IAEA regional intercomparison of in vivo measurements of 131I in the thyroid: the Latin American and Caribbean experience

Abstract

An in vivo intercomparison exercise, organised in the scope of the IAEA Regional Latin American (RLA) Project 9066, was carried out in 2009 aimed to harmonise measurement procedures on the measurement of (131)I in the thyroid among Latin American and Caribbean countries. The exercise consisted in the measurement of an anthropomorphic thyroid phantom spiked with a certified source of (133)Ba. The phantom was supplied by the In Vivo Monitoring Laboratory of Institute for Radiation Protection and Dosimetry (IRD) to 17 Institutions from 12 countries of the regions. Among these, 13 Institutions from 10 countries returned their measurement results as well as a standard report form containing detailed information about their respective counting facilities. All participants reported activities within an acceptable range, considering American National Standard Institute (ANSI) limits. Uncertainties varied from 0.04 to 12.9 %. Although results show that the general performance was acceptable in terms of accuracy, the need for additional action towards the standardisation of uncertainty estimation in this type of measurement in the region should be highlighted.

Thyroid screening of members of the public for iodine isotopes with portable NaI detectors

“…The Monte Carlo calculations used in this paper were validated using the thyroid phantom developed at the IRD which had been used previously as part of an IAEA regional intercomparison exercise for in-vivo thyroid measurement (Dantas, 2011). 133 Ba was used as a substitute for 131 I as it has a photo-peak at almost exactly the same energy as 131 I (356 keV) and a half-life of 10.5 years.…”