نتایج جستجو برای: flattening filter

تعداد نتایج: 127226  

Journal: :International Journal of Radiation Oncology*Biology*Physics 2015

2013
Christopher L. Deufel John A. Antolak

A total skin electron (TSE) floor technique is presented for treating patients who are unable to safely stand for extended durations. A customized flattening filter is used to eliminate the need for field junctioning, improve field uniformity, and reduce setup time. The flattening filter is constructed from copper and polycarbonate, fits into the linac's accessory slot, and is optimized to exte...

2015
Ying Xiao Stephen F. Kry Richard Popple Ellen Yorke Niko Papanikolaou Sotirios Stathakis Ping Xia Saiful Huq John Bayouth James Galvin Fang‐Fang Yin

This report describes the current state of flattening filter-free (FFF) radiotherapy beams implemented on conventional linear accelerators, and is aimed primarily at practicing medical physicists. The Therapy Emerging Technology Assessment Work Group of the American Association of Physicists in Medicine (AAPM) formed a writing group to assess FFF technology. The published literature on FFF tech...

Journal: :Medical physics 2005
Michael K Fix Paul J Keall Jeffrey V Siebers

One limitation to the widespread implementation of Monte Carlo (MC) patient dose-calculation algorithms for radiotherapy is the lack of a general and accurate source model of the accelerator radiation source. Our aim in this work is to investigate the sensitivity of the photon-beam subsource distributions in a MC source model (with target, primary collimator, and flattening filter photon subsou...

Journal: :Medical physics 2012
T Karan V Moiseenko B Gill R Horwood A Minchinton

PURPOSE To establish a radiobiological basis for gated stereotactic body radiotherapy of primary and metastatic liver cancers using volumetric arc radiotherapy in a flattening filter free (FFF) mode. METHODS Human cervical carcinoma, SiHa, non-small cell lung carcinoma, H460, and Chinese hamster V79 cells were irradiated in a water bath with 6MV photons from a Varian TrueBeam linear accelerat...

Journal: :iranian journal of medical physics 0
m. t. bahreyni toosi professor, medical physics research center, bu-ali research institute, mashhad university of medical sciences, mashhad, iran. h. saberi ph.d. student in medical physics, mashhad university of medical sciences, mashhad, iran m. momen nezhad ph.d. student in medical physics, mashhad university of medical sciences, mashhad, iran

introduction:  skin  sparing  is  one  of  the  most  desirable  characteristics  of  high  energy  photon  beams. however, the photons emerging from the target of linacs are contaminated by secondary  electrons  as  a  result  of  their  interactions  with  air,  collimators,  flattening  filter  and  any  other  objects in their path. this phenomenon tends to increase the skin dose received b...

2017
Tomohiro Shimozato Yuichi Aoyama Takuma Matsunaga Katsuyoshi Tabushi

AIM This work investigated the dosimetric properties of a 10-MV photon beam emitted from a medical linear accelerator (linac) with no flattening filter (FF). The aim of this study is to analyze the radiation fluence and energy emitted from the flattening filter free (FFF) linac using Monte Carlo (MC) simulations. MATERIALS AND METHODS The FFF linac was created by removing the FF from a linac ...

Journal: :International Journal of Radiation Oncology*Biology*Physics 2017

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