Calibration of two sup(90)Sr+sup(90)Y dermatological applicators

Abstract

The 90Sr+90Y applicators need to be periodically calibrated, but in Brazil the service it not offered yet. The recommended method for the calibration of this kind of applicators is the use of extrapolation chambers. An alternative method for the calibration of clinical applicators is the use of thermoluminescent dosimeters. A dosimetric method of these applicators was already developed at Instituto de Pesquisas Energéticas e Nucleares (IPEN) and several types of thermoluminescent dosimeters were studied in previous works. The aim of this work was the application of this method to calibrate two dermatological applicators. Thin CaSO4:Dy pellets, with and without 10% of graphite were utilized. The reproducibility of these pellets was studied, and calibration curves were obtained using a standard applicator calibrated at the National Institute of Standards and Technology (NIST), USA. Both applicators showed similar results. The TL materials tested showed usefulness for dosimetry and calibration of this kind of applicators.