National Intercomparison on In Vivo Measurement of Iodine-131 in the Thyroid within a Brazilian Internal Dosimetry Laboratory Network - IAEA PROJECT BRA9055

Abstract

In 2011, in Brazil, a National Intercalibration and Intercomparison exercise on in vivo measurement of iodine-131 in the thyroid was carried out in the scope of the Project IAEABRA9055 “Establishing a National Laboratory Network for Internal Individual Monitoring”. The exercise was conducted by the Institute for Radiation Protection and Dosimetry (IRD) and the Institute for Nuclear and Energetic Research (IPEN), from National Nuclear Energy Commission (CNEN). The objectives of the exercise were to (i) update information on current instrumentation resources available in the in vivo monitoring laboratories in operation in Brazil and to (ii) verify the reliability of the results of measurements of iodine-131 in thyroid provided by those laboratories. The procedure consisted on the measurement of a neck-thyroid anthropomorphic phantom provided by the In Vivo Monitoring Laboratory of IRD, containing two barium-133 standard sources certified by the National Laboratory for Metrology of Ionizing Radiation. Each participant should measure the phantom in a period of five days. The five laboratories are located in the States of Rio de Janeiro, São Paulo, Minas Gerais and Pernambuco, in the following Institutions: Institute for Radiation Protection and Dosimetry, Nuclear Power Station Almirante Alvaro Alberto, Center for the Development of Nuclear Technology, Institute for Nuclear and Energetic Research, and Regional Center for Nuclear Sciences. The results reported included: Activity measured, Minimum Detectable Activity, Accuracy and Precision. The performance of the laboratories was evaluated according to the criteria suggested by ANSI 13.30 indicating their capacity to provide reliable results of iodone-131 content in the thyroid.