A wearable near-infrared diffuse optical system for monitoring in vivo breast tumor hemodynamics during chemotherapy infusions
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Neoadjuvant chemotherapy (NAC) is increasingly being utilized to reduce tumor burden prior to surgery for breast cancer patients with stage II or higher disease. A pathologic complete response (pCR) to NAC has been correlated with longer 5-year survival and is generally considered as an absence of invasive cancer in the breast and axillary nodes at the time of surgery. Unfortunately, only about 10% of patients achieve pCR during NAC, and it may take months after the first infusion to determine response with methods that rely on anatomic information, such as palpation, mammography, ultrasound, and MRI. Functional imaging technologies such as Positron Emission Tomography, Magnetic Resonance Spectroscopy, and more recently, Diffuse Optical Spectroscopy, have shown promise for earlier predictions of therapy response. However, most of these techniques suffer from high expense, lack of portability, and safety issues related to the use of ionizing radiation or exogenous contrast agents. Furthermore, the repeated patient visits required by these techniques may hamper their clinical adoption for this purpose. This project aims to develop a new wearable diffuse optical device that can be used to investigate if very early timepoints during a patient’s first chemotherapy infusion are predictive of overall response (pCR versus non-pCR) to NAC. These timepoints correspond to an already scheduled patient visit and have so far been unexplored for their prognostic value. The development of this continuous-wave diffuse optical imaging device was conducted in three stages. First, a prototype rigid probe was designed and developed to test key optical and electrical components. Second, a high optode-density flexible probe was design and fabricated which can conform to the curved surface of the human breast. Finally, a control box with miniaturized electronics and high-speed electronics was designed and fabricated to complete a clinic-ready system. This system was then tested in both the laboratory setting and as part of a normal-volunteer clinical study in healthy subjects during a breath hold hemodynamic challenge.