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 0 Gy to 20 Gy. 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 0.5 mM to 5 mM). 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.
Correlation between ferrous ammonium sulfate concentration, sensitivity and stability of Fricke gel dosimeters exposed to clinical X-ray beams / M. Marrale, M. Brai, C. Gagliardo, S. Gallo, A. Longo, L. Tranchina, B. Abbate, G. Collura, K. Gallias, V. Caputo, A. Lo Casto, M. Midiri, F. D’Errico. - In: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH. SECTION B, BEAM INTERACTIONS WITH MATERIALS AND ATOMS. - ISSN 0168-583X. - 335(2014 Jun 20), pp. 54-60.
|Titolo:||Correlation between ferrous ammonium sulfate concentration, sensitivity and stability of Fricke gel dosimeters exposed to clinical X-ray beams|
GALLO, SALVATORE (Secondo)
|Parole Chiave:||Clinical photons beam; Gel dosimeter; Magnetic Resonance Imaging; Nuclear magnetic resonance relaxometry|
|Settore Scientifico Disciplinare:||Settore FIS/01 - Fisica Sperimentale|
Settore FIS/07 - Fisica Applicata(Beni Culturali, Ambientali, Biol.e Medicin)
Settore MED/36 - Diagnostica per Immagini e Radioterapia
Settore ING-IND/20 - Misure e Strumentazione Nucleari
|Data di pubblicazione:||20-giu-2014|
|Data ahead of print / Data di stampa:||7-mag-2014|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1016/j.nimb.2014.05.012|
|Appare nelle tipologie:||01 - Articolo su periodico|