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https://www.readbyqxmd.com/read/29220821/predictive-capabilities-of-various-constitutive-models-for-arterial-tissue
#1
Florian Schroeder, Stanislav Polzer, Martin Slažanský, Vojtěch Man, Pavel Skácel
INTRODUCTION: Aim of this study is to validate some constitutive models by assessing their capabilities in describing and predicting uniaxial and biaxial behavior of porcine aortic tissue. METHODS: 14 samples from porcine aortas were used to perform 2 uniaxial and 5 biaxial tensile tests. Transversal strains were furthermore stored for uniaxial data. The experimental data were fitted by four constitutive models: Holzapfel-Gasser-Ogden model (HGO), model based on generalized structure tensor (GST), Four-Fiber-Family model (FFF) and Microfiber model...
November 22, 2017: Journal of the Mechanical Behavior of Biomedical Materials
https://www.readbyqxmd.com/read/29218841/improvement-of-conformal-arc-plans-by-using-deformable-margin-delineation-method-for-stereotactic-lung-radiotherapy
#2
Görkem Güngör, Melek Demir, Gökhan Aydın, Bülent Yapıcı, Banu Atalar, Enis Özyar
PURPOSE: Stereotactic body radiotherapy (SBRT) is an established treatment technique in the management of medically inoperable early stage non-small cell lung cancer (NSCLC). Different techniques such as volumetric modulated arc (VMAT) and three-dimensional conformal arc (DCA) can be used in SBRT. Previously, it has been shown that VMAT is superior to DCA technique in terms of plan evaluation parameters. However, DCA technique has several advantages such as ease of use and considerable shortening of the treatment time...
December 7, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/29205177/evaluation-of-latent-variances-in-monte-carlo-dose-calculations-with-varian-truebeam-photon-phase-spaces-used-as-a-particle-source
#3
Eyad Ali Alhakeem, Sergei F Zavgorodni
<b>Purpose:</b> To evaluate the latent variance (LV) of Varian TrueBeam photon phase-space files (PSF) for open 10x10 cm<sup>2</sup> and small stereotactic fields and estimate the number of phase spaces required to be summed up in order to maintain sub-percent latent variance in Monte Carlo (MC) dose calculations. <b>Method:</b> BEAMnrc/DOSXYZnrc software was used to transport particles from Varian phase-space files (PSFA) through the secondary collimators. Transported particles were scored into another phase-space located under the jaws (PSFB), or transported further through the cone collimators and scored straight below, forming PSFC...
December 5, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29181268/the-flip-flop-fungus-sign-an-fdg-pet-ct-sign-of-benignity
#4
Alex A Nagelschneider, Stephen M Broski, William P Holland, David E Midthun, Anne-Marie Sykes, Val J Lowe, Patrick J Peller, Geoffrey B Johnson
Benign granulomatous processes such as fungal infection may mimic metastatic lung cancer on FDG PET/CT. We found that these processes often have draining lymph node(s) with equal or greater FDG activity than associated lung nodule(s), a "flip-flop" of what is commonly seen in lung cancer. The aim of this study was to examine the utility of this "flip-flop fungus" (FFF) sign for diagnosing benign pulmonary disease. FDG PET/CT scans performed between 9/09-3/13 for the indications of pulmonary nodule or mass were reviewed...
2017: American Journal of Nuclear Medicine and Molecular Imaging
https://www.readbyqxmd.com/read/29174551/surgical-management-of-severe-osteoradionecrosis-of-the-mandibular-bone-by-using-double-free-flap-reconstruction
#5
Niklas Rommel, Marco Rainer Kesting, Nils Hagen Rohleder, Klaus-Dietrich Wolff, Jochen Weitz
PURPOSE: Osteoradionecrosis (ORN) of the jaws represents one of the most severe complications after primary or adjuvant radiation therapy (RT) of large head and neck tumors. In advanced ORN cases, surgical management is generally considered the therapy of choice. However, in several severe ORN patients with extensive bone and soft tissue defects, functional and aesthetic reconstruction represents a huge challenge for any surgeon, with an increased risk of post-operative wound healing disorders...
