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https://www.readbyqxmd.com/read/28220403/dosimetry-in-mars-spectral-ct-topas-monte-carlo-simulations-and-ion-chamber-measurements
#1
Gray Lu, Steven Marsh, Jerome Damet, Pierre Carbonez, John Laban, Christopher Bateman, Anthony Butler, Phil Butler
Spectral computed tomography (CT) is an up and coming imaging modality which shows great promise in revealing unique diagnostic information. Because this imaging modality is based on X-ray CT, it is of utmost importance to study the radiation dose aspects of its use. This study reports on the implementation and evaluation of a Monte Carlo simulation tool using TOPAS for estimating dose in a pre-clinical spectral CT scanner known as the MARS scanner. Simulated estimates were compared with measurements from an ionization chamber...
February 20, 2017: Australasian Physical & Engineering Sciences in Medicine
https://www.readbyqxmd.com/read/28213277/fluorescence-and-computed-tomography-for-assessing-the-biodistribution-of-sirna-after-intratracheal-application-in-mice
#2
Antonia Geyer, Cornelia Lorenzer, Sebastian Gehrig, Manuela Simlinger, Johannes Winkler, Haider Sami, Manfred Ogris
Pulmonary delivery of nucleic acids opens the possibility for direct treatment of lung diseases, like fibrosis, cancer, and infections. Lung retention and biodistribution of nucleic acids remain important issues for the development of suitable therapeutic approaches. Moreover, monitoring the dynamic biodistribution processes of siRNA after aerosol delivery can help in identifying bottlenecks and optimising therapeutic concepts. We investigated dynamic biodistribution events after intratracheal application of chemically stabilised siRNA labeled with near infrared emitting dye AlexaFluor750 (AF750)...
February 14, 2017: International Journal of Pharmaceutics
https://www.readbyqxmd.com/read/28205513/analysis-of-uncertainties-in-monte-carlo-simulated-organ-and-effective-dose-in-chest-ct-scanner-and-scan-related-factors
#3
John Muryn, Ashraf Morgan, Chris Liptak, Frank Dong, Paul Segars, Andrew Primak, Xiang Li
In Monte Carlo simulation of CT dose, many input parameters are required (e.g., bowtie filter properties and scan start/end location). Our goal was to examine the uncertainties in patient dose when input parameters were inaccurate. Using a validated Monte Carlo program, organ dose from a chest CT scan was simulated for an average-size female phantom using a reference set of input parameter values (treated as the truth). Additional simulations were performed in which errors were purposely introduced into the input parameter values...
February 16, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28198784/choroidal-thickness-in-patients-with-stargardt-disease
#4
Esra Vural, Ugur Acar, Mehmet K Sevinc, Mesut Erdurmus, Bekir Kucuk, Seckin Aykas, Gungor Sobaci
PURPOSE: To investigate the relationship between choroidal thicknesses (CT), central foveal thicknesses, multifocal electroretinography (mf-ERG) responses, and best-corrected visual acuity levels in patients with Stargardt disease (STGD). METHODS: A total of 30 eyes of 30 patients with STGD, and 30 age- and sex-matched healthy controls were included in the study. All participants underwent detailed ophthalmic examination including best-corrected visual acuity and spectral domain optical coherence tomography measurements, and also patients with STGD were performed mf-ERG...
February 14, 2017: Retina
https://www.readbyqxmd.com/read/28197873/ct-angiography-of-the-kidney-using-routine-ct-and-the-latest-gemstone-spectral-imaging-combination-of-different-noise-indexes-image-quality-and-radiation-dose
#5
Yongxia Zhao, Yanmin Wu, Ziwei Zuo, Shujie Cheng
OBJECTIVE: The objective of our study was to compare the image quality and radiation dose of computed tomography angiography (CTA) of the kidney in patients with different body mass indexes using routine CT and the latest Gemstone Spectral Imaging (GSI) combination of different noise indexes (NI) with the adaptive statistical iterative reconstruction 2.0 algorithm (ASiR 2.0). METHODS: A total of 120 patients who had undergone a CTA of the kidney were divided into four groups (A, B, C and D), with 30 patients in each group...
