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Advancing combined radiological and optical scanning for breast-conserving surgery margin guidance

Abstract

Breast cancer is one of the most common types of cancer worldwide, and standard-of-care treatment for early-stage disease typically involves a lumpectomy or breast-conserving surgery (BCS). BCS involves the local resection of cancerous tissue, while sparring as much healthy breast tissue as possible. State-of-the-art methods for evaluating BCS margins during the procedure are limited, and consequently, the rate of re-excision procedures due to positive margins after initial BCS is near 20% and variable between providers and medical centers. X-ray micro-computed tomography is emerging as a powerful ex vivo specimen imaging technology, as it provides robust three-dimensional sensing of tumor morphology rapidly. However, X-ray attenuation lacks contrast between soft tissues that are important for clinical decision making during BCS. Optical structured light imaging, including spatial frequency domain imaging and active line scan imaging, can act as adjuvant tools to complement micro-CT, providing wide field-of-view, non-contact sensing of relevant breast tissue subtypes on resection margins that cannot be differentiated by micro-CT alone.

This thesis proposal is dedicated to multimodal imaging of BCS tissues to ultimately improve intraoperative BCS margin assessment, reducing the number of positive margins after initial surgeries and reducing the need for costly follow-up procedures. Volumetric sensing of micro-CT is combined with surface-weighted, sub-diffuse reflectance derived from high spatial frequency structured light imaging (e.g., using sharp sinusoidal or line illumination patterns). Sub-diffuse reflectance plays the key role of providing enhanced contrast to a suite of normal, abnormal benign, and malignant breast tissue subtypes. This finding is corroborated through clinical studies imaging BCS specimen slices post-operatively and is further investigated through an observational clinical trial focused on intraoperative micro-CT and optical imaging of whole, freshly resected BCS tumors. The central thesis of this work is that combining volumetric X-ray imaging and optical scanning provides a synergistic multimodal imaging solution to margin assessment, one that could be readily implemented or retrofitted in X-ray specimen imaging systems and could meaningfully improve surgical guidance during initial BCS procedures.

Thesis Committee

• Brian Pogue, PhD, MacLean Professor of Engineering at Dartmouth
• Keith Paulsen, PhD, Robert A. Pritzker Professor of Biomedical Engineering at Dartmouth
• Michael Jermyn, PhD, Adjunct Assistant Professor of Engineering, Dartmouth
• Richard Barth, MD, Professor of Surgery, Geisel School of Medicine, Dartmouth
• Wendy Wells, MD, Chair and Professor of Pathology and Laboratory Medicine, Geisel School of Medicine, Dartmouth
• Lee Wilke, MD, Professor, Division of Surgical Oncology, U. of Wisconsin School of Medicine and Public Health (external)

Contact

For more information, contact Theresa Fuller at theresa.d.fuller@dartmouth.edu.