Production and radiochemical separation of Tb-161 as a feasible beta therapeutic radioisotope from reactor irradiated Gd target

Terbium-161 (¹⁶¹Tb) is a promising therapeutic radionuclide that has gained significant attention in the field of nuclear medicine in recent years. ¹⁶¹Tb has several favorable characteristics that make it a valuable candidate for targeted radionuclide therapy. The production of No-carrier-added ¹⁶¹Tb was carried out by the neutron activation of natural gadolinium target in the Egyptian Second Research Reactor (ETRR-2) at a thermal neutron flux position of 1.8 × 10¹⁴ ncm^-2s^-1. The radioactivities of ¹⁶¹Tb as well as coproduced Gd radioimpurities were computed theoretically by the MCNPX2.7.0 code and verified by actual measurements, where accepted discrepancies were obtained. The purification of ¹⁶¹Tb from irradiated Gd target was developed by Chelex-100 resin. The elution performance was studied using different eluents, and 0.1 M HNO₃ was found to be the best medium to obtain a high separation efficiency of more than 92% in a short time. The eluted ¹⁶¹Tb was of high chemical, radiochemical, and radionuclidic purities, indicating its potential for effective application in radiopharmaceutical preparation.