February 15, 2017: La Radiologia Medica
https://www.readbyqxmd.com/read/28170301/influence-of-parathyroidectomy-on-bone-calcium-concentration-evaluation-with-spectral-ct-in-patients-with-secondary-hyperparathyroidism-undergoing-hemodialysis-a-prospective-feasibility-study
#6
Qiang Ma, Zhenghan Yang, Xue Han, Fen Liu, Dechun Su, Haidong Xing
Purpose To use spectral computed tomography (CT) to evaluate the influence of parathyroidectomy (PTX) on calcium concentration in trabecular bone and cortical bone in patients undergoing hemodialysis with secondary hyperparathyroidism. Materials and Methods This study was performed with institutional review board approval. Written consent was obtained from each patient. Thirty-eight men (mean age ± standard deviation, 55.69 years ± 8.05; range, 42-72 years) undergoing maintenance hemodialysis who underwent PTX and 40 patients (mean age, 56...
February 7, 2017: Radiology
https://www.readbyqxmd.com/read/28169332/secreted-frizzled-related-protein-1-overexpression-in-gastric-cancer-relationship-with-radiological-findings-of-dual-energy-spectral-ct-and-pet-ct
#7
Huimin Lin, Guoyuan Yang, Bei Ding, Miao Zhang, Mingjun Zhang, Fuhua Yan, Ying Qu, Huan Zhang
We explored the role of secreted frizzled-related protein 1 (sFRP1) overexpression in gastric cancer and its relationship with radiological findings from dual-energy spectral CT(DEsCT) and positron emission tomography/computed tomography (PET/CT). We established mouse metastatic models using the SGC-7901/sFRP1 gastric cancer cell line. A control group was established using the SGC-7901/vector cell line. The models were then scanned with dual-energy spectral CT and PET-CT. Subsequent analysis, including immunohistochemistry and Transferase-mediated deoxyuridine triphosphate-biotin nick end labelling (TUNEL), was performed to confirm the role of sFRP1...
February 7, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28168368/accuracy-of-iodine-quantification-using-dual-energy-ct-in-latest-generation-dual-source-and-dual-layer-ct
#8
Gert Jan Pelgrim, Robbert W van Hamersvelt, Martin J Willemink, Bernhard T Schmidt, Thomas Flohr, Arnold Schilham, Julien Milles, Matthijs Oudkerk, Tim Leiner, Rozemarijn Vliegenthart
OBJECTIVE: To determine the accuracy of iodine quantification with dual energy computed tomography (DECT) in two high-end CT systems with different spectral imaging techniques. METHODS: Five tubes with different iodine concentrations (0, 5, 10, 15, 20 mg/ml) were analysed in an anthropomorphic thoracic phantom. Adding two phantom rings simulated increased patient size. For third-generation dual source CT (DSCT), tube voltage combinations of 150Sn and 70, 80, 90, 100 kVp were analysed...
February 6, 2017: European Radiology
https://www.readbyqxmd.com/read/28149991/exciton-vibrational-resonance-and-dynamics-of-charge-separation-in-the-photosystem-ii-reaction-center
#9
Vladimir I Novoderezhkin, Elisabet Romero, Javier Prior, Rienk van Grondelle
The dynamics of charge separation in the photosystem II reaction center (PSII-RC) in the presence of intramolecular vibrations with their frequency matching the energy gap between the exciton state acting as the primary electron donor and the first charge-transfer (CT) state are investigated. A reduced PSII-RC 4-state model explicitly including a CT state is analyzed within Redfield relaxation theory in the multidimensional exciton-vibrational (vibronic) basis. This model is used to study coherent energy/electron transfers and their spectral signatures obtained by two-dimensional electronic spectroscopy (2DES)...
February 2, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28130851/doppler-vocal-fremitus
#10
Wesley Fiser, Balakrishna Pai, Srikanth Vallurupalli
A young woman with metastatic breast cancer was found to have a regular spectral Doppler event spanning multiple cardiac cycles and timing to her tachypneic respiratory rate, which suggested an extracardiac source. A chest CT confirmed a large mediastinal mass causing a postobstructive pneumonia. This Doppler signal reflected increased turbulence across the obstructed bronchus due to sound wave conduction through a pulmonary consolidation-a Doppler equivalent of "vocal fremitus" elicited by physical examination of a patient with a lung mass or pneumonia...
