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https://www.readbyqxmd.com/read/28343304/geometry-calibration-between-x-ray-source-and-detector-for-tomosynthesis-with-a-portable-x-ray-system
#1
Kohei Sato, Takashi Ohnishi, Masashi Sekine, Hideaki Haneishi
PURPOSE: Tomosynthesis is attracting attention as a low-dose tomography technology compared with X-ray CT. However, conventional tomosynthesis imaging devices are large and stationary. Furthermore, there is a limitation in the working range of the X-ray source during image acquisition. We have previously proposed the use of a portable X-ray device for tomosynthesis that can be used for ward rounds and emergency medicine. The weight of this device can be reduced by using a flat panel detector (FPD), and flexibility is realized by the free placement of the X-ray source and FPD...
March 25, 2017: International Journal of Computer Assisted Radiology and Surgery
https://www.readbyqxmd.com/read/28343303/can-real-time-rgbd-enhance-intraoperative-cone-beam-ct
#2
Javad Fotouhi, Bernhard Fuerst, Wolfgang Wein, Nassir Navab
PURPOSE: Cone-Beam Computed Tomography (CBCT) is an important 3D imaging technology for orthopedic, trauma, radiotherapy guidance, angiography, and dental applications. The major limitation of CBCT is the poor image quality due to scattered radiation, truncation, and patient movement. In this work, we propose to incorporate information from a co-registered Red-Green-Blue-Depth (RGBD) sensor attached near the detector plane of the C-arm to improve the reconstruction quality, as well as correcting for undesired rigid patient movement...
March 25, 2017: International Journal of Computer Assisted Radiology and Surgery
https://www.readbyqxmd.com/read/28343123/estimation-of-red-light-running-frequency-using-high-resolution-traffic-and-signal-data
#3
Peng Chen, Guizhen Yu, Xinkai Wu, Yilong Ren, Yueguang Li
Red-light-running (RLR) emerges as a major cause that may lead to intersection-related crashes and endanger intersection safety. To reduce RLR violations, it's critical to identify the influential factors associated with RLR and estimate RLR frequency. Without resorting to video camera recordings, this study investigates this important issue by utilizing high-resolution traffic and signal event data collected from loop detectors at five intersections on Trunk Highway 55, Minneapolis, MN. First, a simple method is proposed to identify RLR by fully utilizing the information obtained from stop bar detectors, downstream entrance detectors and advance detectors...
March 23, 2017: Accident; Analysis and Prevention
https://www.readbyqxmd.com/read/28342596/the-practical-application-of-scintillation-dosimetry-in-small-field-photon-beam-radiotherapy
#4
Elisa Burke, Daniela Poppinga, Andreas A Schönfeld, Dietrich Harder, Björn Poppe, Hui Khee Looe
Plastic scintillation detectors are a new instrument of stereotactic photon-beam dosimetry. The clinical application of the plastic scintillation detector Exradin W1 at the Siemens Artiste and Elekta Synergy accelerators is a matter of current interest. In order to reduce the measurement uncertainty, precautions have to be taken with regard to the geometrical arrangement of the scintillator, the light-guide fiber and the photodiode in the radiation field. To determine the "Cerenkov light ratio" CLR with a type A uncertainty below 1%, the Cerenkov calibration procedure for small-field measurements based on the two-channel spectral method was used...
March 22, 2017: Zeitschrift Für Medizinische Physik
https://www.readbyqxmd.com/read/28342380/optimization-of-the-compton-camera-for-measuring-prompt-gamma-rays-in-boron-neutron-capture-therapy
#5
Chun-Hui Gong, Xiao-Bin Tang, Di-Yun Shu, Hai-Yan Yu, Chang-Ran Geng
Optimization of the Compton camera for measuring prompt gamma rays (0.478MeV) emitted during boron neutron capture therapy (BNCT) was performed with Geant4. The parameters of the Compton camera were determined as follows: 3cm thick - 10cm wide scatter detector (Silicon), 10cm thick - 10cm wide absorber detector (Germanium), and 1cm distance between the scatter and absorber detectors. For a typical brain tumor treatment, the overall detection efficiency of the optimized Compton camera was approximately 0.1425% using the Snyder's head phantom with a sphere tumor (4cm diameter and ~1cm depth)...
