68-Ga-RM2 PET/MRI in Imaging Patients With Estrogen Receptor-Positive Breast Cancer

PRIMARY OBJECTIVES: I. To evaluate the feasibility of 68-Ga RM2 PET/MRI for identification of estrogen receptor positive primary breast cancer and metastases OUTLINE: Patients receive 68-Ga-RM2 intravenously (IV) and after 45 minutes undergo PET/MRI over 30-60 minutes. After completion of study, patients are followed up at 24-72 hours, and then for 12 months.