Introduction: Electronic portal imaging devices (EPIDs) could potentially be useful for intensity-modulated radiation therapy (IMRT) and VMAT QA. The data density, high resolution, large active area, and efficiency of the MV EPID make it an attractive option. However, EPIDs were designed as imaging devices, not dosimeters, and as a result they do not inherently measure dose in ...

In-vivo dosimetry techniques are currently being applied only by a few Centers because they require time-consuming implementation measurements, and workload for detector positioning and data analysis. The transit in-vivo dosimetry performed by the electronic portal imaging device (EPID) avoids the problem of solid-state detector positioning on the patient. Moreover, the dosimetric characterizat...

Amorphous silicon (a-Si) electronic portal imaging devices (EPIDs) are x-ray detectors frequently used in radiotherapy imaging and dosimetry applications. EPIDs employ a copper plate and gadolinium oxysulfide phosphor screen with an array of a-Si photodiodes to indirectly detect incident radiation. In this study, a previously developed Monte Carlo (MC) model of an aSi EPID has been extended for...

The electronic portal imaging device (EPID) has the potential to be used for in vivo dosimetry during radiation therapy as an additional dose delivery check. In this study we have extended a method developed by A. Piermattei and colleagues in 2006 that made use of EPID transit images (acquired during treatment) to calculate dose in the isocenter point. The extension allows calculation of two-di...

An electronic portal imaging device (EPID) is an effective detector for in vivo transit dosimetry. In fact, it supplies two-dimensional information, does not require special efforts to be used during patient treatment, and can supply data in real time. In the present paper, a new procedure has been proposed to improve the EPID in vivo dosimetry accuracy by taking into account the patient setup ...

The aim of this study was to demonstrate how dosimetry with an amorphous silicon electronic portal imaging device (a-Si EPID) replaced film and ionization chamber measurements for routine pre-treatment dosimetry in our clinic. Furthermore, we described how EPID dosimetry was used to solve a clinical problem. IMRT prostate plans were delivered to a homogeneous slab phantom. EPID transit images w...

PURPOSE The aim of this study is to investigate the performance and limitations of a real-time transit electronic portal imaging device (EPID) dosimetry system for error detection during dynamic intensity modulated radiation therapy (IMRT) treatment delivery. Sites studied are prostate, head and neck (HN), and rectal cancer treatments. METHODS The system compares measured cumulative transit E...

The aim in this study is to develop a generalized strategy for 3D dose verification of IMRT and VMAT planes using EPID transit images in combination with Monte Carlo (MC) simulations. An EPID-based dosimetric verification procedure was developed to convert EPID-measured transit images into 2D exit photon fluence by de-convoluting with the MC-simulated EPID response kernels. The present scatter ...

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...

In this paper the various approaches of EPID-based in vivo IMRT and VMAT dose verification, and their clinical implementation, are described. It will be shown that EPID-based in vivo dosimetry plays an important role in the total chain of verification procedures in a radiotherapy department. EPID-based dosimetry, in combination with in-room imaging, is a fast and accurate tool for 3D in vivo ve...