New scan could reveal if chemo is working in just weeks

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Female * Participant will be receiving neoadjuvant chemotherapy at the Massachusetts General Hospital (MGH) Center for Breast Cancer. * Participants must have measurable disease, defined as at least one lesion that can be accurately measured as ≥10 mm in the longest diameter with breast MRI, mammography or ultrasound. See Section 11 for the evaluation of measurable disease. * Patients must have Humane Epidermal Growth Factor Receptor (HER2) positive (regardless of Hormone Receptor (HR) status) or Triple Negative (TN) disease as confirmed by pathology. HER2 positive is defined according to ASCO-CAP guidelines, and patient will be receiving HER2 directed therapy. TN is defined as Estrogen Receptor \<=1%, Progesterone Receptor \<= 1%, and HER2 negative by American Society of Clinical Oncology (ASCO) - College of American Pathologists (CAP) guidelines. For tumors with discordant or borderline receptor findings, the Principal Investigator will adjudicate the final decision. * Age 18 and above. * Ability to understand and the willingness to sign a written informed consent document Exclusion Criteria: * Patients with open wounds on the breast. * Patients who have undergone breast surgery or breast biopsy 10 days or less prior to the first planned optical imaging scan. * Patients with breast implants. * Patients whose primary lesion is outside the field of view of the optical imaging system. * A history of ipsilateral disease (including invasive breast cancer, ductal carcinoma in situ (DCIS), and benign lesions) or breast surgery. * Patients who are pregnant or trying to become pregnant. * Medical or psychiatric conditions which, in the opinion of the investigator, might result in risk to the subject from participation in the study or inability to complete the study. * For patients who agree to participate in the optional MRI study, these following additional exclusion criteria also apply: * Neurostimulators; * Pacemakers; * Implanted metallic material or devices (metal implants or large tattoos in the field of view); * Severe claustrophobia; * Physical characteristics (weight and/or size) that exceed the capabilities of the MRI scanner; * Known allergy or hypersensitivity reactions to gadolinium, versetamide, or any of the inert ingredients in gadolinium-based contrast agents; * Severe renal insufficiency, e.g., estimated glomerular filtration rate \< 30 mL/min.