This document discusses using radioactive isotopes of rhenium (186Re and 188Re) for cancer treatment. It describes how 188Re is useful for radiotherapy due to its 17-hour half-life and emissions. The author's responsibility was to investigate chelate systems to allow conjugation of rhenium to targeting peptides for in vivo applications. Two N4 chelate ligands were synthesized and characterized, then reacted with rhenium oxide to form complexes for further characterization and testing.