Analysis of the response of PVA-GTA Fricke-gel dosimeters with clinical magnetic resonance imaging
| Autor: | Antonio Bartolotta, Luigi Tranchina, B. Abbate, Maurizio Marrale, Salvatore Gallo, Francesco D'Errico, Giorgio Collura |
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| Přispěvatelé: | Collura, G, Gallo, S, Tranchina, L, Abbate, B, Bartolotta, A, d'Errico, F, Marrale, M |
| Rok vydání: | 2018 |
| Předmět: |
Nuclear and High Energy Physics
Xylenol orange Materials science Settore ING-IND/20 - Misure E Strumentazione Nucleari Dose profile Glutaraldehyde Imaging phantom 030218 nuclear medicine & medical imaging Matrix (chemical analysis) Gel dosimeter 03 medical and health sciences chemistry.chemical_compound Magnetic resonance imaging 0302 clinical medicine Nuclear magnetic resonance Irradiation Glutaraldehydeù Instrumentation Poly-vinyl alcohol X-ray radiotherapy Dosimeter Settore FIS/01 - Fisica Sperimentale Settore FIS/07 - Fisica Applicata(Beni Culturali Ambientali Biol.e Medicin) chemistry 030220 oncology & carcinogenesis Ionization chamber Agarose Settore MED/36 - Diagnostica Per Immagini E Radioterapia |
| Zdroj: | Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms. 414:146-153 |
| ISSN: | 0168-583X |
| Popis: | Fricke gel dosimeters produced with a matrix of Poly-vinyl alcohol (PVA) cross-linked with glutaraldehyde (GTA) were analyzed with magnetic resonance imaging (MRI). Previous studies based on spectrophotometry showed valuable dosimetric features of these gels in terms of X-ray sensitivity and diffusion of the ferric ions produced after irradiation. In this study, MRI was performed on the gels at 1.5 T with a clinical scanner in order to optimize the acquisition parameters and obtain high contrast between irradiated and non-irradiated samples. The PVA gels were found to offer good linearity in the range of 0–10 Gy and a stable signal for several hours after irradiation. The sensitivity was about 40% higher compared to gels produced with agarose as gelling agent. The effect of xylenol orange (XO) on the MRI signal was also investigated: gel dosimeters made without XO show higher sensitivity to x-rays than those made with XO. The dosimetric accuracy of the 3D gels was investigated by comparing their MRI response to percentage depth dose and transversal dose profile measurements made with an ionization chamber in a water phantom. The comparison of PVA-GTA gels with and without XO showed that the chelating agent reduces the MRI sensitivity of the gels. Depth-dose and transversal dose profiles acquired by PVA-GTA gels without XO are more accurate and consistent with the ionization chamber data. However, diffusion effects hinder accurate measurements in the steep dose gradient regions and they should be further reduced by modifying the gel matrix and/or by minimizing the delay between irradiation and imaging. |
| Databáze: | OpenAIRE |
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