhle, Hans; Hieber, Simone E.; Hasan, Samiul; Bikis, Christos; Schulz, Joachim; Costeur, Loïc.; Müller, Bert

    2016-04-01

    X-ray imaging in the absorption contrast mode is an established method of visualising calcified tissues such as bone and teeth. Physically soft tissues such as brain or muscle are often imaged using magnetic resonance imaging (MRI). However, the spatial resolution of MRI is insufficient for identifying individual biological cells within three-dimensional tissue. X-ray grating interferometry (XGI) has advantages for the investigation of soft tissues or the simultaneous three-dimensional visualisation of soft and hard tissues. Since laboratory microtomography (μCT) systems have better accessibility than tomography set-ups at synchrotron radiation facilities, a great deal of effort has been invested in optimising XGI set-ups for conventional μCT systems. In this conference proceeding, we present how a two-grating interferometer is incorporated into a commercially available nanotom m (GE Sensing and Inspection Technologies GmbH) μCT system to extend its capabilities toward phase contrast. We intend to demonstrate superior contrast in spiders (Hogna radiata (Fam. Lycosidae) and Xysticus erraticus (Fam. Thomisidae)), as well as the simultaneous visualisation of hard and soft tissues. XGI is an imaging modality that provides quantitative data, and visualisation is an important part of biomimetics; consequently, hard X-ray imaging provides a sound basis for bioinspiration, bioreplication and biomimetics and allows for the quantitative comparison of biofabricated products with their natural counterparts.

  4. Three dimensional visualization of engineered bone and soft tissue by combined x-ray micro-diffraction and phase contrast tomography.

    PubMed

    Cedola, Alessia; Campi, Gaetano; Pelliccia, Daniele; Bukreeva, Inna; Fratini, Michela; Burghammer, Manfred; Rigon, Luigi; Arfelli, Fulvia; Chang Chen, Rong; Dreossi, Diego; Sodini, Nicola; Mohammadi, Sara; Tromba, Giuliana; Cancedda, Ranieri; Mastrogiacomo, Maddalena

    2014-01-06

    Computed x-ray phase contrast micro-tomography is the most valuable tool for a three dimensional (3D) and non destructive analysis of the tissue engineered bone morphology. We used a Talbot interferometer installed at SYRMEP beamline of the ELETTRA synchrotron (Trieste, Italy) for a precise 3D reconstruction of both bone and soft connective tissue, regenerated in vivo within a porous scaffold. For the first time the x-ray tomographic reconstructions have been combined with x-ray scanning micro-diffraction measurement on the same sample, in order to give an exhaustive identification of the different tissues participating to the biomineralization process. As a result, we were able to investigate in detail the different densities in the tissues, distinguishing the 3D organization of the amorphous calcium phosphate from the collagen matrix. Our experimental approach allows for a deeper understanding of the role of collagen matrix in the organic-mineral transition, which is a crucial issue for the development of new bio-inspired composites.

  5. In situ observation of fracture processes in high-strength concretes and limestone using high-speed X-ray phase-contrast imaging

    NASA Astrophysics Data System (ADS)

    Parab, Niranjan D.; Guo, Zherui; Hudspeth, Matthew; Claus, Benjamin; Lim, Boon Him; Sun, Tao; Xiao, Xianghui; Fezzaa, Kamel; Chen, Weinong W.

    2017-01-01

    The mechanical properties and fracture mechanisms of geomaterials and construction materials such as concrete are reported to be dependent on the loading rates. However, the in situ cracking inside such specimens cannot be visualized using traditional optical imaging methods since the materials are opaque. In this study, the in situ sub-surface failure/damage mechanisms in Cor-Tuf (a reactive powder concrete), a high-strength concrete (HSC) and Indiana limestone under dynamic loading were investigated using high-speed synchrotron X-ray phase-contrast imaging. Dynamic compressive loading was applied using a modified Kolsky bar and fracture images were recorded using a synchronized high-speed synchrotron X-ray imaging set-up. Three-dimensional synchrotron X-ray tomography was also performed to record the microstructure of the specimens before dynamic loading. In the Cor-Tuf and HSC specimens, two different modes of cracking were observed: straight cracking or angular cracking with respect to the direction of loading. In limestone, cracks followed the grain boundaries and voids, ultimately fracturing the specimen. Cracks in HSC were more tortuous than the cracks in Cor-Tuf specimens. The effects of the microstructure on the observed cracking behaviour are discussed. This article is part of the themed issue 'Experimental testing and modelling of brittle materials at high strain rates'.

  6. A smart device for label-free and real-time detection of gene point mutations based on the high dark phase contrast of vapor condensation.

    PubMed

    Zhang, Junqi; Fu, Rongxin; Xie, Liping; Li, Qi; Zhou, Wenhan; Wang, Ruliang; Ye, Jiancheng; Wang, Dong; Xue, Ning; Lin, Xue; Lu, Ying; Huang, Guoliang

    2015-10-07

    A smart device for label-free and real-time detection of gene point mutation-related diseases was developed based on the high dark phase contrast of vapor condensation. The main components of the device included a Peltier cooler and a mini PC board for image processing. Heat from the hot side of the Peltier cooler causes the fluid in a copper chamber to evaporate, and the vapor condenses on the surface of a microarray chip placed on the cold side of the cooler. The high dark phase contrast of vapor condensation relative to the analytes on the microarray chip was explored. Combined with rolling circle amplification, the device visualizes less-to-more hydrophilic transitions caused by gene trapping and DNA amplification. A lung cancer gene point mutation was analysed, proving the high selectivity and multiplex analysis capability of this low-cost device.

  7. Non-Newtonian behavior of magnetized ferrofluids as revealed by high speed x-ray phase contrast imaging

    NASA Astrophysics Data System (ADS)

    Prescod, Joy A.; Cali, A.; Nunez, S.; Smith, R.; Vieira, M.; Trubatch, A. D.; Yecko, P.; Lee, W.-K.

    2011-11-01

    Objects moving through a magnetized ferrofluid experience enhanced drag as a result of the presence of magnetic particles and magnetic particle agglomerations which form due to magnetic attractive forces. The precise impact of an agglomeration on an object depends on the characteristics of the agglomeration, the relative sizes of the object and agglomeration, as well as other control parameters. In this study, high speed phase contrast imaging was used to directly image the impact of long thread-like magnetic particle agglomerations on the rheological properties of ferrofluids. Particularly, numerous types of interactions between these threads and translating objects, including free-falling 500 micron sized solid glass spheres and intermittently rising vapor bubbles were quantified. At these scales, objects may bind to particle threads resulting in momentary re-direction or arrest of the object's trajectory, alluding to a form of yield stress. Therefore, there is a macro-viscosity property in flows of this type, which has a potentially significant impact of the use of ferrofluids in micro-fluidics and drug delivery. Supported by NSF grant no. MPS-1016383.

  8. Research, development and optimization of real time radioscopic characterization of remote handled waste and intermediate level waste, using X-ray imaging at MeV energies

    SciTech Connect

    Halliwell, Stephen

    2007-07-01

    Available in abstract form only. Full text of publication follows: Real time radioscopy (RTR) using X-ray energies of up to 450 keV, is used extensively in the characterization of nuclear waste. The majority of LLW and some ILW in drums and boxes can be penetrated, for successful imaging, by X-rays with energies of up to 450 keV. However, the shielding of many waste packages, and the range of higher density waste matrices, require X-rays at MeV energies, for X-ray imaging to achieve the performance criteria. A broad imaging performance is required to enable the identification of a range of prohibited items, including the ability to see a moving liquid meniscus which indicates the presence of free liquid, in a high density or a waste matrix with substantial containment shielding. Enhanced, high energy X-ray imaging technology to meet the future characterization demands of the nuclear industry required the design and build of a high energy facility, and the implementation of a program of research and development. The initial phase of development has confirmed that digital images meeting the required performance criteria can be made using high energy X-rays. The evaluation of real time imaging and the optimization of imaging with high energy X-rays is currently in progress. (author)

  9. Real-time X-ray absorption spectroscopy of uranium, iron, and manganese in contaminated sediments during bioreduction.

    PubMed

    Tokunag, Tetsu K; Wan, Jiamin; Kim, Yongman; Sutton, Steve R; Newville, Matthew; Lanzirotti, Antonio; Rao, William

    2008-04-15

    The oxidation status of uranium in sediments is important because the solubility of this toxic and radioactive element is much greater for U(VI) than for U(IV) species. Thus, redox manipulation to promote precipitation of UO2 is receiving interest as a method to remediate U-contaminated sediments. Presence of Fe and Mn oxides in sediments at much higher concentrations than U requires an understanding of their redox status as well. This study was conducted to determine changes in oxidation states of U, Fe, and Mn in U-contaminated sediments from Oak Ridge National Laboratory. Oxidation states of these elements were measured in real-time and nondestructively using X-ray absorption spectroscopy on sediment columns supplied with synthetic groundwater containing organic carbon (OC, 0, 3, 10, 30, and 100 mM OC as lactate) for over 400 days. In sediments supplied with OC > or = 30 mM, 80% of the U was reduced to U(IV), with transient reoxidation at about 150 days. Mn(III,IV) oxides were completely reduced to Mn(II) in sediments infused with OC > or = 3 mM. However, Fe remained largely unreduced in all sediment columns, showing that Fe(III) can persist as an electron acceptor in reducing sediments over long times. This result in combination with the complete reduction of all other potential electron acceptors supports the hypothesis that the reactive Fe(III) fraction was responsible for reoxidizing U(IV).

  10. Real-time studies of the atomic layer deposition of metal oxides using Ambient pressure x-ray photoelectron spectroscopy

    NASA Astrophysics Data System (ADS)

    Schnadt, Joachim; Head, Ashley R.; Chaudhary, Shilpi; Yngman, Sofie; Johansson, Niclas; Snezhkova, Olesia; Knudsen, Jan; Andersen, Jesper N.; Bluhm, Hendrik; Mikkelsen, Anders; Timm, Rainer

    2014-03-01

    Performing atomic layer deposition (ALD) of metal oxides at pressures around 0.01 mbar slows the half reactions of the process to allow in situ real-time probing of changes in the surface electronic structure using Ambient pressure x-ray photoelectron spectroscopy (APXPS). By monitoring the ALD process as it occurs, new details on the mechanisms of interface formation and thin film growth can be obtained. The deposition of HfO2 on InAs and the deposition of TiO2 on rutile titania from transition metal complexes and water were studied with APXPS. Predictable, cyclic chemical shifts of ligand and substrate ionizations are seen in the growth of the films, but the kinetics of the film growth differs for the two systems. Upon exposure to the titania surface, the titanium precursor reacts straightaway and gradually proceeds to completion. In contrast, the hafnium precursor does not interact with the surface immediately. Once an activation barrier is surpassed, the reaction occurs instantaneously. By understanding the reactivity of different precursors, the ALD process can be more easily optimized in applications that require thin films of metal oxides such as metal-oxide-semiconductor devices and catalytic surfaces. Support by the Swedish Research Council (grant no. 2010-5080) is gratefully acknowledged.

  11. Aluminum Nitride Grown by Atomic Layer Epitaxy Characterized with Real-Time Grazing Incidence Small Angle X-ray Scattering

    NASA Astrophysics Data System (ADS)

    Anderson, Virginia; Nepal, Neeraj; Johnson, Scooter; Robinson, Zachary; Demasi, Alexander; Hite, Jennifer; Ludwig, Karl; Eddy, Charles

    Aluminum nitride, gallium nitride, and indium nitride are being considered for many applications, and are currently being used commercially for LEDs. These III-nitride films are conventionally deposited by metalorganic chemical vapor deposition and molecular beam epitaxy. Research into depositing III-nitrides with atomic layer epitaxy (ALE) is underway as it is a fabrication friendly technique for thin films at lower temperatures. AlN deposited with ALE at 500°C have been shown to have good crystallinity, but relatively high carbon and oxygen impurities, and understanding the film deposition mechanism is an ongoing project. Grazing incidence small angle x-ray scattering (GISAXS) is sensitive to surface features, making it useful for real time monitoring of deposition processes. AlN was monitored by GISAXS while being deposited with ALE using trimethylaluminum and hydrogen/nitrogen plasma at the Brookhaven National Synchrotron Light Source and the Cornell High Energy Synchrotron Source. The GISAXS of AlN ALE at nominally 400°C, 450°C, and 500°C was compared to ex situ characterization with XPS and AFM.

  12. Real-time x-ray absorption spectroscopy of uranium, iron, and manganese in contaminated sediments during bioreduction

    SciTech Connect

    Tokunaga, Tetsu; Tokunaga, T.K.; Wan, J.; Kim, Y.; Sutton, S.R.; Newville, M.; Lanzirotti, A.; Rao, W.

    2008-01-15

    The oxidation status of uranium in sediments is important because the solubility of this toxic and radioactive element is much greater for U(VI) than for U(IV) species. Thus, redox manipulation to promote precipitation of UO{sub 2} is receiving interest as a method to remediate U-contaminated sediments. Presence of Fe and Mn oxides in sediments at much higher concentrations than U requires understanding of their redox status as well. This study was conducted to determine changes in oxidation states of U, Fe, and Mn in U-contaminated sediments from Oak Ridge National Laboratory. Oxidation states of these elements were measured in real-time and nondestructively using X-ray absorption spectroscopy, on sediment columns supplied with synthetic groundwater containing organic carbon (OC, 0, 3, 10, 30 and 100 mM OC as lactate) for over 400 days. In sediments supplied with OC {ge} 30 mM, 80% of the U was reduced to U(IV), with transient reoxidation at about 150 days. Mn(III,IV) oxides were completely reduced to Mn(II) in sediments infused with OC {ge} 3 mM. However, Fe remained largely unreduced in all sediment columns, showing that Fe(III) can persist as an electron acceptor in reducing sediments over long times. This result in combination with the complete reduction of all other potential electron acceptors supports the hypothesis that the reactive Fe(III) fraction was responsible for reoxidizing U(IV).

  13. Spatial and temporal image characteristics of a real-time large area a-Se x-ray detector

    NASA Astrophysics Data System (ADS)

    Tousignant, Olivier; Demers, Yves; Laperriere, Luc; Mani, Habib; Gauthier, Philippe; Leboeuf, Jonathan

    2005-04-01

    Large area, real-time, amorphous selenium (a-Se) based Flat Panel Detectors (FPD) were recently equipped with low noise front end electronics. In full resolution, 14"x14" detectors (FPD14) and 9"x9" detectors (FPD9) show an electronic noise of 1400 electrons. To evaluate the positive impact of such low noise on image quality, a dedicated report on spatial characteristics (MTF, NPS and DQE) covering the low dose range from 0.6 μR to 12 μR per frame, will be presented in the first section of this paper. For one RQA5 beam quality, DQE corrected for lag extrapolated at zero spatial frequency was equal to 0.6 for quantum noise limited exposure and equal to 0.4 for 0.6 μR. Almost no difference was found between 1x1 and 2x2 resolution mode giving the opportunity to 1x1 fluoroscopy. Recent advances to reduce image temporal artifacts such as lag and ghost will make the second part of this paper. It is demonstrated that the most significant contribution to detector lag is coming from the PIN selenium structure. Above electric field of 10 V/μm charges release from traps following one x-ray exposure could not explain selenium lag. Active ghost correction based on deep trapped charge recombination was developed giving good preliminary results in showing no residual ghost for a high dose rate of 33 mR/min.

  14. Characterising the structural properties of polymer separators for lithium-ion batteries in 3D using phase contrast X-ray microscopy

    NASA Astrophysics Data System (ADS)

    Finegan, Donal P.; Cooper, Samuel J.; Tjaden, Bernhard; Taiwo, Oluwadamilola O.; Gelb, Jeff; Hinds, Gareth; Brett, Dan J. L.; Shearing, Paul R.

    2016-11-01

    Separators are an integral component for optimising performance and safety of lithium-ion batteries; therefore, a clear understanding of how their microstructure affects cell performance and safety is crucial. Phase contrast X-ray microscopy is used here to capture the microstructures of commercial monolayer, tri-layer, and ceramic-coated lithium-ion battery polymer separators. Spatial variations in key structural parameters, including porosity, tortuosity factor and pore size distribution, are determined through the application of 3D quantification techniques and stereology. The architectures of individual layers in multi-layer membranes are characterised, revealing anisotropy in porosity, tortuosity factor and mean pore size of the three types of separator. Detailed structural properties of the individual layers of multi-layered membranes are then related with their expected effect on safety and rate capability of cells.

  15. Effect of fuel and nozzle geometry on the off-axis oscillation of needle in diesel injectors using high-speed X-ray phase contrast imaging

    NASA Astrophysics Data System (ADS)

    Zhang, X.; Liu, J.; Wang, J.

    2016-05-01

    The diesel spray characteristics are strongly influenced by the flow dynamics inside the injector nozzle. Moreover, the off-axis oscillation of needle could lead to variation of orifice flow in the nozzle. In this paper, the needle oscillation was investigated using high-speed X-ray phase contrast imaging and quantitative image processing. The effects of fuel, injection pressure and nozzle geometry on the needle oscillation were analyzed. The results showed that the vertical and horizontal oscillation of needle was independent on the injection pressure. The maximum oscillation range of 14μ m was found. Biodiesel application slightly decreased the needle oscillation due to high viscosity. The needle oscillation range increased generally with increasing hole number. The larger needle oscillation in multi-hole injectors was dominated by the geometry problem or production issue at lower needle lift. In addition, the influence of needle oscillation on the spray morphology was also discussed.

  16. Concept of contrast transfer function for edge illumination x-ray phase-contrast imaging and its comparison with the free-space propagation technique.

    PubMed

    Diemoz, Paul C; Vittoria, Fabio A; Olivo, Alessandro

    2016-05-16

    Previous studies on edge illumination (EI) X-ray phase-contrast imaging (XPCi) have investigated the nature and amplitude of the signal provided by this technique. However, the response of the imaging system to different object spatial frequencies was never explicitly considered and studied. This is required in order to predict the performance of a given EI setup for different classes of objects. To this scope, in the present work we derive analytical expressions for the contrast transfer function of an EI imaging system, using the approximation of near-field regime, and study its dependence upon the main experimental parameters. We then exploit these results to compare the frequency response of an EI system with respect of that of a free-space propagation XPCi one. The results achieved in this work can be useful for predicting the signals obtainable for different types of objects and also as a basis for new retrieval methods.

  17. Validity of Fusion Imaging of Hamster Heart obtained by Fluorescent and Phase-Contrast X-Ray CT with Synchrotron Radiation

    NASA Astrophysics Data System (ADS)

    Wu, J.; Takeda, T.; Lwin, Thet Thet; Huo, Q.; Sunaguchi, N.; Murakami, T.; Mouri, S.; Nasukawa, S.; Fukami, T.; Yuasa, T.; Hyodo, K.; Hontani, H.; Minami, M.; Akatsuka, T.

    2007-01-01

    Fluorescent X-ray CT (FXCT) to depict functional information and phase-contrast X-ray CT (PCCT) to demonstrate morphological information are being developed to analyze the disease model of small animal. To understand the detailed pathological state, integration of both functional and morphological image is very useful. The feasibility of image fusion between FXCT and PCCT were examined by using ex-vivo hearts injected fatty acid metabolic agent (127I-BMIPP) in normal and cardiomyopathic hamsters. Fusion images were reconstructed from each 3D image of FXCT and PCCT. 127I-BMIPP distribution within the heart was clearly demonstrated by FXCT with 0.25 mm spatial resolution. The detailed morphological image was obtained by PCCT at about 0.03 mm spatial resolution. Using image integration technique, metabolic abnormality of fatty acid in cardiomyopathic myocardium was easily recognized corresponding to anatomical structures. Our study suggests that image fusion provides important biomedical information even in FXCT and PCCT imaging.

  18. Validity of Fusion Imaging of Hamster Heart obtained by Fluorescent and Phase-Contrast X-Ray CT with Synchrotron Radiation

    SciTech Connect

    Wu, J.; Takeda, T.; Lwin, Thet Thet; Huo, Q.; Minami, M.; Sunaguchi, N.; Murakami, T.; Mouri, S.; Nasukawa, S.; Fukami, T.; Yuasa, T.; Akatsuka, T.; Hyodo, K.; Hontani, H.

    2007-01-19

    Fluorescent X-ray CT (FXCT) to depict functional information and phase-contrast X-ray CT (PCCT) to demonstrate morphological information are being developed to analyze the disease model of small animal. To understand the detailed pathological state, integration of both functional and morphological image is very useful. The feasibility of image fusion between FXCT and PCCT were examined by using ex-vivo hearts injected fatty acid metabolic agent (127I-BMIPP) in normal and cardiomyopathic hamsters. Fusion images were reconstructed from each 3D image of FXCT and PCCT. 127I-BMIPP distribution within the heart was clearly demonstrated by FXCT with 0.25 mm spatial resolution. The detailed morphological image was obtained by PCCT at about 0.03 mm spatial resolution. Using image integration technique, metabolic abnormality of fatty acid in cardiomyopathic myocardium was easily recognized corresponding to anatomical structures. Our study suggests that image fusion provides important biomedical information even in FXCT and PCCT imaging.

  19. Quantification of signal detection performance degradation induced by phase-retrieval in propagation-based x-ray phase-contrast imaging

    NASA Astrophysics Data System (ADS)

    Chou, Cheng-Ying; Anastasio, Mark A.

    2016-04-01

    In propagation-based X-ray phase-contrast (PB XPC) imaging, the measured image contains a mixture of absorption- and phase-contrast. To obtain separate images of the projected absorption and phase (i.e., refractive) properties of a sample, phase retrieval methods can be employed. It has been suggested that phase-retrieval can always improve image quality in PB XPC imaging. However, when objective (task-based) measures of image quality are employed, this is not necessarily true and phase retrieval can be detrimental. In this work, signal detection theory is utilized to quantify the performance of a Hotelling observer (HO) for detecting a known signal in a known background. Two cases are considered. In the first case, the HO acts directly on the measured intensity data. In the second case, the HO acts on either the retrieved phase or absorption image. We demonstrate that the performance of the HO is superior when acting on the measured intensity data. The loss of task-specific information induced by phase-retrieval is quantified by computing the efficiency of the HO as the ratio of the test statistic signal-to-noise ratio (SNR) for the two cases. The effect of the system geometry on this efficiency is systematically investigated. Our findings confirm that phase-retrieval can impair signal detection performance in XPC imaging.

