Descrizione del lavoro di ricerca
This thesis presents the development of two tissue equivalent and water equivalent chemical dosimeters for the measurement of the three-dimensional dose distribution in radiotherapy and the dose from UV sources.
Current radiotherapy techniques implement treatment plans based on volumetric dose
distributions with complex shapes and sharp gradients. To verify the agreement between these treatment plans and the dose that is actually delivered to the patient, a dosimetric system that is truly three dimensional, sensitive to radiation in each point and tissue equivalent is required. For this purpose, we developed a radio-chromic gel based on polyvinyl alcohol (PVA) chemically cross-linked with glutaraldehyde (GTA). This gel dosimeter has high sensitivity and stability of the signal, i.e. low diffusion of the iron complex. Furthermore, it is transparent and therefore can be imaged with optical techniques, as well as with NMR. The dosimetric characteristics of the PVA-GTA gel were compared to those of a Fricke gelatine gel and to other gel dosimeters previously studied by other investigators.
Even though UVA and UVB rays are commonly adopted in many treatments for skin disease and tumors, a passive and water equivalent dosimeter for both this type of radiations does not exist. We developed an aqueous dosimeter that is sensitive to UVA, UVB and X-rays named Redox-Phen solution. This dosimeter is inexpensive and tissue equivalent, being made of 99% of water. It changes color in the visible region upon irradiation, thus it can be measured via simple optical method, and an evaluation of the exposition can be made also by naked eyes. We studied the influence of the main chemical parameters on the dose-response and storage stability of the dosimeter to select the best formulation and compare it with the performances of other UV passive dosimeters.
Attività formative svolte nel triennio
Corso Periodo Ore
Scientific/academic English Gennaio-marzo 2015 20 Bio-ingegneria delle radiazioni Marzo-maggio 2015 60 Elettronica Digitale Febbraio-giugno 2016 90
Giornata studio
“Prevenzione e protezione dal rischio radon” 11 aprile 2016 7 Giornata studio
“radioattività nelle acque” 18 arpile 2016 7 2nd ESNII plus Summer School 9-11 marzo 2016 17
Marko Moscovitch School
on solid state dosimetry 30 giugno-2 luglio 24
Inlgese B.2.2 Marzo-luglio 2016 80
54° corso Polvani – Forensica nucleare e dosimetria
Lista delle pubblicazioni
Articoli su rivista Marini, A., Lazzeri, L., Cascone, M.G., Ciolini, R., Tana, L., d’Errico, F., 2017. Fricke gel dosimeters with low-diffusion and high-sensitivity based on a chemically cross-linked PVA matrix. Radiation Measurements, 106, 618-621.
Marini, A., Ciribolla, C., Lazzeri, L., d’Errico, F. 2018. Redox-Phen solution: A water equivalent dosimeter for UVA, UVB and X-rays radiation. Radiation Physics and Chemistry, 147, 7-12 Contributi in atti di convegno
d'Errico, F.; Almeida, W.S.; Alves, A.V.S.; Brai, M.; Cascone, M.G.; Corradi, C.; Gagliardo, C.; Gallo, S.; Lazzeri, L.; Marini, A.; Marrale, M.; Souza, S.O.; Sussuchi, E.M., 2015. PVA gel dosimeters for
radiotherapy applications. Proceedings of the 11th International Workshop on Ionizing Radiation Monitoring
Marini, A.; Corradi, C.; Gallo, S.; Cascone, M.G.; Lazzeri, L.; Marrale, M.; d’Errico, F., 2015. Diffusion coefficient of PVA based Fricke gel dosimeters. Proceedings of the Italian National Conference on Condensed Matter Physics FISMAT 2015.
Marini, A., Lazzeri, L., Corradi, C., Cascone, M. G., Marrale, M., Gallo, S., Tranchina, L., Brai, M., Gagliardo, C., d'Errico, F., 2016. Diffusion and sensitivity characteristics of a chemically cross-linked PVA-Fricke gel dosimeter. Proceedings of the 9° Congresso Nazionale AIFM. Abstract pubblicato su: Physica Medica: European Journal of Medical Physics, 32, 41.
Marini, A., Ciribolla, C., Lazzeri, L., d’Errico, F., 2017. Soluzione Redox-Phen: un dosimetro acquoso per raggi UV e X. Atti del Convegno Nazionale AIRP – Sorgenti di radiazioni: dai modelli alle misure
