Análise da oxidação natural do dosímetro químico fricke xilenol gel

Abstract

Facing the need to use the ionizing radiation to the many kinds of cancer treatment by teletherapy, emerge the need of measurements for radiation dose received by patients, once this kind of radiation interferes on the molecular structure, damaging the bones and soft tissues from the organisms. Among the many kinds of dosimeters used for this purpose, the Fricke Xylenol Gel (FXG) dosimeter allows detecting the absorbance of low dose of radiation, from sources like high energy photons and accelerated electrons, beyond it presents similarities to the soft tissues from organisms. Naturally the ferrous ions present on the gel oxides to ferric ions according to the temperatures and place where the FXG is stored, interfering on the transformations induced by the absorbed dose as time of storage is increased. In this manner, for the first time in the literature, this work brings the investigation of the natural oxidation for FXG dosimeter, on pre-irradiation, analyzing the obtained spectrum through a spectrophotometer UV-Visible scanning the wavelengths 400 to 700 nm, on the samples stored at open, closed (out of light) and cooled environments (24.75 ± 1.48; 24.64 ± 1.50 and 6,5 ± 0.92 °C), From the results, after 82 hours of lecture we conclude that light and heat have influences on FXG natural oxidation, where the ambient samples presents the higher oxidation, followed by the closed ambient samples with 24.5% smaller values obtained from absorbance of open ambient samples due to lack of light. This relationship between the absorbance of the samples presents an alternative manner for pre-irradiation measurements, for around of 64.6% of ferrous ions would leave being oxidized, increasing the probability of detection for lower radiation doses and consequent effects by the exposure of these. Those results are important to medical physics, once it determinates the most favorable environment for FXG on dosimetry routines for the many kinds of ionizing radiation.