  20. SU-E-I-90: Characterizing Small Animal Lung Properties Using Speckle Observed with An In-Line X-Ray Phase Contrast Benchtop System

    SciTech Connect

    Garson, A; Gunsten, S; Guan, H; Brody, S; Anastasio, M; Vasireddi, S

    2015-06-15

    Purpose: We demonstrate a novel X-ray phase-contrast (XPC) method for lung imaging representing a paradigm shift in the way small animal functional imaging is performed. In our method, information regarding airway microstructure that is encoded within speckle texture of a single XPC radiograph is decoded to produce 2D parametric images that will spatially resolve changes in lung properties such as microstructure sizes and air volumes. Such information cannot be derived from conventional lung radiography or any other 2D imaging modality. By computing these images at different points within a breathing cycle, dynamic functional imaging will be readily achieved without the need for tomography. Methods: XPC mouse lung radiographs acquired in situ with an in-line X-ray phase contrast benchtop system. The lung air volume is varied and controlled with a small animal ventilator. XPC radiographs will be acquired for various lung air volume levels representing different phases of the respiratory cycle. Similar data will be acquired of microsphere-based lung phantoms containing hollow glass spheres with known distributions of diameters. Image texture analysis is applied to the data to investigate relationships between texture characteristics and airspace/microsphere physical properties. Results: Correlations between Fourier-based texture descriptors (FBTDs) and regional lung air volume indicate that the texture features in 2D radiographs reveal information on 3D properties of the lungs. For example, we find for a 350 × 350 πm2 lung ROI a linear relationship between injected air volume and FBTD value with slope and intercept of 8.9×10{sup 5} and 7.5, respectively. Conclusion: We demonstrate specific image texture measures related to lung speckle features are correlated with physical characteristics of refracting elements (i.e. lung air spaces). Furthermore, we present results indicating the feasibility of implementing the technique with a simple imaging system design, short

  1. X-ray absorption resonances near L2,3-edges from real-time propagation of the Dirac-Kohn-Sham density matrix.

    PubMed

    Kadek, Marius; Konecny, Lukas; Gao, Bin; Repisky, Michal; Ruud, Kenneth

    2015-09-21

    The solution of the Liouville-von Neumann equation in the relativistic Dirac-Kohn-Sham density matrix formalism is presented and used to calculate X-ray absorption cross sections. Both dynamical relaxation effects and spin-orbit corrections are included, as demonstrated by calculations of the X-ray absorption of SF6 near the sulfur L2,3-edges. We also propose an analysis facilitating the interpretation of spectral transitions from real-time simulations, and a selective perturbation that eliminates nonphysical excitations that are artifacts of the finite basis representation.

  2. Qualitative and Quantitative Imaging Evaluation of Renal Cell Carcinoma Subtypes with Grating-based X-ray Phase-contrast CT

    PubMed Central

    Braunagel, Margarita; Birnbacher, Lorenz; Willner, Marian; Marschner, Mathias; De Marco, Fabio; Viermetz, Manuel; Notohamiprodjo, Susan; Hellbach, Katharina; Auweter, Sigrid; Link, Vera; Woischke, Christine; Reiser, Maximilian F.; Pfeiffer, Franz; Notohamiprodjo, Mike; Herzen, Julia

    2017-01-01

    Current clinical imaging methods face limitations in the detection and correct characterization of different subtypes of renal cell carcinoma (RCC), while these are important for therapy and prognosis. The present study evaluates the potential of grating-based X-ray phase-contrast computed tomography (gbPC-CT) for visualization and characterization of human RCC subtypes. The imaging results for 23 ex vivo formalin-fixed human kidney specimens obtained with phase-contrast CT were compared to the results of the absorption-based CT (gbCT), clinical CT and a 3T MRI and validated using histology. Regions of interest were placed on each specimen for quantitative evaluation. Qualitative and quantitative gbPC-CT imaging could significantly discriminate between normal kidney cortex (54 ± 4 HUp) and clear cell (42 ± 10), papillary (43 ± 6) and chromophobe RCCs (39 ± 7), p < 0.05 respectively. The sensitivity for detection of tumor areas was 100%, 50% and 40% for gbPC-CT, gbCT and clinical CT, respectively. RCC architecture like fibrous strands, pseudocapsules, necrosis or hyalinization was depicted clearly in gbPC-CT and was not equally well visualized in gbCT, clinical CT and MRI. The results show that gbPC-CT enables improved discrimination of normal kidney parenchyma and tumorous tissues as well as different soft-tissue components of RCCs without the use of contrast media. PMID:28361951

  3. Diffusion and nucleation in multilayer growth of PTCDI-C8 studied with in situ X-ray growth oscillations and real-time small angle X-ray scattering

    NASA Astrophysics Data System (ADS)

    Zykov, Anton; Bommel, Sebastian; Wolf, Christopher; Pithan, Linus; Weber, Christopher; Beyer, Paul; Santoro, Gonzalo; Rabe, Jürgen P.; Kowarik, Stefan

    2017-02-01

    We study nucleation and multilayer growth of the perylene derivative PTCDI-C8 and find a persistent layer-by-layer growth, transformation of island shapes, and an enhancement of molecular diffusivity in upper monolayers (MLs). These findings result from the evaluation of the ML-dependent island densities, obtained by in situ real-time grazing incidence small angle X-ray scattering measurements and simultaneous X-ray growth oscillations. Complementary ex situ atomic force microscopy snapshots of different growth stages agree quantitatively with both X-ray techniques. The rate and temperature-dependent island density is analyzed using different mean-field nucleation models. Both a diffusion limited aggregation and an attachment limited aggregation model yield in the first two MLs the same critical nucleus size i, similar surface diffusion attempt frequencies in the 1019-1020 s-1 range, and a decrease of the diffusion barrier Ed in the 2nd ML by 140 meV.

  4. On-site Real-Time Inspection System for Pump-impeller using X-band Linac X-ray Source

    NASA Astrophysics Data System (ADS)

    Yamamoto, Tomohiko; Natsui, Takuya; Taguchi, Hiroki; Taniguchi, Yoshihiro; Lee, Ki woo; Hashimoto, Eiko; Sakamoto, Fumito; Sakumi, Akira; Yusa, Noritaka; Uesaka, Mitsuru; Nakamura, Naoki; Yamamoto, Masashi; Tanabe, Eiji

    2009-03-01

    The methods of nondestructive testing (NDT) are generally ultrasonic, neutron, eddy-current and X-rays, NDT by using X-rays, in particular, is the most useful inspection technique having high resolution. We can especially evaluate corroded pipes of petrochemical complex, nuclear and thermal-power plants by the high energy X-ray NDT system. We develop a portable X-ray NDT system with X-band linac and magnetron. This system can generate a 950 keV electron beam. We are able to get X-ray images of samples with 1 mm spatial resolution. This system has application to real time impeller inspection because linac based X-ray sources are able to generate pulsed X-rays. So, we can inspect the rotating impeller if the X-ray pulse rate is synchronized with the impeller rotation rate. This system has application in condition based maintenance (CBM) of nuclear plants, for example. However, 950 keV X-ray source can only be used for thin tubes with 20 mm thickness. We have started design of a 3.95 MeV X-band linac for broader X-ray NDT application. We think that this X-ray NDT system will be useful for corrosion wastage and cracking in thicker tubes at nuclear plants and impeller of larger pumps. This system consists of X-band linac, thermionic cathode electron gun, magnetron and waveguide components. For achieving higher electric fields the 3.95 MeV X-band linac structure has the side-coupled acceleration structure. This structure has more efficient acceleration than the 950 keV linac with alternating periodic structure (APS). We adopt a 1.3 MW magnetron for the RF source. This accelerator system is about 30 cm long. The beam current is about 150 mA, and X-ray dose rate is 10 Gy@1 m/500 pps. In this paper, the detail of the whole system concept and the electromagnetic field of designed linac structure will be reported.

  5. Computer-Aided Diagnosis in Phase Contrast Imaging X-Ray Computed Tomography for Quantitative Characterization of ex vivo Human Patellar Cartilage

    PubMed Central

    Nagarajan, Mahesh B.; Coan, Paola; Huber, Markus B.; Diemoz, Paul C.; Glaser, Christian; Wismüller, Axel

    2014-01-01

    Visualization of ex vivo human patellar cartilage matrix through the phase contrast imaging X-ray computed tomography (PCI-CT) has been previously demonstrated. Such studies revealed osteoarthritis-induced changes to chondrocyte organization in the radial zone. This study investigates the application of texture analysis to characterizing such chondrocyte patterns in the presence and absence of osteoarthritic damage. Texture features derived from Minkowski functionals (MF) and gray-level co-occurrence matrices (GLCM) were extracted from 842 regions of interest (ROI) annotated on PCI-CT images of ex vivo human patellar cartilage specimens. These texture features were subsequently used in a machine learning task with support vector regression to classify ROIs as healthy or osteoarthritic; classification performance was evaluated using the area under the receiver operating characteristic curve (AUC). The best classification performance was observed with the MF features perimeter (AUC: 0.94 ± 0.08) and “Euler characteristic” (AUC: 0.94 ± 0.07), and GLCM-derived feature “Correlation” (AUC: 0.93 ± 0.07). These results suggest that such texture features can provide a detailed characterization of the chondrocyte organization in the cartilage matrix, enabling classification of cartilage as healthy or osteoarthritic with high accuracy. PMID:23744660

  6. Robust phase retrieval for high resolution edge illumination x-ray phase-contrast computed tomography in non-ideal environments

    NASA Astrophysics Data System (ADS)

    Zamir, Anna; Endrizzi, Marco; Hagen, Charlotte K.; Vittoria, Fabio A.; Urbani, Luca; de Coppi, Paolo; Olivo, Alessandro

    2016-08-01

    Edge illumination x-ray phase contrast tomography is a recently developed imaging technique which enables three-dimensional visualisation of low-absorbing materials. Dedicated phase retrieval algorithms can provide separate computed tomography (CT) maps of sample absorption, refraction and scattering properties. In this paper we propose a novel “modified local retrieval” method which is capable of accurately retrieving sample properties in a range of realistic, non-ideal imaging environments. These include system misalignment, defects in the used optical elements and system geometry variations over time due to vibrations or temperature fluctuations. System instabilities were analysed, modelled and incorporated into a simulation study. As a result, an additional modification was introduced to the retrieval procedure to account for changes in the imaging system over time, as well as local variations over the field of view. The performance of the proposed method was evaluated in comparison to a previously used “global retrieval” method by applying both approaches to experimental CT data of a rat’s heart acquired in a non-ideal environment. The use of the proposed method resulted in the removal of major artefacts, leading to a significant improvement in image quality. This method will therefore enable acquiring high-resolution, reliable CT data of large samples in realistic settings.

  7. Computer-aided diagnosis in phase contrast imaging X-ray computed tomography for quantitative characterization of ex vivo human patellar cartilage.

    PubMed

    Nagarajan, Mahesh B; Coan, Paola; Huber, Markus B; Diemoz, Paul C; Glaser, Christian; Wismuller, Axel

    2013-10-01

    Visualization of ex vivo human patellar cartilage matrix through the phase contrast imaging X-ray computed tomography (PCI-CT) has been previously demonstrated. Such studies revealed osteoarthritis-induced changes to chondrocyte organization in the radial zone. This study investigates the application of texture analysis to characterizing such chondrocyte patterns in the presence and absence of osteoarthritic damage. Texture features derived from Minkowski functionals (MF) and gray-level co-occurrence matrices (GLCM) were extracted from 842 regions of interest (ROI) annotated on PCI-CT images of ex vivo human patellar cartilage specimens. These texture features were subsequently used in a machine learning task with support vector regression to classify ROIs as healthy or osteoarthritic; classification performance was evaluated using the area under the receiver operating characteristic curve (AUC). The best classification performance was observed with the MF features perimeter (AUC: 0.94 ±0.08 ) and "Euler characteristic" (AUC: 0.94 ±0.07 ), and GLCM-derived feature "Correlation" (AUC: 0.93 ±0.07). These results suggest that such texture features can provide a detailed characterization of the chondrocyte organization in the cartilage matrix, enabling classification of cartilage as healthy or osteoarthritic with high accuracy.

  8. Three-dimensional visualization of the microvasculature of bile duct ligation-induced liver fibrosis in rats by x-ray phase-contrast imaging computed tomography

    NASA Astrophysics Data System (ADS)

    Xuan, Ruijiao; Zhao, Xinyan; Hu, Doudou; Jian, Jianbo; Wang, Tailing; Hu, Chunhong

    2015-07-01

    X-ray phase-contrast imaging (PCI) can substantially enhance contrast, and is particularly useful in differentiating biological soft tissues with small density differences. Combined with computed tomography (CT), PCI-CT enables the acquisition of accurate microstructures inside biological samples. In this study, liver microvasculature was visualized without contrast agents in vitro with PCI-CT using liver fibrosis samples induced by bile duct ligation (BDL) in rats. The histological section examination confirmed the correspondence of CT images with the microvascular morphology of the samples. By means of the PCI-CT and three-dimensional (3D) visualization technique, 3D microvascular structures in samples from different stages of liver fibrosis were clearly revealed. Different types of blood vessels, including portal veins and hepatic veins, in addition to ductular proliferation and bile ducts, could be distinguished with good sensitivity, excellent specificity and excellent accuracy. The study showed that PCI-CT could assess the morphological changes in liver microvasculature that result from fibrosis and allow characterization of the anatomical and pathological features of the microvasculature. With further development of PCI-CT technique, it may become a novel noninvasive imaging technique for the auxiliary analysis of liver fibrosis.

  9. In situ 3-D mapping of pore structures and hollow grains of interplanetary dust particles with phase contrast X-ray nanotomography

    NASA Astrophysics Data System (ADS)

    Hu, Z. W.; Winarski, R. P.

    2016-09-01

    Unlocking the 3-D structure and properties of intact chondritic porous interplanetary dust particles (IDPs) in nanoscale detail is challenging, which is also complicated by atmospheric entry heating, but is important for advancing our understanding of the formation and origins of IDPs and planetary bodies as well as dust and ice agglomeration in the outer protoplanetary disk. Here, we show that indigenous pores, pristine grains, and thermal alteration products throughout intact particles can be noninvasively visualized and distinguished morphologically and microstructurally in 3-D detail down to ~10 nm by exploiting phase contrast X-ray nanotomography. We have uncovered the surprisingly intricate, submicron, and nanoscale pore structures of a ~10-μm-long porous IDP, consisting of two types of voids that are interconnected in 3-D space. One is morphologically primitive and mostly submicron-sized intergranular voids that are ubiquitous; the other is morphologically advanced and well-defined intragranular nanoholes that run through the approximate centers of ~0.3 μm or lower submicron hollow grains. The distinct hollow grains exhibit complex 3-D morphologies but in 2-D projections resemble typical organic hollow globules observed by transmission electron microscopy. The particle, with its outer region characterized by rough vesicular structures due to thermal alteration, has turned out to be an inherently fragile and intricately submicron- and nanoporous aggregate of the sub-μm grains or grain clumps that are delicately bound together frequently with little grain-to-grain contact in 3-D space.

  10. Robust phase retrieval for high resolution edge illumination x-ray phase-contrast computed tomography in non-ideal environments

    PubMed Central

    Zamir, Anna; Endrizzi, Marco; Hagen, Charlotte K.; Vittoria, Fabio A.; Urbani, Luca; De Coppi, Paolo; Olivo, Alessandro

    2016-01-01

    Edge illumination x-ray phase contrast tomography is a recently developed imaging technique which enables three-dimensional visualisation of low-absorbing materials. Dedicated phase retrieval algorithms can provide separate computed tomography (CT) maps of sample absorption, refraction and scattering properties. In this paper we propose a novel “modified local retrieval” method which is capable of accurately retrieving sample properties in a range of realistic, non-ideal imaging environments. These include system misalignment, defects in the used optical elements and system geometry variations over time due to vibrations or temperature fluctuations. System instabilities were analysed, modelled and incorporated into a simulation study. As a result, an additional modification was introduced to the retrieval procedure to account for changes in the imaging system over time, as well as local variations over the field of view. The performance of the proposed method was evaluated in comparison to a previously used “global retrieval” method by applying both approaches to experimental CT data of a rat’s heart acquired in a non-ideal environment. The use of the proposed method resulted in the removal of major artefacts, leading to a significant improvement in image quality. This method will therefore enable acquiring high-resolution, reliable CT data of large samples in realistic settings. PMID:27502296

  11. Real-time x-ray response of biocompatible solution gate AlGaN/GaN high electron mobility transistor devices

    NASA Astrophysics Data System (ADS)

    Hofstetter, Markus; Howgate, John; Sharp, Ian D.; Funk, Maren; Stutzmann, Martin; Paretzke, Herwig G.; Thalhammer, Stefan

    2010-03-01

    We present the real-time x-ray irradiation response of charge and pH sensitive solution gate AlGaN/GaN high electron mobility transistors. The devices show stable and reproducible behavior under and following x-ray radiation, including a linear integrated response with dose into the μGy range. Titration measurements of devices in solution reveal that the linear pH response and sensitivity are not only retained under x-ray irradiation, but an irradiation response could also be measured. Since the devices are biocompatible, and can be simultaneously operated in aggressive fluids and under hard radiation, they are well-suited for both medical radiation dosimetry and biosensing applications.

  12. In situ and real-time characterization of metal-organic chemical vapor deposition growth by high resolution x-ray diffraction

    SciTech Connect

    Kharchenko, A.; Lischka, K.; Schmidegg, K.; Sitter, H.; Bethke, J.; Woitok, J.

    2005-03-01

    We present an x-ray diffractometer for the analysis of epitaxial layers during (in situ) metal-organic chemical vapor deposition (MOCVD). Our diffractometer has a conventional x-ray source, does not need a goniometer stage, and is not sensitive to precise adjustment of the samples before measurement. It allows us to perform measurements within a few seconds even from rotating and wobbling samples. The first results of laboratory tests performed with our x-ray diffraction system show that it is well suited for in situ and real-time monitoring of the MOCVD growth process. We were able to measure the growth rate of a cubic GaN layer and the intensity and peak position of Bragg reflections of the growing layer in less than 20 s only.

  13. Real time x-ray studies during nanostructure formation on silicon via low energy ion beam irradiation using ultrathin iron films

    SciTech Connect

    El-Atwani, Osman; Suslova, Anastassiya; Gonderman, Sean; Fowler, Justin; El-Atwani, Mohamad; DeMasi, Alexander; Ludwig, Karl; Paul Allain, Jean

    2012-12-24

    Real time grazing incidence small angle x-ray scattering and x-ray fluorescence (XRF) are used to elucidate nanodot formation on silicon surfaces during low energy ion beam irradiation of ultrathin iron-coated silicon substrates. Four surface modification stages were identified: (1) surface roughening due to film erosion, (2) surface smoothing and silicon-iron mixing, (3) structure formation, and (4) structure smoothing. The results conclude that 2.5 Multiplication-Sign 10{sup 15} iron atoms in a 50 nm depth triggers surface nanopatterning with a correlated nanodots distance of 25 nm. Moreover, there is a wide window in time where the surface can have correlated nanostructures even after the removal of all the iron atoms from the sample as confirmed by XRF and ex-situ x-ray photoelectron spectroscopy (XPS). In addition, in-situ XPS results indicated silicide formation, which plays a role in the structure formation mechanism.

  14. Linear, position-sensitive x-ray detector used for real-time calculations of small-angle scattering parameters with submillisecond resolution

    SciTech Connect

    Borso, C.S.

    1984-01-01

    The advent of high-intensity X-ray synchrotron sources has made possible the measurement of fluctuations in small-angle scattering parameters from typical specimens on a submillisecond time scale in real-time. The fundamental design of any fast detector system optimized for such measurements will incorporate some type of solid state detector array capable of rapid encoding algorithms. A prototype with a self-scanning photodiode array has been designed and tested at beamline 1 to 4 at the Stanford Synchrotron Radiation Laboratory (SSRL), and the results indicate that the device will operate at speeds yielding submillisecond temporal resolution in real-time.

  15. Dynamics of respiratory and cardiac CSF motion revealed with real-time simultaneous multi-slice EPI velocity phase contrast imaging.

    PubMed

    Chen, Liyong; Beckett, Alexander; Verma, Ajay; Feinberg, David A

    2015-11-15

    Cerebrospinal fluid (CSF) dynamics have been mostly studied with cardiac-gated phase contrast MRI combining signal from many cardiac cycles to create cine-phase sampling of one time-averaged cardiac cycle. The relative effects of cardiac and respiratory changes on CSF movement are not well understood. There is possible respiration-driven movement of CSF in ventricles, cisterns, and subarachnoid spaces which has not been characterized with velocity measurements. To date, commonly used cine-phase contrast techniques of velocity imaging inherently cannot detect respiratory velocity changes since cardiac-gated data acquired over several minutes randomizes respiratory phase contributions. We have developed an extremely fast, real-time, and quantitative MRI technique to image CSF velocity in simultaneous multi-slice (SMS) echo planar imaging (EPI) acquisitions of 3 or 6 slice levels simultaneously over 30s and observe 3D spatial distributions of CSF velocity. Measurements were made in 10 subjects utilizing a respiratory belt to record respiratory phases and visual cues to instruct subjects on breathing rates. A protocol is able to measure velocity within regions of brain and basal cisterns covered with 24 axial slices in 4 minutes, repeated for 3 velocity directions. These measurements were performed throughout the whole brain, rather than in selected line regions so that a global view of CSF dynamics could be visualized. Observations of cardiac and breathing-driven CSF dynamics show bidirectional respiratory motion occurs primarily along the central axis through the basal cisterns and intraventricular passageways and to a lesser extent in the peripheral Sylvian fissure with little CSF motion present in subarachnoid spaces. During inspiration phase, there is upward (inferior to superior) CSF movement into the cranial cavity and lateral ventricles and a reversal of direction in expiration phase.

  16. Study of Dynamic Behavior and Hazards of VHBR, LOVA, And PSS Propellants under Rapid Ignition And Combustion Conditions by Real-Time X-Ray Radiography

    DTIC Science & Technology

    1991-12-01

    Mroiect (07Q4.Q188). Washington. OC 20503. 1. AGENCY USE ONLY (Leave btonk) 2. REPORT DATE December 9, 1991 3. REPORT TYPE AND OATES COVERED 4. TITLE...ABSTRACT (Maximum 200 words) rjj^ purpose of this work is to study the dynamic behavior in Ithe ccrobustion of three types of propellants used in artillery...APPENDICES Appendix A Study of Combustion Behavior of Very High Burning Rate Propellants Using a Real-Time X-ray Radiography System Appendix B

  17. Real-time observation of coherent acoustic phonons generated by an acoustically mismatched optoacoustic transducer using x-ray diffraction

    SciTech Connect

    Persson, A. I. H.; Andreasson, B. P.; Enquist, H.; Jurgilaitis, A.; Larsson, J.

    2015-11-14

    The spectrum of laser-generated acoustic phonons in indium antimonide coated with a thin nickel film has been studied using time-resolved x-ray diffraction. Strain pulses that can be considered to be built up from coherent phonons were generated in the nickel film by absorption of short laser pulses. Acoustic reflections at the Ni–InSb interface leads to interference that strongly modifies the resulting phonon spectrum. The study was performed with high momentum transfer resolution together with high time resolution. This was achieved by using a third-generation synchrotron radiation source that provided a high-brightness beam and an ultrafast x-ray streak camera to obtain a temporal resolution of 10 ps. We also carried out simulations, using commercial finite element software packages and on-line dynamic diffraction tools. Using these tools, it is possible to calculate the time-resolved x-ray reflectivity from these complicated strain shapes. The acoustic pulses have a peak strain amplitude close to 1%, and we investigated the possibility to use this device as an x-ray switch. At a bright source optimized for hard x-ray generation, the low reflectivity may be an acceptable trade-off to obtain a pulse duration that is more than an order of magnitude shorter.

  18. Real-Time Observation of Laser Heated Metals with High Brightness Monochromatic X-Ray Techniques at Present and Their Future Prospects

    NASA Astrophysics Data System (ADS)

    Daido, H.; Shobu, T.; Yamada, T.; Yamashita, S.; Sugihara, K.; Nishimura, A.; Muramatsu, T.

