keyword
MENU ▼
Read by QxMD icon Read
search

Varian

keyword
https://www.readbyqxmd.com/read/28643753/dosimetric-characteristic-of-physical-wedge-versus-enhanced-dynamic-wedge-based-on-monte-carlo-simulations
#1
Seied Rabie Mahdavi, Ghazale Geraily, Ahmad Mostaar, Arman Zia, Golbarg Esmaili, Somayeh Farahani
AIM OF STUDY: Physical wedges (PWs) are widely used in radiotherapy to obtain tilted isodose curves, but they alter beam quality. Dynamic wedges (DWs) using moving collimator overcome this problem, but measuring their beam data is not simple. The main aim of this study is to obtain all dosimetric parameters of DWs produced by Varian 2100CD with Monte Carlo simulation and compare them to those from PWs. SUBJECTS AND METHODS: To simulate 6 MV photon beams equipped with PW and DW, BEAMnrc code was used...
April 2017: Journal of Cancer Research and Therapeutics
https://www.readbyqxmd.com/read/28643751/quick-efficient-and-effective-patient-specific-intensity-modulated-radiation-therapy-quality-assurance-using-log-file-and-electronic-portal-imaging-device
#2
Rajesh Kumar, H I Amols, M Lovelock, S D Sharma, D Datta
AIM: The aim of work is to explore a quick, efficient, and effective patient-specific intensity-modulated radiation therapy (IMRT) quality assurance (QA). MATERIALS AND METHODS: Software tools were developed to extract and analyze the multi-leaf collimator (MLC) leaf positions (LPs) from electronic portal imaging device (EPID) images for Varian C-series machine and TrueBeam, to extract useful data from MLC log file of C-series linear accelerator (LINAC), to extract useful information from the trajectory log binary file of TrueBeam LINAC, to compare LPs derived from EPID images with log file/trajectory log data, and to analyze IMRT treatment files using the MATLAB programming language...
April 2017: Journal of Cancer Research and Therapeutics
https://www.readbyqxmd.com/read/28640345/abundance-of-the-reef-building-petaloconchus-varians-gastropoda-vermetidae-on-intertidal-rocky-shores-at-ilha-grande-bay-southeastern-brazil
#3
André Breves, Maria Teresa M DE Széchy, Helena P Lavrado, Andrea O R Junqueira
The reef-building vermetid Petaloconchus varians occurs in the western Atlantic Ocean, from the Caribbean Sea to the southern coast of Brazil. The present study evaluated the abundance of P. varians on intertidal rocky shores in Ilha Grande Bay (Rio de Janeiro State), and characterized their reefs, describing the species density, besides the weight and the belt width of the reefs. Petaloconchus varians reefs were recorded at 25 sites, with rocky shores exposed to different wave action (very sheltered, sheltered, semi-exposed and exposed) and slopes (10° to 46°)...
April 2017: Anais da Academia Brasileira de Ciências
https://www.readbyqxmd.com/read/28636755/technical-note-combination-of-multiple-epid-imager-layers-improves-image-quality-and-tracking-performance-of-low-contrast-to-noise-objects
#4
Stephen Sf Yip, Joerg Rottmann, Haijian Chen, Daniel Morf, Rony Füglistaller, Josh Star-Lack, George Zentai, Ross Berbeco
PURPOSE: We hypothesized that combining multiple amorphous silicon flat panel layers increases photon detection efficiency in an electronic portal imaging device (EPID), improving image quality and tracking accuracy of low contrast targets during radiotherapy METHODS: The prototype imager evaluated in this study contained 4 individually programmable layers each with a copper converter layer, Gd2 O2 S scintillator and active-matrix flat panel imager (AMFPI). The imager was placed on a Varian TrueBeam linac and a Las Vegas phantom programmed with sinusoidal motion (peak-to-peak amplitude=20mm, Period=3...
June 21, 2017: Medical Physics
https://www.readbyqxmd.com/read/28625473/effect-of-dir-uncertainty-on-prostate-passive-scattering-proton-therapy-dose-accumulation
#5
Yoshitomo Abe, Noriyuki Kadoya, Kazuhiro Arai, Yoshiki Takayama, Takahiro Kato, Kanako Kimura, Takashi Ono, Tatsuya Nakamura, Hitoshi Wada, Yasuhiro Kikuchi, Keiichi Jingu
Deformable image registration (DIR) is important in dose accumulation. Currently, the impact of DIR-algorithm-associated uncertainties in proton therapy is unclear. Here, we quantify the effect of DIR uncertainties on prostate passive-scattering proton therapy (PSPT) dose accumulation. Ten patients with an intermediate risk for prostate cancer formerly treated by PSPT (PTV D95=78GyE) were studied. Dose distributions from all verification CT images (five images per patient) were warped and accumulated in the planning CT geometries with DIR...
