(source: https://www.rsc.org/periodic-table/element/89/actinium)

Actinium 225 is a very important isotope for radiotherapy. 

Much effort has gone into producing this isotope (Method For Producing Actinium-225 (2004)), separating it from other actinides (Systems, Apparatus And Methods For Separating Actinium, Radium, And Thorium (2019)) and developing complexes and antibodies to target cancer sites (Actinium-225 Complexes And Conjugates For Targeted Radiotherapy (2002),  One-Step Labeling of Antibodies to High Specific Activity with Actinium-225 (2017)).


All patent information has been obtained from Espacenet (European Patent Office).