The objective of the proposed research is to develop a clinical-trial-ready device and to evaluate its practical utility as a routinely used intra-operative tool. Our multidisciplinary group has previously shown that optical techniques can effectively discriminate between malignant and non-malignant breast tissues. The proposed technology will be a multi-channel optical assay device for intra-operative imaging of margins in specimens excised from patients undergoing breast conserving surgery (partial mastectomy) or mastectomy.

Inclusion Criteria:

• Patients undergoing a partial mastectomy or mastectomy for the treatment of an invasive or non-invasive breast malignancy
• Age > 18
• Clinically detectable disease either by physical examination or radiographic studies
• Patients of all ethnic and gender groups will be included. Protocol accrual will be reviewed annually to include a determination of minority and gender representation. If accrual demonstrates under representation of any group with comparison to disease incidence in that group, appropriate measures will be undertaken to increase participation of patients of that minority or gender group.
• Ability to understand and the willingness to sign a written informed consent document

Exclusion Criteria:

• Patients considered in "vulnerable" populations

There are 2 groups of patients and each group contains 20 participants.