June 15, 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28612590/treatment-planning-with-unflattened-as-compared-to-flattened-beams-for-bilateral-carcinoma-of-the-breast
#6
Suresh Tamilarasu, Madeswaran Saminathan, S K Sharma, Anjali P, Abhinav Dewan
Aim: To evaluate the plan quality of 6MV unflattened (UFB) and flattened beam (FB) photon energy using AAA dose calculation algorithms for volumetric arc therapy. Materials and Methods: Plans were generated for bilateral carcinoma of breast and the dose prescribed was 50.4Gy in 28 fractions. Two different plans were made for each patient using 6MV FB and 6MV UFB. Dose calculations were performed on an AAA dose calculation algorithm. Plans were generated on Eclipse TPS and were capable of being delivered with a true beam STx linear accelerator...
May 1, 2017: Asian Pacific Journal of Cancer Prevention: APJCP
https://www.readbyqxmd.com/read/28610700/computation-of-the-electron-beam-quality-formula-see-text-factors-for-the-ne2571-ne2571a-and-ne2581a-thimble-ionization-chambers-using-penelope
#7
F Erazo, L Brualla, A M Lallena
The quality correction factor [Formula: see text] for electron beams was calculated for three thimble ionization chambers, namely, NE2571, NE2571A and NE2581A. The Monte Carlo code PENELOPE was used to estimate the overall correction factor fc,Q of these chambers for electron beams with nominal energies ranging between 6 and 22MeV, corresponding to a Varian Clinac 2100 C/D. A (60)Co beam was used as reference quality Q0. Also eight monoenergetic electron beams reproducing the quality index R50 of the Clinac beams were considered...
June 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28610696/use-of-ptw-microdiamond-for-relative-dosimetry-of-unflattened-photon-beams
#8
Giacomo Reggiori, Antonella Stravato, Maria Pimpinella, Francesca Lobefalo, Vanessa De Coste, Antonella Fogliata, Pietro Mancosu, Fiorenza De Rose, Valentina Palumbo, Marta Scorsetti, Stefano Tomatis
PURPOSE: The increasing interest in SBRT treatments encourages the use of flattening filter free (FFF) beams. Aim of this work was to evaluate the performance of the PTW60019 microDiamond detector under 6MV and 10MVFFF beams delivered with the EDGE accelerator (Varian Medical System, Palo Alto, USA). A flattened 6MV beam was also considered for comparison. METHODS: Short term stability, dose linearity and dose rate dependence were evaluated. Dose per pulse dependence was investigated in the range 0...
June 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28610338/revision-of-the-genus-doryscus-jacoby-coleoptera-chrysomelidae-galerucinae
#9
Chi-Feng Lee
The genus Doryscus Jacoby, 1887 is revised. Twelve new species are described: D. indochinensis sp. nov. from China (Yunnan), India, Laos, Thailand, Vietnam; D. krausi sp. nov. from Laos and Thailand; D. kubani sp. nov., from China (Yunnan); D. geiseri sp. nov. from Singapore and Thailand; D. nepalensis sp. nov. from Bhutan, north India, and Nepal; D. luzonensis sp. nov., and D. mindanaoensis sp. nov. from Philippines; D. barclayi sp. nov., D. boreri sp. nov., D. javanensis sp. nov., and D. sumatrensis sp. nov...
May 19, 2017: Zootaxa
https://www.readbyqxmd.com/read/28608658/massilia-varians-isolated-from-a-clinical-specimen
#10
Jooyoung Cho, Keon Han Kim, Jung Ok Kim, Jun Sung Hong, Seok Hoon Jeong, Kyungwon Lee
We report a case of Massilia varians isolated from a deep finger wound following orthopedic surgery on an immunocompetent patient. The bacterium was identified by 16S rDNA sequence analysis. This is the first case of M. varians isolated from a clinical specimen since the first report in 2008.
May 24, 2017: Infection & Chemotherapy
https://www.readbyqxmd.com/read/28607652/simulation-of-therapeutic-electron-beam-tracking-through-a-non-uniform-magnetic-field-using-finite-element-method
#11
Mohammad Javad Tahmasebibirgani, Reza Maskani, Mohammad Ali Behrooz, Mansour Zabihzadeh, Hojatollah Shahbazian, Jafar Fatahiasl, Nahid Chegeni
INTRODUCTION: In radiotherapy, megaelectron volt (MeV) electrons are employed for treatment of superficial cancers. Magnetic fields can be used for deflection and deformation of the electron flow. A magnetic field is composed of non-uniform permanent magnets. The primary electrons are not mono-energetic and completely parallel. Calculation of electron beam deflection requires using complex mathematical methods. In this study, a device was made to apply a magnetic field to an electron beam and the path of electrons was simulated in the magnetic field using finite element method...
