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https://www.readbyqxmd.com/read/28721330/truebeam-radiosurgery-for-the-treatment-of-trigeminal-neuralgia-preliminary-results-at-a-single-institution
#1
Mena G Kerolus, Neilayan Sen, Sonal Mayekar, Alistar Templeton, Julius Turian, Aidnag Diaz, Lorenzo Munoz, Richard W Byrne, Sepehr Sani
INTRODUCTION: Radiosurgery is now an established method of satisfactory pain control in patients with trigeminal neuralgia (TN). The Varian Truebeam STx (Varian Medical Systems, Palo Alto, CA) linear accelerator (LINAC) system is an arc-based, frameless stereotactic radiosurgery system used for the treatment of TN. To our knowledge, there has been only one published series of patient histories that documents the use of a frameless LINAC system for the treatment of TN. We describe the treatment parameters, patient outcomes, and complications associated with the treatment of TN...
June 16, 2017: Curēus
https://www.readbyqxmd.com/read/28714067/evaluation-of-plastic-scintillator-detector-for-small-field-stereotactic-patient-specific-quality-assurance
#2
Yujiao Qin, Stephen J Gardner, Joshua Kim, Yimei Huang, Ning Wen, Anthony Doemer, Indrin J Chetty
PURPOSE: To evaluate the performance of a commercial plastic scintillator detector (PSD) for small-field stereotactic patient-specific quality assurance (QA) measurements using flattening-filter-free beam. METHODS: A total of ten spherical targets (volume range: [0.03cc-2cc]) were planned with two techniques: (1) Dynamic Conformal Arc (DCA-10 plans), and (2) Volumetric Modulated Arc Therapy (VMAT-10 plans). All plans were generated using Varian Eclipse treatment planning system, and AcurosXB v...
July 17, 2017: Medical Physics
https://www.readbyqxmd.com/read/28711479/identification-of-the-suitable-leaf-margin-for-liver-stereotactic-body-radiotherapy-with-flattening-filter-free-beams
#3
Toshiyuki Ogata, Hideki Nishimura, Hiroshi Mayahara, Kazuyuki Uehara, Takanobu Okayama
The purpose of this study is to identify the suitable leaf margin for liver stereotactic body radiotherapy (SBRT) with flattening filter-free (FFF) beams, as compared with that with flattening filter (FF) beams. SBRT treatment planning for 10 patients with liver cancer was performed using 10-MV FFF and FF beams obtained from a Varian TrueBeam (Varian Medical Systems, Palo Alto, CA) linear accelerator. Each plan was generated with the leaf margin to the planning target volume (PTV) ranging from -3 to 5 mm...
July 12, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/28711478/dosimetric-comparison-of-peripheral-nsclc-sbrt-using-acuros-xb-and-aaa-calculation-algorithms
#4
Chloe C H Ong, Khong Wei Ang, Roger C X Soh, Kah Ming Tin, Jerome H H Yap, James C L Lee, Christopher M Bragg
There is a concern for dose calculation in highly heterogenous environments such as the thorax region. This study compares the quality of treatment plans of peripheral non-small cell lung cancer (NSCLC) stereotactic body radiation therapy (SBRT) using 2 calculation algorithms, namely, Eclipse Anisotropic Analytical Algorithm (AAA) and Acuros External Beam (AXB), for 3-dimensional conformal radiation therapy (3DCRT) and volumetric-modulated arc therapy (VMAT). Four-dimensional computed tomography (4DCT) data from 20 anonymized patients were studied using Varian Eclipse planning system, AXB, and AAA version 10...
July 12, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/28708382/the-effects-of-temperature-and-hydrostatic-pressure-on-metal-toxicity-insights-into-toxicity-in-the-deep-sea
#5
Alastair Brown, Sven Thatje, Chris Hauton
Mineral prospecting in the deep sea is increasing, promoting concern regarding potential ecotoxicological impacts on deep-sea fauna. Technological difficulties in assessing toxicity in deep-sea species has promoted interest in developing shallow-water ecotoxicological proxy species. However, it is unclear how the low temperature and high hydrostatic pressure prevalent in the deep sea affect toxicity, and whether adaptation to deep-sea environmental conditions moderates any effects of these factors. To address these uncertainties we assessed the effects of temperature and hydrostatic pressure on lethal and sublethal (respiration rate, antioxidant enzyme activity) toxicity in acute (96-hour) copper and cadmium exposures, using the shallow-water ecophysiological model organism Palaemon varians...
