Question: what are the properties of the lanthanide and rare earth metal samarium that make it suitable to treat cancer?

Daren Fearon answered on 27 Jun 2014:

Samarium lexidronam can be used to treat pain when cancer has spread to the bone. It is preferentially absorbed in areas of the bone which have been effected by cancer where it can then kill cells as it decays emitting beta particles. The radioactivity of 153Sm and it’s short half life is what makes it suitable for killing cells but it can’t differentiate between healthy cells and cancer cells.