Endorsing Titanium-Scandium Radionuclide Generator for PET and Positronium Imaging

P. Moskala, b, A. Khreptaka, b, J. Choińskic, P. Jonesd, I. Kadenkoe, A. Majkowska-Pilipf, R. Palitg, A. Stolarzc, R. Walczakf, E. Stępieńa, b aM. Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza 11, 30-348 Kraków, Poland bCenter for Theranostics, Jagiellonian University, Kopernika 40, 31-501 Kraków, Poland cHeavy Ion Laboratory, University of Warsaw, Ludwika Pasteura 5A, 02-093 Warsaw, Poland diThemba LABS, National Research Foundation, Old Faure Rd, Mfuleni, 7100 Cape Town, South Africa eDepartment of Nuclear and High Energy Physics, Taras Shevchenko National University of Kyiv, Volodymyrska Str. 64/13, 01601 Kyiv, Ukraine fCentre of Radiochemistry and Nuclear Chemistry, Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195 Warsaw, Poland gDepartment of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Dr Homi Bhabha Rd, Colaba, 400005 Mumbai, India

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The development of positron emission tomography and positronium imaging techniques is strictly related to the availability of suitable radionuclides and robust radiochemistry platforms. Among the emerging candidates, 44Sc has attracted significant interest due to its favourable physical properties, including a half-life of ~4 h, a pure β+ emission profile, and the additional prompt γ-emission that enables advanced triple-photon detection schemes. These characteristics make 44Sc particularly promising for high-resolution imaging and novel quantitative methodologies. However, routine clinical and preclinical implementation requires a practical, sustainable, and cost-efficient production route. In this context, we propose a titanium-scandium radionuclide generator as an optimal solution. This study focuses on optimising the synthesis of the long-lived parent isotope, 44Ti (T1/2=59.1 years), from which 44Sc can be selectively eluted in a chemically pure form when needed. An analysis of various production pathways was conducted, including proton and deuteron reactions on scandium, as well as α-particle and lithium-induced reactions on calcium, to determine the most efficient reaction parameters, target design, and expected yield. Furthermore, we identify some existing cyclotron facilities suitable for implementing this technology. Results indicate that efficient 44Ti production is achievable using proton beams in the 20-30 MeV range under extended irradiation conditions. The proposed generator system would enable routine and decentralised 44Sc supply. Its integration with the novel Jagiellonian positron emission tomography scanner may significantly reduce diagnostic costs and improve access to advanced positron emission tomography imaging in regions with limited medical imaging infrastructure.

DOI:10.12693/APhysPolA.148.S152 topics: 44Ti/44Sc generator, positron emission tomography (PET), positronium imaging, Jagiellonian positron emission tomography (J-PET)