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...

 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 al...

BACKGROUND In volumetric modulated arc therapy (VMAT), gantry angles, dose rate and the MLC positions vary with the radiation delivery. The quality assurance (QA) system should be able to catch the planning and machine errors. The aim of this study was to investigate the sensitivity of three VMAT QA systems to machine errors. METHODS Several types of potential linac machine errors unique to V...

PURPOSE The aim of this study is to evaluate the ability of transit dosimetry using commercial treatment planning system (TPS) and an electronic portal imaging device (EPID) with simple calibration method to verify the beam delivery based on detection of large errors in treatment room. METHODS AND MATERIALS Twenty four fields of intensity modulated radiotherapy (IMRT) plans were selected from...

A Varian Portal Dosimetry system was compared to an isocentrically mounted MapCHECK 2 diode array for volumetric modulated arc therapy (VMAT) QA. A Varian TrueBeam STx with an aS-1000 digital imaging panel was used to acquire VMAT QA images for 13 plans using four photon energies (6, 8, 10 and 15 MV). The EPID-based QA images were compared to the Portal Dose Image Prediction calculated in the V...

Purpose: The goals of this study were to evaluate the use of electronic portal imaging device (EPID) paper images as off-line veri®cation tools and to assess the feasibility of replacing portal ®lms by EPID printed images. Materials and methods: Electronic portal images were acquired using a video-based imaging system. After contrast enhancement, these images were printed and compared to portal...

Amaç: Bu çalışmanın amacı, Yoğunluk Ayarlı Radyoterapi (YART) planlarının hastaya özel kalite kontrolü için kullanılan film, in-vivo elektronik portal görüntüleme cihazları (Electronically Portal Imaging Devices-EPID) ve iki boyutlu (2B) detektörlerin hata tespit yeteneklerini karşılaştırmaktır. Yöntem: çalışmada, Alderson Rando fantom kullanılmıştır. İlk olarak, fantomun bilgisayarlı tomografi...

nowadays, the subject of vision metrology network design is local enhancement of the existing network. in the other words, it has changed from first to third order design concept. to improve the network, locally, some new camera stations should be added to the network in drawback areas. the accuracy of weak points is enhanced by the new images, if the related vision constraints are satisfied si...

Introduction: Radiation therapy is one of the methods of cancer treatment. In this method, it is necessary to avoid harming the healthy tissues of the patient which is in the vicinity of the target, as much as possible. Treatment verification is one of the most important steps of radiation therapy which has two usual methods, using Port film and EPID. The accuracy and precision of treatment in ...