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https://www.readbyqxmd.com/read/28079701/ex-vivo-assessment-of-coronary-atherosclerotic-plaque-by-grating-based-phase-contrast-computed-tomography-correlation-with-optical-coherence-tomography
#1
Christopher Habbel, Holger Hetterich, Marian Willner, Julia Herzen, Kristin Steigerwald, Sigrid Auweter, Ulrich Schüller, Jörg Hausleiter, Steffen Massberg, Maximilian Reiser, Franz Pfeiffer, Tobias Saam, Fabian Bamberg
OBJECTIVES: The aim of this study was to determine the diagnostic accuracy of grating-based phase-contrast computed tomography (gb-PCCT) to classify and quantify coronary vessel characteristics in comparison with optical coherence tomography (OCT) and histopathology in an ex vivo setting. MATERIALS AND METHODS: After excision from 5 heart specimens, 15 human coronary arteries underwent gb-PCCT examination using an experimental imaging setup consisting of a rotating molybdenum anode x-ray tube, a Talbot-Lau grating interferometer, and a single photon counting detector...
January 10, 2017: Investigative Radiology
https://www.readbyqxmd.com/read/28079527/binary-moving-blocker-based-scatter-correction-in-cone-beam-computed-tomography-with-width-truncated-projections-proof-of-concept
#2
Ho Lee, Benjamin Fahimian, Lei Xing
This paper proposes a binary moving-blocker (BMB)-based technique for scatter correction in cone-beam computed tomography (CBCT). In concept, a beam blocker consisting of lead strips, mounted in front of the x-ray tube, moves rapidly in and out of the beam during a single gantry rotation. The projections are acquired in alternating phases of blocked and unblocked cone beams, where the blocked phase results in a stripe pattern in the width direction. To derive the scatter map from the blocked projections, one-dimensional B-Spline interpolation/extrapolation is applied by using the detected information in the shaded regions...
January 12, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28069245/extended-glaze-firing-on-ceramics-for-hard-machining-crack-healing-residual-stresses-optical-and-microstructural-aspects
#3
Iana L Aurélio, Lucio S Dorneles, Liliana G May
OBJECTIVE: To evaluate the effect of extended and conventional (manufacturer-recommended) glaze firings on crack healing, residual stresses, optical characteristics and crystalline structure of four ceramics for hard machining. METHODS: Rectangular specimens were obtained by sectioning densely sintered feldspathic (FEL), leucite- (LEU), lithium disilicate- (DIS), and zirconia-reinforced lithium silicate-based (ZLS) prefabricated ceramic blocks and divided into groups according to the applied glaze firing (n=5): conventional glaze/manufacturer-recommended (G), extended glaze (EG) and control/no heat treatment (C)...
January 6, 2017: Dental Materials: Official Publication of the Academy of Dental Materials
https://www.readbyqxmd.com/read/28060345/combining-solid-state-and-solution-based-techniques-synthesis-and-reactivity-of-chalcogenidoplumbates-ii-or-iv
#4
Günther Thiele, Carsten Donsbach, Isabell Nußbruch, Stefanie Dehnen
The phases of "PbCh2" (Ch = Se, Te) are obtained from solid-state syntheses (i.e., by the fusion of the elements under inert conditions in silica glass ampules). Reduction of such phases by elemental alkaline metals in amines affords crystalline chalcogenidoplumbate(II) salts comprised of [PbTe3](2)(-) or [Pb2Ch3](2)(-) anions, depending upon which sequestering agent for the cations is present: crown ethers, like 18-crown-6, or cryptands, like [2.2.2]crypt. Reactions of solutions of such anions with transition-metal compounds yield (poly-)chalcogenide anions or transition-metal chalcogenide clusters, including one with a µ-PbSe ligand (i...
December 29, 2016: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28059854/perforator-phase-contrast-angiography-of-deep-inferior-epigastric-perforators-a-better-preoperative-imaging-tool-for-flap-surgery-than-computed-tomographic-angiography
#5
Xiangyu Yang, Michael J Miller, Harry T Friel, Allison Slijepcevic, Michael V Knopp
OBJECTIVE: The aim of this study was to demonstrate the feasibility of in vivo perforator visualization by a newly proposed magnetic resonance-based perforator phase contrast angiography (pPCA) technique for deep inferior epigastric perforator (DIEP) flap surgery and to prospectively compare its image quality and clinical value with computed tomographic angiography (CTA), the state-of-the-art perforator imaging technique. MATERIALS AND METHODS: Institutional review board approval and informed consent were obtained...
January 4, 2017: Investigative Radiology
https://www.readbyqxmd.com/read/28058415/gold-supported-two-dimensional-cobalt-oxyhydroxide-coooh-and-multilayer-cobalt-oxide-islands
#6
Jakob Fester, Alex Walton, Zheshen Li, Jeppe V Lauritsen
In the present study, we investigate the facile conversion of Co-O bilayer islands on a Au(111) surface into preferentially O-Co-O trilayers in an oxygen atmosphere and O-Co-O-Co-O multilayers at elevated temperature. We characterize and compare the island morphologies with scanning tunneling microscopy, X-ray photoemission spectroscopy (XPS) and valence band spectroscopy, and show that the cobalt oxidation state changes from Co(2+) in bilayers to purely Co(3+) in trilayers and a mixture of Co(2+) and Co(3+) in the multilayer morphology...
