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. ⁴⁷Sc is a promising therapeutic partner to the diagnostic ⁴³Sc and ⁴⁴Sc 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 ⁴⁷Sc 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 ⁴⁷Sc 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 ⁴⁷Sc 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.