Advances in Spectroscopic Optical Coherence Tomography

Winkelmann, James A

doi:https://doi.org/10.21985/n2-k7hn-v636

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Advances in Spectroscopic Optical Coherence Tomography

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Despite improvements to diagnostics and treatment methods, colorectal cancer remains the second leading cause of cancer death in the United States. Colonoscopies, the gold standard for colorectal cancer screening, can significantly increase the patient’s chance of survival through early detection. However, colonoscopy cost, surgical complications, and patient bowel preparations limit its ability to be utilized as a population-wide diagnostic method. Colonoscopies rely on the presence of large-scale morphological features of cancer progression i.e., tumors. However, these hallmark manifestations are some of the final steps of the cancer progression process and are not evident across the entire organ. At the earliest stage of cancer progression, the field effect occurs which results in an organ-wide change to nanoscale tissue properties and microvasculature. Therefore, field effect detection technology could provide a minimally invasive pre-screen to colonoscopy by only scanning the rectum and not the entire colon. Here we advance spectroscopic optical coherence tomography (a three-dimensional spectroscopy technique) towards detecting field effect biomarkers and work towards a clinically compatible probe for rectal insertion. First, a benchtop spectroscopic optical coherence tomography system was developed that allows for the first time a single system to obtain nanoscale tissue properties at length scales down to 30 nm, single capillary oxygenation, arteriolar level oxygen delivery rates, and morphological imaging up to 2 mm. Second, the first fiber-based visible light optical coherence tomography probe was developed providing an unprecedented axial resolution of ~1.1 microns in tissue and in vivo three-dimensional mapping of nanoscale tissue properties. Third, a blood vessel imaging algorithm called spectral contrast optical coherence tomography angiography was developed. This algorithm allows for three-dimensional imaging of microvasculature with a single scan, the novel ability to image non-flowing blood, and lymphatic capillary imaging with endogenous contrast.

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