introduction polymer gel dosimeters offer a practical solution to 3d dose verification for conventional radiotherapy as well as intensity-modulated and stereotactic radiotherapy. in this study, egsnrc calculated and pagat polymer gel dosimeter measured dose profiles from single shot irradiation with 18 mm collimator of gamma knife in homogeneous and inhomogeneous phantoms were compared with eac...

*Corresponding author: Dr. Nasrollah Jabbari, Department of Medical Physics and Imaging, Faculty of Para medicine, Urmia University of Medical Sciences, Urmia, Iran Fax: +98 441 2770047 E-mail: [email protected] Background: Understanding of the incident electron energy and angular distributions from clinical electron accelerators (linacs) is important for dosimetry and treatment planning. Th...

PURPOSE To create a user friendly, accurate, real time computer simulator to facilitate the design of dual foil scattering systems for electron beams on radiotherapy accelerators. The simulator should allow for a relatively quick, initial design that can be refined and verified with subsequent Monte Carlo (MC) calculations and measurements. METHODS The simulator consists of an analytical algo...

Kilovoltage (kV) cone beam computed tomography (CBCT) images suffer from a substantial scatter contribution. In this study, Monte Carlo (MC) simulations are used to evaluate the scattered radiation present in projection images. These predicted scatter distributions are also used as a scatter correction technique. Images were acquired using a kV CBCT bench top system. The EGSnrc MC code was used...

Introduction: The aim of this study was to investigate the initial electron beam parameters for Monte Carlo model of 6MV photon beam produced by Siemens Oncor® linear accelerator.   Materials and Methods: In this study, the EGSnrc Monte Carlo user codes BEAMnrc and DOSXYZnrc were used. The beamnrc code were used for modelling of a 6 MV photon beam produced by...

background: accurate small radiation field dosimetry is essential in modern radiotherapy techniques such as stereotactic radiosurgery (srs) and intensity modulated radiotherapy (imrt). precise measurement of dosimetric parameters such as beam profile, percentage depth doses and output factor of these beams are complicated due to the electron disequilibrium and the steep dose gradients. in the p...

Locoregional treatment of breast cancer involves adjacent, half blocked fields matched at isocenter. The objective of this work is to study the dosimetric effects of the uncertainties in jaw positioning for such a case, and how a treatment planning protocol including adjacent field overlap of 1 mm affects the dose distribution. A representative treatment plan, involving 6 and 15 photon beams, f...

PURPOSE To quantify uncertainty reduction in small photon field dosimetry through characterization of ionization chambers and calibration conditions using detailed Monte Carlo methods benchmarked against NIST-traceable measurements. METHODS Phase space profiles were obtained using detailed EGSnrc Monte Carlo models for a Varian 6 MV photon linear accelerator, and a NIST-traceable cobalt-60 te...

A novel geometry has been proposed for a hybrid magnetic resonance imaging (MRI)-linac system in which a 6 MV linac is mounted on the open end of a biplanar, low field (0.2 T) MRI magnet on a single gantry that is free to rotate around the patient. This geometry creates a scenario in which the magnetic field vector remains fixed with respect to the incident photon beam, but moves with respect t...