Efficient formation of inert Bi-213 chelates by tetraphosphorus acid analogues of DOTA: towards improved alpha-therapeutics.

Cyclen derivatives bearing four N-methylenephosphonic or -phosphinic acid substituents, e.g., DOTP, are capable of complexing the alpha-emitting radionuclide 213BiIII with higher efficiency and in-vitro stability than the current gold standards DOTA and CHX-A"-DTPA.