    We present the x-ray techniques for characterizing laser heated metals for welding and cutting techniques. At present, with an undulator (70 keV) as well as bending magnet (30 keV) sources at SPring-8 as a probe source, CW 300 W Ytterbium fiber laser irradiates an Aluminum slab as a sample. Simultaneously the x-ray beam probes the sample for real time observation of a molten pool. We observe the convection indicated by the motion of tungsten based particles as a tracer in the molten pool. During the cooling phase, the molten metal is solidified with residual stresses which are affected by the heating and convection processes. In this experiment the time and space resolution are ˜milli-second and several tens of μm, respectively. On the other hand, microscopic short transient phenomena also play a significant role for the quality of a solidified material. For this purpose, we need high energy short pulse x-ray sources. We try to discuss on the capability and limitation of present x-ray sources and the prospect of an ultra high brightness x-ray source as a complementary source for full characterization of the laser heated and cooling processes of metals.

  19. X-Ray Laser Gets First Real-Time Snapshots of a Chemical Flipping a Biological Switch

    SciTech Connect

    2016-11-14

    Scientists have used the powerful X-ray laser at the Department of Energy’s SLAC National Accelerator Laboratory to make the first snapshots of a chemical interaction between two biomolecules – one that flips an RNA “switch” that regulates production of proteins, the workhorse molecules of life. The results, published in Nature, show the game-changing potential of X-ray free-electron lasers, or XFELs, for studying RNA, which guides protein manufacturing in the cell, serves as the primary genetic material in retroviruses such as HIV and also plays a role in most forms of cancer.

  20. Integrating Dimension Reduction and Out-of-Sample Extension in Automated Classification of Ex Vivo Human Patellar Cartilage on Phase Contrast X-Ray Computed Tomography

    PubMed Central

    Nagarajan, Mahesh B.; Coan, Paola; Huber, Markus B.; Diemoz, Paul C.; Wismüller, Axel

    2015-01-01

    Phase contrast X-ray computed tomography (PCI-CT) has been demonstrated as a novel imaging technique that can visualize human cartilage with high spatial resolution and soft tissue contrast. Different textural approaches have been previously investigated for characterizing chondrocyte organization on PCI-CT to enable classification of healthy and osteoarthritic cartilage. However, the large size of feature sets extracted in such studies motivates an investigation into algorithmic feature reduction for computing efficient feature representations without compromising their discriminatory power. For this purpose, geometrical feature sets derived from the scaling index method (SIM) were extracted from 1392 volumes of interest (VOI) annotated on PCI-CT images of ex vivo human patellar cartilage specimens. The extracted feature sets were subject to linear and non-linear dimension reduction techniques as well as feature selection based on evaluation of mutual information criteria. The reduced feature set was subsequently used in a machine learning task with support vector regression to classify VOIs as healthy or osteoarthritic; classification performance was evaluated using the area under the receiver-operating characteristic (ROC) curve (AUC). Our results show that the classification performance achieved by 9-D SIM-derived geometric feature sets (AUC: 0.96 ± 0.02) can be maintained with 2-D representations computed from both dimension reduction and feature selection (AUC values as high as 0.97 ± 0.02). Thus, such feature reduction techniques can offer a high degree of compaction to large feature sets extracted from PCI-CT images while maintaining their ability to characterize the underlying chondrocyte patterns. PMID:25710875

  1. Volumetric quantitative characterization of human patellar cartilage with topological and geometrical features on phase-contrast X-ray computed tomography.

    PubMed

    Nagarajan, Mahesh B; Coan, Paola; Huber, Markus B; Diemoz, Paul C; Wismüller, Axel

    2015-11-01

    Phase-contrast X-ray computed tomography (PCI-CT) has attracted significant interest in recent years for its ability to provide significantly improved image contrast in low absorbing materials such as soft biological tissue. In the research context of cartilage imaging, previous studies have demonstrated the ability of PCI-CT to visualize structural details of human patellar cartilage matrix and capture changes to chondrocyte organization induced by osteoarthritis. This study evaluates the use of geometrical and topological features for volumetric characterization of such chondrocyte patterns in the presence (or absence) of osteoarthritic damage. Geometrical features derived from the scaling index method (SIM) and topological features derived from Minkowski Functionals were extracted from 1392 volumes of interest (VOI) annotated on PCI-CT images of ex vivo human patellar cartilage specimens. These features were subsequently used in a machine learning task with support vector regression to classify VOIs as healthy or osteoarthritic; classification performance was evaluated using the area under the receiver operating characteristic curve (AUC). Our results show that the classification performance of SIM-derived geometrical features (AUC: 0.90 ± 0.09) is significantly better than Minkowski Functionals volume (AUC: 0.54 ± 0.02), surface (AUC: 0.72 ± 0.06), mean breadth (AUC: 0.74 ± 0.06) and Euler characteristic (AUC: 0.78 ± 0.04) (p < 10(-4)). These results suggest that such geometrical features can provide a detailed characterization of the chondrocyte organization in the cartilage matrix in an automated manner, while also enabling classification of cartilage as healthy or osteoarthritic with high accuracy. Such features could potentially serve as diagnostic imaging markers for evaluating osteoarthritis progression and its response to different therapeutic intervention strategies.

  2. Differential X-ray phase contrast tomography of Alzheimer plaques in mouse models: perspectives for drug development and clinical imaging techniques

    NASA Astrophysics Data System (ADS)

    Pinzer, B. R.; Cacquevel, M.; Modregger, P.; Thuering, T.; Stampanoni, M.

    2013-05-01

    Alzheimer's disease (AD) is a looming threat on an ever-ageing population, with devastating effects on the human intellect. A particular characteristic lesion — the extracellular amyloid plaque — accumulates in the brain of AD patients during the course of the disease, and could therefore be used to monitor the progression of the disease, years before the first neurological symptoms appear. In addition, strategies for drug intervention in AD are often based on amyloid reduction, since amyloid plaques are hypothesized to be involved in a chain of reactions leading to the death of neurons. Developments in both fields would benefit from a microscopic technique that is capable of single plaque imaging, ideally in 3D. While such a non-destructive, single-plaque imaging technique does not yet exist for humans, it has been recently shown that synchrotron based differential X-ray phase contrast imaging can be used to visualize individual plaques at μm resolution in mouse models of AD ex-vivo. This method, which relies on a grating interferometer to measure refraction angles induced by fluctuations in the refractive index, yields a precise three-dimensional distribution of single plaques. These data could not only improve the understanding of the evolution of AD or the effectiveness of drugs, but could also help to improve reliable markers for current and future non-invasive clinical imaging techniques. In particular, validation of PET markers with small animal models could be rapidly carried out by co-registration of PET and DPC signals.

  3. Radioluminescence characterization of in situ x-ray nanodosimeters: Potential real-time monitors and modulators of external beam radiation therapy

    SciTech Connect

    Souris, Jeffrey S.; La Riviere, Patrick; Chen, Chin-Tu; Cheng, Shih-Hsun; Chen, Nai-Tzu; Lo, Leu-Wei; Pelizzari, Charles

    2014-11-17

    Europium-doped yttrium oxide (Y{sub 2}O{sub 3}:Eu) has garnered considerable interest recently for its use as a highly efficient, red phosphor in a variety of lighting applications that include fluorescent lamps, plasma, and field emission display panels, light emitting diodes (LEDs), and lasers. In the present work, we describe the development of Y{sub 2}O{sub 3}:Eu nanoparticles for a very different application: in situ, in vivo x-ray dosimetry. Spectroscopic analyses of these nanoparticles during x-ray irradiation reveal surprisingly bright and stable radioluminescence at near-infrared wavelengths, with markedly linear response to changes in x-ray flux and energy. Monte Carlo modeling of incident flux and broadband, wide-field imaging of mouse phantoms bearing both Y{sub 2}O{sub 3}:Eu nanoparticles and calibrated LEDs of similar spectral emission demonstrated significant transmission of radioluminescence, in agreement with spectroscopic studies; with approximately 15 visible photons being generated for every x-ray photon incident. Unlike the dosimeters currently employed in clinical practice, these nanodosimeters can sample both dose and dose rate rapidly enough as to provide real-time feedback for x-ray based external beam radiotherapy (EBRT). The technique's use of remote sensing and absence of supporting structures enable perturbation-free dosing of the targeted region and complete sampling from any direction. With the conjugation of pathology-targeting ligands onto their surfaces, these nanodosimeters offer a potential paradigm shift in the real-time monitoring and modulation of delivered dose in the EBRT of cancer in situ.

  4. Radioluminescence characterization of in situ x-ray nanodosimeters: Potential real-time monitors and modulators of external beam radiation therapy

    NASA Astrophysics Data System (ADS)

    Souris, Jeffrey S.; Cheng, Shih-Hsun; Pelizzari, Charles; Chen, Nai-Tzu; La Riviere, Patrick; Chen, Chin-Tu; Lo, Leu-Wei

    2014-11-01

    Europium-doped yttrium oxide (Y2O3:Eu) has garnered considerable interest recently for its use as a highly efficient, red phosphor in a variety of lighting applications that include fluorescent lamps, plasma, and field emission display panels, light emitting diodes (LEDs), and lasers. In the present work, we describe the development of Y2O3:Eu nanoparticles for a very different application: in situ, in vivo x-ray dosimetry. Spectroscopic analyses of these nanoparticles during x-ray irradiation reveal surprisingly bright and stable radioluminescence at near-infrared wavelengths, with markedly linear response to changes in x-ray flux and energy. Monte Carlo modeling of incident flux and broadband, wide-field imaging of mouse phantoms bearing both Y2O3:Eu nanoparticles and calibrated LEDs of similar spectral emission demonstrated significant transmission of radioluminescence, in agreement with spectroscopic studies; with approximately 15 visible photons being generated for every x-ray photon incident. Unlike the dosimeters currently employed in clinical practice, these nanodosimeters can sample both dose and dose rate rapidly enough as to provide real-time feedback for x-ray based external beam radiotherapy (EBRT). The technique's use of remote sensing and absence of supporting structures enable perturbation-free dosing of the targeted region and complete sampling from any direction. With the conjugation of pathology-targeting ligands onto their surfaces, these nanodosimeters offer a potential paradigm shift in the real-time monitoring and modulation of delivered dose in the EBRT of cancer in situ.

  5. Radioluminescence characterization of in situ x-ray nanodosimeters: Potential real-time monitors and modulators of external beam radiation therapy

    PubMed Central

    Souris, Jeffrey S.; Cheng, Shih-Hsun; Pelizzari, Charles; Chen, Nai-Tzu; La Riviere, Patrick; Chen, Chin-Tu; Lo, Leu-Wei

    2014-01-01

    Europium-doped yttrium oxide (Y2O3:Eu) has garnered considerable interest recently for its use as a highly efficient, red phosphor in a variety of lighting applications that include fluorescent lamps, plasma, and field emission display panels, light emitting diodes (LEDs), and lasers. In the present work, we describe the development of Y2O3:Eu nanoparticles for a very different application: in situ, in vivo x-ray dosimetry. Spectroscopic analyses of these nanoparticles during x-ray irradiation reveal surprisingly bright and stable radioluminescence at near-infrared wavelengths, with markedly linear response to changes in x-ray flux and energy. Monte Carlo modeling of incident flux and broadband, wide-field imaging of mouse phantoms bearing both Y2O3:Eu nanoparticles and calibrated LEDs of similar spectral emission demonstrated significant transmission of radioluminescence, in agreement with spectroscopic studies; with approximately 15 visible photons being generated for every x-ray photon incident. Unlike the dosimeters currently employed in clinical practice, these nanodosimeters can sample both dose and dose rate rapidly enough as to provide real-time feedback for x-ray based external beam radiotherapy (EBRT). The technique's use of remote sensing and absence of supporting structures enable perturbation-free dosing of the targeted region and complete sampling from any direction. With the conjugation of pathology-targeting ligands onto their surfaces, these nanodosimeters offer a potential paradigm shift in the real-time monitoring and modulation of delivered dose in the EBRT of cancer in situ. PMID:25425747

  6. Trial of X-Ray Grating Interferometry for Phase-Contrast Imaging with a Practical X-Ray Tube— Application of Talbot-Lau Interferometry to Medical Imaging —

    NASA Astrophysics Data System (ADS)

    Kido, Kazuhiro; Makifuchi, Chiho; Kiyohara, Junko; Itou, Tsukasa; Honda, Chika

    An imaging system of X-ray grating interferometry, i.e., Talbot-Lau interferometry, was created with a medical X-ray tube, a multi-slit, two X-ray gratings, and an X-ray detector on the basis of design with wave-optic simulation. Imaging performance of the system was examined so that bone cartilage of a chicken wing was depicted clearly with X-ray dose at 3 mGy. Using this imaging system, a small angle scattering image of a cherry was obtained successfully to depict its vascular bundle of the inner structure of the cherry that was invisible in its X-ray absorption image. This imaging trial suggests that the X-ray Talbot-Lau interferometry is a promising tool to detect soft tissue in human body for X-ray image-diagnosis besides the magnetic resonance imaging.

  7. X-Ray Laser Gets First Real-Time Snapshots of a Chemical Flipping a Biological Switch

    ScienceCinema

    None

    2016-12-02

    Scientists have used the powerful X-ray laser at the Department of Energy’s SLAC National Accelerator Laboratory to make the first snapshots of a chemical interaction between two biomolecules – one that flips an RNA “switch” that regulates production of proteins, the workhorse molecules of life. The results, published in Nature, show the game-changing potential of X-ray free-electron lasers, or XFELs, for studying RNA, which guides protein manufacturing in the cell, serves as the primary genetic material in retroviruses such as HIV and also plays a role in most forms of cancer.

  8. Nanopatterning of metal-coated silicon surfaces via ion beam irradiation: Real time x-ray studies reveal the effect of silicide bonding

    SciTech Connect

    El-Atwani, Osman; Gonderman, Sean; Suslova, Anastassiya; Fowler, Justin; El-Atwani, Mohamad; DeMasi, Alexander; Ludwig, Karl; Paul Allain, Jean

    2013-03-28

    We investigated the effect of silicide formation on ion-induced nanopatterning of silicon with various ultrathin metal coatings. Silicon substrates coated with 10 nm Ni, Fe, and Cu were irradiated with 200 eV argon ions at normal incidence. Real time grazing incidence small angle x-ray scattering (GISAXS) and x-ray fluorescence (XRF) were performed during the irradiation process and real time measurements revealed threshold conditions for nanopatterning of silicon at normal incidence irradiation. Three main stages of the nanopatterning process were identified. The real time GISAXS intensity of the correlated peaks in conjunction with XRF revealed that the nanostructures remain for a time period after the removal of the all the metal atoms from the sample depending on the binding energy of the metal silicides formed. Ex-situ XPS confirmed the removal of all metal impurities. In-situ XPS during the irradiation of Ni, Fe, and Cu coated silicon substrates at normal incidence demonstrated phase separation and the formation of different silicide phases that occur upon metal-silicon mixing. Silicide formation leads to nanostructure formation due the preferential erosion of the non-silicide regions and the weakening of the ion induced mass redistribution.

  9. Operation of beam line facilities for real-time x-ray studies at Sector 7 of the advanced photon source. Final Report

    SciTech Connect

    Clarke, Roy

    2003-09-10

    This Final Report documents the research accomplishments achieved in the first phase of operations of a new Advanced Photon Source beam line (7-ID MHATT-CAT) dedicated to real-time x-ray studies. The period covered by this report covers the establishment of a world-class facility for time-dependent x-ray studies of materials. During this period many new and innovative research programs were initiated at Sector 7 with support of this grant, most notably using a combination of ultrafast lasers and pulsed synchrotron radiation. This work initiated a new frontier of materials research: namely, the study of the dynamics of materials under extreme conditions of high intensity impulsive laser irradiation.

  10. Adaptation of a clustered lumpy background model for task-based image quality assessment in x-ray phase-contrast mammography

    PubMed Central

    Zysk, Adam M.; Brankov, Jovan G.; Wernick, Miles N.; Anastasio, Mark A.

    2012-01-01

    Purpose: Since the introduction of clinical x-ray phase-contrast mammography (PCM), a technique that exploits refractive-index variations to create edge enhancement at tissue boundaries, a number of optimization studies employing physical image-quality metrics have been performed. Ideally, task-based assessment of PCM would have been conducted with human readers. These studies have been limited, however, in part due to the large parameter-space of PCM system configurations and the difficulty of employing expert readers for large-scale studies. It has been proposed that numerical observers can be used to approximate the statistical performance of human readers, thus enabling the study of task-based performance over a large parameter-space. Methods: Methods are presented for task-based image quality assessment of PCM images with a numerical observer, the most significant of which is an adapted lumpy background from the conventional mammography literature that accounts for the unique wavefield propagation physics of PCM image formation and will be used with a numerical observer to assess image quality. These methods are demonstrated by performing a PCM task-based image quality study using a numerical observer. This study employs a signal-known-exactly, background-known-statistically Bayesian ideal observer method to assess the detectability of a calcification object in PCM images when the anode spot size and calcification diameter are varied. Results: The first realistic model for the structured background in PCM images has been introduced. A numerical study demonstrating the use of this background model has compared PCM and conventional mammography detection of calcification objects. The study data confirm the strong PCM calcification detectability dependence on anode spot size. These data can be used to balance the trade-off between enhanced image quality and the potential for motion artifacts that comes with use of a reduced spot size and increased exposure time

  11. A real-time regional adaptive exposure method for saving dose-area product in x-ray fluoroscopy

    SciTech Connect

    Burion, Steve; Funk, Tobias; Speidel, Michael A.

    2013-05-15

    Purpose: Reduction of radiation dose in x-ray imaging has been recognized as a high priority in the medical community. Here the authors show that a regional adaptive exposure method can reduce dose-area product (DAP) in x-ray fluoroscopy. The authors' method is particularly geared toward providing dose savings for the pediatric population. Methods: The scanning beam digital x-ray system uses a large-area x-ray source with 8000 focal spots in combination with a small photon-counting detector. An imaging frame is obtained by acquiring and reconstructing up to 8000 detector images, each viewing only a small portion of the patient. Regional adaptive exposure was implemented by varying the exposure of the detector images depending on the local opacity of the object. A family of phantoms ranging in size from infant to obese adult was imaged in anteroposterior view with and without adaptive exposure. The DAP delivered to each phantom was measured in each case, and noise performance was compared by generating noise arrays to represent regional noise in the images. These noise arrays were generated by dividing the image into regions of about 6 mm{sup 2}, calculating the relative noise in each region, and placing the relative noise value of each region in a one-dimensional array (noise array) sorted from highest to lowest. Dose-area product savings were calculated as the difference between the ratio of DAP with adaptive exposure to DAP without adaptive exposure. The authors modified this value by a correction factor that matches the noise arrays where relative noise is the highest to report a final dose-area product savings. Results: The average dose-area product saving across the phantom family was (42 {+-} 8)% with the highest dose-area product saving in the child-sized phantom (50%) and the lowest in the phantom mimicking an obese adult (23%). Conclusions: Phantom measurements indicate that a regional adaptive exposure method can produce large DAP savings without

  12. High frame-rate real-time x-ray imaging of in situ high-velocity rifle bullets

    NASA Astrophysics Data System (ADS)

    D'Aries, Lawrence J.; Miller, Stuart R.; Robertson, Rob; Singh, Bipin; Nagarkar, Vivek V.

    2016-05-01

    High frame-rate imaging is a valuable tool for non-destructive evaluation (NDE) as well as for ballistic impact studies (terminal ballistics), in-flight projectile imaging, studies of exploding ordnance and characterization of other high-speed phenomena. Current imaging systems exist for these studies, however, none have the ability to do in-barrel characterization (in-bore ballistics) to image kinetics of the moving projectile BEFORE it exits the barrel. The system uses an intensified high-speed CMOS camera coupled to a specially designed scintillator to serve as the X-ray detector. The X-ray source is a sequentially fired portable pulsed unit synchronized with the detector integration window and is able to acquire 3,600 frames per second (fps) with mega-pixel spatial resolution and up to 500,000 fps with reduced pixel resolution. This paper will discuss our results imaging .30 caliber bullets traveling at ~1,000 m/s while still in the barrel. Information on bullet deformation, pitch, yaw and integrity are the main goals of this experimentation. Planned future upgrades for imaging large caliber projectiles will also be discussed.

  13. High-Energy X-ray Studies of Real Materials Under Real Conditions and in Real Time

    SciTech Connect

    Almer, Jonathan

    2011-05-11

    High-energy x-rays from 3rd generation synchrotron sources, including the APS, possess a unique combination of high penetration power and high spatial, reciprocal space, and temporal resolution. These characteristics can be exploited to non-destructively measure phase, texture and strain distributions under extreme environments including thermo-mechanical loading, high-pressure, irradiation and supercritical environments. Over the past several years, the 1-ID beamline has developed a number of programs for these purposes, namely (i) high-energy diffraction microscopy, in which grain and sub-grain volumes are mapped in polycrystalline aggregates, and (ii) combined small-and wide-angle x-ray scattering which permits information over a broad range of length scales to be collected from the same (micron-level) volume. These programs have been increasingly used to test and extend predictive simulations of materials behavior over size scales ranging from nm to mm. Select studies will be presented including nucleation and growth of nanomaterials, void and structural evolution in complex composites under thermo-mechanical and irradiated environments, and microstructural changes in layered systems including thermal-barrier coatings, batteries and fuel cells. Finally, extension of these programs, through the planned APS upgrade, to higher spatio-temporal resolution will be described.

  14. A real-time flat-panel X-ray pixel imaging system for low-dose medical diagnostics and craniofacial applications.

    PubMed

    Chapuy, S; Dimcovski, D; Dimcovski, Z; Grigoriev, E; Grob, E; Ligier, Y; Pachoud, M; Riondel, F; Rüfenacht, D; Sayegh, C; Terrier, F; Valley, J F; Verdun, F R

    2000-01-01

    The aim of this study was to evaluate on-line performance of a real-time digital imaging system based on amorphous silicon technology and to compare it with conventional film-screen equipment. The digital detecting imager consists of (1) a converter, which transforms the energy of the incident X rays into light; (2) a real-time digital detecting system, capable of producing as many as 10 pictures per second using a large-area pixel matrix (20 x 20 cm2) based on solid-state amorphous silicon sensor technology with a pitch of 400 microns; and (3) appropriate computer tools for control, real-time image treatment, data representation, and off-line analysis. Different phantoms were used for qualitative comparison with the conventional film-screen technique, with images obtained with both systems at the normal dose (used as a reference), as well as with dose reduction by a factor of 10 to 100. Basic image quality parameters evaluated showed that the response of the detector is linear in a wide range of entrance air kerma; the dynamic range is higher compared with the conventional film-screen combination; the spatial resolution is 1.25 lp per millimeter, as expected from the pixel size; and good image quality is ensured at doses substantially lower than for the film-screen technique. The flat-panel X-ray imager based on amorphous silicon technology implemented in standard radiographic equipment permits acquisition of real-time images in radiology (as many as 10 images per second) of diagnostic quality with a marked reduction of dose (as much as 100 times) and better contrast compared with the standard film technique. Preliminary results obtained with a 100-micron pitch imager based on the same technology show better quality but a less substantial dose reduction. Applications in craniofacial surgery look promising.

