Speaker
Description
A quartet of short-lived terbium isotopes, $^{149}$Tb, $^{152}$Tb, $^{155}$Tb and $^{161}$Tb, has been identified to have complementary decay characteristics with a unique potential to cover all modalities of nuclear medicine in both therapy and diagnostics [1]. Of particular interest is the alpha-emitter, $^{149}$Tb, which could fill the gap in targeted alpha therapy. However, the production of these isotopes, aside from reactor-produced $^{161}$Tb, remains challenging, with current methods unable to meet the demands of sustained preclinical research [2].
The Isotope Separation On-Line (ISOL) technique is currently the only method capable of producing enough activity of $^{149}$Tb, $^{152}$Tb and $^{155}$Tb with high enough radioisotopic purity for development of terbium-based radiopharmaceuticals [2]. However, because terbium is non-volatile, it is notoriously difficult to extract as an ion beam with sufficient intensity and purity. As a result, terbium isotopes are currently produced indirectly through the extraction of laser-ionized dysprosium [1]. The development of isotope extraction via molecular sidebands offers a promising pathway to access non-volatile elements, such as terbium, that are otherwise difficult to extract directly from the target [3–5].
In this work, we report on systematic studies of terbium fluoride beams performed at CERN-ISOLDE, using a tantalum target coupled to a hot plasma ion source with the injection of reactive tetrafluoro-methane (CF$_4$) gas. The ion beam composition was investigated as a function of target, ion source, and gas injection conditions to optimise the terbium fluoride beam delivery. To gain insight into the underlying physics processes, the extended isotopic chain between masses A=144-168 was explored, as well as other lanthanides in this mass range. Beam composition identification and yield measurements were primarily conducted using the ISOLTRAP MR-ToF MS [6], complemented by offline gamma and alpha spectrometry. Moreover, these studies provided valuable information on the behaviour of other lanthanide beams.
The future of large-scale terbium isotope production lies in the optimization of extraction techniques which can be applied at emerging facilities such as ISOL@MYRRHA and TATTOOS@PSI. The presented work is a part of ongoing efforts to optimise production of terbium radionuclides for clinical and preclinical applications.
[1] C. Müller et al. “A unique matched quadruplet of terbium radioisotopes for PET and SPECT and for α-and β-radionuclide therapy: An in vivo proof-of-concept study with a new receptor-targeted folate derivative.” Journal of nuclear medicine 53.12 (2012): 1951-1959.
[2] N. Naskar and S. Lahiri. "Theranostic terbium radioisotopes: challenges in production for clinical application." Frontiers in medicine 8 (2021): 675014.
[3] J. Ballof "Radioactive molecular beams at CERN-ISOLDE." CERN PhD Thesis (2021).
[4] M. Au et al. "Production and purification of molecular 225Ac at CERN-ISOLDE." Journal of Radioanalytical and Nuclear Chemistry 334.1 (2025): 367-379.
[5] M. Au et al. "In-source and in-trap formation of molecular ions in the actinide mass range at CERN-ISOLDE." Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 541 (2023): 375-379.
[6] R. Wolf et al. “ISOLTRAP's multi-reflection time-of-flight mass separator/spectrometer”, International Journal of Mass Spectrometry Volumes 349–350, 1 September 2013, 123-133
| Email address | wiktoria.wojtaczka@kuleuven.be |
|---|---|
| Supervisor's Name | Thomas Elias Cocolios |
| Supervisor's email | thomas.cocolios@kuleuven.be |
| Funding Agency | FWO |
| Classification | Applications of radioactive ion beams |
