Rapid separation of ⁹⁹Mo from proton irradiated thorium target for medical application

Molybdenum-99 is an important radionuclide used in nuclear medicine, and efficient extraction of high purity ⁹⁹Mo from irradiated target is required to meet the medical application demands. A novel method is presented for the separation and purification of ⁹⁹Mo from thorium target irradiated by accelerator proton beam. In this method, ThO₂ target was dissolved in mixed HCl and HF acids, and Mo as MoO₂Cl^n- was preliminary separated from the Th matrices and many other radionuclide impurities using anion exchange chromatography. By precipitation of Mo with α-benzoin oxime (ABO) and secondary anion exchange chromatography purification, an overall chemical recovery of consistently over 80% for ⁹⁹Mo was achieved. A pure ⁹⁹Mo solution matching the requirements for medical purpose (according to European Pharmacopoeias for ⁹⁹Mo produced from neutron irradiated ²³⁵U) was obtained with this method, and the produced ⁹⁹Mo can be directly used for the preparation of ⁹⁹Mo-^99mTc generator.