Upon radiolabeling with appropriate radionuclides, such as gallium-68, technetium-99 m, and copper-64, GRPR antagonists have proven their usefulness as PET/SPECT/CT tracers in several preclinical and clinical studies and have also demonstrated the advantages of using a targeted imaging approach over unspecific tracers, such as 2-[18F]FDG, for BC diagnosis, staging and re-staging (88). This evidence concerns the gene GRPR and breast cancer.