Results 171 to 180 of about 7,410 (208)

EPID in vivo Dosimetry

2018
Introduction: The most modern radiotherapy devices are equipped with an Electronic Portal Imaging Device (EPID) system which is located on opposite side of the machine’s head. EPID system is often used to setting up the position verification during or between radiotherapy sessions.
Mohammadi, Mahdi, Haghparast, Abbas
openaire   +1 more source

Characterization of EPID software for VMAT transit dosimetry

Australasian Physical & Engineering Sciences in Medicine, 2018
Dosimetry check (DC) is a commercial software that allows reconstruction of 3D dose distributions using transit electronic portal imaging device (EPID) images. In this work, we evaluated the suitability of DC software for volumetric modulated arc therapy (VMAT) transit dosimetry.
Marco Esposito, Andrea Bruschi, Paolo Bastiani, Alessandro Ghirelli, Silvia Pini, Serenella Russo, Giovanna Zatelli   +6 more
openaire   +2 more sources

In vivo dosimetry by an aSi‐based EPID

Medical Physics, 2006
A method for the in vivo determination of the isocenter dose, , and mid‐plane dose, , using the transmitted signal measured by 25 central pixels of an aSi‐based EPID is here reported. The method has been applied to check the conformal radiotherapy of pelvic tumors and supplies accurate in vivo dosimetry avoiding many of the disadvantages associated ...
Angelo, Piermattei, Andrea, Fidanzio, Gerardina, Stimato, Luigi, Azario, Luca, Grimaldi, Guido, D'Onofrio, Savino, Cilla, Mario, Balducci, Maria Antonietta, Gambacorta, Nicola, Di Napoli, Numa, Cellini   +10 more
openaire   +2 more sources

Quality assurance measurements of a-si epid performance

Medical Dosimetry, 2004
The performance stability of a Varian aS500 amorphous silicon (a-Si) electronic portal imaging device (EPID) was monitored over an 18-month period using a variety of standard quality assurance (QA) tests. The tests were selected to provide ongoing information about image quality and dose response from the time of EPID acceptance into clinical service ...
Geetha V, Menon, Ron S, Sloboda
openaire   +2 more sources

Compensator quality control with an amorphous silicon EPID

Medical Physics, 2003
The calibration and quality control of compensators is conventionally performed with an ion chamber in a water‐equivalent phantom. In our center, the compensator factor and four off‐axis fluence ratios are measured to verify the central axis beam modulation and orientation of the compensator. Here we report the investigation of an alternative technique
Geetha V, Menon, Ron S, Sloboda
openaire   +2 more sources

Dosimetric IMRT verification with a flat‐panel EPID

Medical Physics, 2003
A convolution‐based calibration procedure has been developed to use an amorphous silicon flat‐panel electronic portal imaging device (EPID) for accurate dosimetric verification of intensity‐modulated radiotherapy (IMRT) treatments. Raw EPID images were deconvolved to accurate, high‐resolution 2‐D distributions of primary fluence using a scatter kernel ...
B, Warkentin, S, Steciw, S, Rathee, B G, Fallone   +3 more
openaire   +2 more sources

Dose‐response characteristics of an amorphous silicon EPID

Medical Physics, 2005
Electronic portal imaging devices (EPIDs) were originally developed for the purpose of patient setup verification. Nowadays, they are increasingly used as dosimeters (e.g., for IMRT verification and linac‐specific QA). A prerequisite for any clinical dosimetric application is a detailed understanding of the detector's dose‐response behavior. The aim of
Peter, Winkler, Alfred, Hefner, Dietmar, Georg   +2 more
openaire   +2 more sources

Transit dosimetry in dynamic IMRT with an a-Si EPID

Medical & Biological Engineering & Computing, 2014
Using an amorphous silicon (a-Si) EPID for transit dosimetry requires detailed characterization of its dosimetric response in a variety of conditions. In this study, a measurement-based model was developed to calibrate an a-Si EPID response to dose for transit dosimetry by comparison with a reference ionization chamber. The ionization chamber reference
Mahsheed Sabet, Pejman Rowshan Farzad, Fred W. Menk, Peter B. Greer   +3 more
openaire   +2 more sources

Simplifying EPID dosimetry for IMRT treatment verification

Medical Physics, 2011
Purpose:Electronic portal imaging devices (EPIDs) are increasingly used for IMRT dose verification, both pretreatment andin vivo. In this study, an earlier developed backprojection model has been modified to avoid the need for patient‐specific transmission measurements and, consequently, leads to a faster procedure.Methods:Currently, the transmission ...
R, Pecharromán-Gallego, Anton, Mans, Jan-Jakob, Sonke, Joep C, Stroom, Igor, Olaciregui-Ruiz, Marcel, van Herk, Ben J, Mijnheer   +6 more
openaire   +2 more sources

Comparison of ghosting effects for three commercial EPIDs

Medical Physics, 2006
Many studies have reported dosimetric characteristics of amorphous silicon electronic portal imaging devices (EPIDs). Some studies ascribed a non‐linear signal to gain ghosting and image lag. Other reports, however, state the effect is negligible. This study compares the signal‐to‐monitor unit (MU) ratio for three different brands of EPID systems.
McDermott, LN, Nijsten, SMJJG, Sonke, J-J, Partridge, M, van Herk, M, Mijnheer, BJ   +5 more
openaire   +4 more sources