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

Area of Science:

• Nuclear Medicine
• Radiochemistry
• Materials Science

Background:

• True theranostic radionuclide pairs are essential in nuclear medicine but face availability challenges.
• Scandium-47 (⁴⁷Sc) is a promising therapeutic radionuclide, complementing diagnostic isotopes like ⁴³Sc and ⁴⁴Sc due to its favorable decay properties.

Purpose of the Study:

• To develop an efficient dry, gas-solid phase separation method for isolating non-carrier-added radioscandium (⁴⁷Sc) from bulk titanium (Ti).
• To characterize the release dynamics of scandium from titanium and optimize recovery yields for potential clinical applications.

Main Methods:

• Investigated the release of ⁴⁷Sc from thin titanium foils at high temperatures (1100 °C) under vacuum.
• Developed a Monte Carlo model to analyze scandium release as a function of temperature and foil thickness.
• Evaluated various catcher materials (gold, titanium, tantalum, brass) for ⁴⁷Sc recovery and assessed the re-leachability of ⁴⁷Sc from gold surfaces.

Main Results:

• Achieved 99.9% release of ⁴⁷Sc from 50 μm thick Ti foil at 1100 °C in vacuum.
• Determined the desorption energy of scandium from titanium surfaces to be 390 ± 5 kJ/mol using the Monte Carlo model.
• Observed maximum overall yields of 65% for ⁴⁷Sc recovery using gold as a catcher material, with significantly lower yields for other materials.
• Found that ⁴⁷Sc could not be quantitatively removed from gold catchers, even with concentrated acids.

Conclusions:

• The developed dry separation method is highly effective for releasing ⁴⁷Sc from titanium.
• Gold surfaces provide the highest recovery yields for evaporated ⁴⁷Sc, although complete removal from the catcher remains a challenge.
• The findings support the potential for improved production and application of ⁴⁷Sc in nuclear medicine theranostics.