Inclusion Criteria:

          -  Females, aged 18 years and older

          -  Able to give written informed consent herself

          -  Definitive pathologic diagnosis by needle core biopsy

          -  Unifocal malignant tumor (T1a-c, N0-1, M0) that does not exceed 15 mm in longest
             dimension and measures at least 5 mm away from the skin and chest wall, or can be
             moved at least 5 mm away from the skin and chest wall by injection of saline or local
             anesthetic

          -  No more than 10 mm of calcifications confined to the tumor on imaging

          -  Tumor is well visualized through ultrasound or x-ray mammography imaging and amenable
             to image-guidance therapy (i.e., a tumor which is well visualized through imaging can
             be identified from surrounding breast tissue and does not have margins obscured by
             other structures or artifacts on the images)

          -  Tumor is well visualized on MRI

          -  Subject with mammographic appearance of overall dense parenchymal tissue may be
             included, as long as a clearly evident marker is present at tumor site

          -  Tumor with less than 25% intraductal component, as determined by core biopsy

          -  No clinically significant co-morbidities (e.g., chronic illnesses existing
             simultaneously with and usually independent of breast cancer) that affect life
             expectancy

          -  Subject weight limited to ≤300 lbs. or ≤136 kg

          -  Subject agrees to comply with standard of care radiation or adjuvant therapy as
             prescribed by physician

        Exclusion Criteria:

          -  Subject younger than 18 years of age

          -  Pregnant or breast-feeding

          -  Tumor poorly visualized by ultrasound or x-ray mammography imaging

          -  Contraindications to administration of gadolinium-based contrast agent, including:
             prior allergic reaction to a gadolinium-based contrast agent, moderate to end-stage
             kidney disease, and/or acute or chronic severe renal insufficiency (Glomerular
             filtration rate (GFR) <30ml/min/1.73 sq. meters)

          -  Contraindications to MRI according to site guidelines (e.g., cardiac pacemaker,
             metallic implants)

          -  History of severe asthma

          -  Tumor measuring greater than 15 mm in longest dimension

          -  Microcalcifications that extend beyond target tumor such that overall longest
             dimension of target tumor and calcifications is longer than 15 mm.

          -  Advanced stage breast cancer

          -  Tumors that are lobular neoplasm, metastatic carcinoma to breast, sarcoma, Phyllodes
             tumor, or Paget's disease

          -  Tumor with only DCIS with microinvasion

          -  Extensive intraductal component in lesion (i.e., >25%) as determined by core biopsy

          -  Subject who is known to be BRCA positive

          -  Tumor that is ER/PR/HER2 negative (TNBC)

          -  Inability to lie in prone or supine position for one hour

          -  Subject who is currently participating in another investigational treatment, device or
             drug study through follow up that would interfere with this trial

          -  Subject who falls into high risk group on Caprini Risk Assessment for deep vein
             thrombosis (DVT) and requires Lovenox (Enoxaparin)

          -  Subject without a definitive HER2 test according to ASCO/CAP guidelines