Pilot Study to Validate Metallic Markers for Image Guided Radiation Therapy for Breast Cancer Tx

Inclusion Criteria: * Pathologically confirmed stage 0, I or II bilateral or unilateral breast cancer * Any invasive adenocarcinoma or intraductal carcinoma * Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2 * Surgical treatment with lumpectomy (partial mastectomy) * Successful placement of intraparenchymal metallic markers at last breast surgery * Pathologic tumor size \< 5.0 cm (Microscopic multifocality is allowed if total pathologic tumor size is within 5 cm) * Axillary sampling (sentinel node or axillary dissection) performed for axillary nodal staging for all invasive cancers. No axillary sampling is required for ductal carcinoma in situ) * Negative margins of excision. * Radiation treatment to begin within 8 weeks after last surgery or last dose of chemotherapy * Negative post-biopsy mammogram if presented with mammographically detected microcalcifications to ensure removal of suspicious calcifications * History of prior cancers is allowed if patient is without evidence of disease at the time of study entry * Ability to understand and the willingness to sign written informed consent document Exclusion Criteria: * Pregnant or breast feeding at time of study entry. Note: Radiation therapy is teratogenic. Women of child bearing potential must agree to use adequate contraception (abstinence, hormonal or barrier method of birth control) prior to and during study participation. Should a woman become pregnant, she should inform the treating physicians immediately. * Prior in-field irradiation * Stage III or IV breast cancer * Inability to place intraparenchymal metallic markers due to excessive bleeding or other intraoperative complication so that the surgeon deems it inadvisable to place the marker * Pathologic tumor size \>/= 5 cm * Positive or unassessed margins of surgical resection * Diffuse calcifications on mammogram pre- or post-operatively * Positive or suspicious post-lumpectomy mammogram or breast magnetic resonance imaging (MRI) * Multicentric carcinoma in more than one quadrant of the breast * Non-epithelial breast malignancy; Paget's disease of the nipple * Personal history of collagen vascular disease clinically judged to be a contraindication to radiation therapy * Recurrent disease or prior history of ipsilateral breast cancer * Psychiatric or addictive disorders that impair patient's voluntary ability to participate in informed consent or protocol procedures