This technology includes a newly designed, truncated Evans Blue (EB) form which allows labeling with metal isotopes for nuclear imaging and radiotherapy. Unlike previous designs, this new form of truncated EB confers site specific mono-labeling of desired molecules. The newly designed truncated EB form can be conjugated to various molecules including small molecules, peptides, proteins and aptamers to improve blood half-life and tumor uptake, and confer better imaging, therapy and radiotherapy. As a proof of concept, we chose to conjugate the new truncated EB to Arg-Gly-Asp (RGD) tripeptide, which binds to integrin avl33. lntegrin avl33 is a molecular marker for angiogenesis which is significantly upregulated in cancerous tissue and can be used as a target for therapy.