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Characterization of GafChromic EBT3 films with 60CO and low

Characterization of GafChromic EBT3 films with 60CO and low energy protons for radiobiology dosimetry.
M. Vadruccia , F. Ambrosinib, R. Cherubinic, C. De Angelisd, G. Espositod, F. Marracinoa, L. Picardia, M. Pimpinellae, C. Ronsivallea, C.
Snelsf, M. A. Tabocchinid,
a: ENEA C.R. Frascati, UT. APRAD Radiation Sources Laboratory, Via E. Fermi, 45, 00044, Frascati (RM), Italy
b: Sapienza Università di Roma - DIET, via Eudossiana, 18, 00184, Roma, Italy
c: INFN-Laboratori Nazionali di Legnaro Viale dell'Università 2, 35020 Legnaro (PD), Italy
d: Istituto Superiore di Sanità - Technology and Health Department, Viale Regina Elena 299, 00161 Roma, Italy
e: ENEA C. R. Casaccia Istituto Nazionale di Metrologia delle Radiazioni Ionizzanti Via Anguillarese, 301 00123 Roma Italy
f: ENEA C.R. Casaccia, UT. BIORAD Radiobiology, Via Anguillarese, 301, 00123, Roma, Italy
e-mail:[email protected]
Keywords: gafchromic EBT3, proton, radiobiology
New GafChromic EBT3 films are now more often used in radiotherapy dosimetry. In this work we present
the characterization of these radiochromic films that we want to use as dosimeters for in-vitro and in-vivo
radiobiology experiments, planned in the framework of the TOP-IMPLART (Terapia Oncologica con Protoni
– Intensity Modulated Proton Linear Accelerator for RadioTherapy) project [1], a ENEA, ISS, IFO-IRE
collaboration aimed to build a protontherapy centre based on a linear accelerator in Rome.
The purpose of this study is to define the behavior, to estimate the sensitivity and to evaluate the
dosimetric uncertainties of these radiochromic dosimeters, using two different ionizing radiation type and
investigating them through a comparison of sensitometric curves.
The films were exposed to photon beams from a 60Co source at INMRI - ENEA (Istituto Nazionale di
Metrologia delle Radiazioni Ionizzanti) [2] working at 0.3 Gy/min, and proton beams in air provided by the
Radiobiology Facility of the 7 MV Van De Graaff CN accelerator at LNL-INFN (Laboratori Nazionali di Legnaro
– Istituto Nazionale di Fisica Nucleare) [3] with energy of 5 MeV and dose rates up to 40 Gy/min. The
irradiations have been performed in a dose range from 0.5 Gy to 30 Gy. The adopted reference dosimetric
system was ionization chamber Farmer NE2571, in the case of 60Co irradiation, and a semiconductor device
for protons. Images of reacted films were digitized with an EPSON 10000XL-PRO scanner and the calibration
curves of dose vs intensity of film darkening and dose vs film optical density have been determined.
Accurate analysis of measurements allowed a precise evaluation of uncertainties.
The results obtained show a different behavior of radiochromic films: by using low energy protons they
evidence for a lower sensitivity with respect to 60Co radiation (around 15 % for low doses) . A sensitivity to
proton energy has been also evidenced varing the energy from 5 MeV to about 4 MeV.
[1]C. Ronsivalle et al. Eur. Phys. J. Plus (2011) 126: 68.
[2]A.S. Guerra, R. F. Laitano, M. Pimpinella Phys. Med. Biol. 41 (1996) 657-674
[3] M. Belli, R. Cherubini et al., Nucl. Inst. and Meth. in Phys. Reas. A 256 (1987) 576-580
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