EPID images acquired in cine mode during arc therapy have inaccurate gantry angles recorded in their image headers. In this work, methods were developed to assess the accuracy of the gantry potentiometer for linear accelerators. As well, assessments of the accuracy of other, more accessible, sources of gantry angle information (i.e., treatment log files, analysis of EPID image headers) were inv...

Normalize the response of electronic portal imaging device (EPID) is the first step toward an EPID-based standardization of Linear Accelerator (linac) dosimetry quality assurance. In this study, we described an approach to generate two-dimensional (2D) pixel sensitivity maps (PSM) for EPIDs response normalization utilizing an alternative beam and dark-field (ABDF) image acquisition technique an...

INTRODUCTION Enhanced dynamic wedges (EDW) are known to increase drastically the radiation therapy treatment efficiency. This paper has the aim to compare linear array measurements of EDW with the calculations of treatment planning system (TPS) and the electronic portal imaging device (EPID) for 15 MV photon energy. MATERIALS AND METHODS The range of different field sizes and wedge angles (fo...

In this project, we investigated the use of an electronic portal imaging device (EPID), together with the treatment planning system (TPS) and MLC log files, to determine the delivered doses to the patient and evaluate the agreement between the treatment plan and the delivered dose distribution. The QA analysis results are presented for 15 VMAT patients using the EPID measurements, the ScandiDos...

PURPOSE To present a clinical case in which real-time intratreatment imaging identified an multileaf collimator (MLC) leaf to be consistently deviating from its programmed and logged position by >1 mm. METHODS An EPID-based exit-fluence dosimetry system designed to prevent gross delivery errors was used to capture cine during treatment images. The author serendipitously visually identified a ...

Abstract In this study, the feasibility of using electronic portal imaging device (EPID) as an analysing equipment for bolus material was evaluated in terms its dosimetric parameters. Seven superflab samples, 4 samples 0.5 cm (S1–S4) and 3 1 thickness (S5–S7), were analysed compared with tissue equivalent water phantom, which selected reference material. Gamma analysis method used to evaluate d...

Beams-eye-view imaging applications such as real-time soft-tissue motion estimation are hindered by the inherently low image contrast of electronic portal imaging devices (EPID) currently available for clinical use. We introduce and characterize a novel EPID design that provides substantially increased detective quantum efficiency (DQE), contrast-to-noise ratio (CNR) and sensitivity without deg...

AIM To compare the accuracy of radiotherapy set-up using an electronic portal imaging device (EPID) versus megavoltage cone beam computed tomography (MV-CBCT) in paediatric patients. MATERIALS AND METHODS In total, 204 pairs of EPID and MV-CBCT were carried out for 72 patients in the first 3 treatment days and weekly thereafter. RESULTS For the whole group, the mean systematic EPID set-up e...

PURPOSE A software program (MU-EPID) has been developed to perform patient specific IMRT pre-treatment QA verification using an electronic portal imaging device. METHODS The software converts measured images of intensity modulated beams delivered to an EPID, into fluence maps that can be imported in the treatment planning system. The dose can then be calculated in the patient anatomy and comp...