Preparation and characterization of radioactive Co/188Re stents intended for lung cancer treatment using an electrodeposition method

A procedure for electroplating a Co/188Re alloy layer on metal coils (stents) at room temperature was developed. The electroplating of the Co/188Re alloy layer was carried out at a current density of 93 A m−2 and produced a physically strong Co/188Re alloy layer that adhered well to a thin gold strike layer on top of the stent material. The final gold layer was also stable. An empirically-found equation correlates the radioactive electroplating efficiency factor to the concentration of the radioisotope and was used to deposit predetermined amounts of radioactivity on the stent surface. Radioactive stents can be prepared and quality control performed within 2 hours using an automated electroplater and dosimetric quality control system. The radioactivity was homogeneously distributed on the stent surface. The in vitro stability in human plasma at 37°C was found to be greater than 95% for both Wallstent and Ultraflex stent after 72 hours of incubation. A clinical pilot trial is planned after successful completion of animal testing.