Rapid preparation method for technetium-99m bicisate

The method currently recommended for the preparation of technetium-99m bicisate (99mTc-bicisate) requires a lengthy 30-min incubation at room temperature. The purpose of this study was to evaluate an alternative method to shorten the preparation time. 99mTc-bicisate was prepared with 3.7 GBq (100 mCi) 99mTc according to the manufacturer's instructions, except for the final incubation step, which was replaced with the microwave heating procedure. A standard thin-layer chromatography (TLC) method (i.e., Baker-Flex silica gel IB-F TLC plate with ethyl acetate as mobile phase) was used for the determination of the radiochemical purity (RCP) of 99mTc-bicisate. Our evaluation with different microwave heating processes (300 W with different heating times) demonstrated that as the microwave heating temperature was increased (i.e., 44 -71 C), an increased percentage of samples reached 95% within 5 min post preparation (n=58). The highest RCP value (i.e., 97.4%±0.5%, n=10) could be obtained immediately after an 8-s microwave heating time at 300 W (microwave temperature at 69 C), and an average RCP value of 96.4%±1.3% (n=90) was maintained throughout the 24-h evaluation period. However, the trend seemed to reverse at higher microwave temperatures (i.e., 76 -90 C), which reconfirmed our initial findings that overheating had no benefit for the preparation of 99mTc-bicisate. To ensure that temperature was the only determining factor, a hot water incubator set at 69 C was used (n=6). Similar RCP results were achieved. In conclusion, the use of a microwave oven at a low heat cycle provides a rapid and efficient way to prepare 99mTc-bicisate. (orig.). With 3 figs., 1 tab