July 14, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28706355/the-influence-of-acquisition-mode-on-the-dosimetric-performance-of-an-amorphous-silicon-electronic-portal-imaging-device
#6
Omemh Bawazeer, Sisira Herath, Siva Sarasanandarajah, Tomas Kron, Pradip Deb
AIMS: This study investigates the impact of cine acquisition mode on the dosimetric characteristics of a Varian aS500 amorphous silicon electronic portal imaging device (a-Si EPID). MATERIALS AND METHODS: The performance of an a-Si EPID operated in cine mode was assessed and compared to its performance when operated in an integrated mode and dose measurements using an ionization chamber. This study was conducted at different photon energies and the EPID performance was assessed as function of the delivered dose, dose rate, multileaf collimator speed, field size, phantom thickness, and intensity-modulated radiation therapy fields...
April 2017: Journal of Medical Physics
https://www.readbyqxmd.com/read/28706350/investigating-the-electronic-portal-imaging-device-for-small-radiation-field-measurements
#7
Arpita Agarwal, Nikhil Rastogi, K J Maria Das, S A Yoganathan, D Udayakumar, Shaleen Kumar
PURPOSE: With the advent of state-of-the-art treatment technologies, the use of small fields has increased, and dosimetry in small fields is highly challenging. In this study, the potential use of Varian electronic portal imaging device (EPID) for small field measurements was explored for 6 and 15 MV photon beams. MATERIALS AND METHODS: The output factors and profiles were measured for a range of jaw-collimated square field sizes starting from 0.8 cm × 0.8 cm to 10 cm × 10 cm using EPID...
April 2017: Journal of Medical Physics
https://www.readbyqxmd.com/read/28693020/propiedades-biomec%C3%A3-nicas-de-la-membrana-limitante-interna-tras-recibir-tratamiento-intrav%C3%A3-treo-con-ocriplasmina
#8
Franziska Vielmuth, Ricarda G Schumann, Volker Spindler, Armin Wolf, Renate Scheler, Wolfgang J Mayer, Paul B Henrich, Christos Haritoglou
Objetivo: Evaluar la rigidez de la membrana limitante interna (MLI) humana y evaluar los posibles cambios de las propiedades mecánicas tras administrar una inyección intravítrea de ocriplasmina para tratar la tracción vitreomacular. Métodos: Este estudio se compone de una serie de casos intervencionales y comparativos de 12 muestras de MLI extraídas mediante cirugía y obtenidas de forma consecutiva de 9 ojos de 9 pacientes después de someterse sin éxito a vitreólisis farmacológica con ocriplasmina...
2017: Ophthalmologica. Journal International D'ophtalmologie
https://www.readbyqxmd.com/read/28689765/unanswered-questions-in-contemporary-heart-failure
#9
Lauren G Gilstrap, David Snipelisky, Omar AbouEzzeddine, Justin Vader, Lauren Cooper, Jacob Kelley, Antonio Perez, Kenneth Varian, Anuradha Lala, Monica Shah, Lynne W Stevenson
Background The epidemiology of heart failure (HF) is changing. This study aims to describe questions that arise during the routine care of heart failure (HF) patients that are unanswered by the current literature and describe how the type and focus of these questions has changed over time. Methods Investigators from the NHLBI-sponsored Heart Failure Apprentice Network collected and categorized questions from 5 academic hospitals over 12 months. A total of 174 unanswered questions were collected and analyzed...
July 6, 2017: Journal of Cardiac Failure
https://www.readbyqxmd.com/read/28687122/evaluation-of-ex-vivo-9-4t-mri-in-post-surgical-specimens-from-temporal-lobe-epilepsy-patients
#10
Benjamin Y M Kwan, Fateme Salehi, Ryan Kope, Donald H Lee, Manas Sharma, Robert Hammond, Jorge G Burneo, David Steven, Terry Peters, Ali R Khan
PURPOSE: This study evaluates hippocampal pathology through usage of ultra-high field 9.4T ex-vivo imaging of resected surgical specimens in patients who have undergone temporal lobe epilepsy surgery. METHOD AND MATERIALS: This is a retrospective interpretation of prospectively acquired data. MRI scanning of resected surgical specimens from patients who have undergone temporal lobe epilepsy surgery was performed on a 9.4T small bore Varian MR magnet. Structural images employed a balanced steady-state free precession sequence (TrueFISP)...
