Optical Fiber Dosimetry System for Gamma Radiation Facilities

This research presents an innovative fiber optic dosimetry sensor tailored for radiation measurement in biological environments. The aim is to achieve a two-dimensional (2D) spatial distribution of radiation by using an array of sensors that are arranged in a custom-designed holder. In this investigation, the FLIXCAT™ FlexHD1 Fiber-Optic Dosimeter (FOD) was irradiated using a ¹³⁷Cs γ-ray source, highlighting a discrepancy of up to 61% between the actual irradiated dose and the reconstructed dose inside animal subjects. Employing the FOD as a novel dosimeter, specifically in in vivo biological systems, necessitated biocompatibility studies to assess their interaction with real tissue and their influence on inflammatory markers in the blood.

This study initiated with the surgical implantation of three cylindrical FODs, along with three standard TLD_100 dosimeters at various in vivo points (behind the neck, right femur, and abdomen). Subsequent to implantation, both FOD and TLD_100 samples were subjected to gamma radiation and analyzed post-extraction. The observed discrepancy between the actual irradiation dose and the reconstructed dose within the animal is due to the dosimeter directly receiving the unimpeded true dose in open air, unlike within the animal’s body, where various tissues attenuate radiation from its point of entry to the dosimeter’s location. This attenuation is influenced by factors like tissue thickness and type and the depth of the dosimeter from the body surface.

For implant validation, Magnetic Resonance Imaging (MRI) was performed to detect the dosimeters at three different points in the animal’s body. MRI confirmed that implants (dosimeters) were present at all three locations without signs of oedema or inflammation. Additionally, there was no cell infiltration, confirming the sterility and biocompatibility of the dosimeters. Our results underscore the potential of the novel FOD in accurately measuring effective radiation doses for various organs in vivo, without inducing adverse effects.