نتایج جستجو برای: polymer gel dosimetry

تعداد نتایج: 201784  

Journal: :Journal of Physics: Conference Series 2004

Azizollah Rahimi Bijan Hashemi, Mohammad Hassan Zahmatkesh Ramin Jaberi Shahab Sheibani

Introduction: Polymer gels are modern dosimeters providing three dimensional dose distributions. These dosimeters can be used in brachytherapy in which the tumor dimension is relatively small and the dose gradient is high. In this study, the ability of the MAGICA polymer gel was investigated for assessing the absolute dose values as well as the dose distribution of low dose rate (LDR) Ir-192 wi...

Asghar Mesbahi, Seyed-Salman Zakariaee

Introduction The purpose of the current study was to determine optical sensitivity of N-isopropyl acrylamide NIPAM and polyacrylamide gelatin and tetrakis hydroxymethyl phosphoniun chloride (PAGAT) polymer gels for different wavelength of visible light spectrum applied in optical computed tomography method. Materials and Methods NIPAM and PAGAT polymer gels with conventional formulations used f...

2008
Y. Mariappan S. L. Vieira J. P. Fernandes A. A. Carneiro M. Fatemi R. L. Ehman

Introduction: Magnetic resonance imaging dependent polymer gel dosimetry is a technique that offers unique advantages for implementing increasingly complex radiotherapy procedures, due to the high spatial resolution and volumetric dosimetry capabilities. The technique involves the estimation of radiation dose distribution based on the changes in MR relaxation parameters caused by radiation indu...

Journal: :iranian journal of medical physics 0
zeynab sanjabi m.sc. of radiation medicine dept., shahid beheshti university, tehran, iran. alireza kamali asl assistant professor, nuclear engineering dept., shahid beheshti university, tehran, iran mohammad hassan zahmatkesh associate professor, shahid beheshti university, evin, tehran, iran saeid bagheri m.sc. in medical physics, shahid beheshti university, tehran, iran

introduction: different dosimetric modalities (e.g., ionization chambers, semiconductors, tlds, radiographic films) often have some problems determining isodose curves and percentage depth doses in high dose gradient regions. research has been ongoing to develop portable high resolution dosimetry devices with accurate absolute dosimetry capabilities and easy data analysis. the ‘presage’ dosimet...

2017
M. Keshtkar M.H. Zahmatkesh A.R. Montazerabadi

BACKGROUND Polymer gel dosimeters combined with magnetic resonance imaging (MRI) can be used for dose verification of advanced radiation therapy techniques. However, the uncertainty of dose map measured by gel dosimeter should be known. The purpose of this study is to investigate the uncertainty related to calibration curve and MRI protocol for MAGIC (Methacrylic and Ascorbic acid in Gelatin In...

2007
Martin Lepage

1. Introduction Magnetic resonance imaging (MRI) can non-invasively and non-destructively probe the magnetization of hydrogen atoms on water molecules in large objects with a high spatial resolution, and in three dimensions. This unique combination of properties is exploited in polymer gel dosimetry since original gel dosimeters, in which viscosity changes were measured and related to the absor...

A. Takavar, A. Vaezzadeh, H.A. Nedaie, M. Keshtkar, M. Naderi, M.H. Zahmatkesh,

Background: Some tissues in human body are radiobiologically different from water and these inhomogeneity must be considered in dose calculation in order to achieve an accurate dose delivery. Dose verification in complex radiation therapy techniques, such as intensity‐modulated radiation therapy (IMRT) calls for volumetric, tissue equivalent and energy independent dosimeter. The purpose of this...

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