July 4, 2017: Journal of Neuroradiology. Journal de Neuroradiologie
https://www.readbyqxmd.com/read/28670056/clinical-experience-with-machine-log-file-software-for-volumetric-modulated-arc-therapy-techniques
#11
Luis Alberto Vazquez-Quino, Claudia Ivette Huerta-Hernandez, Dharanipathy Rangaraj
Mobius FX, an add-on software module from Mobius Medical Systems™ for intensity-modulated radiation therapy (IMRT) quality assurance (QA), uses linac treatment logs to efficiently calculate and verify the 3D dose delivered to patients. An advantage of the Mobius FX module is that it does not require device positioning. In this study, we compared the Mobius FX with another QA option, ArcCheck, as well as with the treatment planning system (TPS) using 30 volumetric-modulated arc therapy (VMAT) plans planned and delivered on a Varian TrueBeam linac...
July 2017: Proceedings of the Baylor University Medical Center
https://www.readbyqxmd.com/read/28660543/therapeutic-strategies-targeting-inherited-cardiomyopathies
#12
REVIEW
Kenneth Varian, W H Wilson Tang
PURPOSE OF REVIEW: Cardiomyopathies due to genetic mutations are a heterogeneous group of disorders that comprise diseases of contractility, myocardial relaxation, and arrhythmias. Our goal here is to discuss a limited list of genetically inherited cardiomyopathies and the specific therapeutic strategies used to treat them. RECENT FINDINGS: Research into the molecular pathophysiology of the development of these cardiomyopathies is leading to the development of novel treatment approaches...
June 28, 2017: Current Heart Failure Reports
https://www.readbyqxmd.com/read/28657114/development-of-a-flattening-filter-free-multiple-source-model-for-use-as-an-independent-monte-carlo-dose-calculation-quality-assurance-tool-for-clinical-trials
#13
Austin M Faught, Scott E Davidson, Richard Popple, Stephen F Kry, Carol Etzel, Geoffrey S Ibbott, David S Followill
PURPOSE: The Imaging and Radiation Oncology Core - Houston (IROC-H) Quality Assurance Center (formerly the Radiological Physics Center) has reported varying levels of compliance from their anthropomorphic phantom auditing program. IROC-H studies have suggested that one source of disagreement between institution submitted calculated doses and measurement is the accuracy of the institution's treatment planning system dose calculations and heterogeneity corrections used. In order to audit this step of the radiation therapy treatment process, an independent dose calculation tool is needed...
June 28, 2017: Medical Physics
https://www.readbyqxmd.com/read/28652953/a-robust-and-affordable-table-indexing-approach-for-multi-isocenter-dosimetrically-matched-fields
#14
Amy Yu, Benjamin Fahimian, Lynn Million, Annie Hsu
Purpose  Radiotherapy treatment planning of extended volume typically necessitates the utilization of multiple field isocenters and abutting dosimetrically matched fields in order to enable coverage beyond the field size limits. A common example includes total lymphoid irradiation (TLI) treatments, which are conventionally planned using dosimetric matching of the mantle, para-aortic/spleen, and pelvic fields. Due to the large irradiated volume and system limitations, such as field size and couch extension, a combination of couch shifts and sliding of patients are necessary to be correctly executed for accurate delivery of the plan...
May 23, 2017: Curēus
https://www.readbyqxmd.com/read/28649722/comparison-of-dvh-based-plan-verification-methods-for-vmat-arccheck-3dvh-system-and-dynalog-based-dose-reconstruction
#15
Masahide Saito, Noriyuki Kadoya, Kiyokazu Sato, Kengo Ito, Suguru Dobashi, Ken Takeda, Hiroshi Onishi, Keiichi Jingu
The purpose of this study was comparing dose-volume histogram (DVH)-based plan verification methods for volumetric modulated arc therapy (VMAT) pretreatment QA. We evaluated two 3D dose reconstruction systems: ArcCHECK-3DVH system (Sun Nuclear corp.) and Varian dynalog-based dose reconstruction (DBDR) system, developed in-house. Fifteen prostate cancer patients (67.6 Gy/26 Fr), four head and neck cancer patient (66 Gy/33 Fr), and four esophagus cancer patients (60 Gy/30 Fr) treated with VMAT were studied...
June 26, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28643753/dosimetric-characteristic-of-physical-wedge-versus-enhanced-dynamic-wedge-based-on-monte-carlo-simulations
#16
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
#17
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
#18
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
#19
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
#20
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...
July 2017: Physica Medica: PM
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