Preliminary experiments to produce lutetium-177 in the TRR-1/M1 Thai research reactor

Lutetium-177 has emerged as a highly efficient radionuclide for medical applications, particularly in the field of targeted radionuclide therapy. Its production has been increasingly optimized through neutron activation techniques, which offer distinct advantages over alternative methods. Utilizing the TRR-1/M1 research reactor, which has been in operation for nearly six decades, provides a strategic opportunity for advancing domestic radioisotope production, thereby supporting the medical sector in Thailand. The TRR-1/M1 reactor, despite its operational age, continues to exhibit considerable potential for contributing to medical research and radioisotope development in Thailand. Preliminary experimental results, conducted at a flux of 1.42 × 10¹² n/cm²/s demonstrated promising outcomes, even under operational constraints such as fuel management limitations. Notably, the direct neutron activation of natural lutetium oxide notably yielded a specific activity of ¹⁷⁷Lu at 10.92 GBq/g (295.06 mCi/g) with a production yield of 44.8%, with projections reaching 222 GBq/g (6 Ci/g) after 40 days of neutron irradiation. In comparison, the indirect method, using natural ytterbium oxide as a precursor, achieved a maximum specific activity of ¹⁷⁷Lu at 6.6 MBq/g (180.3 μCi/g) with a yield of 37.8% of a theoretical maximum of 17.6 MBq/g (476 μCi/g) after only 10 h of neutron activation. These results highlight the feasibility and promise of ¹⁷⁷Lu radioisotope production in Thailand.