Comparisons of activity measurements with radionuclide calibrators a tool for quality assessment and improvement in nuclear medicine

In the present paper, an attempt has been made to ascertain the quality of activity measurements in the field of nuclear medicine in Cuba, on the basis of the results of a national program of ongoing comparisons for assaying gamma emitting radiopharmaceuticals for amount of radioactivity using radionuclide calibrators. Nuclides of the most wide spread use in Cuban nuclear medicine, 131I, 201Tl and 99mTc, as well as two measurement geometries, glass vials and plastic syringes, were employed. The participants' performance is assessed regarding to the value of † 10 % required in the Pharmacopoeia as an accuracy limit of the measurement. Performance tables have been obtained and a c2 statistic is calculated from observed and expected frequencies, with the aim of testing the hypothesis about the independence of some characteristics of the comparison results, at a significance level a equal to 0.05. Particularly, the proportion of satisfactory results in the years 2002 2004 were found to be at the same level, but higher than in 2000. It reveals an improvement of the measurement quality since 2002. The causes of improvement were investigated using the statistical treatment of several data available as supplementary information. Cuban results are also compared with published results for similar comparisons organized in other countries