Introduction: Among the various dosimetric techniques used for characterizingthe radiation beams used in radiation therapy, the electron spinresonance (ESR) arouses increasing interest for applications in varioustherapy procedures. Free radicals are known to be produced when a compoundis irradiated with ionizing radiations. The concentration of radiationinducedfree radicals is proportional to the absorbed dose and this allowsfor dosimetric measurements through ESR technique which enables to quantitativelydetermine the radical concentration.In this work we report the ESR investigation of phenol pellets and thin filmsexposed to various types of radiation beams (clinical photon and electronbeams, mix field neutrons/photons). Phenols are compounds possessinga benzene ring attached to a OH group. After irradiation the final productis a stable phenoxy radical.Materials and methods: Thanks to their size, the phenolic films here presentedare good devices for the dosimetry of beams with high dose gradientand which require accurate knowledge of the precise dose delivered.Photon and electron irradiations at various energies were performed withthe Siemens Primus Lowlinear accelerator present at ARNAS Ospedale Civicodi Palermo, Italy. Thermal neutron irradiations were performed at thethermal neutron column at the Triga Mark II reactor of LENA (LaboratorioEnergia Nucleare Applicata) of Pavia, Italy. ESR dosimeters were readoutby means of a Bruker ECS106 spectrometer equipped with a TE102 rectangularcavity at room temperature.Results: The dose response of both pellets and films was found to be linearfor all beams used in the dose range analyzed. The signal is very stable inthe first days after irradiation. The possibility of obtaining depth dose profilewas investigated. Conclusions: In conclusion, the phenols show radiometric features that designateit as a new material for EPR.
|Numero di pagine||1|
|Stato di pubblicazione||Published - 2016|