In this research study, the investigators are testing a new type of breast camera, called Molecular Breast Imaging, to see if it can find tumors in the subject's breast.

Patients who are suspected to have DCIS based on mammographic findings will be invited to participate in this study. The investigators plan to recruit 200 patients who are scheduled to undergo a breast biopsy for a breast lesion considered suggestive or highly suggestive of DCIS as determined by a radiologist specializing in breast imaging. Each patient will have a suspicious area of calcification on mammography of extent < 3 cm, or a non-focal area of abnormality on ultrasound or MRI that is scheduled for evaluation by biopsy. Each patient will undergo an MBI study immediately prior to biopsy. The study coordinator will approach these patients and inform them of the research project. If they are interested in participating, informed consent will be obtained and the patient will be scheduled for the MBI study prior to the breast biopsy.

Inclusion Criteria:

• Women with a breast lesion suspicious for DCIS who are scheduled for a stereotactic breast biopsy.
• Lesion must be considered suggestive or highly suggestive of malignancy according to the Breast Imaging Reporting and Data System Atlas criteria (BIRADS 4 or 5).
• Women between 25 and 90 years of age.

Exclusion Criteria:

• Unable to understand or sign a consent form.
• Pregnant or lactating.
• Physically unable to sit upright and still for 30-40 minutes.

Prospective patients will be identified by the radiologist based on findings in their mammographic, ultrasound or MRI studies. Patients who are suspected to have DCIS based on mammographic findings will be invited to participate in this study.