Correlation between ferrous ammonium sulfate concentration, sensitivity and stability of Fricke gel dosimeters exposed to clinical X-ray beams

This work describes the characterization of various Fricke-Agarose-Xylenol gels (FXG) dosimeters using NMR relaxometry and MRI analysis. Using X-rays from a clinical linear accelerator (LINAC), the gels were irradiated in the dose range from 0Gy to 20Gy. The photon sensitivity of the FXGs was measur...

Full description

Saved in:
Bibliographic Details
Published in:Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms Beam interactions with materials and atoms, 2014-09, Vol.335, p.54-60
Main Authors: Marrale, Maurizio, Brai, Maria, Gagliardo, Cesare, Gallo, Salvatore, Longo, Anna, Tranchina, Luigi, Abbate, Boris, Collura, Giorgio, Gallias, Kostantinos, Caputo, Vittorio, Lo Casto, Antonio, Midiri, Massimo, D’Errico, Francesco
Format: Article
Language:English
Subjects:
Agarose
Ammonium sulfates
Clinical photons beam
Dosimeters
Gel dosimeter
Inversions
Linear accelerators
Magnetic Resonance Imaging
Nuclear magnetic resonance
Nuclear magnetic resonance relaxometry
Photons
Three dimensional
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:This work describes the characterization of various Fricke-Agarose-Xylenol gels (FXG) dosimeters using NMR relaxometry and MRI analysis. Using X-rays from a clinical linear accelerator (LINAC), the gels were irradiated in the dose range from 0Gy to 20Gy. The photon sensitivity of the FXGs was measured in terms of NMR relaxation rates; its dependence on radiation dose was determined as a function of ferrous ammonium sulfate contents (from 0.5mM to 5mM). Furthermore, the stability of the NMR signal was monitored over several days after irradiation. These measurements were aided by Magnetic Resonance Imaging (MRI) scans which allowed three-dimensional (3D) dose mapping. In order to maximize the MRI response, a systematic study was performed to optimize acquisition sequences and parameters. In particular, we analyzed the dependence of MRI signal on the repetition time (TR) and on the inversion time (TI) using inversion recovery sequences. The results are reported and discussed from the point of view of the dosimeter use in clinical radiotherapy. This work highlights that the optimization of additive content inside gel matrix is fundamental for optimizing photon sensitivity of these detectors.
ISSN:0168-583X
1872-9584
DOI:10.1016/j.nimb.2014.05.012