85 research outputs found

    Application of low tube potentials in CCTA results from the PROTECTION VI study

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    OBJECTIVES The aim of this study was to assess the use of low tube potentials for coronary computed tomography angiography (CCTA) in worldwide clinical practice and its influence on radiation exposure, contrast agent volume, and image quality.BACKGROUND CCTA is frequently used in clinical practice. Lowering of tube potential is a potent method to reduce radiation exposure and to economize contrast agent volume.METHODS CCTAs of 4,006 patients from 61 international study sites were analyzed regarding very-tow (= 130 kVp) tube potentials. The impact on dose-length product (DLP) and contrast agent volume was analyzed. Image quality was determined by evaluation of the diagnostic applicability and assessment of the objective image parameters signal-to-noise-ratio (SNR) and contrast-to-noise-ratio (CNR).RESULTS When compared with conventional tube potentials, low tube potentials were used in 56% of CCTAs (<= 80 kVp 9%; 90 to 100 kVp: 47%), which varied among sites from 0% to 100%. Tube potential reduction was associated with low-cardiovascular risk profile, low body mass index (BMI), and new-generation scanners. Median radiation exposure was lowered by 68% or 50% and median contrast agent volume by 25% or 13% for tube potential protocols of <= 80 kVp or 90 to 100 kVp when compared with conventional tube potentials, respectively (all p < 0.001). With the use of lower tube potentials, the frequency of diagnostic scans was maintained (p = 0.41), whereas SNR and CNR significantly improved (both p < 0.001). Considering BMI eligibility criteria, 58% (n = 946) of conventionally scanned patients would have been suitable for low tube potential protocols, and 44% (n = 831) of patients scanned with 90 to 100 kVp would have been eligible for very-low tube potential CCTA imaging of <= 80 kVp.CONCLUSIONS This large international registry confirms the feasibility of tube potential reduction in clinical practice leading to rower radiation exposure and lower contrast volumes. The current registry also demonstrates that this strategy is stilt underused in daily practice. (C) 2020 by the American College of Cardiology Foundation.Cardiolog

    Volume I. Introduction to DUNE

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    The preponderance of matter over antimatter in the early universe, the dynamics of the supernovae that produced the heavy elements necessary for life, and whether protons eventually decay—these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our universe, its current state, and its eventual fate. The Deep Underground Neutrino Experiment (DUNE) is an international world-class experiment dedicated to addressing these questions as it searches for leptonic charge-parity symmetry violation, stands ready to capture supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. The DUNE far detector technical design report (TDR) describes the DUNE physics program and the technical designs of the single- and dual-phase DUNE liquid argon TPC far detector modules. This TDR is intended to justify the technical choices for the far detector that flow down from the high-level physics goals through requirements at all levels of the Project. Volume I contains an executive summary that introduces the DUNE science program, the far detector and the strategy for its modular designs, and the organization and management of the Project. The remainder of Volume I provides more detail on the science program that drives the choice of detector technologies and on the technologies themselves. It also introduces the designs for the DUNE near detector and the DUNE computing model, for which DUNE is planning design reports. Volume II of this TDR describes DUNE\u27s physics program in detail. Volume III describes the technical coordination required for the far detector design, construction, installation, and integration, and its organizational structure. Volume IV describes the single-phase far detector technology. A planned Volume V will describe the dual-phase technology

    Deep Underground Neutrino Experiment (DUNE), far detector technical design report, volume III: DUNE far detector technical coordination

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    The preponderance of matter over antimatter in the early universe, the dynamics of the supernovae that produced the heavy elements necessary for life, and whether protons eventually decay—these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our universe, its current state, and its eventual fate. The Deep Underground Neutrino Experiment (DUNE) is an international world-class experiment dedicated to addressing these questions as it searches for leptonic charge-parity symmetry violation, stands ready to capture supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. The DUNE far detector technical design report (TDR) describes the DUNE physics program and the technical designs of the single- and dual-phase DUNE liquid argon TPC far detector modules. Volume III of this TDR describes how the activities required to design, construct, fabricate, install, and commission the DUNE far detector modules are organized and managed. This volume details the organizational structures that will carry out and/or oversee the planned far detector activities safely, successfully, on time, and on budget. It presents overviews of the facilities, supporting infrastructure, and detectors for context, and it outlines the project-related functions and methodologies used by the DUNE technical coordination organization, focusing on the areas of integration engineering, technical reviews, quality assurance and control, and safety oversight. Because of its more advanced stage of development, functional examples presented in this volume focus primarily on the single-phase (SP) detector module

    omega-Conotoxin CVIB differentially inhibits native and recombinant N- and P/Q-type calcium channels

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    omega-Conotoxins are routinely used as selective inhibitors of different classes of voltage-gated calcium channels (VGCCs) in excitable cells. In the present study, we examined the potent N-type VGCC antagonist omega-conotoxin CVID and non-selective N- and P/Q-type antagonist CVIB for their ability to block native VGCCs in rat dorsal root ganglion (DRG) neurons and recombinant VGCCs expressed in Xenopus oocytes. omega-Conotoxins CVID and CVIB inhibited depolarization-activated whole-cell VGCC currents in DRG neurons with pIC(50) values of 8.12 +/- 0.05 and 7.64 +/- 0.08, respectively. Inhibition of Ba2+ currents in DRG neurons by CVID (similar to 66% of total) appeared to be irreversible for > 30 min washout, whereas Ba2+ currents exhibited rapid recovery from block by CVIB (>= 80% within 3 min). The recoverable component of the Ba2+ current inhibited by CVIB was mediated by the N-type VGCC, whereas the irreversibly blocked current (similar to 22% of total) was attributable to P/Q-type VGCCs. omega-Conotoxin CVIB reversibly inhibited Ba2+ currents mediated by N- (Ca(v)2.2) and P/Q- (Ca(v)2.1), but not R- (Ca(v)2.3) type VGCCs expressed in Xenopus oocytes. The alpha(2)delta 1 auxiliary subunit co-expressed with Ca(v)2.2 and Ca(v)2.1 reduced the sensitivity of VGCCs to CVIB but had no effect on reversibility of block. Determination of the NMR structure of CVIB identified structural differences to CVID that may underlie differences in selectivity of these closely related conotoxins. omega-Conotoxins CVIB and CVID may be useful as antagonists of N- and P/Q-type VGCCs, particularly in sensory neurons involved in processing primary nociceptive information
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