The document describes a project to develop a nanoparticle-based molecular probe targeted to HER1-overexpressing breast cancer cells for diagnosis. The probe would use quantum dot nanoparticles conjugated to an anti-EGFR single chain antibody for multi-modal MRI and fluorescence imaging of breast cancer in mouse models. The objectives are to develop Gd3+- and 64Cu-labeled quantum dots coated with the targeting antibody, characterize their targeting ability and toxicity, and use them for MRI and fluorescence imaging of breast cancer xenografts in mice.