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https://www.readbyqxmd.com/read/28297459/on-the-use-of-a-convolution-superposition-algorithm-for-plan-checking-in-lung-stereotactic-body-radiation-therapy
#1
Nicholas Hardcastle, Bradley M Oborn, Annette Haworth
Stereotactic body radiation therapy (SBRT) aims to deliver a highly conformal ablative dose to a small target. Dosimetric verification of SBRT for lung tumors presents a challenge due to heterogeneities, moving targets, and small fields. Recent software (M3D) designed for dosimetric verification of lung SBRT treatment plans using an advanced convolution-superposition algorithm was evaluated. Ten lung SBRT patients covering a range of tumor volumes were selected. 3D CRT plans were created using the XiO treatment planning system (TPS) with the superposition algorithm...
September 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297432/difference-in-dose-volumetric-data-between-the-analytical-anisotropic-algorithm-the-dose-to-medium-and-the-dose-to-water-reporting-modes-of-the-acuros-xb-for-lung-stereotactic-body-radiation-therapy
#2
Wambaka A Mampuya, Mitsuhiro Nakamura, Yoshinori Hirose, Takashi Ishigaki, Takashi Mizowaki, Masahiro Hiraoka
The purpose of this study was to evaluate the difference in dose-volumetric data between the analytical anisotropic algorithms (AAA) and the two dose reporting modes of the Acuros XB, namely, the dose to water (AXB-Dw) and dose to medium (AXB-Dm) in lung stereotactic body radiotherapy (SBRT). Thirty-eight plans were generated using the AXB-Dm in Eclipse Treatment Planning System (TPS) and then recalculated with the AXB-Dw and AAA, using identical beam setup. A dose of 50 Gy in 4 fractions was prescribed to the isocenter and the planning target volume (PTV) D95%...
September 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28287739/the-application-of-metabolic-profiling-to-abdominal-aortic-aneurysm-research
#3
Mahim Irfan Qureshi, Michele Greco, Panagiotis Andrea Vorkas, Elaine Holmes, Alun H Davies
Rationale Abdominal aortic aneurysm (AAA) is a complex disease posing diagnostic and therapeutic challenges. Metabonomics may aid in the diagnosis of AAA, determination of individualised risk, discovery of therapeutic targets, and improve understanding of pathogenesis. Objective To review the diversity and outcomes of existing AAA metabonomic research. Methods and Results A systematic review has been performed. Original research studies applying metabonomics to human aneurysmal disease were included. Seven relevant articles were identified: four studies were based on plasma/serum metabolite profiling, and three studies examined aneurysmal tissue...
March 13, 2017: Journal of Proteome Research
https://www.readbyqxmd.com/read/28280809/metal-organic-complex-functionalized-protein-nanopore-sensor-for-aromatic-amino-acids-chiral-recognition
#4
Yanli Guo, Aihua Niu, Feifei Jian, Ying Wang, Fujun Yao, Yongfeng Wei, Lei Tian, Xiaofeng Kang
Chiral recognition at single-molecule level for small active molecules is important, as exhibited by many nanostructures and molecular assemblies in biological systems, but it presents a significant challenge. We report a simple and rapid sensing strategy to discriminate all enantiomers of natural aromatic amino acids (AAA) using a metal-organic complex-functionalized protein nanopore, in which a chiral recognition element and a chiral recognition valve were equipped. A trifunctional molecule, heptakis-(6-deoxy-6-amino)-β-cyclodextrin (am7βCD), was non-covalently lodged within the nanopore of an α-hemolysin (αHL) mutant, (M113R)7-αHL...
March 10, 2017: Analyst
https://www.readbyqxmd.com/read/28273341/still-equivalent-for-dose-calculation-in-the-monte-carlo-era-a-comparison-of-free-breathing-and-average-intensity-projection-ct-datasets-for-lung-sbrt-using-three-generations-of-dose-calculation-algorithms
#5
Kristina Zvolanek, Rongtao Ma, Christina Zhou, Xiaoying Liang, Shuo Wang, Vivek Verma, Xiaofeng Zhu, Qinghui Zhang, Joseph Driewer, Chi Lin, Weining Zhen, Andrew Wahl, Su-Min Zhou, Dandan Zheng
PURPOSE: Inhomogeneity dose modeling and respiratory motion description are two critical technical challenges for lung stereotactic body radiotherapy, an important treatment modality for small size primary and secondary lung tumors. Recent studies revealed lung density-dependent target dose differences between Monte Carlo (Type-C) algorithm and earlier algorithms. Therefore, this study aimed to investigate the equivalence of the two most popular CT datasets for treatment planning, free breathing (FB) and average intensity projection (AIP) CTs, using Type-C algorithms, and comparing with two older generation algorithms (Type-A and Type-B)...
