The purpose of this study is to evaluate molecular breast imaging in the workup of patients with a history of bloody nipple discharge, not reproducible in the office who have a negative clinical breast examination, and a negative diagnostic mammogram and breast ultrasound.

Although the cause of bloody nipple discharge is benign in most cases, the evaluation is focused on excluding a malignant cause. When bloody nipple discharge is clinically reproducible, management traditionally involves surgical duct excision. When bloody nipple discharge is not reproducible and mammogram and ultrasound are negative the management relies on "watchful waiting" - serial breast imaging to exclude a focal finding and continued observation for recurrent bloody nipple discharge. This approach provokes anxiety among patients who do not have a clear explanation for the bloody nipple discharge. Galactography is useful when positive, but has a high false-negative rate. MRI has not been studied in this context and is costly. Ductoscopy may play a diagnostic role in the future, but experience and equipment are limiting variables. The availability of a less costly method of excluding breast cancer would be of great value in this population.

Molecular Breast Imaging (MBI) is a highly promising novel methodology for breast cancer detection developed under the leadership of Dr. Michael O'Connor at Mayo Clinic, Rochester, MN. Preliminary patient studies with our dual-detector system indicate that this system is capable of reliably detecting very small (5-10 mm) malignant lesions in the breast.

Inclusion Criteria:

• Women age 25 - 75
• Women with a negative diagnostic mammogram and ultrasound
• Women with a history of bloody nipple discharge which can not be reproduced by the examining physician or the patient in the office

Exclusion Criteria:

• Pregnant or lactating
• Unable to understand or sign a consent form
• Physically unable to sit upright and still for 40 minutes