نتایج جستجو برای: electronic portal imaging device

تعداد نتایج: 1308923  

Journal: :Physics in medicine and biology 2015
Yiannis Roussakis Rongxiao Zhang Geoff Heyes Gareth Webster Suzannah Mason Stuart Green Brian Pogue Hamid Dehghani

The feasibility of real-time portal imaging during radiation therapy, through the Cherenkov emission (CE) effect is investigated via a medical linear accelerator (CyberKnife(®)) irradiating a partially-filled water tank with a 60 mm circular beam. A graticule of lead/plywood and a number of tissue equivalent materials were alternatively placed at the beam entrance face while the induced CE at t...

2000
Sophie Lavertu Louis-Martin Girouard Jean Pouliot

Purpose: The goals of this study were to evaluate the use of electronic portal imaging device (EPID) paper images as off-line veri®cation tools and to assess the feasibility of replacing portal ®lms by EPID printed images. Materials and methods: Electronic portal images were acquired using a video-based imaging system. After contrast enhancement, these images were printed and compared to portal...

2014
Song Gao Weiliang Du Peter Balter Peter Munro Andrew Jeung

The purpose of this study is to evaluate the accuracy and reproducibility of the IsoCal geometric calibration system for kilovoltage (kV) and megavoltage (MV) imagers on Varian C-series linear accelerators (linacs). IsoCal calibration starts by imaging a phantom and collimator plate using MV images with different collimator angles, as well as MV and kV images at different gantry angles. The sof...

2015
Iori Sumida Hajime Yamaguchi Hisao Kizaki Keiko Aboshi Mari Tsujii Yuji Yamada Masashi Yagi Kazuhiko Ogawa

Pretreatment dose verification with beam-by-beam analysis for intensity-modulated radiation therapy (IMRT) is commonly performed with a gantry angle of 0° using a 2D diode detector array. Any changes in multileaf collimator (MLC) position between the actual treatment gantry angle and 0° may result in deviations from the planned dose. We evaluated the effects of MLC positioning errors between th...

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