January 28, 2017: Echocardiography
https://www.readbyqxmd.com/read/28124106/feasibility-and-accuracy-of-dual-layer-spectral-detector-computed-tomography-for-quantification-of-gadolinium-a-phantom-study
#11
Robbert W van Hamersvelt, Martin J Willemink, Pim A de Jong, Julien Milles, Alain Vlassenbroek, Arnold M R Schilham, Tim Leiner
OBJECTIVES: The aim of this study was to evaluate the feasibility and accuracy of dual-layer spectral detector CT (SDCT) for the quantification of clinically encountered gadolinium concentrations. METHODS: The cardiac chamber of an anthropomorphic thoracic phantom was equipped with 14 tubular inserts containing different gadolinium concentrations, ranging from 0 to 26.3 mg/mL (0.0, 0.1, 0.2, 0.4, 0.5, 1.0, 2.0, 3.0, 4.0, 5.1, 10.6, 15.7, 20.7 and 26.3 mg/mL). Images were acquired using a novel 64-detector row SDCT system at 120 and 140 kVp...
January 25, 2017: European Radiology
https://www.readbyqxmd.com/read/28099156/quasi-monochromatic-imaging-in-x-ray-ct-via-spectral-deconvolution-using-photon-counting-detectors
#12
Sen Wang, Hewei Gao, Li Zhang, Dufan Wu, Xiaofei Xu
Photon-counting detectors can obtain the spectral information from an incident x-ray spectrum, although the detected counts may differ from the incident counts due to the detector response. If uncorrected or uncompensated, the response will lead to distortion in CT reconstruction. With the intention of reducing the distortion and exploring the potential of photon-counting detectors, a novel reconstruction strategy with spectral deconvolution, which attempts to set itself apart from traditional material decomposition frameworks, is proposed in this paper...
January 18, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28097460/synthesis-spectral-characterization-dna-protein-binding-dna-cleavage-cytotoxicity-antioxidative-and-molecular-docking-studies-of-cu-ii-complexes-containing-schiff-base-bpy-phen-ligands
#13
Berelli Anupama, Airva Aruna, Vijjulatha Manga, Sreekanth Sivan, Madamsetty Vijay Sagar, Ravula Chandrashekar
Ternary Cu(II) complexes [Cu(II)(L)(bpy)Cl] 1, [Cu(II)(L)(Phen)Cl] 2 [L = 2,3-dimethyl-1-phenyl-4(2 hydroxy-5-methyl benzylideneamino)-pyrazol-5-one, bpy = 2,2(') bipyridine, phen =1,10 phenanthroline) were synthesized and characterized by elemental analyses, UV-Visible, FT-IR, ESR, Mass, thermogravimetric and SEM EDAX techniques. The complexes exhibit octahedral geometry. The interaction of the Cu(II) with cailf thymus DNA (CT-DNA) was explored by using absorption and fluorescence spectroscopic methods...
January 17, 2017: Journal of Fluorescence
https://www.readbyqxmd.com/read/28096049/monoenergetic-reconstructions-for-imaging-of-coronary-artery-stents-using-spectral-detector-ct-in-vitro-experience-and-comparison-to-conventional-images
#14
Tilman Hickethier, Bettina Baeßler, Jan Robert Kroeger, Jonas Doerner, Gregor Pahn, David Maintz, Guido Michels, Alexander C Bunck
PURPOSE: Accurate assessment of coronary stents using non-invasive CT imaging remains challenging despite new stent materials and improvements in CT technology. Virtual monoenergetic (monoE) images reconstructed from dual energy CT acquisitions potentially decrease artifacts caused by coronary stents. A novel spectral detector technology provides monoE and conventional images simultaneously for all conducted scans. The purpose of our study was to systematically investigate the influence of different monoE reconstructions on the visualization of coronary stent lumen in comparison to conventional images...
January 2017: Journal of Cardiovascular Computed Tomography
https://www.readbyqxmd.com/read/28093625/ultralow-dose-ct-for-pulmonary-nodule-detection-with-chest-x-ray-equivalent-dose-a-prospective-intra-individual-comparative-study
#15
Michael Messerli, Thomas Kluckert, Meinhard Knitel, Stephan Wälti, Lotus Desbiolles, Fabian Rengier, René Warschkow, Ralf W Bauer, Hatem Alkadhi, Sebastian Leschka, Simon Wildermuth
PURPOSE: To prospectively evaluate the accuracy of ultralow radiation dose CT of the chest with tin filtration at 100 kV for pulmonary nodule detection. MATERIALS AND METHODS: 202 consecutive patients undergoing clinically indicated chest CT (standard dose, 1.8 ± 0.7 mSv) were prospectively included and additionally scanned with an ultralow dose protocol (0.13 ± 0.01 mSv). Standard dose CT was read in consensus by two board-certified radiologists to determine the presence of lung nodules and served as standard of reference (SOR)...