April 2017: Electronic Physician
https://www.readbyqxmd.com/read/28604797/a-human-inferred-germline-antibody-binds-to-an-immunodominant-epitope-and-neutralizes-zika-virus
#12
Diogo M Magnani, Cassia G T Silveira, Brandon C Rosen, Michael J Ricciardi, Núria Pedreño-Lopez, Martin J Gutman, Varian K Bailey, Helen S Maxwell, Aline Domingues, Lucas Gonzalez-Nieto, Vivian I Avelino-Silva, Mateus Trindade, Juliana Nogueira, Consuelo S Oliveira, Alvino Maestri, Alvina Clara Felix, José Eduardo Levi, Mauricio L Nogueira, Mauricio A Martins, José M Martinez-Navio, Sebastian P Fuchs, Stephen S Whitehead, Dennis R Burton, Ronald C Desrosiers, Esper G Kallas, David I Watkins
The isolation of neutralizing monoclonal antibodies (nmAbs) against the Zika virus (ZIKV) might lead to novel preventative strategies for infections in at-risk individuals, primarily pregnant women. Here we describe the characterization of human mAbs from the plasmablasts of an acutely infected patient. One of the 18 mAbs had the unusual feature of binding to and neutralizing ZIKV despite not appearing to have been diversified by affinity maturation. This mAb neutralized ZIKV (Neut50 ~ 2 μg/ml) but did not react with any of the four dengue virus serotypes...
June 2017: PLoS Neglected Tropical Diseases
https://www.readbyqxmd.com/read/28604585/development-and-validation-of-a-new-near-infrared-sensor-to-measure-polyethylene-glycol-peg-concentration-in-water
#13
Olivier Buzzi, Shengyang Yuan, Benjamin Routley
A near-infrared absorption based laser sensor has been designed and validated for the real-time measurement of polyethylene glycol (PEG) concentration. The wavelength was selected after the determination of the absorption spectrum of deionised water and PEG solutions using a Varian Cary 6000i spectrophotometer, in order to limit the influence of PEG molecular mass on the absorption measurement. With this new sensor, the water is treated as the attenuating species and the addition of PEG in water reduces the absorbance of the medium...
June 10, 2017: Sensors
https://www.readbyqxmd.com/read/28597229/couch-modelling-for-volumetric-modulated-arc-therapy-vmat
#14
Te-Yu Chyou, Friedlieb Lorenz
The aim of this work was to investigate the impact of the accuracy of a certain couch model on the overall accuracy of the dose calculation. For this purpose two models of the Varian Exact Couch (Varian Medical Systems, Palo Alto, CA, USA) for use in the planning of volumetric modulated arc therapy (VMAT) were created in Monaco 5.1 (Elekta, Stockholm, Sweden). The first was a simplistic model, with the relative electron densities (ED) of structures based entirely on CT Hounsfield units (HU). The second couch model was obtained by assigning the appropriate EDs to the relevant couch structures...
June 2017: Australasian Physical & Engineering Sciences in Medicine
https://www.readbyqxmd.com/read/28592531/use-of-a-recombinant-gamma-2-herpesvirus-vaccine-vector-against-dengue-virus-in-rhesus-monkeys
#15
Georg F Bischof, Diogo M Magnani, Michael Ricciardi, Young C Shin, Aline Domingues, Varian K Bailey, Lucas Gonzalez-Nieto, Eva G Rakasz, David I Watkins, Ronald C Desrosiers
Research on vaccine approaches that can provide long-term protection against dengue virus infection is needed. Here we describe the construction, immunogenicity, and preliminary information on protective capacity of recombinant, replication-competent rhesus monkey rhadinovirus (RRV), a persisting herpesvirus. One RRV construct expressed the non-structural protein 5 (NS5) while a second recombinant expressed a soluble variant of the E protein (E85) of dengue virus 2 (DENV2). Four rhesus macaques received a single vaccination with a mixture of both recombinant RRVs and were subsequently challenged 19 weeks later with 1 x 10(5) PFU of DENV2...
June 7, 2017: Journal of Virology
https://www.readbyqxmd.com/read/28583292/design-of-experiments-in-medical-physics-application-to-the-aaa-beam-model-validation
#16
S Dufreneix, C Legrand, C Di Bartolo, M Bremaud, J Mesgouez, T Tiplica, D Autret
PURPOSE: The purpose of this study is to evaluate the usefulness of the design of experiments in the analysis of multiparametric problems related to the quality assurance in radiotherapy. The main motivation is to use this statistical method to optimize the quality assurance processes in the validation of beam models. METHOD: Considering the Varian Eclipse system, eight parameters with several levels were selected: energy, MLC, depth, X, Y1 and Y2 jaw dimensions, wedge and wedge jaw...
