6533b7ddfe1ef96bd127407e

RESEARCH PRODUCT

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

Anna LongoMaurizio MarraleFrancesco D'erricoFrancesco D'erricoAntonio Lo CastoV. CaputoSalvatore GalloSalvatore GalloB. AbbateMassimo MidiriCesare GagliardoKostantinos GalliasLuigi TranchinaMaria BraiGiorgio Collura

subject

Nuclear and High Energy PhysicsRelaxometryPhotonDosimetermedicine.diagnostic_testChemistrySettore ING-IND/20 - Misure E Strumentazione NucleariDetectorSettore FIS/01 - Fisica SperimentaleMagnetic resonance imagingSignalLinear particle acceleratorSettore FIS/07 - Fisica Applicata(Beni Culturali Ambientali Biol.e Medicin)Nuclear magnetic resonancemedicineIrradiationSettore MED/36 - Diagnostica Per Immagini E RadioterapiaInstrumentationGel dosimeter Agarose Nuclear Magnetic Resonance relaxometryMagnetic Resonance Imaging clinical photons beam

description

Abstract 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 ( T R ) and on the inversion time ( T I ) 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.

yearjournalcountryeditionlanguage
2014-09-01
10.1016/j.nimb.2014.05.012http://hdl.handle.net/10447/96300