March 8, 2017: Medical Physics
https://www.readbyqxmd.com/read/28238422/a-reduced-order-model-for-wall-shear-stress-in-abdominal-aortic-aneurysms-by-proper-orthogonal-decomposition
#6
Gary Han Chang, Clemens M Schirmer, Yahya Modarres-Sadeghi
In this paper, we introduce a method to construct a Reduced-Order Model (ROM) to study the physiological flow and the Wall Shear Stress (WSS) conditions in Abdominal Aortic Aneurysms (AAA). We start the process by running a training case using Computational Fluid Dynamics (CFD) simulations with time-varying flow parameters, such that these parameters cover the range of parameters that we would like to consider in our ROM. We use the inflow angle as the variable parameter in the current study. Then we use the snapshot Proper Orthogonal Decomposition (POD) to construct the reduced-order bases, which are subsequently enhanced using a QR-factorization technique to satisfy the relevant fluid boundary conditions...
February 2, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/28222596/stacking-dependent-electronic-structure-of-trilayer-graphene-resolved-by-nanospot-angle-resolved-photoemission-spectroscopy
#7
Changhua Bao, Wei Yao, Eryin Wang, Chaoyu Chen, José Avila, Maria C Asensio, Shuyun Zhou
The crystallographic stacking order in multilayer graphene plays an important role in determining its electronic structure. In trilayer graphene, rhombohedral stacking (ABC) is particularly intriguing, exhibiting a flat band with an electric-field tunable band gap. Such electronic structure is distinct from simple hexagonal stacking (AAA) or typical Bernal stacking (ABA) and is promising for nanoscale electronics and optoelectronics applications. So far clean experimental electronic spectra on the first two stackings are missing because the samples are usually too small in size (μm or nm scale) to be resolved by conventional angle-resolved photoemission spectroscopy (ARPES)...
March 8, 2017: Nano Letters
https://www.readbyqxmd.com/read/28221665/totally-percutaneous-versus-surgical-cut-down-femoral-artery-access-for-elective-bifurcated-abdominal-endovascular-aneurysm-repair
#8
REVIEW
Madelaine Gimzewska, Alexander Ir Jackson, Su Ern Yeoh, Mike Clarke
BACKGROUND: Abdominal aortic aneurysms (AAAs) are a vascular condition with significant risk attached, particularly if they rupture. It is, therefore, critical to identify and repair these as an elective procedure before they rupture and require emergency surgery. Repair has traditionally been an open surgical technique that required a large incision across the abdomen. Endovascular abdominal aortic aneurysm repairs (EVARs) are now a common alternative. In this procedure, the common femoral artery is exposed via a cut-down approach and a graft introduced to the aneurysm in this way...
February 21, 2017: Cochrane Database of Systematic Reviews
https://www.readbyqxmd.com/read/28214511/identification-of-a-degradation-signal-sequence-within-substrates-of-the-mitochondrial-i-aaa-protease
#9
Anthony J Rampello, Steven E Glynn
The i-AAA protease is a component of the mitochondrial quality control machinery that regulates respiration, mitochondrial dynamics, and protein import. The protease is required to select specific substrates for degradation from among the diverse complement of proteins present in mitochondria, yet the rules that govern this selection are unclear. Here, we reconstruct the yeast i-AAA protease, Yme1p, to examine the in vitro degradation of two intermembrane space chaperone subunits, Tim9 and Tim10. Yme1p degrades Tim10 more rapidly than Tim9 despite high sequence and structural similarity, and loss of Tim10 is accelerated by the disruption of conserved disulfide bonds within the substrate...
