abstractbackground: although electronic portal imaging devices (epids) have originally developed for positioning verification, they can also be used for dosimetric purposes. in the current work, the dose response of minimum detectable thickness of a scanning liquid filled ion chamber epid, slic-epid, and the variation of transmitted dose with the shift of inhomogeneity inside of phantom was als...

abstract background: for treatment verification in radiation therapy. several physical characteristics of scanningliquid filled ionization chamber epid (slic-epid) including: extra build-up layer,reproducibility and uniformity, and noise level were investigated.electronic portal imaging devices (epids) have found an outstanding positionmaterials and methods: equilibrium, 1-30 mm white water mat...

This study compares the EPID dosimetry algorithms of two commercial systems for pretreatment QA, and analyzes dosimetric measurements made with each system alongside the results obtained with a standard diode array. 126 IMRT fields are examined with both EPID dosimetry systems (EPIDose by Sun Nuclear Corporation, Melbourne FL, and Portal Dosimetry by Varian Medical Systems, Palo Alto CA) and th...

Purpose: To validate a locally fabricated phantom of Imatrixx-2D Array by comparing its results with ArcCheck phantom and comparing portal dosimetry measurements with the two phantom studies. Materials and Methods: Electronic Portal Imaging Devices and Epiqa software were used for portal dosimetry. An Imatrixx-2D array with a locally fabricated phantom and ArcCheck cylindrical phantom were used...

Introduction: Electronic portal imaging devices (EPIDs) are extensively used for dosimetric information of pre-treatment field verification and in-vivo dosimetry for Intensity Modulated Radiotherapy (IMRT). In the present work, we have implemented the newly developed portal dosimetry software using independent dose prediction algorithm EPIDose and evaluated this new tool for the pretreatment IM...

Portal dosimetry (PD) was performed for 181 fields from 14 IMRT plans of various clinical sites at gantry zero and source-to-detector distance (SDD) of 100 cm. PD was realized using aSi1000 electronic portal imaging device (EPID) and portal dose prediction (PDP) algorithm implemented in Eclipse treatment planning system (TPS). Agreement of PDP predicted and EPID measured photon fluence/dose dis...

While commissioning Varian's Portal Dose Image Prediction (PDIP) algorithm for portal dosimetry, an asymmetric radial response in the portal imager due to backscatter from the support arm was observed. This asymmetric response led to differences on the order of 2%-3% for simple square fields (< 20 × 20 cm2) when comparing the measured to predicted portal fluences. A separate problem was that...

The feasibility of using portal dosimetry (PD) to verify 6 MV flattening filter-free (FFF) IMRT treatments was investigated. An Elekta Synergy linear accelerator with an Agility collimator capable of delivering FFF beams and a standard iViewGT amorphous silicon (aSi) EPID panel (RID 1640 AL5P) at a fixed SSD of 160 cm were used. Dose rates for FFF beams are up to four times higher than for conv...