The radioactive nuclide used in TAT is:

A new field is Targeted Alpha Therapy (TAT) or alpha radioimmunotherapy, especially for the control of dispersed cancers. The short range of very energetic alpha emissions in tissue means that a large fraction of that radiative energy goes into the targeted cancer cells, once a carrier such as a monoclonal antibody has taken the alpha-emitting radionuclide to exactly the right place. TAT using lead-212 is said to show promise for treating pancreatic, ovarian and melanoma cancers.