January 16, 2017: European Radiology
https://www.readbyqxmd.com/read/28091696/radiation-dose-reduction-in-parasinus-ct-by-spectral-shaping
#16
Matthias S May, Michael Brand, Michael M Lell, Martin Sedlmair, Thomas Allmendinger, Michael Uder, Wolfgang Wuest
INTRODUCTION: Spectral shaping aims to narrow the X-ray spectrum of clinical CT. The aim of this study was to determine the image quality and the extent of radiation dose reduction that can be achieved by tin prefiltration for parasinus CT. METHODS: All scans were performed with a third generation dual-source CT scanner. A study protocol was designed using 100 kV tube voltage with tin prefiltration (200 mAs) that provides image noise levels comparable to a low-dose reference protocol using 100 kV without spectral shaping (25 mAs)...
January 16, 2017: Neuroradiology
https://www.readbyqxmd.com/read/28090811/antibacterial-combination-therapy-using-co-3-cu-2-zn-2-and-pd-2-complexes-their-calf-thymus-dna-binding-studies
#17
Fatemeh Khosravi, Hassan Mansouri-Torshizi
Four Co(III)-, Cu(II)-, Zn(II)- and Pd(II)- based potent antibacterial complexes of formula K3[Co(ox)3].3H2O (I), [Cu(bpy)2Cl]Cl.5H2O (II), [Zn(bpy)3]Cl2 (III) and [Pd(bpy)2](NO3)2 (IV) (where ox is oxalate and bpy is 2,2'-bipyridine) were synthesized. They were characterized by elemental analyses, molar conductance measurements, UV-Vis, FT-IR, (1)H NMR and (13)C NMR spectra. These metal complexes were ordered in three combination series of I+II, I+II+III and I+II+III+IV. Antibacterial activity was tested for each of these four metal complexes and their combinations against gram positive and gram negative bacteria...
January 16, 2017: Journal of Biomolecular Structure & Dynamics
https://www.readbyqxmd.com/read/28089491/satellite-and-central-transitions-selective-1-h-27-al-d-hmqc-experiments-at-very-fast-mas-for-quadrupolar-couplings-determination
#18
Nghia Tuan Duong, Yusuke Nishiyama
Recent study has demonstrated the application of the proton-detected heteronuclear multi-quantum coherence (HMQC) at ultrafast Magic Angle Spinning (MAS) to probe quadrupolar nuclei including (14)N and (35)Cl. In addition, for half-integer quadrupolar nucleus like (35)Cl, the quadrupolar product can be calculated based on the shift difference between the center band of satellite transition (ST) and the central transition (CT) peaks. The applicability of this technique is further investigated on spin I=5/2, namely (27)Al nucleus, and kaolin is chosen as the testing sample...
January 4, 2017: Solid State Nuclear Magnetic Resonance
https://www.readbyqxmd.com/read/28088690/electrochemical-studies-of-dna-interaction-and-antimicrobial-activities-of-mn-ii-fe-iii-co-ii-and-ni-ii-schiff-base-tetraazamacrocyclic-complexes
#19
Anuj Kumar, Vinod Kumar Vashistha, Prashant Tevatia, Randhir Singh
Tetraazamacrocyclic complexes of Mn(II), Fe(III), Co(II) and Ni(II) have been synthesized by template method. These tetraazamacrocycles have been analyzed with various techniques like molar conductance, IR, UV-vis, mass spectral and cyclic voltammetric studies. On the basis of all these studies, octahedral geometry has been assigned to these tetraazamacrocyclic complexes. The DNA binding properties of these macrocyclic complexes have been investigated by electronic absorption spectra, fluorescence spectra, cyclic voltammetric and differential pulse voltammetric studies...
January 6, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28070917/dual-energy-ct-quantitative-imaging-a-comparison-study-between-twin-beam-and-dual-source-ct-scanners
#20
Isabel P Almeida, Lotte E J R Schyns, Michel C Öllers, Wouter van Elmpt, Katia Parodi, Guillaume Landry, Frank Verhaegen
PURPOSE: To assess image quality and to quantify the accuracy of relative electron densities (ρe ) and effective atomic numbers (Zeff ) for three dual-energy computed tomography (DECT) scanners: a novel single-source split-filter (i.e., twin-beam) and two dual-source scanners. METHODS: Measurements were made with a second generation dual-source scanner at 80/140Sn kVp, a third-generation twin-beam single-source scanner at 120 kVp with gold (Au) and tin (Sn) filters, and a third-generation dual-source scanner at 90/150Sn kVp...
January 2017: Medical Physics
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