Synthesis and 99mTc labeling of Ethylcystein Dimer and Its Brain SPECT Image

Et.hylcystein dimer(ECD) was synthesized by dimerization of L-thiazo1idine-4-carboxylic acid in liquid ammonia with sodium metal and successive esterification in ethanolic solution of hydrogen chloride. The purified product was labeled with 99mTc in the presence of sodium glucarate(pH=5.6) and stannous chloride. Best result was obtained from the preparation consisting of O.l mg ECD, 40 μl of 0.4 M sodium glucarate (pH=5.6), and 20 μg of stannous chloride. The labeling efficiency was 90% with previous condition. The labeled 99mTc-ECD was stable at least for 3 hours in PBS(pH 7.4) at room temperature. About. 10m Ci of 99mTc-ECD was injected to normal volunteer, and SPECT image of brain was obtained by triple head camera 10 minutes after injection. The image showed similar distribution of radioactivity in brain with that of HMPAO image.