Determining the producing and quality control parameters of Tc99m (V) DMSA radiopharmaceutic

Radiopharmaceuticals are compounds which are used for diagnosis and therapy in nuclear medicine. After injection to the patients, radiopharmaceutical is localized to tissue which will be scanned. Radiopharmaceuticals emitting gamma rays can be detected by gamma cameras and those which emit positron rays can be detected by Positron Emission Tomography (PET) cameras. The images are called ?Scintigraphy?. Tc99m is the decay product of Mo99. Tc99m is obtained from the Mo99/Tc99m radionuclide generator system. When Tc99m is combined with lyophilized, apyrogen and sterile DMSA (dimercaptosucsinicacid) kit, Tc99m (III) DMSA is formed which is a kidney scanning agent. If pH is increased during preparing the DMSA kit , +5 valence Tc99m is formed and Tc99m (V) DMSA is obtained. This radiopharmaceutical is used for scaning tumors. In literature, there are various preparation and quality control methods for Tc99m (V) DMSA. Because of contradictory reports in the literature there is no method which has been decided upon. For this reason the aim of this work is to determine the preparation and quality control parameters of Tc99m (V) DMSA which can be used in nuclear medicane centers. In this study Tc99m (V) DMSA is prepared at pH values of which are between 7,0 and 9,0. Paper chromatography and electrophoresis are used for quality control.The results indicate that the best percentages of labelling were obtained at pH values between 8,5 and 9,0 and when the product was prepared by the addition of 20-25 mCi Tc99m NaO4 in 2 ml and 0,2 mL NaHCO3 to the DMSA kit. Moreover with the aim of shortening the chromatographic analysis period; development length of the chromatography strip is decreased from 15 cm to 8 cm. Since the radiopharmaceutical is prepared and used in nuclear medicine departments within a short time; the decrease of analysis time is important. It is observed that the results of electrophoresis and thin layer chromatography which is studied by using the same kit gave similar results. But some tailing in the electrophoresis peaks were recognized. Therefore the separation in the choromotograms which is obtained with thin layer choromotograpy is better. On the other hand the analysis time was reduced to 50 minutes. The stability studies showed that Tc99m (V) DMSA is stable for six hours. It is decided that electrophoresis could be an alternative quality control method for Tc99m (V) DMSA in the nuclear medicine departments by the use of a simple equipment; because it is shorter than the other methods. Key Words : Tc99m (V) DMSA, choromatography, radiopharmacy