This study will determine the rate of complete tumor ablation of small breast cancers (≤ 20mm) by Novilase Interstitial Laser Therapy (ILT), and determine the sensitivity and specificity of imaging (MRI, mammography and ultrasound) in detecting residual tumor post ILT ablation as correlated to histopathology from the post-ablation excision.

Inclusion Criteria:

• Females 18 to 80 years of age
• Tumor is well visualized through x-ray mammography or ultrasound imaging and amenable to image guidance therapy (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 must be well visualized (as defined above) on MRI
• Definitive pathologic diagnosis by needle core biopsy
• Unifocal malignant tumor that does not exceed 20mm in diameter and measures at least 5mm away from the skin and chest wall
• Cluster of microcalcifications that do not exceed 10 mm in diameter and measures at least 5mm away from the skin and chest wall
• Subjects with or without palpable lymph nodes
• Subjects with mammographic appearance of overall dense parenchymal tissue may be included, as long as a clearly evident marker is present at tumor site
• Subjects with less than 25% intraductal component
• Subject has no clinically significant co-morbidities (i.e. chronic illnesses existing simultaneously with and usually independent of breast cancer) that affect life expectancy. Subject has given written informed consent
• Subject agrees to comply with follow up visits

Exclusion Criteria:

• Subjects younger than 18 years of age
• Pregnant or breast-feeding women
• Tumors poorly visualized by x-ray mammography or ultrasound imaging
• Women who are morbidly obese (>300 lbs)
• Acute or chronic severe renal insufficiency (Glomerular filtration rate (GFR) <30ml/min/1.73 sq.meters)
• Moderate to end-stage kidney disease and a history of severe asthma or allergies
• Tumors measuring greater than 20mm in diameter
• Subjects with advanced stage breast cancer
• Subjects with prior history of cancer in the ILT treated breast
• Subjects with recurrent breast cancer
• Subjects with lobular neoplasm, metastatic carcinoma to breast, sarcoma, Phylloides tumor, or Paget's disease
• Subjects with benign vascular tumor
• Subjects with benign lesions such as fibroadenoma, atypical ductal hyperplasia, sclerosing adenosis, Papilloma, fibrocystic disease of breast
• Subjects with DCIS with microinvasion
• Subjects with a cluster of microcalcifications whose diameter is larger than 10 mm.
• Subjects with extensive intraductal component and other characteristics not well visualized by imaging studies
• Subjects who are BRCA positive.
• Inability to lie prone or supine for one hour
• Currently participating or enrolled in another investigational treatment, device or drug study through follow up
• Undergoing concurrent neoadjuvant therapies for breast cancer
• Cardiac pacemaker or other metallic implants which would prevent patient from safely undergoing MRI scan