Selective and Efficient Separation of No-Carrier-Added 161Tb from Gd/Dy Matrix Using P350@Resin for Radiopharmaceutical Applications

Terbium-161 (161Tb) is an emerging β−-emitting radionuclide of high interest for targeted radionuclide therapy. However, its reactor-based production presents significant challenges in the efficient separation of 161Tb from target 160Gd and co-produced 161Dy. In this study, the separation of 161Tb by a solvent-impregnated resin P350@resin has been evaluated. A combination of static adsorption and dynamic column experiments was conducted to investigate the separation behavior of Gd3+, Tb3+, and Dy3+. Optimal separation performance was achieved at 0.4–0.6 mol/L HNO3, using a column bed height of 20–28 cm and flow rates of 0.5–1.0 mL/min. A two-step elution protocol enabled near-baseline resolution between Tb and Gd, Dy within 3 h, ensuring high-purity and fast product recovery. Comprehensive characterization using SEM-EDS, FT-IR, and XPS confirmed that metal ion uptake occurs via coordination with phosphoryl groups on the resin. The P350@resin thus enables a simple and selective separation platform for the production of no-carrier-added 161Tb, with high potential for clinical radiopharmaceutical manufacturing.