  15. Using dual-energy x-ray imaging to enhance automated lung tumor tracking during real-time adaptive radiotherapy

    SciTech Connect

    Menten, Martin J. Fast, Martin F.; Nill, Simeon; Oelfke, Uwe

    2015-12-15

    Purpose: Real-time, markerless localization of lung tumors with kV imaging is often inhibited by ribs obscuring the tumor and poor soft-tissue contrast. This study investigates the use of dual-energy imaging, which can generate radiographs with reduced bone visibility, to enhance automated lung tumor tracking for real-time adaptive radiotherapy. Methods: kV images of an anthropomorphic breathing chest phantom were experimentally acquired and radiographs of actual lung cancer patients were Monte-Carlo-simulated at three imaging settings: low-energy (70 kVp, 1.5 mAs), high-energy (140 kVp, 2.5 mAs, 1 mm additional tin filtration), and clinical (120 kVp, 0.25 mAs). Regular dual-energy images were calculated by weighted logarithmic subtraction of high- and low-energy images and filter-free dual-energy images were generated from clinical and low-energy radiographs. The weighting factor to calculate the dual-energy images was determined by means of a novel objective score. The usefulness of dual-energy imaging for real-time tracking with an automated template matching algorithm was investigated. Results: Regular dual-energy imaging was able to increase tracking accuracy in left–right images of the anthropomorphic phantom as well as in 7 out of 24 investigated patient cases. Tracking accuracy remained comparable in three cases and decreased in five cases. Filter-free dual-energy imaging was only able to increase accuracy in 2 out of 24 cases. In four cases no change in accuracy was observed and tracking accuracy worsened in nine cases. In 9 out of 24 cases, it was not possible to define a tracking template due to poor soft-tissue contrast regardless of input images. The mean localization errors using clinical, regular dual-energy, and filter-free dual-energy radiographs were 3.85, 3.32, and 5.24 mm, respectively. Tracking success was dependent on tumor position, tumor size, imaging beam angle, and patient size. Conclusions: This study has highlighted the influence of

  16. Simulating stress-dependent fluid flow in a fractured core sample using real-time X-ray CT data

    NASA Astrophysics Data System (ADS)

    Kling, Tobias; Huo, Da; Schwarz, Jens-Oliver; Enzmann, Frieder; Benson, Sally; Blum, Philipp

    2016-07-01

    Various geoscientific applications require a fast prediction of fracture permeability for an optimal workflow. Hence, the objective of the current study is to introduce and validate a practical method to characterize and approximate single flow in fractures under different stress conditions by using a core-flooding apparatus, in situ X-ray computed tomography (CT) scans and a finite-volume method solving the Navier-Stokes-Brinkman equations. The permeability of the fractured sandstone sample was measured stepwise during a loading-unloading cycle (0.7 to 22.1 MPa and back) to validate the numerical results. Simultaneously, the pressurized core sample was imaged with a medical X-ray CT scanner with a voxel dimension of 0.5 × 0.5 × 1.0 mm3. Fracture geometries were obtained by CT images based on a modification of the simplified missing attenuation (MSMA) approach. Simulation results revealed both qualitative plausibility and a quantitative approximation of the experimentally derived permeabilities. The qualitative results indicate flow channeling along several preferential flow paths with less pronounced tortuosity. Significant changes in permeability can be assigned to temporal and permanent changes within the fracture due to applied stresses. The deviations of the quantitative results appear to be mainly caused by both local underestimation of hydraulic properties due to compositional matrix heterogeneities and the low CT resolution affecting the accurate capturing of sub-grid-scale features. Both affect the proper reproduction of the actual connectivity and therefore also the depiction of the expected permeability hysteresis. Furthermore, the threshold value CTmat (1862.6 HU) depicting the matrix material represents the most sensitive input parameter of the simulations. Small variations of CTmat can cause enormous changes in simulated permeability by up to a factor of 2.6 ± 0.1 and, thus, have to be defined with caution. Nevertheless, comparison with further CT

  17. Real-time observation of the dry oxidation of the Si (100) surface with ambient pressure x-ray photoelectron spectroscopy

    SciTech Connect

    Enta, Y.; Mun, B.S.; Rossi, M.; Ross Jr, P.N.; Hussain, Zahid; Fadley, C.S.; Lee, K.-S.; Kim, S.-K.

    2007-09-20

    We have applied ambient-pressure x-ray photoelectron spectroscopy with Si 2p chemical shifts to study the real-time dry oxidation of Si(100), using pressures in the range of 0.01-1 Torr and temperatures of 300-530 oC, and examining the oxide thickness range from 0 to ~;;25 Angstrom. The oxidation rate is initially very high (with rates of up to ~;;225 Angstrom/h) and then, after a certain initial thickness of the oxide in the range of 6-22 Angstrom is formed, decreases to a slow state (with rates of ~;;1.5-4.0 Angstrom/h). Neither the rapid nor the slow regime is explained by the standard Deal-Grove model for Si oxidation.

  18. Investigating Polymer–Metal Interfaces by Grazing Incidence Small-Angle X-Ray Scattering from Gradients to Real-Time Studies

    PubMed Central

    Schwartzkopf, Matthias; Roth, Stephan V.

    2016-01-01

    Tailoring the polymer–metal interface is crucial for advanced material design. Vacuum deposition methods for metal layer coating are widely used in industry and research. They allow for installing a variety of nanostructures, often making use of the selective interaction of the metal atoms with the underlying polymer thin film. The polymer thin film may eventually be nanostructured, too, in order to create a hierarchy in length scales. Grazing incidence X-ray scattering is an advanced method to characterize and investigate polymer–metal interfaces. Being non-destructive and yielding statistically relevant results, it allows for deducing the detailed polymer–metal interaction. We review the use of grazing incidence X-ray scattering to elucidate the polymer–metal interface, making use of the modern synchrotron radiation facilities, allowing for very local studies via in situ (so-called “stop-sputter”) experiments as well as studies observing the nanostructured metal nanoparticle layer growth in real time. PMID:28335367

  19. Real time evolution of liquid crystalline nanostructure during the digestion of formulation lipids using synchrotron small-angle X-ray scattering.

    PubMed

    Warren, Dallas B; Anby, Mette U; Hawley, Adrian; Boyd, Ben J

    2011-08-02

    The role of the digestion of lipids in facilitating absorption of poorly water-soluble compounds, such as vitamins, is not only an important nutritional issue but is increasingly being recognized as an important determinant in the effectiveness of lipid-based drug formulations. It has been known for some time that lipids often form complex liquid crystalline structures during digestion and that this may impact drug solubilization and absorption. However, until recently we have been unable to detect and characterize those structures in real time and have been limited in establishing the interplay between composition, digestion, and nanostructure. Here, we establish the use of an in vitro lipid digestion model used in conjunction with synchrotron small-angle X-ray scattering by first confirming its validity using known, nondigestible liquid crystalline systems, and then extend the model to study the real time evolution of nanostructure during the digestion of common formulation lipids. The formation of liquid crystalline structures from unstructured liquid formulations is discovered, and the kinetics of formation and dependence on composition is investigated.

  20. Some simple rules for contrast, signal-to-noise and resolution in in-line x-ray phase-contrast imaging.

    PubMed

    Gureyev, Timur E; Nesterets, Yakov I; Stevenson, Andrew W; Miller, Peter R; Pogany, Andrew; Wilkins, Stephen W

    2008-03-03

    Simple analytical expressions are derived for the spatial resolution, contrast and signal-to-noise in X-ray projection images of a generic phase edge. The obtained expressions take into account the maximum phase shift generated by the sample and the sharpness of the edge, as well as such parameters of the imaging set-up as the wavelength spectrum and the size of the incoherent source, the source-to-object and object-to-detector distances and the detector resolution. Different asymptotic behavior of the expressions in the cases of large and small Fresnel numbers is demonstrated. The analytical expressions are compared with the results of numerical simulations using Kirchhoff diffraction theory, as well as with experimental X-ray measurements.

  1. Design and Construction of a High Energy X-Ray R and D Facility, and the Development and Optimization of Real Time Radioisotopic Characterization of Remote Handled Waste at MeV Energies

    SciTech Connect

    Halliwell, S.; Georgiev, G.

    2007-07-01

    Real time radioscopy (RTR) is used extensively for the non-destructive examination (NDE) modality in the characterization of waste using x-ray energies of up to 450 keV. The majority of contact handled waste in drums and boxes such as the standard waste box (SWB) and the B25 box, can be penetrated by x-rays at these energies. However, the shielding within remote handled (RH) waste packages, the high density of many waste matrices, and the large size of other waste packages containing both remote handled and contact handled waste, require x-rays at MeV energies, in order to penetrate the waste matrices to enable x-ray images to be made. To develop, optimize and validate the performance of high energy x-ray imaging systems, requires a shielded vault complete with remote handling equipment for the manipulation of the x-ray generating equipment, the imaging chain, and the surrogate waste being inspected. This paper describes the design and construction of a High Energy X-Ray, R and D facility, and the results of the initial program of work to optimize systems for the real time inspection of RH waste. (authors)

  2. Real-time synchrotoron radiation X-ray diffraction and abnormal temperature dependence of photoluminescence from erbium silicates on SiO{sub 2}/Si substrates

    SciTech Connect

    Omi, H.; Tawara, T.; Tateishi, M.

    2012-03-15

    The erbium silicate formation processes during annealing in Ar gas were monitored by synchrotron radiation grazing incidence X-ray diffraction (GIXD) in real time and the optical properties of the silicates were investigated by photoluminescence measurements in spectral and time-resolved domains. The GIXD measurements show that erbium silicates and erbium oxide are formed by interface reactions between silicon oxide and erbium oxides deposited on silicon oxide by reactive sputtering in Ar gas and O{sub 2}/Ar mixture gas ambiences. The erbium silicates are formed above 1060 degree sign C in Ar gas ambience and above 1010 degree sign C in O{sub 2}/Ar gas ambience, and erbium silicides are dominantly formed above 1250 degree sign C. The I{sub 15/2}-I{sub 13/2} Er{sup 3+} photoluminescence from the erbium oxide and erbium silicate exhibits abnormal temperature dependence, which can be explained by the phonon-assisted resonant absorption of the 532-nm excitation photons into the {sup 2}H{sub 11/2} levels of Er{sup 3+} ions of the erbium compounds.

  3. SU-E-I-91: Quantitative Assessment of Early Hepatocellular Carcinoma and Cavernous Hemangioma of Live Using In-Line Phase-Contrast X-Ray Imaging

    SciTech Connect

    Duan, J

    2015-06-15

    Purpose: To investigate the potential utility of in-line phase-contrast imaging (ILPCI) technique with synchrotron radiation in detecting early hepatocellular carcinoma and cavernous hemangioma of live using in vitro model system. Methods: Without contrast agents, three typical early hepatocellular carcinoma specimens and three typical cavernous hemangioma of live specimens were imaged using ILPCI. To quantitatively discriminate early hepatocellular carcinoma tissues and cavernous hemangioma tissues, the projection images texture feature based on gray level co-occurrence matrix (GLCM) were extracted. The texture parameters of energy, inertia, entropy, correlation, sum average, sum entropy, difference average, difference entropy and inverse difference moment, were obtained respectively. Results: In the ILPCI planar images of early hepatocellular carcinoma specimens, vessel trees were clearly visualized on the micrometer scale. Obvious distortion deformation was presented, and the vessel mostly appeared as a ‘dry stick’. Liver textures appeared not regularly. In the ILPCI planar images of cavernous hemangioma of live specimens, typical vessels had not been found compared with the early hepatocellular carcinoma planar images. The planar images of cavernous hemangioma of live specimens clearly displayed the dilated hepatic sinusoids with the diameter of less than 100 microns, but all of them were overlapped with each other. The texture parameters of energy, inertia, entropy, correlation, sum average, sum entropy, and difference average, showed a statistically significant between the two types specimens image (P<0.01), except the texture parameters of difference entropy and inverse difference moment(P>0.01). Conclusion: The results indicate that there are obvious changes in morphological levels including vessel structures and liver textures. The study proves that this imaging technique has a potential value in evaluating early hepatocellular carcinoma and cavernous

  4. Imaging applications of synchrotron X-ray phase-contrast microtomography in biological morphology and biomaterials science. I. General aspects of the technique and its advantages in the analysis of millimetre-sized arthropod structure.

    PubMed

    Betz, Oliver; Wegst, Ulrike; Weide, Daniela; Heethoff, Michael; Helfen, Lukas; Lee, Wah-Keat; Cloetens, Peter

    2007-07-01

    Synchrotron-generated X-rays provide scientists with a multitude of investigative techniques well suited for the analysis of the composition and structure of all types of materials and specimens. Here, we describe the properties of synchrotron-generated X-rays and the advantages that they provide for qualitative morphological research of millimetre-sized biological organisms and biomaterials. Case studies of the anatomy of insect heads, of whole microarthropods and of the three-dimensional reconstruction of the cuticular tendons of jumping beetles, all performed at the beamline ID19 of the European Synchrotron Radiation Facility (ESRF), are presented to illustrate the techniques of phase-contrast tomography available for anatomical and structural investigations. Various sample preparation techniques are described and compared and experimental settings that we have found to be particularly successful are given. On comparing the strengths and weaknesses of the technique with traditional histological thin sectioning, we conclude that synchrotron radiation microtomography has a great potential in biological microanatomy.

  5. Compressive Phase Contrast Tomography

    SciTech Connect

    Maia, Filipe; MacDowell, Alastair; Marchesini, Stefano; Padmore, Howard A.; Parkinson, Dula Y.; Pien, Jack; Schirotzek, Andre; Yang, Chao

    2010-09-01

    When x-rays penetrate soft matter, their phase changes more rapidly than their amplitude. Interference effects visible with high brightness sources creates higher contrast, edge enhanced images. When the object is piecewise smooth (made of big blocks of a few components), such higher contrast datasets have a sparse solution. We apply basis pursuit solvers to improve SNR, remove ring artifacts, reduce the number of views and radiation dose from phase contrast datasets collected at the Hard X-Ray Micro Tomography Beamline at the Advanced Light Source. We report a GPU code for the most computationally intensive task, the gridding and inverse gridding algorithm (non uniform sampled Fourier transform).

  6. Real-time out-of-plane artifact subtraction tomosynthesis imaging using prior CT for scanning beam digital x-ray system

    SciTech Connect

    Wu, Meng; Fahrig, Rebecca

    2014-11-01

    Purpose: The scanning beam digital x-ray system (SBDX) is an inverse geometry fluoroscopic system with high dose efficiency and the ability to perform continuous real-time tomosynthesis in multiple planes. This system could be used for image guidance during lung nodule biopsy. However, the reconstructed images suffer from strong out-of-plane artifact due to the small tomographic angle of the system. Methods: The authors propose an out-of-plane artifact subtraction tomosynthesis (OPAST) algorithm that utilizes a prior CT volume to augment the run-time image processing. A blur-and-add (BAA) analytical model, derived from the project-to-backproject physical model, permits the generation of tomosynthesis images that are a good approximation to the shift-and-add (SAA) reconstructed image. A computationally practical algorithm is proposed to simulate images and out-of-plane artifacts from patient-specific prior CT volumes using the BAA model. A 3D image registration algorithm to align the simulated and reconstructed images is described. The accuracy of the BAA analytical model and the OPAST algorithm was evaluated using three lung cancer patients’ CT data. The OPAST and image registration algorithms were also tested with added nonrigid respiratory motions. Results: Image similarity measurements, including the correlation coefficient, mean squared error, and structural similarity index, indicated that the BAA model is very accurate in simulating the SAA images from the prior CT for the SBDX system. The shift-variant effect of the BAA model can be ignored when the shifts between SBDX images and CT volumes are within ±10 mm in the x and y directions. The nodule visibility and depth resolution are improved by subtracting simulated artifacts from the reconstructions. The image registration and OPAST are robust in the presence of added respiratory motions. The dominant artifacts in the subtraction images are caused by the mismatches between the real object and the prior CT

  7. Real-time phase-contrast imaging of photothermal treatment of head and neck squamous cell carcinoma: an in vitro study of macrophages as a vector for the delivery of gold nanoshells

    NASA Astrophysics Data System (ADS)

    Yang, Taeseok Daniel; Choi, Wonshik; Yoon, Tai Hyun; Lee, Kyoung Jin; Lee, Jae-Seung; Han, Sang Hun; Lee, Min-Goo; Yim, Hong Soon; Choi, Kyung Min; Park, Min Woo; Jung, Kwang-Yoon; Baek, Seung-Kuk

    2012-12-01

    Photothermal treatment (PTT) using nanoparticles has gained attention as a promising alternative therapy for malignant tumors. One strategy for increasing the selectivity of PTT is the use of macrophages as a cellular vector for delivering nanoparticles. The aim of the present study is to examine the use of macrophages as a cellular vector for efficient PTT and determine the appropriate irradiation power and time of a near-infrared (NIR) laser using real-time phase-contrast imaging. Thermally induced injury and death of cancer cells were found to begin at 44°C to 45°C, which was achieved using the PTT effect with gold nanoshells (NS) and irradiation with a NIR laser at a power of 2 W for 5 min. The peritoneal macrophage efficiently functioned as a cellular vector for the NS, and the cancer cells surrounding the NS-loaded macrophages selectively lost their cellular viability after being irradiated with the NIR laser.

  8. Metalloprotein structures at ambient conditions and in real-time: biological crystallography and spectroscopy using X-ray free electron lasers

    PubMed Central

    Kern, Jan; Yachandra, Vittal K; Yano, Junko

    2016-01-01

    Although the structure of enzymes and the chemistry at the catalytic sites have been studied intensively, an understanding of the atomic-scale chemistry requires a new approach beyond steady state X-ray crystallography and X-ray spectroscopy at cryogenic temperatures. Following the dynamic changes in the geometric and electronic structure of metallo-enzymes at ambient conditions, while overcoming the severe X-ray damage to the redox active catalytic center, is key for deriving reaction mechanisms. Such studies become possible by the intense and ultra-short femtosecond (fs) X-ray pulses from an X-ray free electron by acquiring a signal before the sample is destroyed. This review describes the recent and pioneering uses of XFELs to study the protein structure and dynamics of metallo-enzymes using crystallography, scattering, as well as the chemical structure and dynamics of the catalytic complexes (charge, spin, and covalency) using spectroscopy during the reaction to understand the electron-transfer processes and elucidate the mechanism. PMID:26342144

  9. Technical and clinical results of an experimental flat dynamic (digital) x-ray image detector (FDXD) system with real-time corrections

    NASA Astrophysics Data System (ADS)

    Bruijns, Tom J. C.; Alving, P. L.; Baker, Edmund L.; Bury, Robert F.; Cowen, Arnold R.; Jung, Norbert; Luijendijk, Hans A.; Meulenbrugge, Henk J.; Stouten, Hans J.

    1998-07-01

    A clinical imaging system based upon an amorphous-Silicon (a- Si) flat dynamic (digital) X-ray image detector (FDXD) has been developed. The objectives of this experimental set-up were to determine the physical image quality and to establish the clinical feasibility of a flat-panel x-ray detector for radiography and fluoroscopy (R&F) applications. The FDXD acquires dynamic X-ray images at high frame rates in both continuous and pulsed fluoroscopic modes, lower frame rate exposures and single shots. The system has been installed in a clinical research room at The General Infirmary, Leeds (UK; is being evaluated in a variety of universal R&F contrast medium aided examinations, including barium swallows, meals and enema examinations. In addition, general radiographic examinations have been performed. Both the established benefits and possible drawbacks of this type of system, together with the potential solutions, are discussed in this paper. Approach, design and set-up of the system are presented, and the dose efficiency and image quality achieved in clinical operation are explained. The technical and medical phantom images have been evaluated and analyzed. The results of the clinical examinations in mixed applications are discussed. The results of the measurements and examinations performed to date on this experimental FDXD system confirm the potential of this new type of digital X-ray image detector.

  10. Phase-contrast radiography.

    PubMed

    Gao, D; Pogany, A; Stevenson, A W; Wilkins, S W

    1998-01-01

    For the past 100 years, the paradigm for radiography has been premised on absorption as the sole means of contrast formation and on ray optics as the basis for image interpretation. A new conceptual approach to radiography has been developed that includes phase (ie, refractive) contrast and requires wave optics for proper treatment. This new approach greatly increases the amount of information that can be obtained with radiographic techniques and is particularly well suited to the imaging of soft tissue and of very small features in biologic samples. A key feature of the present technique of phase-contrast radiography is the use of a microfocus x-ray source about an order of magnitude (< or = 20 microm) smaller than that used in conventional radiography. Phase-contrast radiography offers a number of improvements over conventional radiography in a clinical setting, especially in soft-tissue imaging. These improvements include increased contrast resulting in improved visualization of anatomic detail, reduced absorbed dose to the patient, inherent image magnification and high spatial resolution, use of harder x rays, and relative ease of implementation. More technologically advanced detectors are currently being developed and commercialized, which will help fully realize the considerable potential of phase-contrast imaging.

  11. Phase Contrast Imaging

    SciTech Connect

    Menk, Ralf Hendrik

    2008-11-13

    All standard (medical) x-ray imaging technologies, rely primarily on the amplitude properties of the incident radiation, and do not depend on its phase. This is unchanged since the discovery by Roentgen that the intensity of an x-ray beam, as measured by the exposure on a film, was related to the relative transmission properties of an object. However, recently various imaging techniques have emerged which depend on the phase of the x-rays as well as the amplitude. Phase becomes important when the beam is coherent and the imaging system is sensitive to interference phenomena. Significant new advances have been made in coherent optic theory and techniques, which now promise phase information in medical imaging. The development of perfect crystal optics and the increasing availability of synchrotron radiation facilities have contributed to a significant increase in the application of phase based imaging in materials and life sciences. Unique source characteristics such as high intensity, monochromaticity, coherence and high collimating provide an ideal source for advanced imaging. Phase contrast imaging has been applied in both projection and computed tomography modes, and recent applications have been made in the field of medical imaging. Due to the underlying principle of X-ray detection conventional image receptors register only intensities of wave fields and not their phases. During the last decade basically five different methods were developed that translate the phase information into intensity variations. These methods are based on measuring the phase shift {phi} directly (using interference phenomena), the gradient {nabla}{sub {phi}}, or the Laplacian {nabla}{sup 2}{phi}. All three methods can be applied to polychromatic X-ray sources keeping in mind that the native source is synchrotron radiation, featuring monochromatic and reasonable coherent X-ray beams. Due to the vast difference in the coefficients that are driven absorption and phase effects (factor 1

  12. SU-E-I-37: Low-Dose Real-Time Region-Of-Interest X-Ray Fluoroscopic Imaging with a GPU-Accelerated Spatially Different Bilateral Filtering

    SciTech Connect

    Chung, H; Lee, J; Pua, R; Cho, S; Jung, W

    2014-06-01

    Purpose: The purpose of our study is to reduce imaging radiation dose while maintaining image quality of region of interest (ROI) in X-ray fluoroscopy. A low-dose real-time ROI fluoroscopic imaging technique which includes graphics-processing-unit- (GPU-) accelerated image processing for brightness compensation and noise filtering was developed in this study. Methods: In our ROI fluoroscopic imaging, a copper filter is placed in front of the X-ray tube. The filter contains a round aperture to reduce radiation dose to outside of the aperture. To equalize the brightness difference between inner and outer ROI regions, brightness compensation was performed by use of a simple weighting method that applies selectively to the inner ROI, the outer ROI, and the boundary zone. A bilateral filtering was applied to the images to reduce relatively high noise in the outer ROI images. To speed up the calculation of our technique for real-time application, the GPU-acceleration was applied to the image processing algorithm. We performed a dosimetric measurement using an ion-chamber dosimeter to evaluate the amount of radiation dose reduction. The reduction of calculation time compared to a CPU-only computation was also measured, and the assessment of image quality in terms of image noise and spatial resolution was conducted. Results: More than 80% of dose was reduced by use of the ROI filter. The reduction rate depended on the thickness of the filter and the size of ROI aperture. The image noise outside the ROI was remarkably reduced by the bilateral filtering technique. The computation time for processing each frame image was reduced from 3.43 seconds with single CPU to 9.85 milliseconds with GPU-acceleration. Conclusion: The proposed technique for X-ray fluoroscopy can substantially reduce imaging radiation dose to the patient while maintaining image quality particularly in the ROI region in real-time.