June 2, 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28574219/optimization-of-the-dosimetric-leaf-gap-for-use-in-planning-vmat-treatments-of-spine-sabr-cases
#17
Nigel D Middlebrook, Bess Sutherland, Tanya Kairn
The dosimetric leaf gap (DLG) is a beam configuration parameter used in the Varian Eclipse treatment planning system, to model the effects of rounded MLC leaf ends. Measuring the DLG using the conventional sliding-slit technique has been shown to be produce questionable results for some volumetric modulated arc therapy (VMAT) treatments. This study therefore investigated the use of radiochromic film measurements to optimize the DLG specifically for the purpose of producing accurate VMAT plans using a flattening-filter-free (FFF) beam, for use in treating vertebral targets using a stereotactic (SABR, also known as SBRT) fractionation schedule...
June 2, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28545264/reduction-of-dose-to-the-contralateral-breast-by-superflab-use-in-radiation-therapy-for-mammary-carcinomas
#18
Akanksha Solanki, Athiyaman M, Hemalatha A, H S Kumar
Background: Radiation therapy is an integral part of multimodality treatment for locally advanced carcinoma of breast. Radiation doses to nearby critical normal structures like heart, lungs, and contralateral breast (CLB increases risk of second malignancies. In this study, we measured doses to the CLB and studied effects of a 1 cm thickness superflap. Materials and Methods: Fifty post-mastectomy carcinoma breast patients were included in the study.Radiation therapy of 50 Gy was planned in 25 fractions, 5 days a week, using the Eclipse Treatment Planning System version 8...
April 1, 2017: Asian Pacific Journal of Cancer Prevention: APJCP
https://www.readbyqxmd.com/read/28538723/genomic-epidemiology-reveals-multiple-introductions-of-zika-virus-into-the-united-states
#19
Nathan D Grubaugh, Jason T Ladner, Moritz U G Kraemer, Gytis Dudas, Amanda L Tan, Karthik Gangavarapu, Michael R Wiley, Stephen White, Julien Thézé, Diogo M Magnani, Karla Prieto, Daniel Reyes, Andrea M Bingham, Lauren M Paul, Refugio Robles-Sikisaka, Glenn Oliveira, Darryl Pronty, Carolyn M Barcellona, Hayden C Metsky, Mary Lynn Baniecki, Kayla G Barnes, Bridget Chak, Catherine A Freije, Adrianne Gladden-Young, Andreas Gnirke, Cynthia Luo, Bronwyn MacInnis, Christian B Matranga, Daniel J Park, James Qu, Stephen F Schaffner, Christopher Tomkins-Tinch, Kendra L West, Sarah M Winnicki, Shirlee Wohl, Nathan L Yozwiak, Joshua Quick, Joseph R Fauver, Kamran Khan, Shannon E Brent, Robert C Reiner, Paola N Lichtenberger, Michael J Ricciardi, Varian K Bailey, David I Watkins, Marshall R Cone, Edgar W Kopp, Kelly N Hogan, Andrew C Cannons, Reynald Jean, Andrew J Monaghan, Robert F Garry, Nicholas J Loman, Nuno R Faria, Mario C Porcelli, Chalmers Vasquez, Elyse R Nagle, Derek A T Cummings, Danielle Stanek, Andrew Rambaut, Mariano Sanchez-Lockhart, Pardis C Sabeti, Leah D Gillis, Scott F Michael, Trevor Bedford, Oliver G Pybus, Sharon Isern, Gustavo Palacios, Kristian G Andersen
Zika virus (ZIKV) is causing an unprecedented epidemic linked to severe congenital abnormalities. In July 2016, mosquito-borne ZIKV transmission was reported in the continental United States; since then, hundreds of locally acquired infections have been reported in Florida. To gain insights into the timing, source, and likely route(s) of ZIKV introduction, we tracked the virus from its first detection in Florida by sequencing ZIKV genomes from infected patients and Aedes aegypti mosquitoes. We show that at least 4 introductions, but potentially as many as 40, contributed to the outbreak in Florida and that local transmission is likely to have started in the spring of 2016-several months before its initial detection...
June 15, 2017: Nature
https://www.readbyqxmd.com/read/28516048/image-interpolation-improves-the-zonal-analysis-of-cartilage-t2-relaxation-in-mri
#20
Farid Badar, Yang Xia
BACKGROUND: This project aimed to investigate the improvement in the detection of osteoarthritis (OA) in cartilage by the interpolation of T2 images, in the situation when the native MRI resolution is insufficient to resolve the depth-dependent T2 characteristics in articular cartilage (AC). METHODS: Eighteen intact canine knee joints that were healthy or had mild (contralateral) or severe OA were T2-imaged in a 7T/20 cm MRI system at 200 µm/pixel resolution (macro-MRI)...
April 2017: Quantitative Imaging in Medicine and Surgery
keyword
keyword
47924
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"