November 2, 2017: Journal of Cranio-maxillo-facial Surgery
https://www.readbyqxmd.com/read/29172266/dosimetric-validation-of-volumetric-modulated-arc-therapy-vmat-using-aapm-tg-119-benchmark-plans-in-an-upgraded-clinac-2100cd-for-flattening-filter-free-fff-photon-beams
#6
Ashokkumar Sangaiah, K M Ganesh, K Ramalingam, K Karthikeyan, N Jagadheeskumar
Background: Recently we have upgraded our Varian Clinac 2100CD with a 6MV FFF beam, this upgrade being the first of its kind in our country. Even though the dosimetric characteristics of FFF beams have been reported both in experimental and Monte Carlo studies, application in planning and delivery is complex. The aim of this study was to validate the commissioning of upgraded FFF beams dosimetrically using AAPM TG-119 bench mark plans for VMAT and to make a comparison with IMRT plans for both flattened filtered and FFF beams...
November 26, 2017: Asian Pacific Journal of Cancer Prevention: APJCP
https://www.readbyqxmd.com/read/29152898/tolerance-levels-of-ct-number-to-electron-density-table-for-photon-beam-in-radiotherapy-treatment-planning-system
#7
Minoru Nakao, Shuichi Ozawa, Kiyoshi Yamada, Katsunori Yogo, Fumika Hosono, Masahiro Hayata, Akito Saito, Kentaro Miki, Takeo Nakashima, Yusuke Ochi, Daisuke Kawahara, Yoshiharu Morimoto, Toru Yoshizaki, Hiroshige Nozaki, Kosaku Habara, Yasushi Nagata
The accuracy of computed tomography number to electron density (CT-ED) calibration is a key component for dose calculations in an inhomogeneous medium. In a previous work, it was shown that the tolerance levels of CT-ED calibration became stricter with an increase in tissue thickness and decrease in the effective energy of a photon beam. For the last decade, a low effective energy photon beam (e.g., flattening-filter-free (FFF)) has been used in clinical sites. However, its tolerance level has not been established yet...
November 20, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/29146931/a-novel-magnet-actuated-droplet-manipulation-platform-using-a-floating-ferrofluid-film
#8
Chao Yang, Gang Li
In this paper, we propose a novel but versatile magnet-actuated platform for droplet manipulation, which uses a ferrofluid film floating on a liquid surface as magnetic actuator. In contrast to the traditional magnetic droplet manipulation, this platform can handle droplets without magnetically functionalizing them. Due to the immiscibility of the oil-based ferrofluid and water, the droplets desired to be manipulated can stably rest on the surface of the floating ferrofluid film (FFF) under the action of surface tension, thereby offering possibilities for magnetically-driven droplet manipulations...
November 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29131344/aerrow-a-probe-format-graphite-calorimeter-for-absolute-dosimetry-of-high-energy-photon-beams-in-the-clinical-environment
#9
James Renaud, Arman Sarfehnia, Julien Bancheri, Jan Seuntjens
In this work, the design, operation, initial experimental evaluation, and characterization of a small-scale graphite calorimeter probe - herein referred to as the Aerrow - developed for routine use in the clinical environment, is described. Similar in size and shape to a Farmer type cylindrical ionization chamber, the Aerrow represents the first translation of calorimetry intended for direct use by clinical physicists in the radiotherapy clinic METHODS: Based on a numerically-optimized design obtained in previous work, a functioning Aerrow prototype capable of two independent modes of operation (quasi-adiabatic and isothermal) was constructed in-house...
November 13, 2017: Medical Physics
https://www.readbyqxmd.com/read/29130896/characterisation-of-flattening-filter-free-fff-beam-properties-for-initial-beam-set-up-and-routine-qa-independent-of-flattened-beams
#10
David Paynter, Steve J Weston, Vivian P Cosgrove, David I Thwaites
Objectives Flattening filter free beams have reached widespread use for clinical treatment deliveries. The usual methods for FFF beam characterisation for their quality assurance require the use of associated conventional flattened beams (cFF). Methods for QA of FFF without the need to use an associated cFF beams are presented and evaluated against current methods for both FFF and cFF beams. Methods Inflection point normalisation is evaluated against conventional methods for the determination of field size and penumbra for field sizes from 3cm x 3cm to 40cm x40cm at depths from dmax to 20cm in water for matched and unmatched FFF beams and for cFF beams...