January 6, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28048590/we-ab-brb-03-real-time-volumetric-scintillation-dosimetry-for-radiation-therapy
#7
S Beddar
: Despite widespread IMRT treatments at modern radiation therapy clinics, precise dosimetric commissioning of an IMRT system remains a challenge. In the most recent report from the Radiological Physics Center (RPC), nearly 20% of institutions failed an end-to-end test with an anthropomorphic head and neck phantom, a test that has rather lenient dose difference and distance-to-agreement criteria of 7% and 4 mm. The RPC report provides strong evidence that IMRT implementation is prone to error and that improved quality assurance tools are required...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048259/su-g-iep4-10-microimaging-for-different-degrees-of-human-cavernous-hemangioma-of-liver-by-using-in-line-phase-contrast-imaging-ct
#8
J Duan
PURPOSE: Cavernous hemangioma of the liver (CHL) is the most common benign solid tumor of the liver. In this study, we quantitative assessment the different degrees of CHL from microscopic viewpoint by using in-line phase-contrast imaging CT (ILPCI-CT). METHODS: The experiments were performed at x-ray imaging and biomedical application beamline (BL13W1) of Shanghai Synchrotron Radiation Facility (SSRF) in China. Three typical specimens at different stages, i.e., mild, moderate and severe human CHL were imaged using ILPCI-CT at 16keV without contrast agents...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047926/we-ab-brb-04-cherenkov-imaging-for-radiation-therapy-dose-verification-on-patients
#9
B Pogue
: Despite widespread IMRT treatments at modern radiation therapy clinics, precise dosimetric commissioning of an IMRT system remains a challenge. In the most recent report from the Radiological Physics Center (RPC), nearly 20% of institutions failed an end-to-end test with an anthropomorphic head and neck phantom, a test that has rather lenient dose difference and distance-to-agreement criteria of 7% and 4 mm. The RPC report provides strong evidence that IMRT implementation is prone to error and that improved quality assurance tools are required...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047862/we-ab-brb-00-session-in-memory-of-robert-j-shalek-high-resolution-dosimetry-from-2d-to-3d-to-real-time-3d
#10
Harold Li
: Despite widespread IMRT treatments at modern radiation therapy clinics, precise dosimetric commissioning of an IMRT system remains a challenge. In the most recent report from the Radiological Physics Center (RPC), nearly 20% of institutions failed an end-to-end test with an anthropomorphic head and neck phantom, a test that has rather lenient dose difference and distance-to-agreement criteria of 7% and 4 mm. The RPC report provides strong evidence that IMRT implementation is prone to error and that improved quality assurance tools are required...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047511/th-f-209-00-pitfalls-reliability-and-performance-of-diagnostic-x-ray-sources
#11
Rolf Behling
PURPOSE: Performance and reliability of medical X-ray tubes for imaging are crucial from an ethical, clinical and economic perspective. This lecture will deliver insight into the aspects to consider during the decision making process to invest in X-ray imaging equipment. Outdated metric still hampers realistic product comparison. It is time to change this and to comply with latest standards, which consider current technology. Failure modes and ways to avoid down-time of the equipment shall be discussed...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047456/mo-de-207a-06-ecg-gated-ct-reconstruction-for-a-c-arm-inverse-geometry-x-ray-system
#12
J M Slagowski, Dap Dunkerley
PURPOSE: To obtain ECG-gated CT images from truncated projection data acquired with a C-arm based inverse geometry fluoroscopy system, for the purpose of cardiac chamber mapping in interventional procedures. METHODS: Scanning-beam digital x-ray (SBDX) is an inverse geometry fluoroscopy system with a scanned multisource x-ray tube and a photon-counting detector mounted to a C-arm. In the proposed method, SBDX short-scan rotational acquisition is performed followed by inverse geometry CT (IGCT) reconstruction and segmentation of contrast-enhanced objects...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047199/we-ab-brb-01-memorial-introduction-storage-phosphor-panels-for-radiation-therapy-dosimetry
#13
H Li
: Despite widespread IMRT treatments at modern radiation therapy clinics, precise dosimetric commissioning of an IMRT system remains a challenge. In the most recent report from the Radiological Physics Center (RPC), nearly 20% of institutions failed an end-to-end test with an anthropomorphic head and neck phantom, a test that has rather lenient dose difference and distance-to-agreement criteria of 7% and 4 mm. The RPC report provides strong evidence that IMRT implementation is prone to error and that improved quality assurance tools are required...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047114/su-f-e-01-pitfalls-reliability-and-performance-of-diagnostic-x-sources
#14
R Behling
