Neoadjuvant chemotherapy (NAC) is a common breast cancer treatment that involves administering chemotherapy for 3-6 months prior to surgery. This treatment enables more breast-conserving surgeries and even allows for the omission of surgery in some cases. However, about 31% of patients receiving NAC do not respond to the treatment. Therefore, there is a need for real-time methods to predict treatment response and improve patient outcomes. Over the last two decades, diffuse optical imaging has been investigated as a potential solution to this problem. This noninvasive and inexpensive technology uses near or shortwave infrared (NIR or SWIR) light to illuminate tissue, and detects multiply-scattered photons. However, bulky instrumentation and complicated imaging procedures have limited the clinical adoption of this technology. Furthermore, measured biomarkers including oxy- and deoxy-hemoglobin (HbO2 and HHb, respectively), water, and lipid, have had mixed results in terms of prognostic capability. To address these limitations, a new wearable optical probe technology was developed and validated in this project, including a high-optode density NIR probe for monitoring hemodynamics and a first-generation SWIR probe for quantifying water and lipid. Measurements on tissue-mimicking channel flow phantoms confirmed the ability of the NIR probe to quantify absorption contrast in vitro, and a cuff occlusion measurement demonstrated sensitivity to HbO2 and HHb in vivo. Hemodynamic oscillations at the respiratory rate were also explored in healthy volunteers and breast cancer patients as a potential new biomarker. It was demonstrated that traditional and novel breathing-related hemodynamic metrics provide tumor contrast and can potentially track treatment response. A deep-learning algorithm was developed to extract water and lipid concentrations from multi-distance SWIR measurements. The SWIR probe was validated by comparing measured water and lipid concentrations against ground truth values in emulsion phantoms. This work represents a significant step toward the development of technologies for frequent breast cancer treatment monitoring in the clinic and potentially at home.
| Identifer | oai:union.ndltd.org:bu.edu/oai:open.bu.edu:2144/46643 |
| Date | 30 August 2023 |
| Creators | Spink, Samuel S. |
| Contributors | Roblyer, Darren |
| Source Sets | Boston University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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