Water-equivalence study of Staphylococcus aureus-hydrogel-based radiation dosimeters

During the last decades, uninterrupted advances and development of applications of ionizing radiation in highly complex techniques within diverse and multidisciplinary fields increased the need for reliable and precise dosimetry techniques that guarantee radiological quality. The later been especially important in medical physics applications when selecting materials from which phantoms and radiation detectors can be built. The assessment of fundamental physical quantities, such as the mass attenuation coefficient (#mu#/#rho#) and the stopping power (S), considering the projectile particle, become determinant since they allow evaluating dosimetric effects and the degree of equivalence between materials for the different radiation beam qualities. In this sense, there is a large literature dedicated to its study, experimental determination, calculation and/or use in practical situations. The present work focuses on studying the behavior of S and #mu#/#rho# as an approach to assess the water-equivalence of two dosimetric systems based on microbiological agents known as MAA and MAAG, both analyzed in the presence and absence of bacterial content. The study is carried out for different energies of electron, photon and proton beams within the corresponding therapeutic application range, approached from theoretical formalisms, subsequently through the use of simulation techniques with Monte Carlo code: Penelope in the case of photons and electrons and FLUKA in case of protons; finally the systems are analyzed using different experimental methodologies. The obtained results, as assessed by the different implemented approaches, exhibit promising behaviors as water-equivalent systems in terms of good correspondences with liquid water reported data. (author)