RecruitingProcedureBreast Margin Study: Routine Cavity Shave Margins Vs. Selective Margins Using Savi Scout®This is a prospective study comparing partial mastectomy performed with routine cavity shave margins and Savi Scout® localization to partial mastectomy performed with selective margins and Savi Scout® localization. The primary objective is to determine the difference in positive margin rate between the two methods. The secondary objectives are to determine the differences in the rate of re-excision, volume of tissue extracted and Breast-Q® score between the two methods. It is hypothesized that the Savi Scout® will allow for decreased volume of tissue excised when compared to routine cavity shave margins without any difference in positive margin rate or rate of re-excision.