Comparison of three radiochemical purity control methods of (99m)Tc-macroaggregated albumin

(99m)Tc-macroaggregated albumin is widely used to diagnose pulmonary embolism. To control the radiochemical purity of this radiopharmaceutical, three rapid control methods using filter, thin layer chromatography or centrifugation, are described in the academic literature. In this paper, the interactions between impurities and (99m)Tc-macroaggregated albumin were presented. For each control method, the influence of these interactions on the determination of the radiochemical purity of labeled macroaggregated albumin was evaluated. Then, a comparison of radiochemical purity obtained by these three methods was performed in normal condition and with different addition of pertechnetate. Finally, a correlation between these three methods was investigated. The results show a specificity difference between these three control methods. However in practice, this difference has no impact on the evaluation of the radiochemical purity of (99m)Tc-macroaggregated albumin by these three methods. In additions, methods are still correlated with pertechnetate additions in (99m)Tc-macroaggregated albumin suspension. Thus, this study demonstrates that these three control methods are exchangeable in radiopharmacy.