Results 171 to 180 of about 7,739 (203)
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Compensator quality control with an amorphous silicon EPID
Medical Physics, 2003The 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
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Characterization of EPID software for VMAT transit dosimetry
Australasian Physical & Engineering Sciences in Medicine, 2018Dosimetry 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 +6 more
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Dose‐response characteristics of an amorphous silicon EPID
Medical Physics, 2005Electronic 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 +2 more
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Dosimetric IMRT verification with a flat‐panel EPID
Medical Physics, 2003A 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 +3 more
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Simplifying EPID dosimetry for IMRT treatment verification
Medical Physics, 2011Purpose: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 ...
Van Herk, Marcel; id_orcid 0000-0001-6448-898X +7 more
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Comparison of ghosting effects for three commercial EPIDs
Medical Physics, 2006Many 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.
Van Herk, Marcel; id_orcid 0000-0001-6448-898X +6 more
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A MODEL OF EPID SUPPORT ARM BACKSCATTER FOR IMPROVED IMRT AND ARC-IMRT VERIFICATION WITH EPID
Radiotherapy and Oncology, 2009P. Rowshan-Farzad +3 more
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