نتایج جستجو برای: physical penumbra dosimetric parameters dosxyznrc egsnrc

تعداد نتایج: 1201717  

الهی, مهدی, مهدوی, سید ربیع, هاشمی, بیژن,

Background and purpose: The human body is composed of various inhomogenous tissues with a variety of physical and radiological properties. These inhomogeneities could change isodose distributions, increase the probability of geometric errors, and eventually lead to missing of the target irradiation or incorrect isodose coverage in conformal radiation therapy (CRT) due to the uncertainties resul...

2012
Tayeb Allahverdi Pourfallah Mahmoud Allahverdi Mohammad Hasan Zahmatkesh

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...

2011
Sangroh Kim Haijun Song Ehsan Samei Fang‐Fang Yin Terry T. Yoshizumi

Dosimetry in kilovoltage cone beam computed tomography (CBCT) is a challenge due to the limitation of physical measurements. To address this, we used a Monte Carlo (MC) method to estimate the CT dose index (CTDI) and the dose length product (DLP) for a commercial CBCT system. As Dixon and Boone showed that CTDI concept can be applicable to both CBCT and conventional CT, we evaluated weighted CT...

2015
K. Hadad M. Zohrevand R. Faghihi A. Sedighi Pashaki

BACKGROUND HDR brachytherapy is one of the commonest methods of nasopharyngeal cancer treatment. In this method, depending on how advanced one tumor is, 2 to 6 Gy dose as intracavitary brachytherapy is prescribed. Due to high dose rate and tumor location, accuracy evaluation of treatment planning system (TPS) is particularly important. Common methods used in TPS dosimetry are based on computati...

2015
Emma Hedin Anna Bäck Roumiana Chakarova

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...

A Zeghari, R Cherkaoui El Moursli R Saaidi

Purpose: In the last years, some studies investigated dosimetric benefits of a free flattening filter for the photon mode in the radiotherapy field. This study aims to provide a theoretical study published and analysis of basic dosimetric properties for a Saturne 43 Linac head to implement free flattening filter beams clinically. Material and Methods: Thi...

Journal: :Medical physics 2003
J E Bayouth S M Morrill

The objective of this work was to measure the performance characteristics of a double-focus multileaf collimator (MLC) for intensity modulated radiation therapy (IMRT), specifically the variation in penumbra and leakage for narrow fields as a function of field position over a 20x27 cm space available for segmented MLC IMRT. Measurements were made with 6 MV x rays through a MLC containing 29 lea...

2007
PW Chin JP Giddy DG Lewis DW Walker

We present a computing framework for Monte Carlo simulation of radiation transport. In conformity with our belief that Monte Carlo studies should be anchored to physics but not to any particular code, we have enabled different Monte Carlo codes in this environment. The framework embraces the EGSnrc family, FLUKA, MCNP/MCNPX, GEANT4 and PENELOPE; dedicated and non-dedicated resources; shared and...

2013
Asghar Hadadi Mahdi Sadeghi Dariush Sardari Alireza Khanchi Alireza Shirazi

A glass seed consisting of the β--emitting radionuclide 90Y incorporated with radionuclide 153Sm as SPECT marker is proposed for potential application in brachytherapy in order to reduce the undesirable dose to healthy adjacent organs. The aim of this work is to determine the dosimetric characteristics, as suggested in the AAPM TG-60/TG-149 reports, for this seed using Monte Carlo simulation. M...

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