Raman spectroscopy as a tool to study oxygen effects on polymer gel dosimetry

DAVID CHACÓN; JOSÉ VEDELAGO; MIRIAM C. STRUMIA; MAURO VALENTE; FACUNDO MATTEA

Córdoba

Simposio; 14th International Symposium on Radiation Physics (ISRP-14).; 2018

Oral Presentation:Dosimetry plays an essential role in radiology and radiotherapy. Current non-conventional dosimetry, like polymeric gel dosimeters (PGD), are able to register 3D dose distributions and preserve it for long periods of time. In these materials, dose is translated into different polymerization degrees from a mixture of monomers within a gelatin structure. Then, methods that relay on the optical density or electronic density of the polymers are commonly used to determine average or local changes compared to unirradiated materials. These methods provide partial information on the real magnitude that account for the deposited dose on the dosimeter. Alternatively, techniques like Raman spectroscopy is able to provide direct information on the concentration of monomers that polymerized during the irradiation, and in some cases information on the separate inclusion of each species could be extracted, thus providing better and complete interpretations from the irradiated materials. In this investigation, Raman spectroscopy has been used to study a well-known effect on PGD, namely oxygen inhibition (OI), and specifically the polymerization inhibition due to oxygen diffusion through the phantom?s wall materials into PGD previous to their irradiation with a low energy X-ray source. The obtained results were contrasted to optical transmission measurements and Monte Carlo (MC) simulations with similar success