November 13, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29126589/explicit-role-of-ionic-strength-in-retention-behavior-of-polystyrene-latex-particles-in-sedimentation-field-flow-fractionation-slip-boundary-model
#11
Kyunil Rah, Sujeong Han, Jaeyeong Choi, Chul Hun Eum, Seungho Lee
We investigate an explicit role of the ionic strength in the retention behaviors of polystyrene (PS) latex particles in sedimentation field-flow fractionation (SdFFF) by hinging upon the retention theory recently developed [1] asR=(Ro+vb(*))/(1+vb(*)). Here R is an experimental retention ratio, and Ro is the analytical expression of the standard retention theory based on the parabolic flow velocity. The reduced boundary velocityvb(*) is expressed in terms of the ionic strength I of the carrier liquid as vb(*)=vb,o(*)/(1+εI), where vb,o(*)=0...
November 7, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/29097022/three-stage-folded-forehead-flap-for-nasal-reconstruction-objective-and-subjective-measurements-of-aesthetic-and-functional-outcomes
#12
Warren Noel, Jean-Brice Duron, Samer Jabbour, Marc Revol, Sarra Mazouz-Dorval
BACKGROUND: The three-stage folded forehead flap (FFF) proved to be a simple and readily available method of lining replacement. To date, no clinical trial has evaluated the outcomes of the FFF on the nose shape and function. METHODS: Patients undergoing a full-thickness unilateral alar reconstruction with a forehead flap between January of 2010 and December of 2015 were included for analysis. Patients were divided into two groups: The FFF group included patients that had a unilateral alar reconstruction using a three-stage FFF; the standard forehead flap (SFF) group included patients that had a reconstruction using a two-stage forehead flap in combination with another method for lining reconstruction...
October 17, 2017: Journal of Plastic, Reconstructive & Aesthetic Surgery: JPRAS
https://www.readbyqxmd.com/read/29053107/spectral-imaging-using-clinical-megavoltage-beams-and-a-novel-multi-layer-imager
#13
Marios E Myronakis, Rony Fueglistaller, Joerg Rottmann, Yue-Houng Hu, Adam Wang, Paul Baturin, Pascal Huber, Daniel Morf, Josh M Star-Lack, Ross I Berbeco
We assess the feasibility of clinical megavoltage (MV) spectral imaging for material and bone separation with a novel multi-layer imager (MLI) prototype. The MLI provides higher detective quantum efficiency and lower noise than conventional electronic portal imagers. Simulated experiments were performed using a validated Monte Carlo model of the MLI to estimate energy absorption and energy separation between the MLI components. Material separation was evaluated experimentally using solid water and aluminum (Al), copper (Cu) and gold (Au) for 2...
October 20, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29048848/-present-situation-and-development-trends-of-asymmetrical-flow-field-flow-fractionation
#14
Qihui Liang, Di Wu, Bailing Qiu, Nanyin Han
Field-flow fractionation (FFF) is a kind of mature separation technologies in the field of bioanalysis, feasible of separating analytes with the differences of certain physical and chemical properties by the combination effects of two orthogonal force fields (flow field and external force field). Asymmetrical flow field-flow fractionation (AF4) is a vital subvariant of FFF, which applying a vertical flow field as the second dimension force field. The separation in AF4 opening channel is carried out by any composition carrier fluid, universally and effectively used in separation of bioparticles and biopolymers due to the non-invasivity feature...
September 8, 2017: Se Pu, Chinese Journal of Chromatography
https://www.readbyqxmd.com/read/29048329/measurement-and-modeling-of-out-of-field-doses-from-various-advanced-post-mastectomy-radiotherapy-techniques
#15
Jihyung Yoon, David Heins, Xiaodong Zhao, Mary Sanders, Rui Zhang
More and more advanced radiotherapy techniques have been adopted for post-mastectomy radiotherapies (PMRT). Patient dose reconstruction is challenging for these advanced techniques because they increase the low out-of-field dose area while the accuracy of out-of-field dose calculations by current commercial treatment planning systems (TPSs) is poor. We aim to measure and model the out-of-field radiation doses from various advanced PMRT techniques. PMRT treatment plans for an anthropomorphic phantom were generated, including volumetric modulated arc therapy (VMAT) with standard and flattening-filter-free (FFF) photon beams, mixed beam therapy, 4-field intensity modulated radiation therapy (IMRT), and Tomotherapy...
