Desenvolvimento de um protocolo para obtenção de dose absorvida na água (Dw) em fontes de braquiterapia de alta taxa de dose, utilizando dosimetria Fricke

Abstract

In radiotherapy areas around the world, it has been demonstrated that an external audit system represents an important value in quality assurance for the treatments offered, reducing errors in dose delivery and ensuring better results for patients. Some international institutions such as the International Atomic Energy Agency (IAEA) and the ESTRO-Equal network have developed auditing systems for radiotherapy or external source therapy, leaving aside brachytherapy, due to the Laboratory of Radiological Sciences of the State University Rio de Janeiro (LCR/UERJ) and the Center for Radiological Physics (RCP) have participated in a project that aims to verify the dosimetry of two high-dose brachytherapy treatments with Ir-192 or Co-60 in Brazilian hospitals and on behalf of world by comparison between the decay of the source according to the manufacturer's calibration certificate and the intensity of the same at clinical environment. The audit system will be based on chemical dosimetry known as Fricke which, after several studies, has been considered a reference dosimeter for its ability to determine the Absorbed Dose in water based on the oxidation of ferrous to ferric ions as a result of the solution interaction with ionizing radiation, offering results with lower uncertainties than those observed using other types of dosimetry. As part of one of the stages of the project entitled “Development of a methodology for auditing dosimetry in Brachytherapy”, the LCR Fricke Laboratory has developed a system for irradiating the fricke solution that can be reproduced in several hospital centers and allows for subsequent intercomparison with other dosimetric systems. The present work aims to offer a clear and easily reproducible protocol so that the system can be irradiated in the countries participating in the project, allowing the results to be evaluated and proving its viability as an audit system for High Dose Rate Brachytherapy.