[en] Technetium-^99mTc is the most widely used radionuclide for obtaining diagnostic imaging in nuclear medicine and its demand is growing every year. In order to provide metrological traceability to producers and end users in Brazil to fulfil nuclear regulatory requirements for radiopharmaceuticals, National Laboratory of Ionizing Radiation Metrology/Institute of Radioprotection and Dosimetry attended, in 2013, an activity comparison measurement of ^99mTc through BIPM Transfer Instrument SIRTI. The measurement results and the degree of equivalence between the key comparison reference value and LNMRI value are presented. The LNMRI result agreed with the measured value by SIRTI within one standard uncertainty. (author)

[en] Highlights: • ¹³⁴Cs Participation in International Reference System - BIPM. • Measurement methods used: anticoincidence, coincidence and CIEMAT/NIST liquid scintillation methods. • Activity results determined by three methods were consistent within k = 1. • The agreement with SIR/BIPM and LNMRI/IRD value is better than 0.5%. • LNMRI/IRD, as National Metrology Institute, is able to provide certificated ¹³⁴Cs solution with uncertainty better than 1%. - Abstract: From a commercial supplier a solution containing ¹³⁴Cs has been standardized at National Laboratory for Ionizing Radiation Metrology (LNMRI) for the first time using three Liquid scintillation based measurement. These measurement methods are 4πβ-γ live-timed anticoincidence counting, 4πβ-γ coincidence counting and ³H-standard efficiency tracing with the CNET methods. The results obtained by anticoincidence counting was adopted as reference value and its combined uncertainty was 0.38%. The agreement of this reference value with coincidence counting and CNET methods were 0.39% and 0.34% respectively and were in consistency with each uncertainty method. The weighted mean results coincidence counting and CNET methods are also in close agreement 0.03% with anticoincidence counting method and meets the requirement of primary and national standard. This standardization was made in order to reduce the uncertainty in ¹³⁴Cs measurement in Brazil and also following a request made by Bureau International des Poids and Mesures for new submission to International Reference System. The LNMRI last submission was made in 1987. Therefore from a ¹³⁴Cs master solution a NIST ampoules was prepared and LNMRI/IRD submitted it to the International Reference System, Bureau International of Poids and Measures (SIR/BIPM). In this paper will be analyzed the LNMRI measurement and performance each measurement methods and also take into account the reference value of KCDB, we determined also the ¹³⁴Cs gamma emission probabilities of main energy.

[en] In the case of a radiological accident, there are characteristic phases: discovery and initial assistance with first aid; the triage and monitoring of the affected population; the release of the affected people; forward the victims to medical care; as well as the preparation of the report on the accident. In addition, studies and associated researches performed in the later period. Monitors, dosimeters and measuring systems should be calibrated by contaminating radionuclide standards. The radioactive sources used must be metrologically reliable. In Brazil, this function is performed by LNMRI/IRD/CNEN, designated by INMETRO, which Radionuclide Metrology Laboratory is responsible for the standardization and supply of radioactive sources in diverse geometries and matrices. This laboratory has a stock of radionuclide solutions with controlled environmental variables for the preparation of sources, which are calibrated and standardized by mean of primary and secondary systems. It is also responsible for the dissemination of standards and, in order to establish the metrological traceability of national standards, participates in international key-comparisons promoted by BIPM and regional metrology organizations. Internally, it promotes the National Comparison Programs for laboratories for the analysis of environmental samples and the traceability for producing centers of radiopharmaceuticals and Nuclear Medicine Services in the country. The paper presents the demand for ¹³⁷Cs related to the radioactive accident in Goiania/Brazil and the significant results for the main radionuclides standardized by the Radionuclide Metrology Laboratory for international key-comparisons and national comparisons to provide metrological traceability. With the obtained results, the LNMRI of Brazil integrates the international metrology BIPM network and fulfills its function of supplying, with about a hundred of radioactive standards, the country's needs in different applications, including attendance to radiological accident. (author)

[en] Highlights: • Participation in BIPM international key-comparison of activity measurements of ⁶⁸(Ge + Ga) piloted by NIST. • The agreement between comparison reference value and LNMRI/IRD value is better than 0.3 %. • Activity results determined by three methods were consistent with k = 2. • LNMRI/IRD, as Designed Metrology Institute, is able to provide certificated solution ⁶⁸(Ge + Ga), with uncertainty better than 1.3 %. • ⁶⁸(Ge + Ga) can be used as a surrogate for ¹⁸F in quality control of radiation measurements equipment of nuclear medicine. - Abstract: In this work, a ⁶⁸(Ge+Ga) solution has been standardized at the National Institute of Ionizing Radiation Metrology (LNMRI), in Brazil, in the frame of an international key comparison CCRI(II)-K2.Ge-68 piloted by National Institute of Standards and Technology (NIST/USA). The 4πβ(LS)-γ(NaI(Tl)) anticoincidence method with live-time and extended dead-time was used and its result was validated by 4πβ(LS)-γ(NaI(Tl)) coincidence counting and liquid scintillation counting using the Triple to Double Coincidence Ratio (TDCR) method. The deviations of the activity concentration values of coincidence and TDCR measurements from the anticoincidence result were 1.7% and 0.63%, respectively, which were within experimental evaluated uncertainties at ~95% level of confidence (coverage factor k = 2). The combined relative standard uncertainties were 0.65%, 0.70% and 0.53% for anticoincidence, coincidence and TDCR methods, respectively. These values are consistent with the results reported by Cessna at the ICRM2017 conference.