PURPOSE: Performance and reliability of medical X-ray tubes for imaging are crucial from an ethical, clinical and economic perspective. This lecture will deliver insight into the aspects to consider during the decision making process to invest in X-ray imaging equipment. Outdated metric still hampers realistic product comparison. It is time to change this and to comply with latest standards, which consider current technology. Failure modes and ways to avoid down-time of the equipment shall be discussed...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28046855/th-f-209-01-pitfalls-reliability-and-performance-of-diagnostic-x-ray-sources
#15
R Behling
PURPOSE: Performance and reliability of medical X-ray tubes for imaging are crucial from an ethical, clinical and economic perspective. This lecture will deliver insight into the aspects to consider during the decision making process to invest in X-ray imaging equipment. Outdated metric still hampers realistic product comparison. It is time to change this and to comply with latest standards, which consider current technology. Failure modes and ways to avoid down-time of the equipment shall be discussed...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28046529/we-ab-brb-02-methods-and-applications-of-3d-radiochromic-dosimetry
#16
M Oldham
: Despite widespread IMRT treatments at modern radiation therapy clinics, precise dosimetric commissioning of an IMRT system remains a challenge. In the most recent report from the Radiological Physics Center (RPC), nearly 20% of institutions failed an end-to-end test with an anthropomorphic head and neck phantom, a test that has rather lenient dose difference and distance-to-agreement criteria of 7% and 4 mm. The RPC report provides strong evidence that IMRT implementation is prone to error and that improved quality assurance tools are required...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28043139/structural-stability-vibrational-properties-and-photoluminescence-in-cssni3-perovskite-upon-the-addition-of-snf2
#17
Athanassios G Kontos, Andreas Kaltzoglou, Eirini Siranidi, Dimitrios Palles, Giasemi K Angeli, Michalis K Arfanis, Vassilis Psycharis, Yannis S Raptis, Efstratios I Kamitsos, Pantelis N Trikalitis, Constantinos C Stoumpos, Mercouri G Kanatzidis, Polycarpos Falaras
The CsSnI3 perovskite and the corresponding SnF2-containing material with nominal composition CsSnI2.95F0.05 were synthesized by solid-state reactions and structurally characterized by powder X-ray diffraction. Both materials undergo rapid phase transformation upon exposure to air from the black orthorhombic phase (B-γ-CsSnI3) to the yellow orthorhombic phase (Y-CsSnI3), followed by irreversible oxidation into Cs2SnI6 within several hours. The phase transition occurs at a significantly lower rate in the SnF2-containing material rather than in the pure perovskite...
January 3, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28042800/how-many-photons-are-needed-to-reconstruct-random-objects-in-coherent-x-ray-diffractive-imaging
#18
T Jahn, R N Wilke, Y Chushkin, T Salditt
This paper presents an investigation of the reconstructibility of coherent X-ray diffractive imaging diffraction patterns for a class of binary random `bitmap' objects. Combining analytical results and numerical simulations, the critical fluence per bitmap pixel is determined, for arbitrary contrast values (absorption level and phase shift), both for the optical near- and far-field. This work extends previous investigations based on information theory, enabling a comparison of the amount of information carried by single photons in different diffraction regimes...
January 1, 2017: Acta Crystallographica. Section A, Foundations and Advances
https://www.readbyqxmd.com/read/28027773/ex-vivo-characterization-of-pathologic-fluids-with-quantitative-phase-contrast-computed-tomography
#19
Vivien Richter, Marian S Willner, John Henningsen, Lorenz Birnbacher, Mathias Marschner, Julia Herzen, Melanie A Kimm, Peter B Noe L, Ernst J Rummeny, Franz Pfeiffer, Alexander A Fingerle
PURPOSE: X-ray phase-contrast imaging (PCI) provides additional information beyond absorption characteristics by detecting the phase shift of the X-ray beam passing through material. The grating-based system works with standard polychromatic X-ray sources, promising a possible clinical implementation. PCI has been shown to provide additional information in soft-tissue samples. The aim of this study was to determine if ex vivo quantitative phase-contrast computed tomography (PCCT) may differentiate between pathologic fluid collections...
January 2017: European Journal of Radiology
https://www.readbyqxmd.com/read/28024847/dark-field-imaging-recent-developments-and-potential-clinical-applications
#20
Masami Ando, Naoki Sunaguchi, Daisuke Shimao, Adam Pan, Tetsuya Yuasa, Kensaku Mori, Yoshifumi Suzuki, Ge Jin, Jong-Ki Kim, Jae-Hong Lim, Seung-Jun Seo, Shu Ichihara, Norihiko Ohura, Rajiv Gupta
This paper describes an X-ray phase contrast imaging technique using analyzer-based optics called X-ray Dark-Field Imaging that has been under development for the past 10years. We describe the theory behind XDFI, the X-ray optics required for implementing it in practice, and algorithms used for 2D, 2.5D, and 3D image reconstruction. The XDFI optical chain consists of an asymmetrically cut, Bragg-type monochromator-collimator that provides a planar monochromatic X-ray beam, a positioning stage for the specimens, a Laue-case angle analyzer, and one or two cameras to capture the dark and bright field images...
December 2016: Physica Medica: PM
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