Quality assessment of Tc-99m methylene diphosphonate (MDP) radiopharmaceutical prepared using different cold kit fractionation methods

Tc-99m Methylene diphosphonate (MDP) is prepared in house by labeling MDP cold kit. Each kit is a single time use vial and contains large amounts of reagent sufficient for preparing multiple doses. Therefore, several centers are adopting the practice of fractionating the MDP kit so that it can be used multiple times. The aim of the study was to evaluate the effect of kit fractionation on radiopharmaceutical property. Materials and Methods: The MDP kit was fractionated using two different approaches, namely, vial and syringe method. The quality of Tc-99m MDP prepared using these approaches was assessed and compared with that prepared by the conventional method. The image quality was evaluated in a total of 100 patients. Results: The vial and syringe fractionated Tc-99m MDP showed >95% RCP till the 4th and 2nd days of fractionation, respectively. Percentage radiochemical purity deteriorated to 83.6% and 88% on the 8th day of fractionation in the vial and syringe method, respectively. No microbial growth was observed in any of these methods till the 8th day of fractionation. The reconstituted MDP solution during all preparations was clear and colorless in appearance with pH ranging from 6.5 to 7.5. The image contrast, contrast-to-noise, and signal-to-noise ratio were statistically similar in both methods compared to the conventional method until the 2nd day of fractionation. The image quality data showed no statistical difference among images of vial and syringe fractionated MDP as compared to the conventional unfractionated Tc-99m MDP. The observations revealed that if fractionated with utmost care, both methods yield almost similar results. (author)