October 19, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29030203/characterization-and-clinical-evaluation-of-a-novel-2d-detector-array-for-conventional-and-flattening-filter-free-fff-imrt-pre-treatment-verification
#16
Yuvaraj Sekar, Johannes Thoelking, Miriam Eckl, Irakli Kalichava, Dwi Seno Kuncoro Sihono, Frank Lohr, Frederik Wenz, Hansjoerg Wertz
BACKGROUND AND PURPOSE: The novel MatriXX(FFF) (IBA Dosimetry, Germany) detector is a new 2D ionization chamber detector array designed for patient specific IMRT-plan verification including flattening-filter-free (FFF) beams. This study provides a detailed analysis of the characterization and clinical evaluation of the new detector array. MATERIAL AND METHODS: The verification of the MatriXX(FFF) was subdivided into (i) physical dosimetric tests including dose linearity, dose rate dependency and output factor measurements and (ii) patient specific IMRT pre-treatment plan verifications...
October 10, 2017: Zeitschrift Für Medizinische Physik
https://www.readbyqxmd.com/read/29017804/nanomanufacturing-through-microfluidic-assisted-nanoprecipitation-advanced-analytics-and-structure-activity-relationships
#17
Roberto Donno, Arianna Gennari, Enrique Lallana, Julio M Rios De La Rosa, Richard d'Arcy, Kevin Treacher, Kathryn Hill, Marianne Ashford, Nicola Tirelli
We have employed microfluidics (cross-shaped chip) for the preparation of drug-loaded poly(lactic acid-co-glycolic acid) (PLGA) nanoparticles. The polymer precipitates from an acetone solution upon its controlled laminar mixing (flow focusing) with an aqueous solution of a surfactant, allowing for an operator-independent, up-scalable and reproducible preparative process of nanoformulations. Firstly, using PEGylated surfactants we have compared batch and microfluidic processes, and showed the superior reproducibility of the latter and its strong dependency on the acetone/water ratio (flow rate ratio)...
October 7, 2017: International Journal of Pharmaceutics
https://www.readbyqxmd.com/read/29017734/anatomy-of-the-vasculature-of-the-lower-leg-and-harvest-of-a-fibular-flap-a-systematic-review
#18
REVIEW
A K Abou-Foul, A Fasanmade, S Prabhu, F Borumandi
The fibular free flap (FFF) is based on the peroneal artery, which has a consistent anatomy and makes a minimal contribution to the pedal circulation. However, certain anatomical variations in the vasculature of the leg might leave the peroneal artery with a major role in the perfusion of the foot, and to raise a FFF could lead to ischaemic complications. Our aim was to review the implications of anatomical variants on planning and harvest of a FFF. We systematically reviewed all relevant publications, and included 28 cases that described a dominant peroneal artery and FFF...
November 2017: British Journal of Oral & Maxillofacial Surgery
https://www.readbyqxmd.com/read/29016574/microvascular-free-flaps-in-oral-and-maxillofacial-reconstruction-following-cancer-ablation
#19
Santosh Kumar Yadav, Suraksha Shrestha
Microsurgical free flaps have become the first choice for reconstruction of oral and maxillofacial (OMF) defects after tumor resection. Till recently the pectoralis major myocutaneous flap (PMMC) was considered to be the benchmark for OMF reconstruction. This philosophy is changing fast with rapid advancement in reconstructive microsurgery. Years of innovation in reconstructive microsurgery has given us a reasonably good number of excellent flaps. Tremendous work has been put into producing some exceptionally brilliant research articles, sometimes contradicting each other...
September 8, 2017: Journal of Nepal Health Research Council
https://www.readbyqxmd.com/read/28990427/chew-on-this-not-all-first-finger-foods-are-created-equal
#20
Nicol Awadalla, Tammy Pham, Ruth Milanaik
The American Academy of Pediatrics (AAP) recommends when to start first finger foods (FFFs) and what types of foods to start with, but it is unclear whether products marketed as FFF comply with these recommendations. We evaluated FFF products for compliance with AAP recommendations and product safety using 41 adult product testers, who were asked to dissolve each product in their mouth. Product characteristics, comments pertaining to product safety, and time to dissolve each product were recorded. Only 2 products met all AAP criteria, and safety concerns were raised for an additional 2 products...
October 1, 2017: Clinical Pediatrics
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