Calibration of 90Sr /90Y Ophthalmic Brachytherapy Planar Sources Using Thermoluminescent Samples, a PMMA Phantom and Monte Carlo Simulation

Abstract

In some parts of Brazil, 90Sr/90Y clinical applicators are still used for dermatological and ophthalmic treatments, despite the availability of new technologies worldwide and the use of Ru-106/Rh-106 Eye Applicator. This is because they are less expensive and easier to use. Calibration and periodic recalibration of these applicators to verify the absorbed dose rate are essential to ensure accuracy in clinical treatments. In this study, the thermoluminescent response of LiF pellets was evaluated to determine the reproducibility, linearity of response, and dose-response curves. Dose rates for some clinical applicators were determined using the LiF pellets, a PMMA phantom and the Monte Carlo method, following a project based on ISO 21439 (2009). This standard recommends the use of small detectors such as LiF for this type of calibration.