Fonslet, J.Lee, BoonTran, T. A.Siragusa, M.Jensen, M.Kibedi, TiborStuchbery, AndrewSeverin, G. W.2020-06-160031-9155http://hdl.handle.net/1885/205190¹³⁵La has favorable nuclear and chemical properties for Auger-based targeted internal radiotherapy. Here we present detailed investigations of the production, emissions, and dosimetry related to ¹³⁵La therapy. ¹³⁵La was produced by 16.5 MeV proton irradiation of metallic natBa on a medical cyclotron, and was isolated and purified by trap-and-release on weak cation-exchange resin. The average production rate was 407  ±  19 MBq µA−1 (saturation activity), and the radionuclidic purity was 98% at 20 h post irradiation. Chemical separation recovered  >  98 % of the ¹³⁵La with an effective molar activity of 70  ±  20 GBq µmol−1. To better assess cellular and organ dosimetry of this nuclide, we have calculated the x-ray and Auger emission spectra using a Monte Carlo model accounting for effects of multiple vacancies during the Auger cascade. The generated Auger spectrum was used to calculate cellular S-factors. ¹³⁵La was produced with high specific activity, reactivity, radionuclidic purity, and yield. The emission spectrum and the dosimetry are favorable for internal radionuclide therapy.This work was supported by the European Union Seventh Framework Programme FP7/2007-2013 under Grant 602820 (Mathias), and by the Australian Research Council Discovery Grant DP14 0103317.10 pagesapplication/pdfen-AU© 2017 Institute of Physics and Engineering in Medicine. http://ioppublishing.org/wp-content/uploads/2016/05/J-VAR-LF-0216-Author-Rights-New-5.pdf This is an author-created, un-copyedited version of an article accepted for publication/published in Physics in Medicine and Biology. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at DOI 10.1088/1361-6560/aa9b44 (Publisher journal website as of 16/6/2020)lanthanum, radionuclide therapy, isotope production, La-135, Auger therapy2017-12-2910.1088/1361-6560/aa9b442019-11-25