نتایج جستجو برای: fluence

تعداد نتایج: 3950  

Journal: :Optics express 2013
Fredrik Uhlén Daniel Nilsson Anders Holmberg Hans M Hertz Christian G Schroer Frank Seiboth Jens Patommel Vivienne Meier Robert Hoppe Andreas Schropp Hae Ja Lee Bob Nagler Eric Galtier Jacek Krzywinski Harald Sinn Ulrich Vogt

Focusing hard x-ray free-electron laser radiation with extremely high fluence sets stringent demands on the x-ray optics. Any material placed in an intense x-ray beam is at risk of being damaged. Therefore, it is crucial to find the damage thresholds for focusing optics. In this paper we report experimental results of exposing tungsten and diamond diffractive optics to a prefocused 8.2 keV free...

Journal: :iranian journal of medical physics 0
alireza vejdani-noghreiyan physics department, faculty of sciences, university of neyshabur, neyshabur, iran atiyeh ebrahimi-khankook physics department, faculty of sciences, university of neyshabur, neyshabur, iran

introduction international commission on radiological protection (icrp) has provided a comprehensive discussion on threshold dose for radiation-induced cataract in icrp publication 116. accordingly, various parts of the eye lens have different radio-sensitivities. recently, some studies have been performed to develop a realistic eye model with the aim of providing accurate estimation of fluence...

2009
Danielle Worthy Qiuwen Wu

Planning and delivery in HN-IMRT has been challenging for the Elekta linac because of numerous machine limitations. Direct aperture optimization (DAO) algorithms have had success in simplifying the planning process and improving plan quality. Commercial adaptations of DAO allow for widespread use in many clinics; however clinical validation of these methods is still needed. In this work we eval...

Journal: :Physics in medicine and biology 2013
H Palmans L Al-Sulaiti P Andreo D Shipley A Lühr N Bassler J Martinkovič J Dobrovodský S Rossomme R A S Thomas A Kacperek

The conversion of absorbed dose-to-graphite in a graphite phantom to absorbed dose-to-water in a water phantom is performed by water to graphite stopping power ratios. If, however, the charged particle fluence is not equal at equivalent depths in graphite and water, a fluence correction factor, kfl, is required as well. This is particularly relevant to the derivation of absorbed dose-to-water, ...

Journal: :Ophthalmology 2014
So Hyun Bae Jangwon Heo Cinoo Kim Tae Wan Kim Joo Young Shin Joo Yong Lee Su Jeong Song Tae Kwann Park Sang Woong Moon Hum Chung

PURPOSE To compare the efficacy and safety between low-fluence photodynamic therapy (PDT) and the intravitreal ranibizumab in the treatment of chronic central serous chorioretinopathy (CSC). DESIGN Prospective, randomized, single-center, parallel-arm, controlled trial. PARTICIPANTS Thirty-four eyes of 32 patients with chronic CSC with >6 months' duration of symptoms or recurrent CSC were ra...

2016
Iori Sumida Hajime Yamaguchi Indra J. Das Hisao Kizaki Keiko Aboshi Mari Tsujii Yuji Yamada Osamu Suzuki Yuji Seo Fumiaki Isohashi Kazuhiko Ogawa

Patient-specific quality assurance for intensity-modulated radiation therapy (IMRT) dose verification is essential. The aim of this study is to provide a new method based on the relative error distribution by comparing the fluence map from the treatment planning system (TPS) and the incident fluence deconvolved from the electronic portal imaging device (EPID) images. This method is validated fo...

Journal: :Medical physics 2012
Thomas A D Brown Kenneth R Hogstrom Diane Alvarez Kenneth L Matthews Kyungmin Ham

PURPOSE Ion chamber dosimetry is being used to calibrate dose for cell irradiations designed to investigate photoactivated Auger electron therapy at the Louisiana State University Center for Advanced Microstructures and Devices (CAMD) synchrotron facility. This study performed a dosimetry intercomparison for synchrotron-produced monochromatic x-ray beams at 25 and 35 keV. Ion chamber depth-dose...

Journal: :Radiation Oncology (London, England) 2007
Nicolini Giorgia Fogliata Antonella Vanetti Eugenio Clivio Alessandro Ammazzalorso Filippo Cozzi Luca

BACKGROUND The study summarised in this report aimed to investigate the interplay between fluence complexity, dose calculation algorithms, dose calculation spatial resolution and delivery characteristics (monitor units, effective field width and dose delivery against dose prediction agreement) was investigated. A sample set of complex planning cases was selected and tested using a commercial tr...

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