March 19, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28342327/influence-of-terrestrial-radionuclides-on-environmental-gamma-exposure-in-a-uranium-deposit-in-para%C3%A3-ba-brazil
#6
José Araújo Dos Santos Júnior, Romilton Dos Santos Amaral, Rômulo Simões Cezar Menezes, Juan Reinaldo Estevez Álvarez, Josineide Marques do Nascimento Santos, Zahily Herrero Fernández, Jairo Dias Bezerra, Alberto Antônio da Silva, Kennedy Francys Rodrigues Damascena, José de Almeida Maciel Neto
One of the main natural uranium deposits in Brazil is located in the municipality of Espinharas, in the State of Paraíba. This area may present high levels of natural radioactivity due to the presence of these radionuclides. Since this is a populated area, there is need for a radioecological dosimetry assessment to investigate the possible risks to the population. Based on this problem, the objective of this study was to estimate the environmental effective dose outdoors in inhabited areas influenced by the uranium deposit, using the specific activities of equivalent uranium, equivalent thorium and (40)K and conversion factors...
March 22, 2017: Ecotoxicology and Environmental Safety
https://www.readbyqxmd.com/read/28340391/optimization-of-the-marinelli-beaker-dimensions-using-genetic-algorithm
#7
Seyed Mehrdad Zamzamian, Seyed Abolfazl Hosseini, Mohammad Samadfam
A computational code, based on the genetic algorithm and MCNPX version 2.6 code was developed and used to investigate the effects of some important parameters of HPGe detector (such as Al cap thickness, dead-layer thickness and Ge hole size) on optimum dimensions of marinelli beaker. In addition, the effects of detector material on optimal beaker dimensions were also investigated. Finally, the optimized beaker dimensions at various beaker volumes (300, 500, 700, 1000 and 1500 cm(3)) were determined for some conventional Ge detectors with different crystal sizes (16 sizes)...
March 21, 2017: Journal of Environmental Radioactivity
https://www.readbyqxmd.com/read/28340363/benchmark-integral-neutron-experiments-for-fe-be-and-c-with-dt-neutron-by-liquid-scintillation-detector
#8
He Tie, Zheng Pu, Xiao Jun, Zhu Chuanxin, Yang Jian, Guo Haiping
The measurements of iron, beryllium and carbon sphere neutron leakage spectra using BC501A detector by DT neutron source are presented. The experiments were carried out in Institute of Nuclear Physics and Chemistry (INPC), China. Neutron leakage spectra in a wide energy range at angles of 0° and 30° from the direction of incident deuteron beam were obtained. The results show the leakage neutron flux decreases notably with the spherical shell increasing when neutron energy >10MeV. When neutron energy <6MeV the leakage neutron distribution tends to lower energy side with the shell increase...
December 20, 2016: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28339918/can-clinically-relevant-dose-errors-in-patient-anatomy-be-detected-by-gamma-passing-rate-or-modulation-complexity-score-in-volumetric-modulated-arc-therapy-for-intracranial-tumors
#9
Shingo Ohira, Yoshihiro Ueda, Masaru Isono, Akira Masaoka, Misaki Hashimoto, Masayoshi Miyazaki, Masaaki Takashina, Masahiko Koizumi, Teruki Teshima
We investigated whether methods conventionally used to evaluate patient-specific QA in volumetric-modulated arc therapy (VMAT) for intracranial tumors detect clinically relevant dosimetric errors. VMAT plans with coplanar arcs were designed for 37 intracranial tumors. Dosimetric accuracy was validated by using a 3D array detector. Dose deviations between the measured and planned doses were evaluated by gamma analysis. In addition, modulation complexity score for VMAT (MCSv) for each plan was calculated. Three-dimensional dose distributions in patient anatomy were reconstructed using 3DVH software, and clinical deviations in dosimetric parameters between the 3DVH doses and planned doses were calculated...
