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 × 10