Characterization of EBT3 Films response p to ionization radiations Charbel koumeir Charbel koumeir GIP ARRONAX-Nantes (France) GIP ARRONAX Nantes (France) 1
Outline ► ARRONAX facility ► EBT3 radiochromic film dosimetry ► EBT3 i ► EBT3 irradiation with alpha particle di ti ith l h ti l ► Relative response to other ionization radiations ► Relative response to other ionization radiations ► Conclusions ► Conclusions 2
ARRONAX an Accelerator for Research in Radiochemistry and Oncology at A l t f R h i R di h i t d O l t Nantes Atlantique 3 Fields of investigations: Radionuclides production for nuclear medicine Associated research fields Radiolysis, Radiobiology and Radiolysis, Radiobiology and Nuclear Physics T Training i i https://www.arronax-nantes.fr/ 3
Its unique characteristics Caracteristics: Multi-particles High energy Flexible range of intensity g y Beam Accelerated Energy range gy g Range in g Intensity y particles (MeV) Water (cm) (µA) H- 30- 70 0,8- 3,8 < 375 Proton HH+ 17 0,3 <50 D- 15-35 0,1-0,6 <50 Deuteron He++ 0,3 <70 Alpha 68 4
ARRONAX: the facility 4 Vaults devoted to isotope production and connected to hot cells through a pneumatic system P3 AX P2 Vault P1 devoted to a neutron activator system ( collaboration with AAA company ) y ( y ) p A2 A2 P1 A1 Vault AX devoted to research experiments 5
Beamlines Cyclotron (30.45 MHz, 65 kV) in the central vault P Pulsing System 3 Ax P 2 P 1 1 A A 2 A 1 6
Inert and living matter under irradiation ► Cross section measurements ► High Ion Beam Analysis ► Radiolysis studies ► Radiobiology studies ► Detectors characterization for beam diagnostics and dosimetry 7
EBT3 film composition EBT3 Film Active layer The active layer is composed of diacetylene monomer crystals 1 diacetylene monomer crystals 1 Microscopy image (SEM) 2 Structure of GAFChromic EBT3 Film 20 µm Chemical formula 2 1-F.Fiorini and D.Kirby. Physica Medica, (2014) 2-Alexandra.Rink. PhD thesis, University of Toronto, 2008. 8
Polymerization process upon irradiation Diacetylene monomers (a), upon exposure to ionizing radiation, polymerizes into (b) butatriene structure polymer; as the polymer chain grows, it rearranges via (c) an intermediate between butatriene structure and acetylene structure, into (d) acetylene structure polymer 1 1-Alexandra.Rink. PhD thesis, University of Toronto, 2008. 9
EBT3 analysis Irradiated EBT3 Film Visible absorbance spectra 1 ф ф The net optical density (netOD) is defined: p y ( ) ф ф The film is scanned, before The film is scanned, before and after irradiation, to measure the pixel value of unexposed (PV 0 ) and exposed area (PV). d (PV) PV bckg is the pixel value of a black opaque cardboard 1-International Specialty Products (ISP) product information 10
EBT3 film calibrations J. Sorriaux et al, Physica Medica 29 (2013) 599-606 11
EBT3 film calibrations The maximum difference is around 10% The superposition of red channel calibration curves for several high energy modalities The response of the EBT3 film shows weak energy and particles types dependencies at high energy beam at high energy beam J. Sorriaux et al, Physica Medica 29 (2013) 599-606 12
EBT3 film applications 2D dosimeter submillimeter resolution 13
EBT3 film applications 2D dosimeter submillimeter resolution D Depth dose profile th d fil 14
Energy dependence of EBT3 film The EBT3 film presents, at Low energy beam, an under response (a lower darkening) called, quenching or saturation effect 1 An under response also has been observed for photons beam in the range of low kilovoltage 2 1-A. Carnicer et al, Radiation Measurements 59 (2013) 225-232. 2-J. Villarreal-Barajas et al, Journal of Applied Clinical Medical Physics, 15, (2014), N1. 15
Saturation effect in case of high LET: in case of high LET: ► The saturation effect could be explained by the saturation of the polymerization reactions which gives a lower netOD polymerization reactions which gives a lower netOD. Therefore, an amount of the deposited dose is not used. ► The high LET leads to a high density of radicals created with a small inter-distance. Then, the chains formed could be different and less absorb photons of the visible light. 16
EBT3 irradiations Calibration Curves realized: ► Al h ► Alpha beams with energy between 20 and 44 MeV (ARRONAX) b ith b t 20 d 44 M V (ARRONAX) ► Proton 66 MeV (ARRONAX) ► Ascending part of the Bragg peak of a 68 MeV alpha beam (ARRONAX) ► Carbon 72MeV/n (GANIL) ► Carbon 72MeV/n (GANIL) ► Photons (225kV-10MV) (ICO-GANIL) Collaborations: Institut de Cancérologie de lOuest (ICO)-Nantes Institut de Cancérologie de lOuest (ICO) Nantes Centre ARCHADE/GANIL-Caen SUBATECH l b SUBATECH laboratory- Nantes t N t 17
