Quality control on radiochemical purity in Technetium-99m radiopharmaceuticals labelling: three years of experience on 2280 procedures

Objective: the purpose of this study was to offer an example of evaluations of the ISO9001 certified internal quality assurance (QA) system of 99m Tc-radiopharmaceutical preparations and quality control in vivo use, using industrial kits and generators in order to identify possible sources of errors in the procedures labeling and quality control procedures. Methods: The study was performed at a single institution over a period of three years (July 1 st , 2011 - July 1 st , 2014), and included a total of 2280 radiopharmaceutical preparations prepared by four different technologists. All the radiopharmaceutical preparations and quality controls were performed according to each SPC provided by the manufacturer. The radiopharmaceutical preparations were the following (trade names are reported in brackets): 99m Tc-albumin colloid [Nanocoll] (n=349), 99m Tc-oxidronate [Technescan®hdp] (n=701), 99m Tc-exametazime [Ceretec] (n=169), 99m Tc-sestamibi [Cardiolite] (n=92), 99m Tc-albumin aggregated [Technescan®lyomaa] (n=140), 99m Tc-tetrofosmin [Myoview]) (n=567), 99m Tc-diethylene triamine pentacetic acid [Technescan®dtpa] (n=254), and 99m Tc-dimercapto succinic acid [Renocis®] (n=8). Data were analyzed to determine the number and type of radiopharmaceutical labelling failure and to derive the sources of these failures to define corrective actions and optimize the quality assurance program. Results: A total of 2280 procedures were performed and recorded. Following the quality control procedure six out of the 2280 preparations (0.26%) were non-conforming for clinical use with the RCP limits indicated in the SPC. Five of these were due to gross technical errors in measurements and manual procedures and were immediately repeated, returning within the limits of acceptability. The sixth failure was due to short incubation time, though compliant with the manufacturer’s instructions. Conclusions: We concluded that the quality of the final product depends on a controlled production system based on the implementation of specific standard operating procedures (ISO9001, SOP) for each radiopharmaceutical production, according to strict adherence to the SPC of each radiopharmaceutical. Based on these conclusions, in our opinion every quality control suggesting a possible error in the synthesis procedure recommended in the SPC should be immediately reported to the manufacturer, for a revision of the SPC, as well as to the regulatory agencies for an alert. This strategy may in fact allow the continuous improvement of the labelling procedures and therefore the optimization of the quality control procedures frequency to ensure both patients safety and a more rational management of resources for economic sustainability.