February 16, 2017: Journal of Molecular Biology
https://www.readbyqxmd.com/read/28193267/abdominal-ultrasound-scanning-versus-non-contrast-computed-tomography-as-screening-method-for-abdominal-aortic-aneurysm-a-validation-study-from-the-randomized-dancavas-study
#10
Mads Liisberg, Axel C Diederichsen, Jes S Lindholt
BACKGROUND: Validating non-contrast-enhanced computed tomography (nCT) compared to ultrasound sonography (US) as screening method for abdominal aortic aneurysm (AAA) screening. METHODS: Consecutively attending men (n = 566) from the pilot study of the randomized Danish CardioVascular Screening trial (DANCAVAS trial), underwent nCT and US examination. Diameters were measured in outer-to-outer fashion. Sensitivity and specificity were done testing each modality against each other as reference standard...
February 14, 2017: BMC Medical Imaging
https://www.readbyqxmd.com/read/28163182/abdominal-pain-in-the-presence-of-small-abdominal-aortic-aneurysms-if-in-doubt-cut-it-out
#11
Efstratios Georgakarakos, Nikolaos Schoretsanitis, Georgios Koufopoulos, Konstantinos Paulou, Miltos K Lazarides
Although small (<5 cm) abdominal aortic aneurysms (AAA) have been associated with symptoms and indication for intervention scarcely, the clinicians should never exclude such potential association especially in the absence of other overt pathological findings. In such cases, a surgical exploration with consequent intervention, if feasible, should be justified to prevent a detrimental evolution in a dubious scenario. In this article, we present 2 cases of patients with small AAA presenting with severe abdominal pain...
February 3, 2017: Annals of Vascular Surgery
https://www.readbyqxmd.com/read/28144113/clinical-implications-of-eclipse-analytical-anisotropic-algorithm-and-acuros-xb-algorithm-for-the-treatment-of-lung-cancer
#12
Gangarapu Sri Krishna, Vuppu Srinivas, Palreddy Yadagiri Reddy
The aim of the present study was to investigate the dose-volume variations of planning target volume (PTV) and organs at risks (OARs) in 15 left lung cancer patients comparing analytical anisotropic algorithm (AAA) versus Acuros XB algorithm. Originally, all plans were created using AAA with a template of dose constraints and optimization parameters, and the patients were treated using intensity modulated radiotherapy. In addition, another set of plans was created by performing only dose calculations using Acuros algorithm without doing any reoptimization...
October 2016: Journal of Medical Physics
https://www.readbyqxmd.com/read/28129470/the-water-channel-aqp1-is-expressed-in-human-atherosclerotic-vascular-lesions-and-aqp1-deficiency-augments-angiotensin-ii-induced-atherosclerosis-in-mice
#13
Pamela Wintmo, Søren H Johansen, Pernille B L Hansen, Jes S Lindholt, Sigitas Urbonavicius, Lars M Rasmussen, Peter Bie, Boye L Jensen, Jane Stubbe
AIM: The water channel aquaporin 1 (AQP1) promotes endothelial cell migration. It was hypothesized that AQP1 promotes neovascularization and growth of atherosclerotic plaques. METHODS: AQP1 immunoreactivity and protein abundance was examined in human and murine atherosclerotic lesions and aortic aneurysms. Apolipoprotein E (ApoE) knockout (-/-) and AQP1-/-ApoE-/- were developed and fed western diet (WD) for 8 and 16 weeks to accelerate the atherosclerosis process...
January 27, 2017: Acta Physiologica
https://www.readbyqxmd.com/read/28102317/time-resolved-neutron-scattering-provides-new-insight-into-protein-substrate-processing-by-a-aaa-unfoldase
#14
Ziad Ibrahim, Anne Martel, Martine Moulin, Henry S Kim, Michael Härtlein, Bruno Franzetti, Frank Gabel
We present a combination of small-angle neutron scattering, deuterium labelling and contrast variation, temperature activation and fluorescence spectroscopy as a novel approach to obtain time-resolved, structural data individually from macromolecular complexes and their substrates during active biochemical reactions. The approach allowed us to monitor the mechanical unfolding of a green fluorescent protein model substrate by the archaeal AAA+ PAN unfoldase on the sub-minute time scale. Concomitant with the unfolding of its substrate, the PAN complex underwent an energy-dependent transition from a relaxed to a contracted conformation, followed by a slower expansion to its initial state at the end of the reaction...
