Traceability from governmental producers of radiopharmaceuticals in measuring (18)F in Brazil.

Since the inception of its proficiency test program to evaluate radionuclide measurement in hospitals and clinics, the National Metrology Laboratory of Ionizing Radiation-LNMRI, that represents Brazilian National Metrology Institute (NMI) for ionizing radiation has expanded its measurement and calibration capability. Requirements from the National Health Surveillance Agency from Ministry of Health (ANVISA), to producers of radiopharmaceuticals provided an opportunity to improve the full traceability chain to the highest level. Fluorodeoxyglucose (FDG-(18)F) is the only radiopharmaceutical simultaneously produced by all Brazilian radiopharmaceutical production centers (RPCs). By running this proficiency test, LNMRI began to provide them with the required traceability. For evaluation, the ratio of RPC to reference value results and ISO/IEC17043:2010 criteria were used. The reference value established as calibration factor on the secondary standard ionization chamber was obtained from three absolute measurements systems, and routinely confirmed in each round of proficiency test by CIEMAT/NIST liquid scintillation counting. The γ-emitting impurities were checked using a High-Purity Germanium (HPGe) detector. The results show that Brazilian RPCs are in accordance with (accuracy within ±10%) the Brazilian standard for evaluation of measurements with radionuclide calibrators (CNEN NN 3.05., 2013). Nevertheless, the RPCs should improve the methodology of uncertainty estimates, essential when using the statistical criteria of ISO/IEC 17043 standard, in addition to improving accuracy to levels consistent with their position in the national traceability chain.

Natural radionuclides in drinking water supplies of São Paulo State, Brazil and consequent population doses.

The activity concentrations of 228Ra, 226Ra and 222Rn have been analysed in 452 drinking water supplies of São Paulo State. This study started in 1994 and covered 54% of the 574 existing counties. Concentrations up to 235 and 131 mBq l-1 were observed for 226Ra and 228Ra, respectively, whereas 222Rn concentrations reached 315 Bq l-1. Radiation doses up to 0.3, 0.6 and 3.2 mSv yr-1 were estimated for the critical organs, for the ingestion of 226Ra, 226Ra and 222Rn, respectively. The corresponding committed effective doses reached values of 6 x 10(-3), 2 x 10(-2) and 3 x 10(-1) mSv yr-1, for the same radionuclides. These results indicate that 222Rn makes the highest contribution to the total effective dose.