background: in this study the basic radiation properties of n-isopropylacrylamaide polymer gel dosimeter were determined together with verification of its soft tissue equivalency. materials and methods: the nipam gel was prepared and irradiated approximately 2 h after manufacturing. the magnetic resonance (mr) images were made 24 h after irradiation. the nuclear magnetic resonance (nmr) respons...

parameters that have to be measured in gel dosimetry. however, the resolution in gel is strongly dependant on gel composition. selection of optimum method in dose response readout and proper values of parameters can result in noise reduction as well as improvement of contrast, and spatial resolution considerably. materials and methods: magica polymer gel dosimeters were manufactured and irradia...

Abstract-A mathematical modeling was adopted to calculate the ferric ion diffusion coefficient based on the radiation induced magnetic resonance (MR) image intensity change in Fricke-agarose gels. A fast magnetic resonance imaging acquisition technique was employed to avoid the smearing of acquired data due to diffusion over an extended period of time. Our results showed that for a Fricke-agaro...

The purpose of this study was to evaluate dependence of PAGAT polymer gel dosimeter 1/T2 on different electron and photon energies for a standard clinically used Co therapy unit and an electa linear accelerator.Using MRI, the formulation to give the maximum change in the transverse relaxation rate R2(1/T2) was determined to be 4.5% N,N'-methylen-bis-acrylamide(bis), 4.5% acrylamid(AA), 5% gelat...

background:  in this study a series of basic dosimetric properties of a low-density (ld) gel dosimeter are investigated. the dose response is studied regarding to linearity, sensitivity, dose-rate and energy dependence as well as lung tissue equivalence. materials and methods: the ld gel was made by mixing the polymer gel with expanded polystyrene spheres. energy dependence was studied at two d...

This work illustrates a procedure to assess the overall accuracy associated with Gamma Knife treatment planning using plugging. The main role of source plugging or blocking is to create dose falloff in the junction between a target and a critical structure. We report the use of MAGAT gel dosimeter for verification of an experimental treatment plan based on plugging. The polymer gel contained in...

This paper explores the combination of cone beam optical computed tomography with an N-isopropylacrylamide (NIPAM)-based polymer gel dosimeter for three-dimensional dose imaging of small field deliveries. Initial investigations indicate that cone beam optical imaging of polymer gels is complicated by scattered stray light perturbation. This can lead to significant dosimetry failures in comparis...

Background: In this study the basic radiation properties of N-isopropylacrylamaide polymer gel dosimeter were determined together with verification of its soft tissue equivalency. Materials and Methods: The NIPAM gel was prepared and irradiated approximately 2 h after manufacturing. The magnetic resonance (MR) images were made 24 h after irradiation. The nuclear magnetic resonance (NMR) respons...

Background: There are various methods to read out responses of a polymer-gel dosimeter, among which the Magnetic Resonance Imaging (MRI) technique is the most common one. Optimizing imaging protocols can have significant effect on the sensitivity and the dose resolution of polymer gel dosimeters. This study has investigated the effects of the number of echoes (NOE) and the echo time spacing (ES...