Novel Silicone-Coated (125)I Seeds for the Treatment of Extrahepatic Cholangiocarcinoma

(125)I seeds coated with titanium are considered a safe and effective interstitial brachytherapy for tumors, while the cost of (125)I seeds is a major problem for the patients implanting lots of seeds. The aim of this paper was to develop a novel silicone coating for (125)I seeds with a lower cost. In order to show the radionuclide utilization ratio, the silicone was coated onto the seeds using the electro-spinning method and the radioactivity was evaluated, then the anti-tumor efficacy of silicone (125)I seeds was compared with titanium (125)I seeds. The seeds were divided into four groups: A (control), B (pure silicone), C (silicone (125)I), D (titanium (125)I) at 2 Gy or 4 Gy. Their anti-tumour activity and mechanism were assessed in vitro and in vivo using a human extrahepatic cholangiocarcinoma cell line FRH-0201 and tumor-bearing BALB/c nude mice. The silicone (125)I seeds showed higher radioactivity; the rate of cell apoptosis in vitro and the histopathology in vivo demonstrated that the silicone (125)I seeds shared similar anti-tumor efficacy with the titanium (125)I seeds for the treatment of extrahepatic cholangiocarcinoma, while they have a much lower cost.