Morphology-Driven ^99m Tc Extraction from Molybdenum Disulfide Nanomaterials

The radionuclide ^99mTc, obtained as a decay product of ⁹⁹Mo from a ⁹⁹Mo/^99mTc generator, is extensively used as a diagnostic agent in nuclear medicine. Presently, high specific activity ⁹⁹Mo is predominantly produced in nuclear reactors as a byproduct from ²³⁵U fission. However, this approach generates large amounts of nuclear waste and also faces challenges due to the decommissioning of aging research reactors. Alternative production routes using ⁹⁸Mo or ¹⁰⁰Mo as target materials have gained attention, but they inevitably result in low specific activity ⁹⁹Mo. Additionally, the limited adsorption capacity of the aluminum oxide, the conventional sorbent in the ⁹⁹Mo/^99mTc generator, restricts its use with low specific activity ⁹⁹Mo. We therefore propose to use molybdenum-based nanomaterials functioning as both target as well as generator material for the selective extraction of ^99mTc. By circumventing the necessity for sorbent material, we greatly increase the amount of Mo in the generator itself such that the low specific activity is no longer an issue. The ability to selectively extract ^99mTc while keeping the nanomaterial intact allows for re-irradiation, making the process recyclable. We have synthesized MoS₂ nanomaterials with distinct morphologies─nanoflowers, nanotubes, calcinated nanotubes, and nanodispersed sheets─and evaluated their properties. The material morphology significantly influenced the physicochemical properties, consequently impacting the ^99mTc extraction efficiencies. Among these materials, nanodispersed sheets, having the highest surface area (124 ± 35 m²/g), exhibited superior performance, achieving 12% ^99mTc extraction in methylethylketone (MEK) with negligible Mo contamination. These nanodispersed sheets also demonstrated excellent structural stability over multiple irradiation-extraction cycles, paving the way for a recyclable and cost-effective ⁹⁹Mo/^99mTc generator.