  13. Portable, real-time alloy identification of metallic wear debris from machinery lubrication systems: laser-induced breakdown spectroscopy versus x-ray fluorescence

    NASA Astrophysics Data System (ADS)

    Suresh, Pooja

    2014-05-01

    Alloy identification of oil-borne wear debris captured on chip detectors, filters and magnetic plugs allows the machinery maintainer to assess the health of the engine or gearbox and identify specific component damage. Today, such identification can be achieved in real time using portable, at-line laser-induced breakdown spectroscopy (LIBS) and Xray fluorescence (XRF) instruments. Both techniques can be utilized in various industries including aviation, marine, railways, heavy diesel and other industrial machinery with, however, some substantial differences in application and instrument performance. In this work, the performances of a LIBS and an XRF instrument are compared based on measurements of a wide range of typical aerospace alloys including steels, titanium, aluminum and nickel alloys. Measurement results were analyzed with a staged correlation technique specifically developed for the purposes of this study - identifying the particle alloy composition using a pre-recorded library of spectral signatures. The analysis is performed in two stages: first, the base element of the alloy is determined by correlation with the stored elemental spectra and then, the alloy is identified by matching the particle's spectral signature using parametric correlation against the stored spectra of all alloys that have the same base element. The correlation analysis has achieved highly repeatable discrimination between alloys of similar composition. Portable LIBS demonstrates higher detection accuracy and better identification of alloys comprising lighter elements as compared to that of the portable XRF system, and reveals a significant reduction in the analysis time over XRF.

  14. The initial oxidation of Al-Mg alloys: Depth-resolved quantitative analysis by angle-resolved x-ray photoelectron spectroscopy and real-time in situ ellipsometry

    NASA Astrophysics Data System (ADS)

    Panda, E.; Jeurgens, L. P. H.; Mittemeijer, E. J.

    2009-12-01

    Real-time in situ spectroscopic ellipsometry and in situ, angle-resolved x-ray photoelectron spectroscopy (AR-XPS) have been applied to establish the relationships between the growth kinetics and the developing microstructure of ultrathin (<3 nm) oxide films grown on clean Al-1.12 at. % Mg alloy surfaces by thermal oxidation in the temperature range T =300-485 K. To this end, procedures for the depth-resolved quantitative AR-XPS analysis of ultrathin, multiple-element, and/or multiphase oxide overgrowths on binary alloy surfaces were developed. As a result, the relationships between the relative depth distributions of Al and Mg in the developing oxide films, the oxide-film growth kinetics, and the oxidation-induced compositional changes in the AlMg alloy substrate could be established as a function of the oxidation conditions.

  15. Cross-sectional void fraction distribution measurements in a vertical annulus two-phase flow by high speed X-ray computed tomography and real-time neutron radiography techniques

    SciTech Connect

    Harvel, G.D. |; Hori, K.; Kawanishi, K.

    1995-09-01

    A Real-Time Neutron Radiography (RTNR) system and a high speed X-ray Computed tomography (X-CT) system are compared for measurement of two-phase flow. Each system is used to determine the flow regime, and the void fraction distribution in a vertical annulus flow channel. A standard optical video system is also used to observe the flow regime. The annulus flow channel is operated as a bubble column and measurements obtained for gas flow rates from 0.0 to 30.01/min. The flow regimes observed by all three measurement systems through image analysis shows that the two-dimensional void fraction distribution can be obtained. The X-CT system is shown to have a superior temporal resolution capable of resolving the void fraction distribution in an (r,{theta}) plane in 33.0 ms. Void fraction distribution for bubbly flow and slug flow is determined.

  16. Effects of damping-off caused by Rhizoctonia solani anastomosis group 2-1 on roots of wheat and oil seed rape quantified using X-ray Computed Tomography and real-time PCR

    PubMed Central

    Sturrock, Craig J.; Woodhall, James; Brown, Matthew; Walker, Catherine; Mooney, Sacha J.; Ray, Rumiana V.

    2015-01-01

    Rhizoctonia solani is a plant pathogenic fungus that causes significant establishment and yield losses to several important food crops globally. This is the first application of high resolution X-ray micro Computed Tomography (X-ray μCT) and real-time PCR to study host–pathogen interactions in situ and elucidate the mechanism of Rhizoctonia damping-off disease over a 6-day period caused by R. solani, anastomosis group (AG) 2-1 in wheat (Triticum aestivum cv. Gallant) and oil seed rape (OSR, Brassica napus cv. Marinka). Temporal, non-destructive analysis of root system architectures was performed using RooTrak and validated by the destructive method of root washing. Disease was assessed visually and related to pathogen DNA quantification in soil using real-time PCR. R. solani AG2-1 at similar initial DNA concentrations in soil was capable of causing significant damage to the developing root systems of both wheat and OSR. Disease caused reductions in primary root number, root volume, root surface area, and convex hull which were affected less in the monocotyledonous host. Wheat was more tolerant to the pathogen, exhibited fewer symptoms and developed more complex root systems. In contrast, R. solani caused earlier damage and maceration of the taproot of the dicot, OSR. Disease severity was related to pathogen DNA accumulation in soil only for OSR, however, reductions in root traits were significantly associated with both disease and pathogen DNA. The method offers the first steps in advancing current understanding of soil-borne pathogen behavior in situ at the pore scale, which may lead to the development of mitigation measures to combat disease influence in the field. PMID:26157449

  17. Effects of damping-off caused by Rhizoctonia solani anastomosis group 2-1 on roots of wheat and oil seed rape quantified using X-ray Computed Tomography and real-time PCR.

    PubMed

    Sturrock, Craig J; Woodhall, James; Brown, Matthew; Walker, Catherine; Mooney, Sacha J; Ray, Rumiana V

    2015-01-01

    Rhizoctonia solani is a plant pathogenic fungus that causes significant establishment and yield losses to several important food crops globally. This is the first application of high resolution X-ray micro Computed Tomography (X-ray μCT) and real-time PCR to study host-pathogen interactions in situ and elucidate the mechanism of Rhizoctonia damping-off disease over a 6-day period caused by R. solani, anastomosis group (AG) 2-1 in wheat (Triticum aestivum cv. Gallant) and oil seed rape (OSR, Brassica napus cv. Marinka). Temporal, non-destructive analysis of root system architectures was performed using RooTrak and validated by the destructive method of root washing. Disease was assessed visually and related to pathogen DNA quantification in soil using real-time PCR. R. solani AG2-1 at similar initial DNA concentrations in soil was capable of causing significant damage to the developing root systems of both wheat and OSR. Disease caused reductions in primary root number, root volume, root surface area, and convex hull which were affected less in the monocotyledonous host. Wheat was more tolerant to the pathogen, exhibited fewer symptoms and developed more complex root systems. In contrast, R. solani caused earlier damage and maceration of the taproot of the dicot, OSR. Disease severity was related to pathogen DNA accumulation in soil only for OSR, however, reductions in root traits were significantly associated with both disease and pathogen DNA. The method offers the first steps in advancing current understanding of soil-borne pathogen behavior in situ at the pore scale, which may lead to the development of mitigation measures to combat disease influence in the field.

  18. Real-time high-resolution X-ray imaging and nuclear magnetic resonance study of the hydration of pure and Na-doped C3A in the presence of sulfates

    SciTech Connect

    Kirchheim,, A. P.; Dal Molin, D.C.; Emwas, Abdul-Hamid; Provis, J.L.; Fischer, P.; Monteiro, P.J.M.

    2010-12-01

    This study details the differences in real-time hydration between pure tricalcium aluminate (cubic C{sub 3}A or 3CaO {center_dot} Al{sub 2}O{sub 3}) and Na-doped tricalcium aluminate (orthorhombic C{sub 3}A or Na{sub 2}Ca{sub 8}Al{sub 6}O{sub 18}), in aqueous solutions containing sulfate ions. Pure phases were synthesized in the laboratory to develop an independent benchmark for the reactions, meaning that their reactions during hydration in a simulated early age cement pore solution (saturated with respect to gypsum and lime) were able to be isolated. Because the rate of this reaction is extremely rapid, most microscopy methods are not adequate to study the early phases of the reactions in the early stages. Here, a high-resolution full-field soft X-ray imaging technique operating in the X-ray water window, combined with solution analysis by {sup 27}Al nuclear magnetic resonance (NMR) spectroscopy, was used to capture information regarding the mechanism of C{sub 3}A hydration during the early stages. There are differences in the hydration mechanism between the two types of C{sub 3}A, which are also dependent on the concentration of sulfate ions in the solution. The reactions with cubic C{sub 3}A (pure) seem to be more influenced by higher concentrations of sulfate ions, forming smaller ettringite needles at a slower pace than the orthorhombic C{sub 3}A (Na-doped) sample. The rate of release of aluminate species into the solution phase is also accelerated by Na doping.

  19. Time and resources of peripherally inserted central catheter insertion procedures: a comparison between blind insertion/chest X-ray and a real time tip navigation and confirmation system

    PubMed Central

    Tomaszewski, Kenneth J; Ferko, Nicole; Hollmann, Sarah S; Eng, Simona C; Richard, Howard M; Rowe, Lynn; Sproule, Susan

    2017-01-01

    Background The Sherlock 3CG™ Tip Confirmation System (TCS) provides real-time peripherally inserted central catheter (PICC) tip insertion information using passive magnetic navigation and patient cardiac electrical activity. It is an alternative tip confirmation method to fluoroscopy or chest X-ray for PICC tip insertion confirmation in adults. The purpose of this study was to evaluate time and cost of the Sherlock 3CG TCS and blind insertion with chest X-ray tip confirmation (BI/CXR) for PICC insertions. Methods A cross-sectional, observational Time and Motion study was conducted. Data were collected at four hospitals in the US. Two hospitals used Sherlock 3CG TCS and two hospitals used BI/CXR to place/confirm successful PICC tip location. Researchers observed PICC insertions, collecting data from the beginning (ie, PICC kit opening) to catheter tip confirmation (ie, released for intravenous [IV] therapy). An economic model was developed to project outcomes for a larger population. Results A total of 120 subjects were enrolled, with 60 subjects enrolled in each arm and 30 enrolled at each of the four US hospitals. The mean time from initiation of the PICC procedure to the time to release for IV therapy was 33.93 minutes in the Sherlock 3CG arm and 176.32 minutes in the BI/CXR arm (p < 0.001). No malpositions were observed for PICC insertions using the Sherlock 3CG TCS, while 20% of subjects in the BI/CXR arm had a malposition. BI/CXR subjects had significantly more total malpositions (mean 0.23 vs. 0, p < 0.001). For a hypothetical population of 1,000 annual patients, adoption of Sherlock 3CG TCS was predicted to be cost saving compared with BI/CXR in all three analysis years. Conclusion The results from this study demonstrate that Sherlock 3CG TCS, when compared with BI/CXR, is a superior alternative with regard to time to release subject to therapy, malposition rates, and minimization of X-ray exposure. PMID:28223832

  20. Phase contrast imaging of cochlear soft tissue

    NASA Astrophysics Data System (ADS)

    Shintani Smith, Stephanie; Hwang, Margaret; Rau, Christoph; Fishman, Andrew J.; Lee, Wah-Keat; Richter, Claus-Peter

    2011-03-01

    A noninvasive technique to image soft tissue could expedite diagnosis and disease management in the auditory system. We propose inline phase contrast imaging with hard X-rays as a novel method that overcomes the limitations of conventional absorption radiography for imaging soft tissue. In this study, phase contrast imaging of mouse cochleae was performed at the Argonne National Laboratory Advanced Photon Source. The phase contrast tomographic reconstructions show soft tissue structures of the cochlea, including the inner pillar cells, the inner spiral sulcus, the tectorial membrane, the basilar membrane, and the Reissner's membrane. The results suggest that phase contrast X-ray imaging and tomographic techniques hold promise to noninvasively image cochlear structures at an unprecedented cellular level.

  1. Upper Gastrointestinal (GI) Tract X-Ray (Radiography)

    MedlinePlus

    ... real-time x-ray called fluoroscopy and a barium-based contrast material to produce images of the ... and an orally ingested contrast material such as barium . An x-ray (radiograph) is a noninvasive medical ...

  2. Upconversion nanophosphors Naluf₄:Yb,Tm for lymphatic imaging in vivo by real-time upconversion luminescence imaging under ambient light and high-resolution X-ray CT.

    PubMed

    Sun, Yun; Peng, Juanjuan; Feng, Wei; Li, Fuyou

    2013-01-01

    Lanthanide upconversion nanophosphor (UCNP) has attracted increasing attention for potential applications in bioimaging due to its excellence in deep and high contrast imaging. To date, most upconversion imaging applications were demonstrated in dark surroundings without ambient light for higher signal-to-noise ratio, which hindered the application of optical imaging guided surgery. Herein, the new established NaLuF₄-based UCNP (NaLuF₄:Yb,Tm, ~17 nm) with bright upconversion emission around 800 nm as imaging signal was used to realize imaging under ambient light to provide more convenient for clinician. Moreover, due to the existance of heavy element lutetium (Lu) in the host lattice, the NaLuF₄:Yb,Tm nanoparticles can also be used as an X-ray CT imaging agent to enhance the imaging depth and in vivo imaging resolution.

  3. Unraveling the Hydrogenation of TiO 2 and Graphene Oxide/TiO 2 Composites in Real Time by in Situ Synchrotron X-ray Powder Diffraction and Pair Distribution Function Analysis

    SciTech Connect

    Nguyen-Phan, Thuy-Duong; Liu, Zongyuan; Luo, Si; Gamalski, Andrew D.; Vovchok, Dimitry; Xu, Wenqian; Stach, Eric A.; Polyansky, Dmitry E.; Fujita, Etsuko; Rodriguez, José A.; Senanayake, Sanjaya D.

    2016-02-18

    The functionalization of graphene oxide (GO) and graphene by TiO2 and other metal oxides has attracted considerable attention due to numerous promising applications in catalysis, energy conversion, and storage. We propose hydrogenation of this class of materials as a promising way to tune catalytic properties by altering the structural and chemical transformations that occur upon H incorporation. We also investigate the structural changes that occur during the hydrogenation process using in situ powder X-ray diffraction and pair distribution function analysis of GO–TiO2 and TiO2 under H2 reduction. Sequential Rietveld refinement was employed to gain insight into the evolution of crystal growth of TiO2 nanoparticles in the presence of two-dimensional (2D) GO nanosheets. GO sheets not only significantly retarded the nucleation and growth of rutile impurities, stabilizing the anatase structure, but was also partially reduced to hydrogenated graphene by the introduction of atomic hydrogen into the honeycomb lattice. We discuss the hydrogenation processes and the resulting composite structure that occurs during the incorporation of atomic H and the dynamic structural transformations that leads to a highly active photocatalyst.

  4. Unraveling the Hydrogenation of TiO 2 and Graphene Oxide/TiO 2 Composites in Real Time by in Situ Synchrotron X-ray Powder Diffraction and Pair Distribution Function Analysis

    DOE PAGES

    Nguyen-Phan, Thuy-Duong; Liu, Zongyuan; Luo, Si; ...

    2016-02-18

    The functionalization of graphene oxide (GO) and graphene by TiO2 and other metal oxides has attracted considerable attention due to numerous promising applications in catalysis, energy conversion, and storage. We propose hydrogenation of this class of materials as a promising way to tune catalytic properties by altering the structural and chemical transformations that occur upon H incorporation. We also investigate the structural changes that occur during the hydrogenation process using in situ powder X-ray diffraction and pair distribution function analysis of GO–TiO2 and TiO2 under H2 reduction. Sequential Rietveld refinement was employed to gain insight into the evolution of crystalmore » growth of TiO2 nanoparticles in the presence of two-dimensional (2D) GO nanosheets. GO sheets not only significantly retarded the nucleation and growth of rutile impurities, stabilizing the anatase structure, but was also partially reduced to hydrogenated graphene by the introduction of atomic hydrogen into the honeycomb lattice. We discuss the hydrogenation processes and the resulting composite structure that occurs during the incorporation of atomic H and the dynamic structural transformations that leads to a highly active photocatalyst.« less

  5. Dynamic crystal rotation resolved by high-speed synchrotron X-ray Laue diffraction

    SciTech Connect

    Huang, J. W.; E, J. C.; Huang, J. Y.; Sun, T.; Fezzaa, K.; Luo, S. N.

    2016-03-30

    Dynamic compression experiments are performed on single-crystal Si under split Hopkinson pressure bar loading, together with simultaneous high-speed (250–350 ns resolution) synchrotron X-ray Laue diffraction and phase-contrast imaging. A methodology is presented which determines crystal rotation parameters,i.e.instantaneous rotation axes and angles, from two unindexed Laue diffraction spots. Two-dimensional translation is obtained from dynamic imaging by a single camera. High-speed motion of crystals, including translation and rotation, can be tracked in real timeviasimultaneous imaging and diffraction.

  6. Dynamic crystal rotation resolved by high-speed synchrotron X-ray Laue diffraction

    PubMed Central

    Huang, J. W.; E, J. C.; Huang, J. Y.; Sun, T.; Fezzaa, K.; Luo, S. N.

    2016-01-01

    Dynamic compression experiments are performed on single-crystal Si under split Hopkinson pressure bar loading, together with simultaneous high-speed (250–350 ns resolution) synchrotron X-ray Laue diffraction and phase-contrast imaging. A methodology is presented which determines crystal rotation parameters, i.e. instantaneous rotation axes and angles, from two unindexed Laue diffraction spots. Two-dimensional translation is obtained from dynamic imaging by a single camera. High-speed motion of crystals, including translation and rotation, can be tracked in real time via simultaneous imaging and diffraction. PMID:27140150

  7. Kinetics of alpha-PcCu --> beta-PcCu isothermal conversion in air and thermal behavior of beta-PcCu from in situ real-time laboratory parallel-beam X-ray powder diffraction.

    PubMed

    Ballirano, Paolo; Caminiti, Ruggero

    2009-07-09

    The kinetics of the alpha-PcCu --> beta-PcCu conversion in air has been followed, under isothermal conditions, in situ real-time in the 423-443 K temperature range. Data have been fitted following the JMAK model. The reaction order of the kinetics at 423 K is consistent with a diffusion controlled, deceleratory nucleation rate process for 2D laminar particles, whereas at higher temperatures it is consistent with a phase boundary controlled, deceleratory nucleation rate process for 2D laminar particles. At 423 K, the overall transformation mechanism implies three steps: growth of the alpha-PcCu phase, disordering of adjacent columns of molecules of phthalocyanine, and nucleation and growth of the beta-PcCu phase. The calculated empirical activation energy is of 187 kJ/mol significantly greater than that for the alpha-PcCo --> beta-PcCo conversion. This fact seems to support the reported different structures of alpha-PcCo and alpha-PcCu. Investigation of the thermal behavior of beta-PcCu indicates a strongly anisotropic thermal expansion that follows the alpha(c) > alpha(a) approximately = alpha(b) trend. Moreover, the beta angle decreases with increasing temperature. Such anisotropy is consistent with the geometry of the very weak N3...H3 hydrogen bond which acts mainly along the c axis.

  8. Reconstruction methods for phase-contrast tomography

    SciTech Connect

    Raven, C.

    1997-02-01

    Phase contrast imaging with coherent x-rays can be distinguished in outline imaging and holography, depending on the wavelength {lambda}, the object size d and the object-to-detector distance r. When r << d{sup 2}{lambda}, phase contrast occurs only in regions where the refractive index fastly changes, i.e. at interfaces and edges in the sample. With increasing object-to-detector distance we come in the area of holographic imaging. The image contrast outside the shadow region of the object is due to interference of the direct, undiffracted beam and a beam diffracted by the object, or, in terms of holography, the interference of a reference wave with the object wave. Both, outline imaging and holography, offer the possibility to obtain three dimensional information of the sample in conjunction with a tomographic technique. But the data treatment and the kind of information one can obtain from the reconstruction is different.

  9. Phase contrast portal imaging using synchrotron radiation

    NASA Astrophysics Data System (ADS)

    Umetani, K.; Kondoh, T.

    2014-07-01

    Microbeam radiation therapy is an experimental form of radiation treatment with great potential to improve the treatment of many types of cancer. We applied a synchrotron radiation phase contrast technique to portal imaging to improve targeting accuracy for microbeam radiation therapy in experiments using small animals. An X-ray imaging detector was installed 6.0 m downstream from an object to produce a high-contrast edge enhancement effect in propagation-based phase contrast imaging. Images of a mouse head sample were obtained using therapeutic white synchrotron radiation with a mean beam energy of 130 keV. Compared to conventional portal images, remarkably clear images of bones surrounding the cerebrum were acquired in an air environment for positioning brain lesions with respect to the skull structure without confusion with overlapping surface structures.

  10. Phase contrast portal imaging using synchrotron radiation

    SciTech Connect

    Umetani, K.; Kondoh, T.

    2014-07-15

    Microbeam radiation therapy is an experimental form of radiation treatment with great potential to improve the treatment of many types of cancer. We applied a synchrotron radiation phase contrast technique to portal imaging to improve targeting accuracy for microbeam radiation therapy in experiments using small animals. An X-ray imaging detector was installed 6.0 m downstream from an object to produce a high-contrast edge enhancement effect in propagation-based phase contrast imaging. Images of a mouse head sample were obtained using therapeutic white synchrotron radiation with a mean beam energy of 130 keV. Compared to conventional portal images, remarkably clear images of bones surrounding the cerebrum were acquired in an air environment for positioning brain lesions with respect to the skull structure without confusion with overlapping surface structures.

  11. Some aspects of analytical chemistry as applied to water quality assurance techniques for reclaimed water: The potential use of X-ray fluorescence spectrometry for automated on-line fast real-time simultaneous multi-component analysis of inorganic pollutants in reclaimed water

    NASA Technical Reports Server (NTRS)

    Ling, A. C.; Macpherson, L. H.; Rey, M.

    1981-01-01

    The potential use of isotopically excited energy dispersive X-ray fluorescence (XRF) spectrometry for automated on line fast real time (5 to 15 minutes) simultaneous multicomponent (up to 20) trace (1 to 10 parts per billion) analysis of inorganic pollutants in reclaimed water was examined. Three anionic elements (chromium 6, arsenic and selenium) were studied. The inherent lack of sensitivity of XRF spectrometry for these elements mandates use of a preconcentration technique and various methods were examined, including: several direct and indirect evaporation methods; ion exchange membranes; selective and nonselective precipitation; and complexation processes. It is shown tha XRF spectrometry itself is well suited for automated on line quality assurance, and can provide a nondestructive (and thus sample storage and repeat analysis capabilities) and particularly convenient analytical method. Further, the use of an isotopically excited energy dispersive unit (50 mCi Cd-109 source) coupled with a suitable preconcentration process can provide sufficient sensitivity to achieve the current mandated minimum levels of detection without the need for high power X-ray generating tubes.

