Abstract
Background: Theranostic strategies, which combine diagnostic and therapeutic agents, involve select radionuclides that allow diagnostic imaging and tailored radionuclide therapy in the same patient. An example of an FDA-approved theranostic pair are the 68Ga and 177Lu labeled DOTATATE peptides, which are used to image neuroendocrine tumors, predict treatment response, and treat disease. However, when using radionuclides of two different elements, differences in the pharmacokinetic and pharmacodynamic profile of the agent can occur. Theranostic agents that incorporate the matched-pair radionuclides of Sc, 43Sc/47Sc or 44Sc/47Sc, would guarantee identical chemistries and pharmacological profiles. The aim of this study was to investigate production of 43,44,47Sc via proton-induced nuclear reactions on Ti nuclei using a 24MeV cyclotron. Methods: Al, Nb, and Ta target holders were used with Ti foils and pressed TiO2 to produce Sc radionuclides with proton energies up to 24MeV. Irradiated targets were digested using NH4HF2 and HCl in a closed perfluoroalkoxy alkane vessel in 90min. Scandium radionuclides were purified via ion-exchange chromatography using branched N,N,N’,N’-tetra-2-ethylhexyldiglycolamide (BDGA). The Ti target material was recovered via alkali-precipitation with ammonia solution. Results: Titanium foil and TiO2 were digested with an average efficiency of (98±3)% and (95±1)%, respectively. The typical digestion time was 45min (Ti foil) and 75min (TiO2). The average Sc recovery was (94±3)% and the average Ti recoveries from digested Ti foil and TiO2 post-precipitation as TiO2 were (108±8)% and (104±5)% of initial mass, respectively. Conclusion: This work demonstrated a robust method for the cyclotron production of Sc radionuclides that could be used with natural or enriched TiO2 target material.
- PET
- Radiochemistry
- Radionuclide Therapy
- Cyclotron Production
- Scandium-43
- Scandium-44
- Scandium-47
- Ti Digestion
- Copyright © 2020 by the Society of Nuclear Medicine and Molecular Imaging, Inc.