نتایج جستجو برای: fricke gel dosimeter

تعداد نتایج: 107206  

Journal: :iranian journal of medical physics 0
hossein hasani m.sc. student in medical radiation engineering, science and research branch, islamic azad university, tehran, iran hasan nedaie assistant professor, radiotherapy and oncology dept., tehran university of medical sciences, cancer research center, center institute, tehran, iran mohammad hasan zahmatkesh associate professor, medical physics dept., novin medical radiation institute, tehran, iran mahmood allahverdi associate professor, medical physics dept., tehran university of medical sciences, tehran, iran saeid bagheri m.sc. of medical physics, novin medical radiation institute, shahid beheshti university, tehran, iran sajad mirzaie m.sc. student in medical radiation engineering, science and research branch, islamic azad university, tehran, iran

introduction: in radiotherapy, methods of treatment planning are becoming increasingly more complicated. this requires verification of the doses delivered to increasingly smaller and more precise regions. radiotherapy techniques are continuously employing smaller and smaller field sizes to deliver tighter radiation doses with higher therapeutic ratios, generating interest among researchers to p...

H. Pourbeigi, M.H. Zahmatkesh, Sh. Akhlaghpoor,

Background: Since 1984 MRI gel dosimetry has been introduced as a potential technique for 3D dosimetry. Most of the studies have measured R1 (1/T1) or R2 (1/T2) properties of the gel depending on the gel type. We have studied image intensity change in the Fricke gel by different MRI protocols. Materials and Methods: Gel Dosimeters contain 0.4 mM ferrous sulphate, 1 mM NaCl, 50 mM H2SO4 and 1% b...

Elham Edalatkhah, Peiman Rezaeian

Introduction: Transfusion of irradiated blood is recommended by the guidelines for cardiosurgery, cancer surgery, severe trauma and congenital immune deficient recipients. To prevent post- transfusion graft-versus-host disease (PT-GVHD), blood cells may be irradiated by gamma rays. The absorbed dose range for blood irradiation is typically 15 to 50 Gy. As the assurance that blo...

Journal: :iranian journal of radiation research 0
sh. akhlaghpoor dr. sh. akhlaghpoor, novin medical radiation institute, p.o.box: 14665/599, tehran, iran; fax:(98) 218086782 m.h. zahmatkesh h. pourbeigi

background: since 1984 mri gel dosimetry has been introduced as a potential technique for 3d dosimetry. most of the studies have measured r1 (1/t1) or r2 (1/t2) properties of the gel depending on the gel type. we have studied image intensity change in the fricke gel by different mri protocols. materials and methods: gel dosimeters contain 0.4 mm ferrous sulphate, 1 mm nacl, 50 mm h2so4 and 1% b...

2014
S. M. Gafar

In this study the spectrophotometric response of the Toluidine Blue O (TBO)-gelatin gel dosimeter irradiated with gamma rays was characterized. Preparation of dyed-gelatin gel takes place in neutral medium; to give eventually gel dosimeter has a sharp absorbance peak at 635 nm that bleaches quantitatively upon irradiation and the colour change can be measured with UV-VIS spectrophotometer. The ...

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.A. Mahmoud, A.A. Rahman, I.S. Mustafa, N.N.A Razak, N.Z. Yahaya, S. Kandaiya,

Background: An effective polymer gel dosimeter can be fabricated by varying the composition of its chemical components. Materials and Methods: The MAGAT gel dosimeter formulations that used different compositions of Methacrylic acid (MAA) and gelatin were extensively investigated in the present study according to the R2–dose response and R2–dose sensitivity. The irradiation of M...

2017
C Boudou M C Biston J F Adam H Elleaume

In synchrotron stereotactic radiotherapy (SSR) the tumor is loaded with a high Z element, and exposed to monochromatic x-rays from a synchrotron source, in stereotactic conditions. The SSR treatment efficiency is related to the heavy element concentration achievable in the tumor, to the radiation energy, and the irradiation geometry [1,2]. The experimental dose verification of SSR in three dime...

2017
Heather M Whitney Daniel F Gochberg C Waldenberg A Karlsson Hauer

The normoxic polymer gel dosimeter based on N-isopropyl acrylamide (NiPAM) is a promising full 3D-dosimeter with high spatial resolution and near tissue equivalency. NiPAM gel samples were irradiated to different doses using a linear accelerator. The absorbed dose was evaluated using MRI and statistical significance of the analysed data was calculated. The analysis was carried out using an in-h...

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