AUTHOR=Talip Zeynep , Borgna Francesca , Müller Cristina , Ulrich Jiri , Duchemin Charlotte , Ramos Joao P. , Stora Thierry , Köster Ulli , Nedjadi Youcef , Gadelshin Vadim , Fedosseev Valentin N. , Juget Frederic , Bailat Claude , Fankhauser Adelheid , Wilkins Shane G. , Lambert Laura , Marsh Bruce , Fedorov Dmitry , Chevallay Eric , Fernier Pascal , Schibli Roger , van der Meulen Nicholas P. 

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

JOURNAL=Frontiers in Medicine

VOLUME=8

YEAR=2021

URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2021.643175

DOI=10.3389/fmed.2021.643175

ISSN=2296-858X

ABSTRACT=<p>The β<sup>−</sup>-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 <sup>168</sup>Er<sub>2</sub>O<sub>3</sub>. 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 <sup>169</sup>Er from <sup>168</sup>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 <sup>169</sup>Er. The quality of the <sup>169</sup>Er product permitted radiolabeling and pre-clinical studies. A preliminary <italic>in vitro</italic> experiment was accomplished, using a <sup>169</sup>Er-PSMA-617, to show the potential of <sup>169</sup>Er to reduce tumor cell viability.</p>