BME PhD Prospectus Defense - Sam Spink

  • Starts: 11:00 am on Thursday, June 4, 2020

Title: “Paced breathing hemodynamics in breast tumors measured with a high optode-density wearable diffuse optical probe”

Committee: Darren Roblyer, PhD – BU BME (Advisor, Chair) David Boas, PhD – BU BME Irving Bigio, PhD – BU BME Naomi Ko, MD – BUSM Medicine, Hematology and Medical Oncology Adam Eggebrecht, PhD – WUSTL Radiology

Abstract: It is becoming increasingly common to treat locally advanced breast cancer (LABC) patients with neoadjuvant chemotherapy (NAC) in order to shrink tumor size so that more breast-preserving surgeries can be performed. However, only 30% of LABC patients receiving NAC achieve a pathologic complete response. It would be valuable to predict patients’ response to NAC at early time points so that the treatment regimen could be dynamically altered to improve patient outcomes. Diffuse optical imaging (DOI) has been utilized to noninvasively identify biomarkers that can predict treatment response within the first days, weeks, and months of treatment, with these studies primarily focusing on monitoring changes in hemoglobin, lipid, and water over these time scales. However, less explored in tumors are hemodynamics occurring at time scales on the order of seconds to minutes. Furthermore, the majority of DOI tools used in these studies suffer from limited portability, flexibility, spatial information, and/or lack of patient comfort.

The goal of the proposed work is to utilize a wearable, high optode-density continuous¬ wave (CW) diffuse optical probe to monitor hemodynamics related to paced breathing in both healthy and diseased populations, and to determine if metrics related to these hemodynamics can identify tumor contrast. Previously designed in the Roblyer Lab, this rigid-flex probe consists of 32 LED sources and 16 detectors, and can conform to the shape of breast tissue. Measurements during a cuff occlusion indicate that the probe can quantify hemodynamics temporally, and measurements on spatially-complex phantoms will be used to validate the ability to reconstruct spatial contrast. A normal volunteer study is currently ongoing, and preliminary results indicate that paced breathing hemodynamics can be quantified in healthy subjects. A clinical study is proposed that will involve measurements on breast cancer patients in order to determine if tumor contrast be identified with these hemodynamic metrics, using both topographic and tomographic reconstructions.