New excitation functions for proton induced reactions on natural gadolinium up to 70 MeV with focus on $^{149}$ Tb production

International audienceTerbium is one of the most interesting elements for new potential theranostics applications. Indeed, the physical properties of four of its radionuclides ( $^{149}$ Tb, $^{152}$ Tb, $^{155}$ Tb, $^{161}$ Tb) allow their use in each main applications of nuclear medicine. $^{149}$ Tb is the lowest mass alpha emitter with suitable physical properties for receptor-targeted alpha therapy (TAT), and the only one among the radiolanthanides. Currently $^{149}$ Tb is only produced through spallation reactions induced by high-energy proton beam coupled with mass separation to obtain suitable purity. The aim of the present work is to investigate the production of $^{149}$ Tb using commercial cyclotrons by irradiation of natural gadolinium target. New excitation functions for proton-induced nuclear reactions on natural gadolinium have been measured. Our results extend current knowledge up to 70 MeV and are in good agreement with existing data at low energy. From this new set of data, production yield estimations are calculated and discussed