Experimental setup for alpha beam irradiation ► 4 He 2+ beam of 68 MeV was provided by Arronax cyclotron Arronax cyclotron ► Beam intensity between 1 and 10 pA between 1 and 10 pA
Experimental setup for alpha beam irradiation
Experimental setup for alpha beam irradiation
EBT3 films analysis ► After irradiation, exposed films, as well as unexposed films for background correction, were stored at room temperature. ► Films were scanned 48 ± 1 hour after irradiation with ► Fil d 48 ± 1 h ft i di ti ith an Epson V700 scanner, in transmission mode and landscape orientation ► The images produced were 48 bit RGB color images with a spatial resolution of 150 dpi. ► These images were analyzed using the green channel because the green channel is suited for high dose range [4-50Gy] [4 50Gy] 21
EBT3 films results: single film irradiation ► Irradiation of a single film = reference irradiation ► The variation between the two sets of points remains well smaller than the error bars. ► This comparison shows that the measurements were repeatable 22
EBT3 films results: films stack irradiation Active Alpha energy LET [MeV.g -1 .cm 2 ] layer [MeV] position 44.8 170 1 38.4 193 2 31 2 31.2 230 230 3 3 22.0 304 4 23
EBT3 films analysis 24
EBT3 films analysis ► The response of the film in position 1 is the same as the response from the reference irradiation: [the deposited dose by the primary beam is preponderant relative to the doses of the secondary particles doses of the secondary particles generated by the other films of the Stack]. ► The two configurations, single film and stacked films, are equivalent to the irradiation of EBT3 films in this energy irradiation of EBT3 films in this energy range of alpha beams. The differences remain in the error bars 25
EBT3 films results: films stack irradiation ► For the other positions, the responses of the films are also the same as the response of the reference i irradiation. di ti ► The results show no effect of the LET in the energy range [20-45 MeV], LET in the energy range [20 45 MeV] although the LET varies by a factor around 2. ► From a dosimetry point of view, the same calibration response of the EBT3 film to the alpha beams can be used in film to the alpha beams can be used in a large range of incident energy. The differences remain in the error bars 26
EBT3 films results: photons 10 MV, e- 6MV For photons and electrons irradiations, we used a clinical linear accelerator (NOVALIS, BrainLab) at the Institut de Cancérologie de l’Ouest (ICO) (Nantes, France). 27
EBT3 films results: relative efficiency ► To quantify the quenching effect, we use the relative efficiency ( RE ) defined as the ratio between the dose delivered by photons and the dose delivered by a given beam for the same optical density: ► RE is constant in the function of the dose. ► A saturation effect of 20% is observed. 28
EBT3 films results: relative efficiency Efficacité relative % aux photons de 10 MV (ICO) 0MV ency %1 tive efficie Relat ► The saturation effect decreases slowly in the low LET range ► The saturation effect decreases slowly in the low LET range ► Alpha and carbon beams, with the same LET, produce the same effect ► The saturation effect is accentuated for the beam at low energy with high LET 29
Conclusions Conclusions ► The cyclotron ARRONAX has broad characteristics (energy, particle, dose rate). The different platform are opened for collaborations. ► The EBT3 calibration for alpha beams [20-45 MeV] shows a saturation effect of 20% relatively to high energy photon beam. ► The saturation effect seems to depend not only on the high ionization density (ion track structure) ionization density (ion track structure). ► Further irradiation, with the same analysis protocol, should be realized at the Bragg peak of the proton, alpha, and carbon beams. 30
Antoine Basset Antoine Basset Michel Cherel Michel Cherel Sophie Chiavassa Gregory Delpon Babacar Diouf Anne-Marie Frelin Arnaud Guertin Ferid Haddad Charbel Koumeir Coralie Lederoff Gaetan Le Nezet Vincent Métivier Nathalie Michel Freddy Poirier Noel Servagent Nicolas Varmenot Several of these projects are supported in part by the “Agence National de la Recherche”, called “Investissements d’Avenir”, Equipex ArronaxPlus n°ANR-11- EQPX-0004 EQPX 0004 31
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