Using radioactive waste for targeted alpha therapy: Advancing a sovereign Australian supply of ²²⁵Ac and ²¹²Pb

This review outlines an opportunity to convert radioactive waste into nuclear medicine cancer treatments. Whilst focussed on Australia, parallels can be drawn to the identification and exploitation of radioactive waste internationally. Targeted Alpha (α) Therapy treatments (TATs) are emerging as a 'game changer' in the efficacy of nuclear medicine treatments in terms of cancer regression and remission, patient survival and quality of life. Clinically, TATs have demonstrated unprecedented efficacy in patients who have failed all other lines of radiotherapy treatment using beta-emitting isotopes. By 2030, ∼60 % of all radiotherapy treatment will be administered as TATs. Unfortunately, few cancer patients receive this treatment due to a limited sovereign and global supply of precursor radionuclides. This review focusses on the identification of radioactive waste streams that may allow the separation of ²²⁸Ra and ²²⁶Ra isotopes. Radionuclide transmutation allows production of ²²⁵Ac and ²¹²Pb as key therapeutic TATs. Key findings indicate that the viability of creating theranostic isotopes from radioactive waste will depend on; identifying suitable sources to eliminate sovereign supply risk; securing access to, or ownership of, suitable sources; radionuclide activity within source; composition and mineralogy influencing extraction and selectivity for target radionuclides; safe residue disposal; volume/mass of current or legacy sources; regulatory and policy guidance; risk profile; advocacy from peak medical associations; and, investment capital to establish infrastructure and pilot production facilities. Prospective sources for the target ²²⁸Ra and ²²⁶Ra isotopes include; reverse osmosis brine reject, barren lixiviant or tailings derived from uranium mining; oil and gas industry scales or produced waters, critical mineral processing solutes and solids; and legacy research sources.