This is a prospective, one-arm, observational study which will enroll patients with newly diagnosed breast cancer scheduled for diagnostic breast MRI for preoperative staging/extent of disease evaluation as part of standard of care. Participation in this research study includes a directed breast PET/MRI and PET/CT with the investigational radiopharmaceutical, FFNP. FFNP uptake of the known, biopsy-proven malignancy will be measured on the PET/MRI and PET/CT examinations using standardized uptake values (SUV) and tumor-to-normal tissue ratios.