Owing to the favorable nuclear and chemical characteristics of 18F for PET diagnostic imaging applications including an appropriate physical half-life (109.7 min) and low positron (β+) energy (0.64 MeV) (Okarvi, 2001; Varagnolo et al., 2000), we here present the radiolabeling with 18F and in vitro and in vivo evaluation of new MUC1 and its FA hybrid peptides for the diagnosis of breast cancer using PET imaging. Here, MUC1 is linked to breast carcinoma.