The purpose of this study is to determine if PEM scan can improve axillary lymph node staging by assessing if they are involved by cancer. Your doctor may refer you for a PEM scan, PEM stands for positron emission mammography, a relatively new and advanced application of positron emission tomography or PET scanning. For decades, PET has helped doctors diagnose and treat disease.

Subjects will receive bilateral (both sides) breast and axillary PEM scans. All recruited subjects chosen for the study will have biopsy proven breast cancer and are eligible for chemotherapy. They will undergo bilateral breast MRI for staging which is considered standard of care. Breast MRI and PEM scans will be performed at at baseline (phase 0 or pre-operative phase), 2nd MRI and PEM after 1 to 2 weeks of NAC (phase 1) and 3rd MRI and PEM after 1 to 2 weeks of phase 1 (phase 2). DCE-MRI and PEM will be performed not more than 14 days apart within each phase. Cranio-Caudal (CC) and Medial Lateral Oblique (MLO) PEM views will be performed of both the ipsilateral and contralateral breast and axillae by a Mammography Technologist trained in mammographic positioning.

Inclusion Criteria:

• Women 18-75 years old with newly diagnosed breast cancer who are considered candidates for breast conserving surgery (i.e. lumpectomy).

Exclusion Criteria:

• Children (<18 years old)
• Pregnant or Lactating women
• Diabetic patients (Type I or II)
• Patients who are scheduled for a sentinel node procedure using radioactive Tc-99m within 24 hours of PEM
• Patients who have NOT undergone a standard of care bilateral breast MRI at UC.