Optical Coherence Tomography

Optical Coherence tomography (OCT) is a technique that makes it possible to see deep inside an object using light without cutting the object. It is one of the most promising biomedical diagnostic tools available today. It is a non-invasive tomography technique that provides three dimensional images of tissue without sectioning or puncturing with a needle. We can use OCT for non-invasive disease diagnosis in a variety of diseases including glaucoma, Barrett’s esophagus, Celiac Disease, etc.

In one of my projects as a post-doc, we are developing an optical device that is in the shape and size of a Tylenol pill or capsule. This tethered capsule is swallowed by a patient, then goes down the esophagus into the stomach. As it goes through the esophagus it performs video rate imaging of the entire esophagus at a high (~15μm) resolution. Unlike current endoscopies, it not only provides images of the surface of the esophagus, but also from deep inside the tissue. This is a central aspect of OCT. The entire procedure takes 2 to 3 minutes and does not require sedation or anesthesia. Data is processed in real time and can be seen by the doctor immediately. The doctor can examine the data and ask the patients relevant questions straightaway so as to narrow down the potential disease possibilities and arrive at more reliable conclusions.

In the diagnosis of celiac disease for example, the current standard of care is to sedate the patient, insert a needle-based device and collect small pieces of tissue from several points in the esophagus. The tissue is frozen, sliced, stained chemically and observed under a microscope. The diagnosis process takes several days to weeks. In contrast, OCT provides real time results without sedation and is significantly more reliable since we image the entire esophagus as opposed to taking samples at a small number of point (quasi “random” sampling). Such techniques are likely to improve patient care dramatically in the future.

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