March 3, 2017: Journal of Radiation Research
https://www.readbyqxmd.com/read/28339273/search-for-electronic-recoil-event-rate-modulation-with-4-years-of-xenon100-data
#10
E Aprile, J Aalbers, F Agostini, M Alfonsi, F D Amaro, M Anthony, F Arneodo, P Barrow, L Baudis, B Bauermeister, M L Benabderrahmane, T Berger, P A Breur, A Brown, E Brown, S Bruenner, G Bruno, R Budnik, L Bütikofer, J Calvén, J M R Cardoso, M Cervantes, D Cichon, D Coderre, A P Colijn, J Conrad, J P Cussonneau, M P Decowski, P de Perio, P Di Gangi, A Di Giovanni, S Diglio, G Eurin, J Fei, A D Ferella, A Fieguth, D Franco, W Fulgione, A Gallo Rosso, M Galloway, F Gao, M Garbini, C Geis, L W Goetzke, Z Greene, C Grignon, C Hasterok, E Hogenbirk, R Itay, B Kaminsky, G Kessler, A Kish, H Landsman, R F Lang, D Lellouch, L Levinson, Q Lin, S Lindemann, M Lindner, J A M Lopes, A Manfredini, I Maris, T Marrodán Undagoitia, J Masbou, F V Massoli, D Masson, D Mayani, M Messina, K Micheneau, B Miguez, A Molinario, M Murra, J Naganoma, K Ni, U Oberlack, P Pakarha, B Pelssers, R Persiani, F Piastra, J Pienaar, V Pizzella, M-C Piro, G Plante, N Priel, L Rauch, S Reichard, C Reuter, A Rizzo, S Rosendahl, N Rupp, J M F Dos Santos, G Sartorelli, M Scheibelhut, S Schindler, J Schreiner, M Schumann, L Scotto Lavina, M Selvi, P Shagin, M Silva, H Simgen, M V Sivers, A Stein, D Thers, A Tiseni, G Trinchero, C Tunnell, H Wang, Y Wei, C Weinheimer, J Wulf, J Ye, Y Zhang
We report on a search for electronic recoil event rate modulation signatures in the XENON100 data accumulated over a period of 4 yr, from January 2010 to January 2014. A profile likelihood method, which incorporates the stability of the XENON100 detector and the known electronic recoil background model, is used to quantify the significance of periodicity in the time distribution of events. There is a weak modulation signature at a period of 431_{-14}^{+16} day in the low energy region of (2.0-5.8) keV in the single scatter event sample, with a global significance of 1...
March 10, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28339107/studies-of-signal-estimation-bias-in-grating-based-x-ray-multi-contrast-imaging
#11
Xu Ji, Yongshuai Ge, Ran Zhang, Ke Li, Guang-Hong Chen
PURPOSE: In grating-based x-ray multi-contrast imaging, signals of three contrast mechanisms-absorption contrast, differential phase contrast (DPC), and dark-field contrast-can be estimated from the same set of acquired data. The estimated sig-nals, N0 (related to absorption), N1 (related to dark-field), and ϕ (related to DPC) may be intrinsically biased. However, it is yet unclear how large these biases are and how the data acquisition parameters affect the biases in the extracted signals...
March 24, 2017: Medical Physics
https://www.readbyqxmd.com/read/28338948/comparing-measured-and-calculated-doses-in-interventional-cardiology-procedures
#12
M W Oliveira da Silva, L V Canevaro, J Hunt, B B D Rodrigues
Interventional cardiology requires complex procedures and can result in high doses and dose rates to the patient and medical staff. The many variables that influence the dose to the patient and staff include the beam position and angle, beam size, kVp, filtration, kerma-area product and focus-skin distance. A number of studies using the Monte Carlo method have been undertaken to obtain prospective dose assessments. In this paper, detailed irradiation scenarios were simulated mathematically and the resulting dose estimates were compared with real measurements made previously under very similar irradiation conditions and geometries...
March 16, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28338940/feasibility-study-for-identification-of-static-and-dynamic-exposure-using-ccd-imaging-technique-for-caso4-dy-tl-dosemeters
#13
Kshama Srivastava, Seepika Soin, B K Sapra, P Ratna, D Datta
The occupational exposure incurred by the radiation workers due to the external radiation is estimated using personal dosemeter placed on the human body during the monitoring period. In certain situations, it is required to determine whether the dosemeter alone was exposed accidentally/intentionally in radiation field (static exposure) or was exposed while being worn by a worker moving in his workplace (dynamic exposure). The present thermoluminscent (TL) based personnel monitoring systems are not capable of distinguishing between the above stated (static and dynamic) exposure conditions...
March 2, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28338068/a-portable-immunosensor-with-differential-pressure-gauges-readout-for-alpha-fetoprotein-detection
#14
Qingping Wang, Rongjie Li, Kang Shao, Yue Lin, Weiqiang Yang, Longhua Guo, Bin Qiu, Zhenyu Lin, Guonan Chen
A portable, affordable and simple detector is requested in a "Point-of-Care-Testing" (POCT) system. In this study, we exploited the potentialities of Differential Pressure Gauge (DPG) to the orientation of POCT technology. Alpha fetoprotein (AFP) was chosen as a model analyte that could specifically recognized by its antigen, and a tiny outfits equipped with a DPG was employed as the signal readout. Pt/SiO2 nanospheres were synthesized and modified with the detection antibody. In the presence of target, a sandwich of immunocomplex specifically formed and the Pt/SiO2 had been modified on the capture antibody...
