Phase IV Trial to Evaluate Breast Brachytherapy Using the Mammosite-Ml®

This study will evaluate the local control rate, cosmetic results, and complication rates of breast brachytherapy delivered using the MammoSite-ML® when used as the sole method of radiation therapy or as a boost technique for patients with stage I-II carcinoma of the breast (\< 3 cm), (non-lobular histology) treated with lumpectomy with histologically negative surgical margins by at least 2 mm, negative axillary lymph nodes, and DCIS. Hypotheses: * For selected patients with stage I breast carcinoma and Ductal Carcinoma In Situ (DCIS), radiation therapy delivered with brachytherapy alone using the MammoSite-ML® is technically feasible and reproducible with acceptable complication rates. * Cosmetic results after brachytherapy will be similar to that obtained after traditional whole breast external beam radiation therapy. * Local tumor control rate in the breast after brachytherapy will be similar to that of conventional external beam radiation therapy, with less inconvenience and potentially less cost to the patient, given the selection criteria which minimize the risk of clinically significant multicentric or extensive residual carcinoma following lumpectomy.