RESUMEN

The potentiometric titration method was used for characterization of uranium compounds to be applied in intercomparison programs. The method is applied with traceability assured using a potassium dichromate primary standard. A semi-automatic version was developed to reduce the analysis time and the operator variation. The standard uncertainty in determining the total concentration of uranium was around 0.01%, which is suitable for uranium characterization and compatible with those obtained by manual techniques.

Asunto(s)

Potenciometría/métodos , Radiometría/métodos , Radiometría/normas , Robótica/métodos , Uranio/análisis , Uranio/química , Algoritmos , Brasil , Semivida , Internacionalidad , Potenciometría/normas , Dosis de Radiación , Estándares de Referencia , Valores de Referencia , Robótica/normas

RESUMEN

Proficiency tests were applied to assess the performance of 74 nuclear medicine services in activity measurements of (131)I, (123)I, (99)Tc(m), (67)Ga and (201)Tl. These tests produced 913 data sets from comparison programmes promoted by the National Laboratory for Ionizing Radiation Metrology (LNMRI) from 1999 to 2006. The data were evaluated against acceptance criteria for accuracy and precision and assigned as Acceptable or Not acceptable accordingly. In addition, three other statistical parameters were used as complementary information for performance evaluation which related to normative requirements and to radionuclide calibrators. The results have shown a necessity to improve quality control procedures and unsatisfactory performances of radionuclide calibrators, which incorporate Geiger-Müller detectors.

Asunto(s)

Medicina Nuclear , Radioisótopos/análisis , Radiofármacos/química , Brasil , Reproducibilidad de los Resultados

RESUMEN

Radioactive solutions of (65)Zn and (241)Am were standardized within the frame of the CCRI (II)/BIPM key comparisons carried out recently in 2003. The activity concentrations (in Bqg(-1)) were determined using the 4pi(proportional counter)-gamma coincidence counting method with efficiency extrapolation. Liquid scintillation methods were also used for (241)Am activity determination. The 1115.5 keV of (65)Zn and the 26.35 and 59.54 keV of (241)Am gamma-ray emission probabilities were determined as 0.4971, 0.0206 and 0.3587, respectively, using a planar germanium detector. The associated relative uncertainties were 0.33%, 1.56% and 0.47%, respectively.