Analytical and rheological studies of modified gel dosimeters exposed to X-ray beams

Mass Density Characterization of Hydrogel-Based Systems Inoculated with Bacterial Strains and Dose-Response Performance of Escherichia coli Inoculation

This study aims to determine the density of two hydrogel-based media, medium with agar-agar and medium with agar-agar and glucose, which are suitable for both irradiation and bacterial growth, considering the presence or absence of Staphylococcus aureus and Escherichia coli strains. The viability of Escherichia coli cell-inoculated systems was also evaluated to explore potential applications in radiation dosimetry within the 0-10 Gy range, using spectrophotometric and bacterial culture methods. Mass density measurements were performed at varying temperatures using two approaches: the first one, based on direct measurements of mass and volume, yielded densities comparable to liquid water, with uncertainties ranging from 9 to 16%, while the second approach, employing Archimedes' principle (mass in air vs. mass in a liquid of known density), produced more accurate results, with uncertainties between 0.04 and 0.08%, thus proving more reliable for density determinations. Furthermore, the feasibility study of Escherichia coli-inoculated systems for ionizing radiation dosimetry demonstrated a linear spectrophotometric response to radiation doses across the investigated range, particularly for samples stored at 25 °C. The studied systems were characterized in terms of the corresponding growth curve and post-irradiation bacterial survival, supporting their potentiality as reliable ionizing radiation dosimeters.

Chemical Overview of Gel Dosimetry Systems: A Comprehensive Review

Advances in radiotherapy technology during the last 25 years have significantly improved both dose conformation to tumors and the preservation of healthy tissues, achieving almost real-time feedback by means of high-precision treatments and theranostics. Owing to this, developing high-performance systems capable of coping with the challenging requirements of modern ionizing radiation is a key issue to overcome the limitations of traditional dosimeters. In this regard, a deep understanding of the physicochemical basis of gel dosimetry, as one of the most promising tools for the evaluation of 3D high-spatial-resolution dose distributions, represents the starting point for developing new and innovative systems. This review aims to contribute thorough descriptions of the chemical processes and interactions that condition gel dosimetry outputs, often phenomenologically addressed, and particularly formulations reported since 2017.