Results 201 to 210 of about 40,542 (246)

An electronic portal imaging device as a physics tool

Medical Dosimetry, 1997
An electronic portal imaging device (EPID) can be used not only to acquire megavoltage patient images but also to measure certain radiation beam parameters of the linear accelerator. EPID images can be used to verify field junctions, center of collimator rotation, or radiation vs. light field coincidence.
A, Curtin-Savard, E B, Podgorsak
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A quality control test for electronic portal imaging devices

Medical Physics, 1996
A quality control (QC) test suitable for routine daily use has been developed for video based electronic portal imaging devices. It provides an objective and quantitative test for acceptable image quality on the basis of the high contrast spatial resolution and the contrast‐to‐noise ratio (CNR).
R, Rajapakshe, K, Luchka, S, Shalev
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Portal dose measurements with electronic portal imaging devices

2000 IEEE Nuclear Science Symposium. Conference Record (Cat. No.00CH37149), 2002
Summary form only given. Measuring portal dose with an electronic portal imaging device in external beam radiotherapy can be used to perform routine dosimetric quality control checks on linear accelerators and to verify treatments (in vivo dosimetry). For both the fluoroscopic CCD camera based systems and the systems based on an array of liquid-filled ...
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Prospective clinical evaluation of an electronic portal imaging device

International Journal of Radiation Oncology*Biology*Physics, 1996
To determine whether the clinical implementation of an electronic portal imaging device can improve the precision of daily external beam radiotherapy.In 1991, an electronic portal imaging device was installed on a dual energy linear accelerator in our clinic.
J M, Michalski, M V, Graham, W R, Bosch, J, Wong, R L, Gerber, A, Cheng, A, Tinger, R K, Valicenti   +7 more
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Portal dose measurement in radiotherapy using an electronic portal imaging device (EPID)

Physics in Medicine and Biology, 1995
Physical characteristics of a commercially available electronic portal imaging device (EPID), relevant to dosimetric applications in high-energy photon beams, have been investigated. The EPID basically consists of a fluorescent screen, mirrors and a CCD camera.
B J, Heijmen, K L, Pasma, M, Kroonwijk, V G, Althof, J C, de Boer, A G, Visser, H, Huizenga   +6 more
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A method for controlling image acquisition in electronic portal imaging devices

Physics in Medicine and Biology, 2000
Certain types of camera-based electronic portal imaging devices (EPIDs) which initiate image acquisition based on sensing a change in video level have been observed to trigger unreliably at the beginning of dynamic multileaf collimation sequences. A simple, novel means of controlling image acquisition with an Elekta linear accelerator (Elekta Oncology ...
A G, Glendinning, S G, Hunt, D E, Bonnett   +2 more
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Dosimetric characteristics of a liquid-filled electronic portal imaging device

International Journal of Radiation Oncology*Biology*Physics, 1995
To determine the characteristics of a commercial electronic portal imaging device (EPID), based on a two-dimensional matrix of liquid-filled ionization chambers, for transmission dose measurements during patient treatment.Electronic portal imaging device measurements were performed in a cobalt-60 beam and two accelerator x-ray beams, and compared with ...
Van Herk, Marcel, Essers, M, Hoogervorst, B R, van Herk, M, Lanson, H, Mijnheer, B J   +5 more
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Quality assurance of electron beams using a Varian electronic portal imaging device

Physics in Medicine and Biology, 2013
The feasibility of utilizing an electronic portal imaging device (EPID) for the quality assurance of electron beams was investigated. This work was conducted on a Varian 2100iX machine equipped with an amorphous silicon (aS1000) portal imager. The linearity of the imager pixel response as a function of exposed dose was first confirmed.
Y, Wang, R, Heaton, B, Norrlinger, M, Islam   +3 more
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Characterization of a high-elbow, fluoroscopic electronic portal imaging device for portal dosimetry

Physics in Medicine and Biology, 1999
The application of a newly developed fluoroscopic (CCD-camera based) electronic portal imaging device (EPID) in portal dosimetry is investigated. A description of the EPID response to dose is presented in terms of stability, linearity and optical cross-talk inside the mechanical structure.
Boer, J.C.J. de, Heijmen, B.J.M., Pasma, K.L., Visser, A.G.   +3 more
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Electronic Portal Imaging Devices Using Artificial Neural Networks

2018
The aim of this work was to use the Artificial Neural Network (ANN) in External Beam Radiation Therapy (EBRT), especially for pre-treatment patient-specific quality assurance of Conformational Radiation Therapy (CRT) and Intensity-Modulated Radiation Therapy (IMRT) using Electronic Portal Imaging Device (EPID).
Chatrie, Frédéric, Younan, Fouad, Mazurier, Jocelyne, Simon, Luc, Vieillevigne, Laure, Ferrand, Régis, Barbeiro, Ana Rita, Le Lann, Marie-Véronique, V, Franceries, Xavier   +8 more
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