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...

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...

Background: In this work investigation of the normoxic PAGAT polymer gel dosimeter such as sensitivity, the R2-dose response with post time and the percentage depth dose (PDD) of PAGAT polymer gel dosimeter have been undertaken. Materials and Methods: Using MRI, the formulation to give the maximum change in the transverse relaxation rate R2 was determined to be 4.5% N,N'-methylenbis- ...

Accurate dose measurement tools are needed to evaluate the radiation dose delivered to patients by using modern and sophisticated radiation therapy techniques. However, the adequate tools which enable us to directly measure the dose distributions in three-dimensional (3D) space are not commonly available. One such 3D dose measurement device is the polymer-based dosimeter, which changes the mate...

Fricke solution has a wide range of applications as radiation detector and dosimetry. It is particularly appreciated in terms of relevant comparative advantages, like tissue-equivalence when prepared in aqueous media like gel matrix, continuous mapping capability, independence of dose rate and incident direction, as well as linear dose response. This work presents the development and characteri...

Abstract Three different dosimetry systems were prepared based on diphenyl thiocarbazone (DTH) dye: polymer films made with, poly(vinyl alcohol), DTH liquid dosimeter and gel dosimeter. All the received several gamma doses. The three analyzing by UV–Vis spectrophotometery before after irradiation. effective dose range in linear part of these is between 1–10 kGy, 0.3–2 50–200 Gy. dosimeters reli...