| This dissertation describes investigations of microscopic endogenous optical contrast sources in normal and diseased breast tissues. Emphasis has been placed on investigation of the scattering and refractive index properties that can be detected using coherence-based optical techniques. Studies have been conducted in various biological systems, including isolated cells, animal models, and surgically excised human specimens. These investigations have shown that coherence-based techniques can measure clinically relevant scattering and refractive index changes with high sensitivity, allowing for accurate differentiation between breast tissue types.; These findings have been applied to the clinical problems of metastatic cell identification and biopsy needle localization. The latter is important due to the high rate of nondiagnostic tissue removal using current guidance techniques. Up to 10% of the approximately one million breast needle biopsies performed every year in the United States yield incorrect samples and inconclusive diagnoses, often resulting in additional surgical procedures. This poor outcome is due in large part to the inability of clinicians to spatially localize suspicious tissues during biopsy procedures. This problem has been addressed with the development of a clinically compatible fiber optic needle device capable of accurately measuring refractive index and scattering in situ. Preliminary intraoperative investigations with this device have yielded promising results. |