  12. Cosmic x ray physics

    NASA Technical Reports Server (NTRS)

    Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

    1990-01-01

    The annual progress report on Cosmic X Ray Physics is presented. Topics studied include: the soft x ray background, proportional counter and filter calibrations, the new sounding rocket payload: X Ray Calorimeter, and theoretical studies.

  13. Cosmic x ray physics

    NASA Technical Reports Server (NTRS)

    Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

    1991-01-01

    The annual progress report on Cosmic X Ray Physics for the period 1 Jan. to 31 Dec. 1990 is presented. Topics studied include: soft x ray background, new sounding rocket payload: x ray calorimeter, and theoretical studies.

  14. Chest X-Ray

    MedlinePlus

    ... by Image/Video Gallery Your radiologist explains chest x-ray. Transcript Welcome to Radiology Info dot org! Hello, ... you about chest radiography also known as chest x-rays. Chest x-rays are the most commonly performed ...

  15. Joint x-ray

    MedlinePlus

    X-ray - joint; Arthrography; Arthrogram ... x-ray technologist will help you position the joint to be x-rayed on the table. Once in place, pictures are taken. The joint may be moved into other positions for more ...

  16. Neutron and X-ray Detectors

    SciTech Connect

    Carini, Gabriella; Denes, Peter; Gruener, Sol; Lessner, Elianne

    2012-08-01

    The Basic Energy Sciences (BES) X-ray and neutron user facilities attract more than 12,000 researchers each year to perform cutting-edge science at these state-of-the-art sources. While impressive breakthroughs in X-ray and neutron sources give us the powerful illumination needed to peer into the nano- to mesoscale world, a stumbling block continues to be the distinct lag in detector development, which is slowing progress toward data collection and analysis. Urgently needed detector improvements would reveal chemical composition and bonding in 3-D and in real time, allow researchers to watch “movies” of essential life processes as they happen, and make much more efficient use of every X-ray and neutron produced by the source The immense scientific potential that will come from better detectors has triggered worldwide activity in this area. Europe in particular has made impressive strides, outpacing the United States on several fronts. Maintaining a vital U.S. leadership in this key research endeavor will require targeted investments in detector R&D and infrastructure. To clarify the gap between detector development and source advances, and to identify opportunities to maximize the scientific impact of BES user facilities, a workshop on Neutron and X-ray Detectors was held August 1-3, 2012, in Gaithersburg, Maryland. Participants from universities, national laboratories, and commercial organizations from the United States and around the globe participated in plenary sessions, breakout groups, and joint open-discussion summary sessions. Sources have become immensely more powerful and are now brighter (more particles focused onto the sample per second) and more precise (higher spatial, spectral, and temporal resolution). To fully utilize these source advances, detectors must become faster, more efficient, and more discriminating. In supporting the mission of today’s cutting-edge neutron and X-ray sources, the workshop identified six detector research challenges

  17. X-ray laser microscope apparatus

    DOEpatents

    Suckewer, Szymon; DiCicco, Darrell S.; Hirschberg, Joseph G.; Meixler, Lewis D.; Sathre, Robert; Skinner, Charles H.

    1990-01-01

    A microscope consisting of an x-ray contact microscope and an optical microscope. The optical, phase contrast, microscope is used to align a target with respect to a source of soft x-rays. The source of soft x-rays preferably comprises an x-ray laser but could comprise a synchrotron or other pulse source of x-rays. Transparent resist material is used to support the target. The optical microscope is located on the opposite side of the transparent resist material from the target and is employed to align the target with respect to the anticipated soft x-ray laser beam. After alignment with the use of the optical microscope, the target is exposed to the soft x-ray laser beam. The x-ray sensitive transparent resist material whose chemical bonds are altered by the x-ray beam passing through the target mater GOVERNMENT LICENSE RIGHTS This invention was made with government support under Contract No. De-FG02-86ER13609 awarded by the Department of Energy. The Government has certain rights in this invention.

  18. Development of x-ray laminography under an x-ray microscopic condition

    SciTech Connect

    Hoshino, Masato; Uesugi, Kentaro; Takeuchi, Akihisa; Suzuki, Yoshio; Yagi, Naoto

    2011-07-15

    An x-ray laminography system under an x-ray microscopic condition was developed to obtain a three-dimensional structure of laterally-extended planar objects which were difficult to observe by x-ray tomography. An x-ray laminography technique was introduced to an x-ray transmission microscope with zone plate optics. Three prototype sample holders were evaluated for x-ray imaging laminography. Layered copper grid sheets were imaged as a laminated sample. Diatomite powder on a silicon nitride membrane was measured to confirm the applicability of this method to non-planar micro-specimens placed on the membrane. The three-dimensional information of diatom shells on the membrane was obtained at a spatial resolution of sub-micron. Images of biological cells on the membrane were also obtained by using a Zernike phase contrast technique.

  19. Visualization of neurons in the brain with phase-contrast CT

    NASA Astrophysics Data System (ADS)

    Onodera, Hiroshi; Hoshino, Masato; Takashima, Kenta; Uesugi, Kentaro; Yagi, Naoto

    2012-07-01

    Three-dimensional structural analysis of brain is essential to understand neuronal function and brain pathology. The phase-contrast X-ray imaging technique uses an X-ray interferometer and is an extremely sensitive method to visualize structures with low X-ray absorbance. Since the phase shifts caused by light elements can be detected as interference patterns in spite of nearly zero absorption coefficients, the signal/noise ratio for the phase-contrast images of the brain is expected to be hundreds times higher than that obtained with the conventional X-ray absorption contrast method. With phase-contrast imaging technique, we could visualize brain microstructures and specific types of neurons, such as the pyramidal cells in the hippocampus. Phase-contrast CT is a promising technique for nondestructive visualization of brain and spinal cord.

  20. Phase contrast MR angiography techniques.

    PubMed

    Dumoulin, C L

    1995-08-01

    Phase contrast MR methods encode information from macroscopic motion into the phase of the MR signal. Phase contrast methods can be applied with small and large fields-of-view, can give quantitative measures of velocity, and provide excellent suppression of signals from stationary tissue. Unlike time-of-flight methods, phase contrast methods directly measure flow and thus are not hindered by the artifactual appearance of tissue having short T1. Phase contrast angiograms can be two-dimensional (thin slice or projectile), three-dimensional, and/or time resolved and have applications throughout the body.

  1. Axial Tomography from Digitized Real Time Radiography

    DOE R&D Accomplishments Database

    Zolnay, A. S.; McDonald, W. M.; Doupont, P. A.; McKinney, R. L.; Lee, M. M.

    1985-01-18

    Axial tomography from digitized real time radiographs provides a useful tool for industrial radiography and tomography. The components of this system are: x-ray source, image intensifier, video camera, video line extractor and digitizer, data storage and reconstruction computers. With this system it is possible to view a two dimensional x-ray image in real time at each angle of rotation and select the tomography plane of interest by choosing which video line to digitize. The digitization of a video line requires less than a second making data acquisition relatively short. Further improvements on this system are planned and initial results are reported.

  2. Axial tomography from digitized real time radiography

    SciTech Connect

    Zolnay, A.S.; McDonald, W.M.; Doupont, P.A.; McKinney, R.L.; Lee, M.M.

    1985-01-18

    Axial tomography from digitized real time radiographs provides a useful tool for industrial radiography and tomography. The components of this system are: x-ray source, image intensifier, video camera, video line extractor and digitizer, data storage and reconstruction computers. With this system it is possible to view a two dimensional x-ray image in real time at each angle of rotation and select the tomography plane of interest by choosing which video line to digitize. The digitization of a video line requires less than a second making data acquisition relatively short. Further improvements on this system are planned and initial results are reported.

  3. Phase contrast image segmentation using a Laue analyser crystal

    NASA Astrophysics Data System (ADS)

    Kitchen, Marcus J.; Paganin, David M.; Uesugi, Kentaro; Allison, Beth J.; Lewis, Robert A.; Hooper, Stuart B.; Pavlov, Konstantin M.

    2011-02-01

    Dual-energy x-ray imaging is a powerful tool enabling two-component samples to be separated into their constituent objects from two-dimensional images. Phase contrast x-ray imaging can render the boundaries between media of differing refractive indices visible, despite them having similar attenuation properties; this is important for imaging biological soft tissues. We have used a Laue analyser crystal and a monochromatic x-ray source to combine the benefits of both techniques. The Laue analyser creates two distinct phase contrast images that can be simultaneously acquired on a high-resolution detector. These images can be combined to separate the effects of x-ray phase, absorption and scattering and, using the known complex refractive indices of the sample, to quantitatively segment its component materials. We have successfully validated this phase contrast image segmentation (PCIS) using a two-component phantom, containing an iodinated contrast agent, and have also separated the lungs and ribcage in images of a mouse thorax. Simultaneous image acquisition has enabled us to perform functional segmentation of the mouse thorax throughout the respiratory cycle during mechanical ventilation.

  4. Phase contrast image guidance for synchrotron microbeam radiotherapy

    NASA Astrophysics Data System (ADS)

    Pelliccia, Daniele; Crosbie, Jeffrey C.; Larkin, Kieran G.

    2016-08-01

    Recent image guidance developments for preclinical synchrotron microbeam radiotherapy represent a necessary step for future clinical translation of the technique. Image quality can be further improved using x-ray phase contrast, which is readily available at synchrotron facilities. We here describe a methodology for phase contrast image guidance at the Imaging and Medical Beamline at the Australian Synchrotron. Differential phase contrast is measured alongside conventional attenuation and used to improve the image quality. Post-processing based on the inverse Riesz transform is employed on the measured data to obtain noticeably sharper images. The procedure is extremely well suited for applications such as image guidance which require both visual assessment and sample alignment based on semi automatic image registration. Moreover, our approach can be combined with all other differential phase contrast imaging techniques, in all cases where a quantitative evaluation of the refractive index is not required.

  5. Evaluation of edge effect due to phase contrast imaging for mammography.

    PubMed

    Matsuo, Satoru; Katafuchi, Tetsuro; Tohyama, Keiko; Morishita, Junji; Yamada, Katsuhiko; Fujita, Hiroshi

    2005-08-01

    It is well-known that the edge effect produced by phase contrast imaging results in the edge enhancement of x-ray images and thereby sharpens those images. It has recently been reported that phase contrast imaging using practical x-ray tubes with small focal spots has improved image sharpness as observed in the phase contrast imaging with x-ray from synchrotron radiation or micro-focus x-ray tubes. In this study, we conducted the phase contrast imaging of a plastic fiber and plant seeds using a customized mammography equipment with a 0.1 mm focal spot, and the improvement of image sharpness was evaluated in terms of spatial frequency response of the images. We observed that the image contrast of the plastic fiber was increased by edge enhancement, and, as predicted elsewhere, spectral analysis revealed that as the spatial frequencies of the x-ray images increased, so did the sharpness gained through phase contrast imaging. Thus, phase contrast imaging using a practical molybdenum anode tube with a 0.1 mm-focal spot would benefit mammography, in which the morphological detectability of small species such as microcalcifications is of great concern. And detectability of tumor-surrounded glandular tissues in dense breast would be also improved by the phase contrast imaging.

  6. X-Ray Lasers

    ERIC Educational Resources Information Center

    Chapline, George; Wood, Lowell

    1975-01-01

    Outlines the prospects of generating coherent x rays using high-power lasers and indentifies problem areas in their development. Indicates possible applications for coherent x rays in the fields of chemistry, biology, and crystallography. (GS)

  7. X-ray (image)

    MedlinePlus

    X-rays are a form of ionizing radiation that can penetrate the body to form an image on ... will be shades of gray depending on density. X-rays can provide information about obstructions, tumors, and other ...

  8. Bone x-ray

    MedlinePlus

    ... not being scanned. Alternative Names X-ray - bone Images Skeleton Skeletal spine Osteogenic sarcoma - x-ray References ... urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows ...

  9. X-ray

    MedlinePlus

    ... think you might be pregnant. Alternative Names Radiography Images X-ray X-ray References Geleijns J, Tack ... urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows ...

  10. Extremity x-ray

    MedlinePlus

    ... sensitive to the risks of an x-ray. Images X-ray References Kelly DM. Congenital anomalies of ... urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows ...

  11. X-Ray Toolkit

    SciTech Connect

    2015-10-20

    Radiographic Image Acquisition & Processing Software for Security Markets. Used in operation of commercial x-ray scanners and manipulation of x-ray images for emergency responders including State, Local, Federal, and US Military bomb technicians and analysts.

  12. Sinus x-ray

    MedlinePlus

    Paranasal sinus radiography; X-ray - sinuses ... sinus x-ray is taken in a hospital radiology department. Or the x-ray may be taken ... Brown J, Rout J. ENT, neck, and dental radiology. In: Adam A, Dixon AK, Gillard JH Schaefer- ...

  13. Hand x-ray

    MedlinePlus

    X-ray - hand ... A hand x-ray is taken in a hospital radiology department or your health care provider's office by an ... technician. You will be asked to place your hand on the x-ray table, and keep it ...

  14. Grid-Based Fourier Transform Phase Contrast Imaging

    NASA Astrophysics Data System (ADS)

    Tahir, Sajjad

    Low contrast in x-ray attenuation imaging between different materials of low electron density is a limitation of traditional x-ray radiography. Phase contrast imaging offers the potential to improve the contrast between such materials, but due to the requirements on the spatial coherence of the x-ray beam, practical implementation of such systems with tabletop (i.e. non-synchrotron) sources has been limited. One recently developed phase imaging technique employs multiple fine-pitched gratings. However, the strict manufacturing tolerances and precise alignment requirements have limited the widespread adoption of grating-based techniques. In this work, we have investigated a technique recently demonstrated by Bennett et al. that utilizes a single grid of much coarser pitch. Our system consisted of a low power 100 microm spot Mo source, a CCD with 22 microm pixel pitch, and either a focused mammography linear grid or a stainless steel woven mesh. Phase is extracted from a single image by windowing and comparing data localized about harmonics of the grid in the Fourier domain. A Matlab code was written to perform the image processing. For the first time, the effects on the diffraction phase contrast and scattering amplitude images of varying grid types and periods, and of varying the window function type used to separate the harmonics, and the window widths, were investigated. Using the wire mesh, derivatives of the phase along two orthogonal directions were obtained and new methods investigated to form improved phase contrast images.

  15. X-ray binaries

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Satellite X-ray experiments and ground-based programs aimed at observation of X-ray binaries are discussed. Experiments aboard OAO-3, OSO-8, Ariel 5, Uhuru, and Skylab are included along with rocket and ground-based observations. Major topics covered are: Her X-1, Cyg X-3, Cen X-3, Cyg X-1, the transient source A0620-00, other possible X-ray binaries, and plans and prospects for future observational programs.

  16. Phase contrast portal imaging for image-guided microbeam radiation therapy

    NASA Astrophysics Data System (ADS)

    Umetani, Keiji; Kondoh, Takeshi

    2014-03-01

    High-dose synchrotron microbeam radiation therapy is a unique treatment technique used to destroy tumors without severely affecting circumjacent healthy tissue. We applied a phase contrast technique to portal imaging in preclinical microbeam radiation therapy experiments. Phase contrast portal imaging is expected to enable us to obtain higherresolution X-ray images at therapeutic X-ray energies compared to conventional portal imaging. Frontal view images of a mouse head sample were acquired in propagation-based phase contrast imaging. The phase contrast images depicted edge-enhanced fine structures of the parietal bones surrounding the cerebrum. The phase contrast technique is expected to be effective in bony-landmark-based verification for image-guided radiation therapy.

  17. X-ray omni microscopy.

    PubMed

    Paganin, D; Gureyev, T E; Mayo, S C; Stevenson, A W; Nesterets, Ya I; Wilkins, S W

    2004-06-01

    The science of wave-field phase retrieval and phase measurement is sufficiently mature to permit the routine reconstruction, over a given plane, of the complex wave-function associated with certain coherent forward-propagating scalar wave-fields. This reconstruction gives total knowledge of the information that has been encoded in the complex wave-field by passage through a sample of interest. Such total knowledge is powerful, because it permits the emulation in software of the subsequent action of an infinite variety of coherent imaging systems. Such 'virtual optics', in which software forms a natural extension of the 'hardware optics' in an imaging system, may be useful in contexts such as quantitative atom and X-ray imaging, in which optical elements such as beam-splitters and lenses can be realized in software rather than optical hardware. Here, we develop the requisite theory to describe such hybrid virtual-physical imaging systems, which we term 'omni optics' because of their infinite flexibility. We then give an experimental demonstration of these ideas by showing that a lensless X-ray point projection microscope can, when equipped with the appropriate software, emulate an infinite variety of optical imaging systems including those which yield interferograms, Zernike phase contrast, Schlieren imaging and diffraction-enhanced imaging.

  18. X-Ray

    MedlinePlus

    ... of gray. For some types of X-ray tests, a contrast medium — such as iodine or barium — is introduced into your body to provide greater detail on the images. X-ray technology is used to examine many parts of the ...

  19. Chest X-Ray

    MedlinePlus Videos and Cool Tools

    ... Site Index A-Z Spotlight Recently posted: Anal Cancer Facet Joint Block Video: Lung Cancer Screening Video: Upper GI Tract X-ray Video: ... of lung conditions such as pneumonia, emphysema and cancer. A chest x-ray requires no special preparation. ...

  20. X-ray Spectrometry.

    ERIC Educational Resources Information Center

    Markowicz, Andrzej A.; Van Grieken, Rene E.

    1984-01-01

    Provided is a selective literature survey of X-ray spectrometry from late 1981 to late 1983. Literature examined focuses on: excitation (photon and electron excitation and particle-induced X-ray emission; detection (wavelength-dispersive and energy-dispersive spectrometry); instrumentation and techniques; and on such quantitative analytical…

  1. X-ray beamsplitter

    DOEpatents

    Ceglio, Natale M.; Stearns, Daniel S.; Hawryluk, Andrew M.; Barbee, Jr., Troy W.

    1989-01-01

    An x-ray beamsplitter which splits an x-ray beam into two coherent parts by reflecting and transmitting some fraction of an incident beam has applications for x-ray interferometry, x-ray holography, x-ray beam manipulation, and x-ray laser cavity output couplers. The beamsplitter is formed of a wavelength selective multilayer thin film supported by a very thin x-ray transparent membrane. The beamsplitter resonantly transmits and reflects x-rays through thin film interference effects. A thin film is formed of 5-50 pairs of alternate Mo/Si layers with a period of 20-250 A. The support membrane is 10-200 nm of silicon nitride or boron nitride. The multilayer/support membrane structure is formed across a window in a substrate by first forming the structure on a solid substrate and then forming a window in the substrate to leave a free-standing structure over the window.

  2. Dental x-rays

    MedlinePlus

    ... X-rays are a form of high energy electromagnetic radiation. The x-rays penetrate the body to form ... for detecting cavities, unless the decay is very advanced and deep. Many ... The amount of radiation given off during the procedure is less than ...

  3. X-ray beamsplitter

    DOEpatents

    Ceglio, N.M.; Stearns, D.G.; Hawryluk, A.M.; Barbee, T.W. Jr.

    1987-08-07

    An x-ray beamsplitter which splits an x-ray beam into two coherent parts by reflecting and transmitting some fraction of an incident beam has applications for x-ray interferometry, x-ray holography, x-ray beam manipulation, and x-ray laser cavity output couplers. The beamsplitter is formed of a wavelength selective multilayer thin film supported by a very thin x-ray transparent membrane. The beamsplitter resonantly transmits and reflects x-rays through thin film interference effects. A thin film is formed of 5--50 pairs of alternate Mo/Si layers with a period of 20--250 A. The support membrane is 10--200 nm of silicon nitride or boron nitride. The multilayer/support membrane structure is formed across a window in a substrate by first forming the structure on a solid substrate and then forming a window in the substrate to leave a free-standing structure over the window. 6 figs.

  4. Real-time and Sub-wavelength Ultrafast Coherent Diffraction Imaging in the Extreme Ultraviolet

    PubMed Central

    Zürch, M.; Rothhardt, J.; Hädrich, S.; Demmler, S.; Krebs, M.; Limpert, J.; Tünnermann, A.; Guggenmos, A.; Kleineberg, U.; Spielmann, C.

    2014-01-01

    Coherent Diffraction Imaging is a technique to study matter with nanometer-scale spatial resolution based on coherent illumination of the sample with hard X-ray, soft X-ray or extreme ultraviolet light delivered from synchrotrons or more recently X-ray Free-Electron Lasers. This robust technique simultaneously allows quantitative amplitude and phase contrast imaging. Laser-driven high harmonic generation XUV-sources allow table-top realizations. However, the low conversion efficiency of lab-based sources imposes either a large scale laser system or long exposure times, preventing many applications. Here we present a lensless imaging experiment combining a high numerical aperture (NA = 0.8) setup with a high average power fibre laser driven high harmonic source. The high flux and narrow-band harmonic line at 33.2 nm enables either sub-wavelength spatial resolution close to the Abbe limit (Δr = 0.8λ) for long exposure time, or sub-70 nm imaging in less than one second. The unprecedented high spatial resolution, compactness of the setup together with the real-time capability paves the way for a plethora of applications in fundamental and life sciences. PMID:25483626

  5. Real-time and sub-wavelength ultrafast coherent diffraction imaging in the extreme ultraviolet.

    PubMed

    Zürch, M; Rothhardt, J; Hädrich, S; Demmler, S; Krebs, M; Limpert, J; Tünnermann, A; Guggenmos, A; Kleineberg, U; Spielmann, C

    2014-12-08

    Coherent Diffraction Imaging is a technique to study matter with nanometer-scale spatial resolution based on coherent illumination of the sample with hard X-ray, soft X-ray or extreme ultraviolet light delivered from synchrotrons or more recently X-ray Free-Electron Lasers. This robust technique simultaneously allows quantitative amplitude and phase contrast imaging. Laser-driven high harmonic generation XUV-sources allow table-top realizations. However, the low conversion efficiency of lab-based sources imposes either a large scale laser system or long exposure times, preventing many applications. Here we present a lensless imaging experiment combining a high numerical aperture (NA = 0.8) setup with a high average power fibre laser driven high harmonic source. The high flux and narrow-band harmonic line at 33.2 nm enables either sub-wavelength spatial resolution close to the Abbe limit (Δr = 0.8λ) for long exposure time, or sub-70 nm imaging in less than one second. The unprecedented high spatial resolution, compactness of the setup together with the real-time capability paves the way for a plethora of applications in fundamental and life sciences.

  6. X-ray generator

    DOEpatents

    Dawson, John M.

    1976-01-01

    Apparatus and method for producing coherent secondary x-rays that are controlled as to direction by illuminating a mixture of high z and low z gases with an intense burst of primary x-rays. The primary x-rays are produced with a laser activated plasma, and these x-rays strip off the electrons of the high z atoms in the lasing medium, while the low z atoms retain their electrons. The neutral atoms transfer electrons to highly excited states of the highly striped high z ions giving an inverted population which produces the desired coherent x-rays. In one embodiment, a laser, light beam provides a laser spark that produces the intense burst of coherent x-rays that illuminates the mixture of high z and low z gases, whereby the high z atoms are stripped while the low z ones are not, giving the desired mixture of highly ionized and neutral atoms. To this end, the laser spark is produced by injecting a laser light beam, or a plurality of beams, into a first gas in a cylindrical container having an adjacent second gas layer co-axial therewith, the laser producing a plasma and the intense primary x-rays in the first gas, and the second gas containing the high and low atomic number elements for receiving the primary x-rays, whereupon the secondary x-rays are produced therein by stripping desired ions in a neutral gas and transfer of electrons to highly excited states of the stripped ions from the unionized atoms. Means for magnetically confining and stabilizing the plasma are disclosed for controlling the direction of the x-rays.