March 24, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28337501/behavior-of-thiophanate-methyl-and-propiconazole-in-grape-and-mango-fruits-under-the-egyptian-field-conditions
#15
Amira Sh Soliman, Rania M A Helmy, Islam N Nasr, Mohamed S Abbas, Hend A Mahmoud, Wayne Jiang
This research aims at determining residues of thiophanate methyl and propiconazole in grape and mango fruits as an indication for their persistence in this environmental compartment. Fruit extracts were analyzed for thiophanate methyl using High Performance Liquid Chromatography and using Gas Chromatography Electron Capture Detector (GC/ECD), respectively. The results indicated that propiconazole had a less environmental impact since propiconazole had shorter residue half-lives which were 1.24 and 1.19 days in grape and mango fruits, respectively, while thiophanate methyl had half-lives of 2...
March 23, 2017: Bulletin of Environmental Contamination and Toxicology
https://www.readbyqxmd.com/read/28337411/physiological-and-pathological-high-frequency-oscillations-have-distinct-sleep-homeostatic-properties
#16
Nicolás von Ellenrieder, François Dubeau, Jean Gotman, Birgit Frauscher
OBJECTIVE: The stage of sleep is a known modulator of high-frequency oscillations (HFOs). For instance, high amplitude slow waves during NREM sleep and the subtypes of REM sleep were shown to contribute to a better separation between physiological and pathological HFOs. This study investigated rates and spatial spread of the different HFO types (physiological and pathological ripples in the 80-250 Hz frequency band, and fast ripples above 250 Hz) depending on time spent in sleep across the different sleep cycles...
2017: NeuroImage: Clinical
https://www.readbyqxmd.com/read/28337396/development-of-a-miniature-mass-spectrometer-and-an-automated-detector-for-sampling-explosive-materials
#17
Yuichiro Hashimoto
The development of a robust ionization source using the counter-flow APCI, miniature mass spectrometer, and an automated sampling system for detecting explosives are described. These development efforts using mass spectrometry were made in order to improve the efficiencies of on-site detection in areas such as security, environmental, and industrial applications. A development team, including the author, has struggled for nearly 20 years to enhance the robustness and reduce the size of mass spectrometers to meet the requirements needed for on-site applications...
2017: Mass Spectrometry
https://www.readbyqxmd.com/read/28336966/an-integrated-h-g-scheme-identifying-areas-for-soil-remediation-and-primary-heavy-metal-contributors-a-risk-perspective
#18
Bin Zou, Xiaolu Jiang, Xiaoli Duan, Xiuge Zhao, Jing Zhang, Jingwen Tang, Guoqing Sun
Traditional sampling for soil pollution evaluation is cost intensive and has limited representativeness. Therefore, developing methods that can accurately and rapidly identify at-risk areas and the contributing pollutants is imperative for soil remediation. In this study, we propose an innovative integrated H-G scheme combining human health risk assessment and geographical detector methods that was based on geographical information system technology and validated its feasibility in a renewable resource industrial park in mainland China...
March 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28336946/real-time-observational-evidence-of-changing-asian-dust-morphology-with-the-mixing-of-heavy-anthropogenic-pollution
#19
Xiaole Pan, Itsushi Uno, Zhe Wang, Tomoaki Nishizawa, Nobuo Sugimoto, Shigekazu Yamamoto, Hiroshi Kobayashi, Yele Sun, Pingqing Fu, Xiao Tang, Zifa Wang
Natural mineral dust and heavy anthropogenic pollution and its complex interactions cause significant environmental problems in East Asia. Due to restrictions of observing technique, real-time morphological change in Asian dust particles owing to coating process of anthropogenic pollutants is still statistically unclear. Here, we first used a newly developed, single-particle polarization detector and quantitatively investigate the evolution of the polarization property of backscattering light reflected from dust particle as they were mixing with anthropogenic pollutants in North China...
March 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28336006/influence-of-the-integral-quality-monitor-transmission-detector-on-high-energy-photon-beams-a-multi-centre-study
#20
Bozidar Casar, Marlies Pasler, Sonja Wegener, David Hoffman, Cinzia Talamonti, Jianguo Qian, Ignasi Mendez, Denis Brojan, Bruce Perrin, Martijn Kusters, Richard Canters, Stefania Pallotta, Primoz Peterlin
PURPOSE: The influence of the Integral Quality Monitor (IQM) transmission detector on photon beam properties was evaluated in a preclinical phase, using data from nine participating centres: (i) the change of beam quality (beam hardening), (ii) the influence on surface dose, and (iii) the attenuation of the IQM detector. METHODS: For 6 different nominal photon energies (4 standard, 2 FFF) and square field sizes from 1×1cm(2) to 20×20cm(2), the effect of IQM on beam quality was assessed from the PDD20,10 values obtained from the percentage dose depth (PDD) curves, measured with and without IQM in the beam path...
March 20, 2017: Zeitschrift Für Medizinische Physik
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