Positron Emission Tomography (PET) Using Hormone Receptor Ligands in Breast Cancer

Inclusion Criteria: * Male and Female patients * Aged 18 or older at the time of breast cancer diagnosis * Patients with invasive breast cancer at least 1 cm in size. Patients who have had a prior surgical excision are eligible provided there is a residual of at least a 1 cm area suspected on imaging studies. * Histopathologic review at MSKCC confirming diagnosis of invasive breast cancer (ductal, lobular, or inflammatory breast cancer). * Patients who are operative candidates. Patient will have surgery to include either mastectomy or lumpectomy. Radiologic assisted excisions such as needle localization are also eligible. * Patients with bilateral breast cancer are eligible. * Patients with metastatic cancer, provided they need surgical biopsy. * Patients who are undergoing sentinel node mapping (day before or sameday mapping). * Patient must sign informed consent. Exclusion Criteria: * Previous or concurrent malignancy (except basal and squamous skin cancer and stage 0 cervical cancer) * Patients who are pregnant or nursing * Patients unable to tolerate PET or PET/CT * Patients with known active infection, autoimmune or inflammatory disease such as sarcoidosis, and rheumatoid arthritis. * Patients with non invasive breast cancer such as DCIS. * Patients who have received prior radiation therapy to the affected breast. * Patients who have received prior chemotherapy, including neoadjuvant chemotherapy or hormonal therapy for breast cancer. * Patients living in a residential care or correctional facility.