¹⁶¹Tb is a new, promising radionuclide for tumor therapy. It is produced by irradiation of ¹⁶⁰Gd with neutrons at the Swiss Spallation Neutron Source SINQ at PSI. For radiolabeling reactions 4 mg of ¹⁶¹Tb have to be isolated chemically from 100 mg ¹⁶⁰Gd, with a separation factor better than 10⁶! These neighboring lanthanides can be separated using cation exchange chromatography. The separation has to be performed in lead shielded hotcells and with remote control.
The process allows the production of therapeutic amounts of ¹⁶¹Tb in formulation and quality useful for radiopharmaceutical applications.

The work has been performed by Holger Dorrer and Konstantin Zhernosekov in the group of Prof. Andreas Türler.