Theranostic Terbium Radioisotopes: Challenges in Production for Clinical Application

Currently, research on terbium has gained a momentum owing to its four short-lived radioisotopes, 149Tb, 152Tb, 155Tb, and 161Tb, all of which can be considered in one or another field of nuclear medicine. The members of this emerging quadruplet family have appealing nuclear characteristics and have the potential to do justice to the proposed theory of theranostics nuclear medicine, which amalgamates therapeutic and diagnostic radioisotopes together. The main challenge for in vivo use of these radioisotopes is to produce them in sufficient quantity. This review discusses that, at present, neither light charged particle nor the heavy ion (HI) activation are suitable for large-scale production of neutron deficient terbium nuclides. Three technological factors like (i) enrichment of stable isotopes to a considerable level, (ii) non-availability of higher energies in commercial cyclotrons, and (iii) non-availability of the isotope separation technique coupled with commercial accelerators limit the large scale production of terbium radionuclides by light charged particle activation. If in future, the technology can overcome these hurdles, then the light charged particle activation of enriched targets would produce a high amount of useful terbium radionuclides. On the other hand, to date, the spallation reaction coupled with an online isotope separator has been found suitable for such a requirement, which has been adopted by the CERN MEDICIS programme. The therapeutic 161Tb radionuclide can be produced in a reactor by neutron bombardment on enriched 160Gd target to produce 161Gd which subsequently decays to 161Tb. The radiochemical separation is mandatory even if the ISOL technique is used to obtain high radioisotopic purity of the desired radioisotope.

Charged particle activation facility in NPI CAS and in future GANIL/SPIRAL2-NFS

The proton, deuteron and alpha induced reactions are of a great interest for the assessment of induced radioactivity of accelerator components, targets and beam stoppers as well as isotope production for medicine and also to nuclear astrophysics. We present a new irradiation chamber for activation measurements, that forms a prolongation of long-term experimental activities using stacked-foil activation technique in NPI CAS, Řež. The chamber is based on an airlock system and is coupled to a pneumatic transfer system delivered by KIT Karlsruhe. This system is installed in GANIL/SPIRAL2-NFS and will be used for proton, deuteron and alpha particle activation measurements with long- and short-lived isotopes.