[186/188Re] rhenium-ethylene dicysteine (Re-Ec): preparation and evaluation for possible use in endovascular brachytherapy

188ReO4-, 188Re-MAG3, and 188Re-DTPA are currently under investigation as radiation sources in liquid-filled balloons for prevention of restenosis following coronary angioplasty. Because 99mTc-labeled ethylene dicysteine (EC) is a well-established agent for renal tubular function imaging, the use of [188Re] rhenium-labeled EC as a potential agent for prevention of restenosis after angioplasty is worth evaluation. In this article, the preparation and pharmacological behavior of [188/186Re]Re complex of EC are reported. The yield of the Re complex was optimized by varying the parameters of complexation. The complex prepared under the optimized conditions was found to be stable over a period of 7 days when stored at pH 2 and at 4 deg. C. The pharmacological behavior of [188/186Re]Re-EC confirms its similarity to 188Re-MAG3 and its superiority over 188ReO4- for use in endovascular brachytherapy