Introduction: Electronic portal imaging devices (EPIDs) are fundamentally used for instantaneous verification of the patient set‐up, block shape, and leaf positions during radiation therapy. In radiotherapy, situations arise in which an inclined PTV must be treated mutually with adjacent nodal regions. This methodology is most widely used for matching tangential/lateral breas...

Introduction: Electronic portal imaging devices (EPIDs) could be used to dose verification of radiotherapy treatment plans. In vivo dose verification is performed to reduce differences found between dose delivered to the patient and the prescribed dose. The aim of this study was to perform a fast and efficient technique for the verification of delivered dose to the patient usin...

Dose distributions can often be significantly improved by modulating the two-dimensional intensity profile of the individual x-ray beams. One technique for delivering intensity modulated beams is dynamic multileaf collimation (DMLC). However, DMLC is complex and requires extensive quality assurance. In this paper a new method is presented for a pretreatment dosimetric verification of these inte...

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...

Introduction: Physical wedge as a useful tool has been utilized in radiotherapy to modify photon beam shape and intensity such that it distributes dose uniformly in tumor site and reduces hot points. Since during Linac commissioning dosimetric parameters like output factors and lateral dose profiles are measured only for symmetric open and wedged fields, so calculation the par...

Introduction: The use of electronic portal imaging devices (EPIDs) is a method for the dosimetric verification of radiotherapy plans both pretreatment and in-vivo. The aim of this study was to test a 2D EPID-based dosimetry algorithm for dose verification of some plans inside a homogenous and anthropomorphic phantom and in-vivo, as well. Materials and Methods: </strong...

PURPOSE Craniospinal irradiation poses technical difficulties that may be addressed with the use of the newer technologies that have become available over the past decade. The use of CT simulation allows improved target localisation and beam geometry definition while significantly reducing the treatment simulation time. We have developed a CT-based technique for whole CNS irradiation in the sup...

Introduction: The incidence of breast cancer increases with the rate of 1-2% at the world. Radiation therapy is one of the available choices for breast cancer treatment. The single isocentre half-beam block technique is considered as a standard technique to avoid hot and cold spots within the PTV. The major advantage of half beam technique is that the both contralateral breast...

Increasing use of high dose rate, flattening filter free (FFF), and/or small-sized field beams presents a significant challenge to the medical physics community. In this work, we develop a strategy of using a high spatial resolution and high frame rate amorphous silicon flat panel electronic portal imaging device (EPID) for dosimetric measurements of these challenging cases, as well as for conv...

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...