نتایج جستجو برای: finite element gafchromic film

تعداد نتایج: 481855  

2018
Mehrdad Shahmohammadi Beni Dragana Krstic Dragoslav Nikezic Kwan Ngok Yu

Commercially available radiochromic films are primarily designed for clinical X-ray dosimetry. These films change color upon exposures to radiation as a result of solid-state polymerization (SSP). Built on a previous model developed for SSP upon exposures to ultraviolet (UV) radiation, a new model was developed in the present work for X-ray-induced coloration in Gafchromic EBT3 films. Monte Car...

2015
B. Venkata Narayana Diwakar Reddy

A comprehensive method of theoretical analysis for finite Squeeze Film Damper using finite element method is presented. The modified Reynolds equation in the film is solved using the finite element discretization. A Galerkin variational method is applied for solving modified Reynolds equation to determine the pressures as well as load carrying capacities. The pressure distribution and load carr...

2014
Volker Rudat Alaa Nour Abdul Aziz Alaradi Adel Mohamed Saleh Altuwaijri

PURPOSE The purpose of this study was to compare the surface dose of 7-field IMRT (7 F-IMRT), tangential beam IMRT (TB-IMRT), and tangential beam 3D-CRT (3D-CRT) of breast cancer patients receiving adjuvant radiotherapy by means of in vivo GafChromic film dosimetry. MATERIAL AND METHODS Breast cancer patients receiving adjuvant radiotherapy of the whole breast or the chest wall were eligible ...

2016
Toshizo Katsuda Rumi Gotanda Tatsuhiro Gotanda Takuya Akagawa Nobuyoshi Tanki Tadao Kuwano Kouichi Yabunaka

This study investigates an X-ray dose measurement method for computed tomography using Gafchromic films. Nonuniformity of the active layer is a major problem in Gafchromic films. In radiotherapy, nonuniformity error is reduced by applying the double-exposure technique, but this is impractical in diagnostic radiology because of the heel effect. Therefore, we propose replacing the X-rays in the d...

2007
Robert Y.L. Chu Tin Lam Yongguang Liang

The location and field size of the incident X-ray beam in panoramic dental radiography cannot be ascertained visually most of the time. However, these parameters are needed for quality control and dosimetry determination. To alleviate this problem, we tested GafChromic XR-QA film on two panoramic systems. For each system, we used the length of a cross-sectional image of the incident beam and th...

2017
Mohammad Javad Tahmasebibirgani Reza Maskani Mohammad Ali Behrooz Mansour Zabihzadeh Hojatollah Shahbazian Jafar Fatahiasl Nahid Chegeni

INTRODUCTION In radiotherapy, megaelectron volt (MeV) electrons are employed for treatment of superficial cancers. Magnetic fields can be used for deflection and deformation of the electron flow. A magnetic field is composed of non-uniform permanent magnets. The primary electrons are not mono-energetic and completely parallel. Calculation of electron beam deflection requires using complex mathe...

2012
Chris J. Mart Howard R. Elson Michael A. S. Lamba

Some of the lowest voltages used in radiotherapy are termed Grenz and superficial X-rays of ~ 20 and ~ 100 kVp, respectively. Dosimetrically, the surface doses from these beams are calculated with the use of a free in-air air kerma measurement combined with a backscatter factor and the appropriate ratio of mass energy absorption coefficients from the measurement material to water. Alternative t...

Journal: :Physics in medicine and biology 2005
Martin J Butson Tsang Cheung Peter K N Yu

Gafchromic XR type-R radiochromic film is a relatively new product designed for use at clinical diagnostic x-ray energies both qualitatively and quantitatively. This short note investigates the energy response characteristics of this high-sensitivity radiochromic film for both diagnostic and therapeutic x-ray energies. Results are also compared to conventional silver halide x-ray film for energ...

Journal: :Medical physics 2012
T Giaddui Y Cui Z Yegingil J Xie W Chen J Galvin Y Yu Y Xiao

PURPOSE To study the effect of different filters on the dose response curves of the Gafchromic XRQA2 film. To measure the kV XVI cone-beam CT (CBCT) surface dose received during 3D and 4D imaging protocols in three body regions (head and neck, chest and pelvis). METHODS GafChromic XR- QA2 film (International Specialty Products, Wayne, NJ) dose response curves were generated for three irradiat...

Journal: :Medical physics 2007
Alexandra Rink I Alex Vitkin David A Jaffray

The response of radiochromic film, GafChromic EBT, was investigated for dependence on x-ray beam energy using a previously reported real-time optical readout approach. X-ray beams of energy from 75 kVp to 18 MV were employed. The dose-induced change in optical density for the EBT film was compared to values obtained for GafChromic HS and MD-55 films, exposed under the same conditions. All respo...

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