Towards a dry separation method of radioscandium from bulk amounts of titanium.

True theranostic radionuclide pairs are gaining interest in nuclear medicine. However, their application is limited due to their reduced availability. Sc is a promising therapeutic partner to the diagnostic Sc and Sc due to its ideal half-life and beta energy. This study attempted to develop a dry, gas-solid phase separation of non-carrier-added radioscandium from macro amounts of titanium. The results showed a 99.9% release of Sc from Ti foil of 50 μm thickness at 1100 °C in vacuum. Furthermore, a Monte Carlo model was developed to describe the release of Sc from Ti as a function of temperature and foil thickness. With this model the desorption energy of Sc from Ti surfaces was determined to be 390 ± 5 kJ/mol in excellent agreement with theoretical predictions. In an attempt to recover the evaporated Sc on a cold finger, highest overall yields of 65% were observed for gold surfaces. For other catcher materials such as Ti, Ta, and brass significantly lower overall yields between 27 and 47% were determined. Furthermore, it was not possible to quantitatively remove the Sc from the Au catcher, even when washing with concentrated acids. Attempts to increase the release of scandium from thick, sintered Ti samples failed to show an improvement over solid titanium.