The production and characterization of 161terbium radioisotope for cancer therapy using the Bandung TRIGA research reactor

Terbium-161( 161 Tb) is an emerging therapeutic radiolanthanide that emits low-energy β⁻particles together with Auger and conversion electrons, making it a promising radionuclide for targeted cancer therapy. This study evaluates the feasibility of laboratory-scale 161 Tb production using the 400 kW Bandung TRIGA research reactor through an integrated approach combining reactor-specific neutronic simulations, experimental irradiation, radiochemical separation, and physicochemical characterization. Neutronic analysis and irradiation design for enriched Gd 2 O 3 targets were performed using sequential MCNP and ORIGEN2 calculations to estimate 161 Tb activity and assess irradiation efficiency in the reactor core. Theoretical calculations using 5–25 mg of enriched Gd 2 O 3 (98.4% 160 Gd) predicted 161 Tb activities of 0.85–4.3 mCi. Experimental irradiation of a 5 mg target yielded 61–89% of the theoretical activity, indicating good agreement under the applied conditions. The irradiated targets were processed by extraction chromatography to separate 161 Tb from the Gd/Tb matrix and formulate the final products as 161 TbCl 3 . Product quality was evaluated by γ-spectrometry, paper chromatography, and paper electrophoresis. The resulting 161 TbCl 3 solution exhibited radiochemical and radionuclidic purities of 99.13±1.14% and 99.94±0.05%, respectively. Radionuclidic purity remained above 99% for more than two weeks after preparation, while radiochemical purity remained above 95% for up to three weeks at room temperature. The final solution was clear, colorless, and had a pH of 1.0–1.5. These results demonstrate that the Bandung TRIGA research reactor can reliably produce laboratory-scale of 161 Tb that meet key physicochemical quality requirements, while providing a scientific basis for irradiation optimization and future scale-up studies toward larger-scale production.