Protherium has been coined from “Pro” in Latin meaning “for”, “the purpose of”, then “Ther” shortens from “Therapy”, and the termination “ium”, used in some historically important and still in use radioactive nuclides such as Technetium, Gallium, Rhenium, Lutetium or Actinium. Indeed, the termination does not reflect the most recent progresses in therapy such as Iodine, Lead or Astatine.

It happens that Protherium is also an obsolete word for a subclass of mammals that included egg-laying mammals, also known as Prototheria. This group counts the living monotremes, such as the platypus and echidnas. Considering that the platypus is one of the most unique and fascinating creatures on Earth - a mammal that secretes milk, lays egg, has a duck-like bill, and venomous spurs - there is a clear parallel with radiopharmaceuticals, which stand as the most original, complex and intriguing drugs in the pharmaceutical world.