Separation of ¹⁶¹Tb radioisotope from irradiated ¹⁶⁰Gd enriched of gadolinium oxide target using extraction chromatography method

Cancer is one of the leading causes of death worldwide. World Health Organization (WHO) declared that cancer patients are increasing every year and ²/₃ of them are come from developing countries, including Indonesia. Terbium-161 (¹⁶¹Tb) is a low β^- emitter which has E_β^-average of 0.150 MeV and a half-life (T_1/2) of 6.9 days, so ¹⁶¹Tb is a potential radioisotope for therapy of small cancer. Beside that, ¹⁶¹Tb also emits internal conversion and Auger electrons, which can give better therapeutics effect. Radiochemical separation of ¹⁶¹Tb from irradiated ⁶⁰Gd enriched of gadolinium oxide target has been carried out by extraction chromatography method using Ln resin. ¹⁶¹Tb radioisotope was obtained from ¹⁶⁰Gd (n,γ) ¹⁶¹Gd⟶^{β- 161}Tb nuclear reaction in RSG-G.A. Siwabessy at a thermal neutron flux of ~10¹⁴ n.cm^-2.s^-1 for ± 4 days using 5 mg of enriched gadolinium oxide target (98.2 % of ¹⁶⁰Gd isotope enrichment). Irradiated gadolinium oxide target was dissolved in 2 N HCl solution. ¹⁶¹Tb radioisotope was separated from irradiated Gd₂O₃ enriched with extraction chromatographic method using 1 and 2 g of Ln resin with 50-100 µm particle size as a stationary phase and nitric acid solution with 0.8 N and 3 N concentrations as mobile phases to separate gadolinium and terbium isotope, respectively. The results showed that optimum condition on separation of ¹⁶¹Tb can be obtained using 2 g of Ln resin with the yield of 93.2 ± 2.1 %. While Gd recovery was obtained for 98.11 ± 1.2 %. Separated of ¹⁶¹Tb fractions have the radionuclide purity of 99.92 ± 0.5 %. The final product of ¹⁶¹Tb solution was obtained in the chemical form of ¹⁶¹TbCl₃ with the radiochemical purity 99.83 ± 0.2 %. (author)