  7. Hard x-ray Zernike microscopy reaches 30 nm resolution.

    SciTech Connect

    Chen, Y.; Chen, T.; Yi, J.; Chu, Y.; Lee, W.-K.; Wang, C.; Kempson, I.; Hwu, Y.; Gajdosik, V.; Margaritondo, G.

    2011-03-30

    Since its invention in 1930, Zernike phase contrast has been a pillar in optical microscopy and more recently in x-ray microscopy, in particular for low-absorption-contrast biological specimens. We experimentally demonstrate that hard-x-ray Zernike microscopy now reaches a lateral resolution below 30?nm while strongly enhancing the contrast, thus opening many new research opportunities in biomedicine and materials science.

  8. Hard x-ray Zernike Microscopy Reaches 30 nm Resolution

    SciTech Connect

    Chen, Y.T.; Chu, Y.; Chen, T-Y.; Yi, J.; Lee, W-K.; Wang, C-L.; Kempson, I. M.; Hwu, Y.; Gajdosik, V.; Margaritondo, G.

    2011-03-30

    Since its invention in 1930, Zernike phase contrast has been a pillar in optical microscopy and more recently in x-ray microscopy, in particular for low-absorption-contrast biological specimens. We experimentally demonstrate that hard-x-ray Zernike microscopy now reaches a lateral resolution below 30 nm while strongly enhancing the contrast, thus opening many new research opportunities in biomedicine and materials science.

  9. X-ray crystallography

    NASA Technical Reports Server (NTRS)

    2001-01-01

    X-rays diffracted from a well-ordered protein crystal create sharp patterns of scattered light on film. A computer can use these patterns to generate a model of a protein molecule. To analyze the selected crystal, an X-ray crystallographer shines X-rays through the crystal. Unlike a single dental X-ray, which produces a shadow image of a tooth, these X-rays have to be taken many times from different angles to produce a pattern from the scattered light, a map of the intensity of the X-rays after they diffract through the crystal. The X-rays bounce off the electron clouds that form the outer structure of each atom. A flawed crystal will yield a blurry pattern; a well-ordered protein crystal yields a series of sharp diffraction patterns. From these patterns, researchers build an electron density map. With powerful computers and a lot of calculations, scientists can use the electron density patterns to determine the structure of the protein and make a computer-generated model of the structure. The models let researchers improve their understanding of how the protein functions. They also allow scientists to look for receptor sites and active areas that control a protein's function and role in the progress of diseases. From there, pharmaceutical researchers can design molecules that fit the active site, much like a key and lock, so that the protein is locked without affecting the rest of the body. This is called structure-based drug design.

  10. X-ray laser

    DOEpatents

    Nilsen, Joseph

    1991-01-01

    An X-ray laser (10) that lases between the K edges of carbon and oxygen, i.e. between 44 and 23 Angstroms, is provided. The laser comprises a silicon (12) and dysprosium (14) foil combination (16) that is driven by two beams (18, 20) of intense line focused (22, 24) optical laser radiation. Ground state nickel-like dysprosium ions (34) are resonantly photo-pumped to their upper X-ray laser state by line emission from hydrogen-like silicon ions (32). The novel X-ray laser should prove especially useful for the microscopy of biological specimens.

  11. X-ray superbubbles

    NASA Technical Reports Server (NTRS)

    Cash, W.

    1983-01-01

    Four regions of the galaxy, the Cygnus Superbubble, the Eta Carina complex, the Orion/Eridanus complex, and the Gum Nebula, are discussed as examples of collective effects in the interstellar medium. All four regions share certain features, indicating a common structure. The selection effects which determine the observable X-ray properties of the superbubbles are discussed, and it is demonstrated that only a very few more in our Galaxy can be detected in X rays. X-ray observation of extragalactic superbubbles is shown to be possible but requires the capabilities of a large, high quality, AXAF class observatory.

  12. Lumbosacral spine x-ray

    MedlinePlus

    X-ray - lumbosacral spine; X-ray - lower spine ... The test is done in a hospital x-ray department or your health care provider's office by an x-ray technician. You will be asked to lie on the x-ray table ...

  13. Thoracic spine x-ray

    MedlinePlus

    Vertebral radiography; X-ray - spine; Thoracic x-ray; Spine x-ray; Thoracic spine films; Back films ... The test is done in a hospital radiology department or in the health care provider's office. You will lie on the x-ray table in different positions. If the x-ray ...

  14. Mesh-based phase contrast Fourier transform imaging

    NASA Astrophysics Data System (ADS)

    Tahir, Sajjad; Bashir, Sajid; MacDonald, C. A.; Petruccelli, Jonathan C.

    2017-04-01

    Traditional x-ray radiography is limited by low attenuation contrast in materials of low electron density. Phase contrast imaging offers the potential to improve the contrast between such materials, but due to the requirements on the spatial coherence of the x-ray beam, practical implementation of such systems with tabletop (i.e. non-synchrotron) sources has been limited. One phase imaging technique employs multiple fine-pitched gratings. However, the strict manufacturing tolerances and precise alignment requirements have limited the widespread adoption of grating-based techniques. In this work, we have investigated a recently developed technique that utilizes a single grid of much coarser pitch. Our system consisted of a low power 100 μm spot Mo source, a CCD with 22 μm pixel pitch, and either a focused mammography linear grid or a stainless steel woven mesh. Phase is extracted from a single image by windowing and comparing data localized about harmonics of the mesh in the Fourier domain. The effects on the diffraction phase contrast and scattering amplitude images of varying grid types and periods, and of varying the width of the window function used to separate the harmonics were investigated. Using the wire mesh, derivatives of the phase along two orthogonal directions were obtained and combined to form improved phase contrast images.

  15. X-ray - skeleton

    MedlinePlus

    ... medlineplus.gov/ency/article/003381.htm X-ray - skeleton To use the sharing features on this page, ... ray views may be uncomfortable. If the whole skeleton is being imaged, the test usually takes 1 ...

  16. Industrial X-Ray Imaging

    NASA Technical Reports Server (NTRS)

    1997-01-01

    In 1990, Lewis Research Center jointly sponsored a conference with the U.S. Air Force Wright Laboratory focused on high speed imaging. This conference, and early funding by Lewis Research Center, helped to spur work by Silicon Mountain Design, Inc. to break the performance barriers of imaging speed, resolution, and sensitivity through innovative technology. Later, under a Small Business Innovation Research contract with the Jet Propulsion Laboratory, the company designed a real-time image enhancing camera that yields superb, high quality images in 1/30th of a second while limiting distortion. The result is a rapidly available, enhanced image showing significantly greater detail compared to image processing executed on digital computers. Current applications include radiographic and pathology-based medicine, industrial imaging, x-ray inspection devices, and automated semiconductor inspection equipment.

  17. Cosmic x ray physics

    NASA Technical Reports Server (NTRS)

    Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

    1992-01-01

    This final report covers the period 1 January 1985 - 31 March 1992. It is divided into the following sections: the soft x-ray background; proportional counter and filter calibrations; sounding rocket flight preparations; new sounding rocket payload: x-ray calorimeter; and theoretical studies. Staff, publications, conference proceedings, invited talks, contributed talks, colloquia and seminars, public service lectures, and Ph. D. theses are listed.

  18. X-ray microscopy of live biological micro-organisms

    NASA Astrophysics Data System (ADS)

    Raja Al-Ani, Ma'an Nassar

    Real-time, compact x-ray microscopy has the potential to benefit many scientific fields, including microbiology, pharmacology, organic chemistry, and physics. Single frame x-ray micro-radiography, produced by a compact, solid-state laser plasma source, allows scientists to use x-ray emission for elemental analysis, and to observe biological specimens in their natural state. In this study, x-ray images of mouse kidney tissue, live bacteria, Pseudomonas aeruginosa and Burkholderia cepacia, and the bacteria's interaction with the antibiotic gentamicin, are examined using x-ray microscopy. For the purposes of comparing between confocal microscopy and x-ray microscopy, we introduced to our work the technique of gold labeling. Indirect immunofluorescence staining and immuno-gold labeling were applied on human lymphocytes and human tumor cells. Differential interference contrast microscopy (DIC) showed the lymphocyte body and nucleus, as did x-ray microscopy. However, the high resolution of x-ray microscopy allows us to differentiate between the gold particles bound to the antibodies and the free gold. A compact, tabletop Nd: glass laser is used in this study to produce x-rays from an Yttrium target. An atomic force microscope is used to scan the x-ray images from the developed photo-resist. The use of compact, tabletop laser plasma sources, in conjunction with x-ray microscopy, is a new technique that has great potential as a flexible, user-friendly scientific research tool.

  19. X-ray Binaries

    NASA Astrophysics Data System (ADS)

    Lewin, Walter H. G.; van Paradijs, Jan; van den Heuvel, Edward Peter Jacobus

    1997-01-01

    Preface; 1. The properties of X-ray binaries, N. E. White, F. Nagase and A. N. Parmar; 2. Optical and ultraviolet observations of X-ray binaries J. van Paradijs and J. E. McClintock; 3. Black-hole binaries Y. Tanaka and W. H. G. Lewin; 4. X-ray bursts Walter H. G. Lewin, Jan Van Paradijs and Ronald E. Taam; 5. Millisecond pulsars D. Bhattacharya; 6. Rapid aperiodic variability in binaries M. van der Klis; 7. Radio properties of X-ray binaries R. M. Hjellming and X. Han; 8. Cataclysmic variable stars France Anne-Dominic Córdova; 9. Normal galaxies and their X-ray binary populations G. Fabbiano; 10. Accretion in close binaries Andrew King; 11. Formation and evolution of neutron stars and black holes in binaries F. Verbunt and E. P. J. van den Heuvel; 12. The magnetic fields of neutron stars and their evolution D. Bhattacharya and G. Srinivasan; 13. Cosmic gamma-ray bursts K. Hurley; 14. A catalogue of X-ray binaries Jan van Paradijs; 15. A compilation of cataclysmic binaries with known or suspected orbital periods Hans Ritter and Ulrich Kolb; References; Index.

  20. In-line phase contrast micro-CT reconstruction for biomedical specimens.

    PubMed

    Fu, Jian; Tan, Renbo

    2014-01-01

    X-ray phase contrast micro computed tomography (micro-CT) can non-destructively provide the internal structure information of soft tissues and low atomic number materials. It has become an invaluable analysis tool for biomedical specimens. Here an in-line phase contrast micro-CT reconstruction technique is reported, which consists of a projection extraction method and the conventional filter back-projection (FBP) reconstruction algorithm. The projection extraction is implemented by applying the Fourier transform to the forward projections of in-line phase contrast micro-CT. This work comprises a numerical study of the method and its experimental verification using a biomedical specimen dataset measured at an X-ray tube source micro-CT setup. The numerical and experimental results demonstrate that the presented technique can improve the imaging contrast of biomedical specimens. It will be of interest for a wide range of in-line phase contrast micro-CT applications in medicine and biology.

  1. A phantom study to characterize the imaging quality of a phase-contrast tomosynthesis prototype

    NASA Astrophysics Data System (ADS)

    Wu, Di; Ghani, Muhammad U.; Miao, Hui; Li, Yuhua; Chen, Wei R.; Wu, Xizeng; Liu, Hong

    2013-02-01

    This research is aimed at studying the advantages of an x-ray phase-contrast tomosynthesis prototype by using phantoms. A prototype system is assembled with a micro-focus x-ray source, a rotating stage and a computed radiography detector mounted on an optical rail. A custom designed bubble wrap phantom is used in experiments. Angular projection images are acquired from -20° to +20° with 2° interval. The in-plane slices are reconstructed. The feature area on the phantom is observed. The prototype system provides an intrinsic way to investigate the potential and imaging quality of a phase-contrast tomosynthesis imaging method. As the result, phase-contrast tomosynthesis imaging method is demonstrated for its advantages in avoiding structure noise and overlapping issues by comparing the results acquired by computed radiography and phase-contrast radiography.

  2. Phase-contrast enhanced mammography: A new diagnostic tool for breast imaging

    NASA Astrophysics Data System (ADS)

    Wang, Zhentian; Thuering, Thomas; David, Christian; Roessl, Ewald; Trippel, Mafalda; Kubik-Huch, Rahel A.; Singer, Gad; Hohl, Michael K.; Hauser, Nik; Stampanoni, Marco

    2012-07-01

    Phase contrast and scattering-based X-ray imaging can potentially revolutionize the radiological approach to breast imaging by providing additional and complementary information to conventional, absorption-based methods. We investigated native, non-fixed whole breast samples using a grating interferometer with an X-ray tube-based configuration. Our approach simultaneously recorded absorption, differential phase contrast and small-angle scattering signals. The results show that this novel technique - combined with a dedicated image fusion algorithm - has the potential to deliver enhanced breast imaging with complementary information for an improved diagnostic process.

  3. Phase-contrast enhanced mammography: A new diagnostic tool for breast imaging

    SciTech Connect

    Wang Zhentian; Thuering, Thomas; David, Christian; Roessl, Ewald; Trippel, Mafalda; Kubik-Huch, Rahel A.; Singer, Gad; Hohl, Michael K.; Hauser, Nik; Stampanoni, Marco

    2012-07-31

    Phase contrast and scattering-based X-ray imaging can potentially revolutionize the radiological approach to breast imaging by providing additional and complementary information to conventional, absorption-based methods. We investigated native, non-fixed whole breast samples using a grating interferometer with an X-ray tube-based configuration. Our approach simultaneously recorded absorption, differential phase contrast and small-angle scattering signals. The results show that this novel technique - combined with a dedicated image fusion algorithm - has the potential to deliver enhanced breast imaging with complementary information for an improved diagnostic process.

  4. TU-G-207-00: Emerging Applications of X-Ray Imaging

    SciTech Connect

    2015-06-15

    Last few years has witnessed the development of novel of X-ray imaging modalities, such as spectral CT, phase contrast CT, and X-ray acoustic/fluorescence/luminescence imaging. This symposium will present the recent advances of these emerging X-ray imaging modalities and update the attendees with knowledge in various related topics, including X-ray photon-counting detectors, X-ray physics underlying the emerging applications beyond the traditional X-ray imaging, image reconstruction for the novel modalities, characterization and evaluation of the systems, and their practical implications. In addition, the concept and practical aspects of X-ray activatable targeted nanoparticles for molecular X-ray imaging will be discussed in the context of X-ray fluorescence and luminescence CT. Learning Objectives: Present background knowledge of various emerging X-ray imaging techniques, such as spectral CT, phase contrast CT and X-ray fluorescence/luminescence CT. Discuss the practical need, technical aspects and current status of the emerging X-ray imaging modalities. Describe utility and future impact of the new generation of X-ray imaging applications.

  5. Hard X-ray Microscopic Imaging Of Human Breast Tissues

    NASA Astrophysics Data System (ADS)

    Park, Sung H.; Kim, Hong T.; Kim, Jong K.; Jheon, Sang H.; Youn, Hwa S.

    2007-01-01

    X-ray microscopy with synchrotron radiation will be a useful tool for innovation of x-ray imaging in clinical and laboratory settings. It helps us observe detailed internal structure of material samples non-invasively in air. And, it also has the potential to solve some tough problems of conventional breast imaging if it could evaluate various conditions of breast tissue effectively. A new hard x-ray microscope with a spatial resolution better than 100 nm was installed at Pohang Light Source, a third generation synchrotron radiation facility in Pohang, Korea. The x-ray energy was set at 6.95 keV, and the x-ray beam was monochromatized by W/B4C monochromator. Condenser and objective zone plates were used as x-ray lenses. Zernike phase plate next to condenser zone plate was introduced for improved contrast imaging. The image of a sample was magnified 30 times by objective zone plate and 20 times by microscope objective, respectively. After additional 10 times digital magnification, the total magnifying power was up to 6000 times in the end. Phase contrast synchrotron images of 10-μm-thick female breast tissue of the normal, fibroadenoma, fibrocystic change and carcinoma cases were obtained. By phase contrast imaging, hard x-rays enable us to observe many structures of breast tissue without sample preparations such as staining or fixation.

  6. X-Ray Phase Imaging for Breast Cancer Detection

    DTIC Science & Technology

    2011-09-01

    introduce the phase retrieval method that is based on the transport of intensity equation (TIE), which describes how the phase contrast is encoded in the...understand how the phase contrast is encoded in the projec- tion images. This understanding can be gained from the x- ray propagation equation such as the...ray intensity I ~rDð Þ is determined not only by attenuation map A2o ~rð Þ in the projection, but also by the encoded phase contrast, that is, by the

  7. Principles of X-ray Navigation

    SciTech Connect

    Hanson, John Eric; /SLAC

    2006-03-17

    X-ray navigation is a new concept in satellite navigation in which orientation, position and time are measured by observing stellar emissions in x-ray wavelengths. X-ray navigation offers the opportunity for a single instrument to be used to measure these parameters autonomously. Furthermore, this concept is not limited to missions in close proximity to the earth. X-ray navigation can be used on a variety of missions from satellites in low earth orbit to spacecraft on interplanetary missions. In 1997 the Unconventional Stellar Aspect Experiment (USA) will be launched as part of the Advanced Research and Global Observation Satellite (ARGOS). USA will provide the first platform for real-time experimentation in the field of x-ray navigation and also serves as an excellent case study for the design and manufacturing of space qualified systems in small, autonomous groups. Current techniques for determining the orientation of a satellite rely on observations of the earth, sun and stars in infrared, visible or ultraviolet wavelengths. It is possible to use x-ray imaging devices to provide arcsecond level measurement of attitude based on star patterns in the x-ray sky. This technique is explored with a simple simulation. Collimated x-ray detectors can be used on spinning satellites to provide a cheap and reliable measure of orientation. This is demonstrated using observations of the Crab Pulsar taken by the high Energy Astronomy Observatory (HEAO-1) in 1977. A single instrument concept is shown to be effective, but dependent on an a priori estimate of the guide star intensity and thus susceptible to errors in that estimate. A star scanner based on a differential measurement from two x-ray detectors eliminates the need for an a priori estimate of the guide star intensity. A first order model and a second order model of the two star scanner concepts are considered. Many of the stars that emit in the x-ray regime are also x-ray pulsars with frequency stability approaching a

  8. The Scanning X-Ray Microprobe at the Esrf ``X-Ray Microscopy'' Beamline

    NASA Astrophysics Data System (ADS)

    Susini, J.; Salomé, M.; Fayard, B.; Ortega, R.; Kaulich, B.

    The development of high brilliance X-ray sources coupled with advances in manufacturing technologies of focusing optics has led to significant improvements in submicrometer probes for spectroscopy, diffraction and imaging applications. For instance, X-ray microscopy in the 1-10 keV energy range is better-suited for analyzing trace elements in fluorescence yield. This article will be biased towards submicron fluorescence microscopy developed on the ID21 beamline at the ESRF. The main technical developments, involving new focusing lenses or novel phase contrast method, are presented. Strengths and weaknesses of X-ray microscopy and spectromicroscopy techniques are discussed and illustrated by examples in biology, materials science and geology.

  9. Magnetic field induced differential neutron phase contrast imaging

    SciTech Connect

    Strobl, M.; Treimer, W.; Walter, P.; Keil, S.; Manke, I.

    2007-12-17

    Besides the attenuation of a neutron beam penetrating an object, induced phase changes have been utilized to provide contrast in neutron and x-ray imaging. In analogy to differential phase contrast imaging of bulk samples, the refraction of neutrons by magnetic fields yields image contrast. Here, it will be reported how double crystal setups can provide quantitative tomographic images of magnetic fields. The use of magnetic air prisms adequate to split the neutron spin states enables a distinction of field induced phase shifts and these introduced by interaction with matter.

  10. Two dimensional x-ray phase imaging using single grating interferometer with embedded x-ray targets.

    PubMed

    Morimoto, Naoki; Fujino, Sho; Yamazaki, Amane; Ito, Yasuhiro; Hosoi, Takuji; Watanabe, Heiji; Shimura, Takayoshi

    2015-06-29

    Using multidot metal targets embedded in a diamond substrate, we created a single-grating Talbot-Lau interferometer and used it to capture two dimensional (2D) x-ray phase images. The ensemble of these targets constitutes a tiny virtual array of x-ray source and enables x-ray phase-contrast imaging with no source or absorption grating within a 1 m source-detector distance for 8 keV x-rays. We directly resolved a dot-pattern self-image of the phase grating with 6 µm pitch by using an x-ray image detector with 24 µm pixels and obtained 2D differential-phase and dark-field images from a single-exposure. Using the 2D differential-phase images, we also obtained a phase image with no streak artifacts.

  11. Real Time Network Assessment

    DTIC Science & Technology

    2013-07-12

    Demonstrate a simple system Conduct a feasibility assessment of data storage, maintenance, and integration requirements Test a web-based data feed...Real Time Network Assessment Prototype We demonstrated the feasibility of linking near real time network analytics to mashups and web- based...combining similar concepts into single node) Stemmers Thesauri application Network position Statistical common patterns Pronoun identification

  12. Are Human Peripheral Nerves Sensitive to X-Ray Imaging?

    PubMed Central

    Scopel, Jonas Francisco; de Souza Queiroz, Luciano; O’Dowd, Francis Pierce; Júnior, Marcondes Cavalcante França; Nucci, Anamarli; Hönnicke, Marcelo Gonçalves

    2015-01-01

    Diagnostic imaging techniques play an important role in assessing the exact location, cause, and extent of a nerve lesion, thus allowing clinicians to diagnose and manage more effectively a variety of pathological conditions, such as entrapment syndromes, traumatic injuries, and space-occupying lesions. Ultrasound and nuclear magnetic resonance imaging are becoming useful methods for this purpose, but they still lack spatial resolution. In this regard, recent phase contrast x-ray imaging experiments of peripheral nerve allowed the visualization of each nerve fiber surrounded by its myelin sheath as clearly as optical microscopy. In the present study, we attempted to produce high-resolution x-ray phase contrast images of a human sciatic nerve by using synchrotron radiation propagation-based imaging. The images showed high contrast and high spatial resolution, allowing clear identification of each fascicle structure and surrounding connective tissue. The outstanding result is the detection of such structures by phase contrast x-ray tomography of a thick human sciatic nerve section. This may further enable the identification of diverse pathological patterns, such as Wallerian degeneration, hypertrophic neuropathy, inflammatory infiltration, leprosy neuropathy and amyloid deposits. To the best of our knowledge, this is the first successful phase contrast x-ray imaging experiment of a human peripheral nerve sample. Our long-term goal is to develop peripheral nerve imaging methods that could supersede biopsy procedures. PMID:25757086

  13. Deterministic retrieval of complex Green's functions using hard X rays.

    PubMed

    Vine, D J; Paganin, D M; Pavlov, K M; Uesugi, K; Takeuchi, A; Suzuki, Y; Yagi, N; Kämpfe, T; Kley, E-B; Förster, E

    2009-01-30

    A massively parallel deterministic method is described for reconstructing shift-invariant complex Green's functions. As a first experimental implementation, we use a single phase contrast x-ray image to reconstruct the complex Green's function associated with Bragg reflection from a thick perfect crystal. The reconstruction is in excellent agreement with a classic prediction of dynamical diffraction theory.

