Results 221 to 230 of about 66,716 (273)

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
openaire   +2 more sources

Dosimetric investigation and portal dose image prediction using an amorphous silicon electronic portal imaging device

Medical Physics, 2001
A two step algorithm to predict portal dose images in arbitrary detector systems has been developed recently. The current work provides a validation of this algorithm on a clinically available, amorphous silicon flat panel imager. The high‐atomic number, indirect amorphous silicon detector incorporates a gadolinium oxysulfide phosphor scintillating ...
B M, McCurdy, K, Luchka, S, Pistorius
openaire   +2 more sources

Markerless Tumor Motion Tracking in Cine Images from Megavoltage Electronic Portal Imaging Device

Journal of the Korean Physical Society, 2019
Lung tumor motion is challenging for image guided radiation treatment (IGRT) with a margin reduction. Locating the tumor using megavoltage (MV) cine image from electronic portal imaging device (EPID) is one solution. In this study, tumor localization was
K. Cheong, Jai-Woong Yoon, Soah Park, Sei-Kwon Kang   +3 more
semanticscholar   +1 more source

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
openaire   +3 more sources

Transmission dosimetry with a liquid-filled electronic portal imaging device

International Journal of Radiation Oncology*Biology*Physics, 1996
To assess the accuracy of transmission dose rate measurements for various phantom-detector geometries, performed with an electronic portal imaging device (EPID) and to compare these transmission dose rate values with exit dose rate data.Transmission dose rate values on the central beam axis and beam profiles were measured with an EPID consisting of a ...
Essers, Marion, Boellaard, Ronald, Van Herk, Marcel, Lanson, Hugo, Mijnheer, Ben   +4 more
openaire   +3 more sources

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
openaire   +2 more sources

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
openaire   +4 more sources

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
openaire   +2 more sources

Verification of compensator thicknesses using a fluoroscopic electronic portal imaging device

Medical Physics, 1999
A method is presented for verification of compensator thicknesses using a fluoroscopic electronic portal imaging device (EPID). The method is based on the measured transmission through the compensator, defined by the ratio of the portal dose with the compensator in the beam and the portal dose without the compensator in the beam.
Pasma, KL (Kasper), Kroonwijk, M, Dieren, EB, Visser, AG (Andries), Heijmen, Ben   +4 more
openaire   +3 more sources

Portal dose image verification: the collapsed cone superposition method applied with different electronic portal imaging devices

Physics in Medicine and Biology, 2006
Two different commercial electronic portal imaging devices (EPIDs), one based on a liquid ion chamber matrix and the other based on a fluoroscopic CCD camera, were used to acquire readings that, through a calibration procedure, provided images proportional to the absolute dose to a virtual water slab located at the EPID plane. The transformation of the
Christina Vallhagen, Dahlgren, Karsten, Eilertsen, Trude Dahl, Jørgensen, Anders, Ahnesjö   +3 more
openaire   +2 more sources