Cyclotron production of 44Sc for clinical application

Abstract 44 Sc is a promising β + -emitter for molecular imaging with intermediate half-life of 4 h. Due to the chemical similarity of Sc 3+ to the Lu 3+ and Y 3+ cations, 44 Sc-DOTA bioconjugates are expected to demonstrate similar properties in vivo as the 177 Lu- and 90 Y-bioconjugates, what is important in planning the radionuclide therapy. 44 Sc can be obtained from the 44 Ti / 44 Sc generator. An alternative method for 44 Sc production can be the irradiation of 44 Ca target at small cyclotrons. The aim of our work was to optimize the parameters of 44 CaCO 3 irradiation and to develop a simple procedure for 44 Sc separation from the calcium target. For optimization study, 44 CaCO 3 targets were irradiated by protons in the energy range of 5.6–17.5 MeV with 9 MeV being found to be the best energy for 44 Ca irradiations. A simple and fast separation procedure of 44 Sc from calcium target was developed using chelating resin Chelex 100. DOTATATE conjugate was successfully radiolabelled with high yield at elevated temperature using the produced 44 Sc. While 44 CaCO 3 is relatively expensive, the cost of 44 Sc-DOTATATE production can be reduced by target recovery. Due to low proton energy required to produce GBq activity level of 44 Sc, the availability of 44 Sc radioisotope could be enhanced to open new opportunities for applications in medical imaging.