background : this study was set to determine the optimal technique of breast cancer with supraclavicular fossa irradiation. methods : three techniques was compared in this study. techniques were two point symmetric (2p-sym), two point asymmetric (2p-asym) and single point (sp). in 2p-sym all of beams were symmetric, in 2p-asym tangential beams were symmetric and supra was asymmetric, in sp all ...

Electronic portal imaging devices (EPIDs) have been the preferred tools for verification of patient positioning for radiotherapy in recent decades. Since EPID images contain dose information, many groups have investigated their use for radiotherapy dose measurement. With the introduction of the amorphous-silicon EPIDs, the interest in EPID dosimetry has been accelerated because of the favourabl...

We proposed to perform a basic dosimetry commissioning on a new imager sys-tem, the Varian aS1200 electronic portal imaging device (EPID) and TrueBeam 2.0 linear accelerator for flattened (FF) and flattening filter-free (FFF) beams, then to develop an image-based quality assurance (QA) model for verification of the system delivery accuracy for intensity-modulated radiation therapy (IMRT) treat-...

PURPOSE To investigate the use of asymmetric collimators and a single isocenter for delivering a uniform, accurate dose of radiation to the head, neck, and supraclavicular lymph nodes. METHODS AND MATERIALS A linear accelerator with a pair of asymmetric collimators is required for this technique. An isocenter was placed at the junction of the lateral head and neck fields and the anterior supr...

This study evaluated the agreement of fiducial marker localization between two modalities--an electronic portal imaging device (EPID) and cone-beam computed tomography (CBCT)--using a low-dose, half-rotation scanning protocol. Twenty-five prostate cancer patients with implanted fiducial markers were enrolled. Before each daily treatment, EPID and half-rotation CBCT images were acquired. Transla...

Introduction: The most modern radiotherapy devices are equipped with an Electronic Portal Imaging Device (EPID) system which is located on opposite side of the machine’s head. EPID system is often used to setting up the position verification during or between radiotherapy sessions. Material and Methods: Various types of dosimeters have been used to setting up ...

background: the dosimetric performance of eclipse 6.5 three dimensional treatment planning system (3dtps) is evaluated by comparing the calculated and measured dose in two dimensions following the guide lines of american association for physicists in medicine task group 53. materials and methods: the calculations were performed by the 3dtps for symmetric as well as asymmetric fields for standar...

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...

Introduction: Electronic Portal Imaging Device (EPID) and Cone Beam Computed Tomography (CBCT) are the preferred tools of Image Guided Radiotherapy (IGRT) and Dose Guided Radiotherapy (DGRT) which have been used for Radiotherapy treatment verifications. As a result, the number of publications dealing with these two tools for radiation treatment verification has increased consi...