The investigators propose to validate the utility of their novel hybrid imaging technique for accurate diagnosis of breast lesions, and for assessing chemotherapy response of cancer treatment and predicting treatment efficacy. The investigators' unique hybrid technique is implemented by simultaneously deploying near infrared (NIR) optical sensors and a commercial ultrasound (US) transducer mounted on a hand-held probe, and utilizing co-registered lesion structure information provided by ultrasound to improve the optical tomography.