  14. Clocking femtosecond X rays.

    PubMed

    Cavalieri, A L; Fritz, D M; Lee, S H; Bucksbaum, P H; Reis, D A; Rudati, J; Mills, D M; Fuoss, P H; Stephenson, G B; Kao, C C; Siddons, D P; Lowney, D P; Macphee, A G; Weinstein, D; Falcone, R W; Pahl, R; Als-Nielsen, J; Blome, C; Düsterer, S; Ischebeck, R; Schlarb, H; Schulte-Schrepping, H; Tschentscher, Th; Schneider, J; Hignette, O; Sette, F; Sokolowski-Tinten, K; Chapman, H N; Lee, R W; Hansen, T N; Synnergren, O; Larsson, J; Techert, S; Sheppard, J; Wark, J S; Bergh, M; Caleman, C; Huldt, G; van der Spoel, D; Timneanu, N; Hajdu, J; Akre, R A; Bong, E; Emma, P; Krejcik, P; Arthur, J; Brennan, S; Gaffney, K J; Lindenberg, A M; Luening, K; Hastings, J B

    2005-03-25

    Linear-accelerator-based sources will revolutionize ultrafast x-ray science due to their unprecedented brightness and short pulse duration. However, time-resolved studies at the resolution of the x-ray pulse duration are hampered by the inability to precisely synchronize an external laser to the accelerator. At the Sub-Picosecond Pulse Source at the Stanford Linear-Accelerator Center we solved this problem by measuring the arrival time of each high energy electron bunch with electro-optic sampling. This measurement indirectly determined the arrival time of each x-ray pulse relative to an external pump laser pulse with a time resolution of better than 60 fs rms.

  15. Early Detection of Amyloid Plaque in Alzheimer’s Disease via X-ray Phase CT

    DTIC Science & Technology

    2016-08-01

    matter and white matter in x-ray PCCT image is substantially higher than that in conventional CT image, (ii) given identical x-ray dose, the PCCT...corresponding to the attenuation contrast, differential phase contrast and dark field contrast, respectively. The imaging performance of the prototype system has... matter White matter Figure 9. CT images of the AD brain specimen corresponding to attenuation contrast (a) and phase contrast (b) (image in-plane

  16. X-ray phase imaging with a laboratory source using selective reflection from a mirror.

    PubMed

    Pelliccia, Daniele; Paganin, David M

    2013-04-22

    A novel approach for hard x-ray phase contrast imaging with a laboratory source is reported. The technique is based on total external reflection from the edge of a mirror, aligned to intercept only half of the incident beam. The mirror edge thus produces two beams. The refraction x-rays undergo when interacting with a sample placed before the mirror, causes relative intensity variations between direct and reflected beams. Quantitative phase contrast and pure absorption imaging are demonstrated using this method.

  17. Massively parallel X-ray holography

    SciTech Connect

    Spence, John C.H; Marchesini, Stefano; Boutet, Sebastien; Sakdinawat, Anne E.; Bogan, Michael J.; Bajt, Sasa; Barty, Anton; Chapman, Henry N.; Frank, Matthias; Hau-Riege, Stefan P.; Szöke, Abraham; Cui, Congwu; Shapiro, David A.; Howells, MAlcolm R.; Shaevitz, Joshua W; Lee, Joanna Y.; Hajdu, Janos; Seibert, Marvin M.

    2008-08-01

    Advances in the development of free-electron lasers offer the realistic prospect of nanoscale imaging on the timescale of atomic motions. We identify X-ray Fourier-transform holography1,2,3 as a promising but, so far, inefficient scheme to do this. We show that a uniformly redundant array4 placed next to the sample, multiplies the efficiency of X-ray Fourier transform holography by more than three orders of magnitude, approaching that of a perfect lens, and provides holographic images with both amplitude- and phase-contrast information. The experiments reported here demonstrate this concept by imaging a nano-fabricated object at a synchrotron source, and a bacterial cell with a soft-X-ray free-electron laser, where illumination by a single 15-fs pulse was successfully used in producing the holographic image. As X-ray lasers move to shorter wavelengths we expect to obtain higher spatial resolution ultrafast movies of transient states of matter

  18. X-ray fluorescence experiment

    NASA Technical Reports Server (NTRS)

    Adler, I.; Trombka, J. I.; Gerard, J.; Schmadebeck, R.; Lowman, P.; Blodgett, H.; Yin, L.; Eller, E.; Lamothe, R.; Gorenstein, P.

    1972-01-01

    The preliminary results from the Sco X-1 and Cyg X-1 obtained from the Apollo 15 X-ray detector data are presented along with preliminary results of the X-ray fluorescence spectrometric data of the lunar surface composition. The production of the characteristic X-rays following the interaction of solar X-rays with the lunar surface is described along with the X-ray spectrometer. Preliminary analyses of the astronomical X-ray observation and the X-ray fluorescence data are presented.

  19. Results from the first preclinical CT scanner with grating based phase contrast and a rotating gantry

    NASA Astrophysics Data System (ADS)

    Bech, Martin; Tapfer, Arne; Velroyen, Astrid; Yaroshenko, Andre; Pauwels, Bart; Bruyndonckx, Peter; Liu, Xuan; Sasov, Alexander; Mohr, Jürgen; Walter, Marco; Pfeiffer, Franz

    2012-07-01

    After successful demonstrations of soft-tissue phase-contrast imaging with grating interferometers at synchrotron radiation sources and at laboratory based x-ray tubes, a first preclinical CT scanner with grating based phase contrast imaging modality has been constructed. The rotating gantry is equipped with a three-grating interferometer, a 50 watt tungsten anode source and a Hamamatsu flat panel detector. The total length of the interferometer is 45 cm, and the bed of the scanner is optimized for mice, with a scanning diameter of 35 mm. From one single scan both phase-contrast and standard attenuation based tomography can be attained, providing an overall gain in image contrast.

  20. Results from the first preclinical CT scanner with grating based phase contrast and a rotating gantry

    SciTech Connect

    Bech, Martin; Tapfer, Arne; Velroyen, Astrid; Yaroshenko, Andre; Pauwels, Bart; Bruyndonckx, Peter; Liu Xuan; Sasov, Alexander; Mohr, Juergen; Walter, Marco; Pfeiffer, Franz

    2012-07-31

    After successful demonstrations of soft-tissue phase-contrast imaging with grating interferometers at synchrotron radiation sources and at laboratory based x-ray tubes, a first preclinical CT scanner with grating based phase contrast imaging modality has been constructed. The rotating gantry is equipped with a three-grating interferometer, a 50 watt tungsten anode source and a Hamamatsu flat panel detector. The total length of the interferometer is 45 cm, and the bed of the scanner is optimized for mice, with a scanning diameter of 35 mm. From one single scan both phase-contrast and standard attenuation based tomography can be attained, providing an overall gain in image contrast.

  1. X-ray beam finder

    DOEpatents

    Gilbert, H.W.

    1983-06-16

    An X-ray beam finder for locating a focal spot of an X-ray tube includes a mass of X-ray opaque material having first and second axially-aligned, parallel-opposed faces connected by a plurality of substantially identical parallel holes perpendicular to the faces and a film holder for holding X-ray sensitive film tightly against one face while the other face is placed in contact with the window of an X-ray head.

  2. Neck x-ray

    MedlinePlus

    ... look at cervical vertebrae. These are the 7 bones of the spine in the neck. ... A neck x-ray can detect: Bone joint that is out of position (dislocation) Breathing in a foreign object Broken bone (fracture) Disk problems (disks ...

  3. Abdominal x-ray

    MedlinePlus

    ... a kidney stone Identify blockage in the intestine Locate an object that has been swallowed Help diagnose diseases, such as tumors or other conditions Normal Results The x-ray will show normal structures for a person your age. What Abnormal Results Mean Abnormal findings ...

  4. Phase Effects on Mesoscale Object X-ray Attenuation Radiographs

    SciTech Connect

    Martz, Jr., H E; Aufderheide, M B; Barty, A; Hau-Riege, S; Lehman, S K; Kozioziemski, B J; Schneberk, D J

    2005-11-08

    Digital x-ray radiography and computed tomography methods are commonly used to characterize mesoscale objects (mm size objects with {micro}m size features). However the ability of these methods to provide high spatial resolution images is dependent, in part, on object recovery algorithms that account for phase effects [1]. The objective of this work is the development and validation of algorithms to model phase-contrast effects observed in x-ray radiographic systems, and to use these algorithms for quantitative object recovery. This work has three distinct tasks. First, we are modifying HADES [2,3] to model x-ray phase contrast and are investigating whether multislice techniques within the object are needed to fully capture the physics seen in x-ray data. Second, we are developing object recovery approaches. Third, we are validating these simulations against x-ray systems using well-known objects. At the end of this R&D, we will have a set of validated x-ray forward modeling codes including the effects of phase and an understanding of the current object recovery methods limitations.

  5. Scanning X-Ray Nanodiffraction on Dictyostelium discoideum

    PubMed Central

    Priebe, Marius; Bernhardt, Marten; Blum, Christoph; Tarantola, Marco; Bodenschatz, Eberhard; Salditt, Tim

    2014-01-01

    We have performed scanning x-ray nanobeam diffraction experiments on single cells of the amoeba Dictyostelium discoideum. Cells have been investigated in 1), freeze-dried, 2), frozen-hydrated (vitrified), and 3), initially alive states. The spatially resolved small-angle x-ray scattering signal shows characteristic streaklike patterns in reciprocal space, which we attribute to fiber bundles of the actomyosin network. From the intensity distributions, an anisotropy parameter can be derived that indicates pronounced local variations within the cell. In addition to nanobeam small-angle x-ray scattering, we have evaluated the x-ray differential phase contrast in view of the projected electron density. Different experimental aspects of the x-ray experiment, sample preparation, and data analysis are discussed. Finally, the x-ray results are correlated with optical microscopy (differential phase contrast and confocal microscopy of mutant strains with fluorescently labeled actin and myosin II), which have been carried out in live and fixed states, including optical microscopy under cryogenic conditions. PMID:25468345

  6. Quantitative Phase Imaging with a Scanning Transmission X-Ray Microscope

    PubMed Central

    de Jonge, M. D.; Hornberger, B.; Holzner, C.; Legnini, D.; Paterson, D.; McNulty, I.; Jacobsen, C.; Vogt, S.

    2010-01-01

    We obtain quantitative phase reconstructions from differential phase contrast images obtained with a scanning transmission x-ray microscope and 2.5 keV x rays. The theoretical basis of the technique is presented along with measurements and their interpretation. PMID:18518198

  7. Geometry-constraint-scan imaging for in-line phase contrast micro-CT.

    PubMed

    Fu, Jian; Yu, Guangyuan; Fan, Dekai

    2014-01-01

    X-ray phase contrast computed tomography (CT) uses the phase shift that x-rays undergo when passing through matter, rather than their attenuation, as the imaging signal and may provide better image quality in soft-tissue and biomedical materials with low atomic number. Here a geometry-constraint-scan imaging technique for in-line phase contrast micro-CT is reported. It consists of two circular-trajectory scans with x-ray detector at different positions, the phase projection extraction method with the Fresnel free-propagation theory and the filter back-projection reconstruction algorithm. This method removes the contact-detector scan and the pure phase object assumption in classical in-line phase contrast Micro-CT. Consequently it relaxes the experimental conditions and improves the image contrast. This work comprises a numerical study of this technique and its experimental verification using a biomedical composite dataset measured at an x-ray tube source Micro-CT setup. The numerical and experimental results demonstrate the validity of the presented method. It will be of interest for a wide range of in-line phase contrast Micro-CT applications in biology and medicine.

  8. Dynamic Studies of Lung Fluid Clearance with Phase Contrast Imaging

    SciTech Connect

    Kitchen, Marcus J.; Williams, Ivan; Irvine, Sarah C.; Morgan, Michael J.; Paganin, David M.; Lewis, Rob A.; Pavlov, Konstantin; Hooper, Stuart B.; Wallace, Megan J.; Siu, Karen K. W.; Yagi, Naoto; Uesugi, Kentaro

    2007-01-19

    Clearance of liquid from the airways at birth is a poorly understood process, partly due to the difficulties of observing and measuring the distribution of air within the lung. Imaging dynamic processes within the lung in vivo with high contrast and spatial resolution is therefore a major challenge. However, phase contrast X-ray imaging is able to exploit inhaled air as a contrast agent, rendering the lungs of small animals visible due to the large changes in the refractive index at air/tissue interfaces. In concert with the high spatial resolution afforded by X-ray imaging systems (<100 {mu}m), propagation-based phase contrast imaging is ideal for studying lung development. To this end we have utilized intense, monochromatic synchrotron radiation, together with a fast readout CCD camera, to study fluid clearance from the lungs of rabbit pups at birth. Local rates of fluid clearance have been measured from the dynamic sequences using a single image phase retrieval algorithm.

  9. Synchrotron x-ray modification of nanoparticle superlattice formation

    NASA Astrophysics Data System (ADS)

    Lu, Chenguang; Akey, Austin J.; Herman, Irving P.

    2012-09-01

    The synchrotron x-ray radiation used to perform small angle x-ray scattering (SAXS) during the formation of three-dimensional nanoparticle superlattices by drop casting nanoparticle solutions affects the structure and the local crystalline order of the resulting films. The domain size decreases due to the real-time SAXS analysis during drying and more macroscopic changes are visible to the eye.

  10. Exploiting coherence for real-time studies by single-bunch imaging.

    PubMed

    Rack, A; Scheel, M; Hardy, L; Curfs, C; Bonnin, A; Reichert, H

    2014-07-01

    First real-time studies of ultra-fast processes by single-bunch imaging at the European Synchrotron Radiation Facility are reported. By operating the storage ring of the ESRF in single-bunch mode with its correspondingly increased electron bunch charge density per singlet, the polychromatic photon flux density at insertion-device beamlines is sufficient to capture hard X-ray images exploiting the light from a single bunch (the corresponding bunch length is 140 ps FWHM). Hard X-ray imaging with absorption contrast as well as phase contrast in combination with large propagation distances is demonstrated using spatial samplings of 11 µm and 35 µm pixel size. The images acquired allow one to track crack propagation in a bursting piece of glass, breaking of an electrical fuse as well as cell wall rupture in an aqueous foam. Future developments and their potential in the frame of the proposed Phase II of the ESRF Upgrade Program are discussed.

  11. Broadband high resolution X-ray spectral analyzer

    DOEpatents

    Silver, Eric H.; Legros, Mark; Madden, Norm W.; Goulding, Fred; Landis, Don

    1998-01-01

    A broad bandwidth high resolution x-ray fluorescence spectrometer has a performance that is superior in many ways to those currently available. It consists of an array of 4 large area microcalorimeters with 95% quantum efficiency at 6 keV and it produces x-ray spectra between 0.2 keV and 7 keV with an energy resolution of 7 to 10 eV. The resolution is obtained at input count rates per array element of 10 to 50 Hz in real-time, with analog pulse processing and thermal pile-up rejection. This performance cannot be matched by currently available x-ray spectrometers. The detectors are incorporated into a compact and portable cryogenic refrigerator system that is ready for use in many analytical spectroscopy applications as a tool for x-ray microanalysis or in research applications such as laboratory and astrophysical x-ray and particle spectroscopy.

  12. Broadband high resolution X-ray spectral analyzer

    DOEpatents

    Silver, E.H.; Legros, M.; Madden, N.W.; Goulding, F.; Landis, D.

    1998-07-07

    A broad bandwidth high resolution X-ray fluorescence spectrometer has a performance that is superior in many ways to those currently available. It consists of an array of 4 large area microcalorimeters with 95% quantum efficiency at 6 keV and it produces X-ray spectra between 0.2 keV and 7 keV with an energy resolution of 7 to 10 eV. The resolution is obtained at input count rates per array element of 10 to 50 Hz in real-time, with analog pulse processing and thermal pile-up rejection. This performance cannot be matched by currently available X-ray spectrometers. The detectors are incorporated into a compact and portable cryogenic refrigerator system that is ready for use in many analytical spectroscopy applications as a tool for X-ray microanalysis or in research applications such as laboratory and astrophysical X-ray and particle spectroscopy. 6 figs.

  13. VETA x ray data acquisition and control system

    NASA Technical Reports Server (NTRS)

    Brissenden, Roger J. V.; Jones, Mark T.; Ljungberg, Malin; Nguyen, Dan T.; Roll, John B., Jr.

    1992-01-01

    We describe the X-ray Data Acquisition and Control System (XDACS) used together with the X-ray Detection System (XDS) to characterize the X-ray image during testing of the AXAF P1/H1 mirror pair at the MSFC X-ray Calibration Facility. A variety of X-ray data were acquired, analyzed and archived during the testing including: mirror alignment, encircled energy, effective area, point spread function, system housekeeping and proportional counter window uniformity data. The system architecture is presented with emphasis placed on key features that include a layered UNIX tool approach, dedicated subsystem controllers, real-time X-window displays, flexibility in combining tools, network connectivity and system extensibility. The VETA test data archive is also described.

  14. X-ray backscatter imaging for aerospace applications

    SciTech Connect

    Shedlock, Daniel; Edwards, Talion; Toh, Chin

    2011-06-23

    Scatter x-ray imaging (SXI) is a real time, digital, x-ray backscatter imaging technique that allows radiographs to be taken from one side of an object. This x-ray backscatter imaging technique offers many advantages over conventional transmission radiography that include single-sided access and extremely low radiation fields compared to conventional open source industrial radiography. Examples of some applications include the detection of corrosion, foreign object debris, water intrusion, cracking, impact damage and leak detection in a variety of material such as aluminum, composites, honeycomb structures, and titanium.

  15. Time-resolved x-ray crystallography of heme proteins

    PubMed Central

    Royer, William E.

    2012-01-01

    Heme proteins, with their natural photosensitivity, are excellent systems for the application of time-resolved crystallographic methods. Ligand dissociation can be readily initiated by a short laser pulse with global structural changes probed at the atomic level by X-rays in real time. Third generation synchrotrons provide 100ps X-ray pulses of sufficient intensity for monitoring very fast processes. Successful application of such time-resolved crystallographic experiments requires that the structural changes being monitored are compatible with the crystal lattice. These techniques have permitted observing allosteric transitions in real time for a cooperative dimeric hemoglobin. PMID:18433638

  16. Time-Resolved X-Ray Crystallography of Heme Proteins

    SciTech Connect

    Srajer, Vukica; Royer, Jr., William E.

    2008-04-29

    Heme proteins, with their natural photosensitivity, are excellent systems for the application of time-resolved crystallographic methods. Ligand dissociation can be readily initiated by a short laser pulse with global structural changes probed at the atomic level by X-rays in real time. Third-generation synchrotrons provide 100-ps X-ray pulses of sufficient intensity for monitoring very fast processes. Successful application of such time-resolved crystallographic experiments requires that the structural changes being monitored are compatible with the crystal lattice. These techniques have recently permitted observing for the first time allosteric transitions in real time for a cooperative dimeric hemoglobin.

  17. X-Ray Astronomy

    NASA Technical Reports Server (NTRS)

    Wu, S. T.

    2000-01-01

    Dr. S. N. Zhang has lead a seven member group (Dr. Yuxin Feng, Mr. XuejunSun, Mr. Yongzhong Chen, Mr. Jun Lin, Mr. Yangsen Yao, and Ms. Xiaoling Zhang). This group has carried out the following activities: continued data analysis from space astrophysical missions CGRO, RXTE, ASCA and Chandra. Significant scientific results have been produced as results of their work. They discovered the three-layered accretion disk structure around black holes in X-ray binaries; their paper on this discovery is to appear in the prestigious Science magazine. They have also developed a new method for energy spectral analysis of black hole X-ray binaries; four papers on this topics were presented at the most recent Atlanta AAS meeting. They have also carried Monte-Carlo simulations of X-ray detectors, in support to the hardware development efforts at Marshall Space Flight Center (MSFC). These computation-intensive simulations have been carried out entirely on the computers at UAH. They have also carried out extensive simulations for astrophysical applications, taking advantage of the Monte-Carlo simulation codes developed previously at MSFC and further improved at UAH for detector simulations. One refereed paper and one contribution to conference proceedings have been resulted from this effort.

  18. X-Ray Vision

    NASA Technical Reports Server (NTRS)

    Ramsey, B. D.; Elsner, R. F.; Engelhaupt, D.; Kolodziejczak, J. J.; ODell, S. L.; Speegle, C. O.; Weisskopf, M. C.

    2004-01-01

    We are fabricating optics for the hard-x-ray region using electroless nickel replication. The attraction of this process, which has been widely used elsewhere, is that the resulting full shell optics are inherently stable and thus can have very good angular resolution. The challenge with this process is to develop lightweight optics (nickel has a relatively high density of 8.9 g/cu cm), and to keep down the costs of mandrel fabrication. We accomplished the former through the development of high-strength nickel alloys that permit very thin shells without fabrication- and handling-induced deformations. For the latter, we have utilized inexpensive grinding and diamond turning to figure the mandrels and then purpose-built polishing machines to finish the surface. In-house plating tanks and a simple water-bath separation system complete the process. To date we have built shells ranging in size from 5 cm diameter to 50 cm, and with thickness down to 100 micron. For our HERO balloon program, we are fabricating over 200 iridium-coated shells, 250 microns thick, for hard-x-ray imaging up to 75 keV. Early test results on these have indicated half-power-diameters of 15 arcsec. The status of these and other hard-x-ray optics will be reviewed.

  19. X-ray Spectrometer

    NASA Technical Reports Server (NTRS)

    Porter, F. Scott

    2004-01-01

    The X-ray Spectrometer (XRS) instrument is a revolutionary non-dispersive spectrometer that will form the basis for the Astro-E2 observatory to be launched in 2005. We have recently installed a flight spare X R S microcalorimeter spectrometer at the EBIT-I facility at LLNL replacing the XRS from the earlier Astro-E mission and providing twice the resolution. The X R S microcalorimeter is an x-ray detector that senses the heat deposited by the incident photon. It achieves a high energy resolution by operating at 0.06K and by carefully controlling the heat capacity and thermal conductance. The XRS/EBIT instrument has 32 pixels in a square geometry and achieves an energy resolution of 6 eV at 6 keV, with a bandpass from 0.1 to 12 keV (or more at higher operating temperature). The instrument allows detailed studies of the x-ray line emission of laboratory plasmas. The XRS/EBIT also provides an extensive calibration "library" for the Astro-E2 observatory.

  20. Real-time radiography

    SciTech Connect

    Bossi, R.H.; Oien, C.T.

    1981-02-26

    Real-time radiography is used for imaging both dynamic events and static objects. Fluorescent screens play an important role in converting radiation to light, which is then observed directly or intensified and detected. The radiographic parameters for real-time radiography are similar to conventional film radiography with special emphasis on statistics and magnification. Direct-viewing fluoroscopy uses the human eye as a detector of fluorescent screen light or the light from an intensifier. Remote-viewing systems replace the human observer with a television camera. The remote-viewing systems have many advantages over the direct-viewing conditions such as safety, image enhancement, and the capability to produce permanent records. This report reviews real-time imaging system parameters and components.