Can we reach suitable 161 Tb purity for medical applications using the 160 Gd(d,n) reaction?

Terbium is a chemical element that has several radioactive isotopes with suitable physical characteristics to be used in medical applications either for imaging or for therapy. This makes terbium a promising element to implement the theranostic approach. For therapeutic applications, Tb (T = 6.89 d) is suitable for targeted β-therapy. The main production route is through neutron capture reaction in nuclear reactors. In this work, we explored an alternative production route, the Gd(d,n) Tb reaction. We have measured its production cross-section as well as those of possible co-produced contaminants, with a special focus on Tb (T = 72.3 d). To achieve this, cross-section measurements were made from natural gadolinium target. Production yields of 10.3 MBq/μA/h for the Tb and 1.5 MBq/μA/h for the Tb were obtained at 20 MeV. A Tb radionuclidic purity of 86% was achieved over the 8 MeV-20 MeV energy range. The co-production of other terbium isotopes limits the interest of using higher energies. Based on the limited purity of Tb using the Gd(d,n) Tb reaction, we conclude that it is not a production route suitable for medical applications. Although, this may be reconsidered when mass separation technique with high efficiency will be available.