Study of the proton-induced production of the theranostic radionuclide 47Sc

The research activities reported in this thesis were conducted in the framework of a collaboration between the Physics and Astronomy Department of the Padova University and the Legnaro National Laboratories of the National Institute of Nuclear Physics (INFN-LNL), where the LARAMED (LAboratory of RADionuclides for MEDicine) project was developed since 2012. The aim of this project is to investigate new or alternative cyclotron-based production routes for standard or emerging medical radionuclides for innovative radiopharmaceuticals. 47Sc is a promising theranostic radionuclide thanks to its γ and β− decay emissions which can be employed in imaging and therapeutic medical applications, respectively. At present, the challenge is to find a valid production route which allows to obtain large and enough pure quantities. The first step to evaluate a possible production route is the measurement of the cross-sections. For this reason, in this work the proton-induced nuclear reactions on enriched 48Ti, 49Ti and 50Ti targets are presented, concerning not only the production of 47Sc but also of its contaminants, namely 43Sc, 44m,gSc, 46Sc, 48Sc, 48V, and 43K. Co-produced contaminants play a key role in the assessment of the purity of the final product: their production has to be avoided to reduce the useless radiation dose to a patient. The quantification of the extra dose administered to human organs is possible through dosimetric simulations. In this thesis dosimetric analysis for the production routes involving enriched 48Ti, 49Ti and 50Ti targets and the natV are provided, considering the DOTA-folate conjugate cm10 as an example of radiopharmaceutical. Limitation in the amount of the additional dose due to co-produced contaminants allows to individuate which are the optimal beam energy interval and irradiation time for the 47Sc production. From cross-section trends and dosimetric studies, with also the support of theoretical simulations performed by collaborators expert in nuclear modelling, a multilayer target composed by a first layer of natV and a second layer of 50Ti was designed, and described in an INFN patent (request number 102023000018477), to maximize the 47Sc production keeping the presence of contaminants below 1%.