Chelants and macrocyclic metal complexes thereof, methods of preparing the chelants and macrocyclic metal complexes, and radiopharmaceutical compositions comprising the macrocyclic metal complexes are disclosed. Methods of using the macrocyclic metal complexes as radiopharmaceuticals for the diagnosis of cardiovascular disorders, infectious diseases and cancer are also disclosed. Chelants as bifunctional chelators (BFCs) for the radiolabeling of target-specific biomolecules, such as proteins, peptides, peptidomimetics, non-peptide receptor ligands, enzyme inhibitors, and enzyme substrates are disclosed. Methods of using macrocyclic metal complexes containing the chelant-biomolecule conjugates as target-specific diagnostic radiopharmaceuticals that selectively localize at sites of disease and allow an image to be obtained of the loci using gamma scintigraphy are disclosed. Methods of use of the radiopharmaceuticals as imaging agents for the diagnosis of cardiovascular disorders, such as thromboembolic disease or atherosclerosis, infectious disease and cancer are further disclosed.