January 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28087488/cathepsin-k-targeted-sub-micron-particles-for-regenerative-repair-of-vascular-elastic-matrix
#15
Brenton Jennewine, Jonathan Fox, Anand Ramamurthi
Abdominal Aortic Aneurysms (AAA) involve slow dilation and weakening of the aortic wall due to breakdown of structural matrix components, such as elastic fibers by chronically overexpressed matrix metalloproteinases (MMPs), primarily, MMPs-2 and -9. Auto-regenerative repair of disrupted elastic fibers by smooth muscle cells (SMCs) at the AAA site is intrinsically poor and together with chronic proteolysis prevents restoration of elastin homeostasis, necessary to enable AAA growth arrest or regression to a healthy state...
January 10, 2017: Acta Biomaterialia
https://www.readbyqxmd.com/read/28079254/pharmacological-treatment-of-vascular-risk-factors-for-reducing-mortality-and-cardiovascular-events-in-patients-with-abdominal-aortic-aneurysm
#16
REVIEW
Lindsay Robertson, Edmond Atallah, Gerard Stansby
BACKGROUND: Pharmacological prophylaxis has been proven to reduce the risk of cardiovascular events in individuals with atherosclerotic occlusive arterial disease. However, the role of prophylaxis in individuals with abdominal aortic aneurysm (AAA) remains unclear. Several studies have shown that despite successful repair, those people with AAA have a poorer rate of survival than healthy controls. People with AAA have an increased prevalence of coronary heart disease and risk of cardiovascular events...
January 12, 2017: Cochrane Database of Systematic Reviews
https://www.readbyqxmd.com/read/28048599/su-f-t-400-clinical-comparison-of-an-imrt-plan-computed-with-four-algorithms
#17
J Barbiere, A Ndlovu
PURPOSE: This work demonstrates clinical differences in a prostate IMRT plan DVH depending on which of four common algorithms is used for computation. Previous comparisons were often based on simple static or re-optimized IMRT plans which may not be clearly indicative of the clinical end result due solely to the computation algorithm. METHODS: A step and shoot prostate multiple field IMRT plan was created in Pinnacle with a Collapsed Cone Convolution Superposition (CCCS) algorithm...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048385/su-g-brc-07-evaluation-of-aaa-focal-spot-size-for-srs-planning-using-end-to-end-dosimetric-data
#18
S Gardner, A Doemer, B Miller, N Wen, I Chetty
PURPOSE: To use end-to-end dosimetric measurements with Gafchromic film to evaluate the effects of focal spot size parameter for small-field dose calculations using AAA for SRS lesions. METHODS: A total of 13 plans, corresponding to 7 patients previously treated with cranial SRS, were analyzed in this study (target volume range:[0.67cc,13.9cc]). The plans included DCA delivery (4 plans total) and VMAT delivery (9 plans total). All plans were mapped to a solid water phantom (15 cm thickness; isocenter and film plane at 7...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048314/su-d-204-07-retrospective-correlation-of-dose-accuracy-with-regions-of-local-failure-for-early-stage-lung-cancer-patients-treated-with-stereotactic-body-radiotherapy
#19
S Devpura, H Li, C Liu, C Fraser, M Ajlouni, B Movsas, I Chetty
PURPOSE: To correlate dose distributions computed using six algorithms for recurrent early stage non-small cell lung cancer (NSCLC) patients treated with stereotactic body radiotherapy (SBRT), with outcome (local failure). METHODS: Of 270 NSCLC patients treated with 12Gyx4, 20 were found to have local recurrence prior to the 2-year time point. These patients were originally planned with 1-D pencil beam (1-D PB) algorithm. 4D imaging was performed to manage tumor motion...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048103/su-g-brc-11-impact-of-dose-calculation-algorithms-on-lung-sbrt-treatments
#20
J Rosenfield, X Yang, X Dong, E Elder, K Higgins, A Dhabaan
PURPOSE: To investigate potential dosimetrical differences between the Acuros XB (AXB) and AAA dose calculation algorithms, with a specific focus on lung SBRT treatments involving inherently high degrees of anatomical heterogeneity, small field sizes, and varying tumor locations relative to critical structures. METHODS: A cohort of 20 SBRT patients treated in our clinic was selected to include varying lung tumor locations. For each patient, the Eclipse treatment planning system was employed to generate a lung SBRT plan using the AXB dose calculation algorithm, in addition to the AAA plan previously calculated for clinical use...
June 2016: Medical Physics
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