Production of Mass-Separated Erbium-169 Towards the First Preclinical in vitro Investigations.

The β ^- -particle-emitting erbium-169 is a potential radionuclide toward therapy of metastasized cancer diseases. It can be produced in nuclear research reactors, irradiating isotopically-enriched ¹⁶⁸ Er ₂ O ₃ . This path, however, is not suitable for receptor-targeted radionuclide therapy, where high specific molar activities are required. In this study, an electromagnetic isotope separation technique was applied after neutron irradiation to boost the specific activity by separating ¹⁶⁹ Er from ¹⁶⁸ Er targets. The separation efficiency increased up to 0.5% using resonant laser ionization. A subsequent chemical purification process was developed as well as activity standardization of the radionuclidically pure ¹⁶⁹ Er. The quality of the ¹⁶⁹ Er product permitted radiolabeling and pre-clinical studies. A preliminary in vitro experiment was accomplished, using a ¹⁶⁹ Er-PSMA-617, to show the potential of ¹⁶⁹ Er to reduce tumor cell viability.
Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
(Copyright © 2021 Talip, Borgna, Müller, Ulrich, Duchemin, Ramos, Stora, Köster, Nedjadi, Gadelshin, Fedosseev, Juget, Bailat, Fankhauser, Wilkins, Lambert, Marsh, Fedorov, Chevallay, Fernier, Schibli and van der Meulen.)