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Advances in optical coherence tomography expand clinical applications

Researchers from MIT along with Acacia Communications recently developed the first optical coherence tomography system that provides opportunities for long-range measurements and imaging of cubic meter volumes which would allow clinicians to see deeper and clearer images of the anatomy, according to a paper published in Optica.

“Optical coherence tomography (OCT) is a powerful 3-D imaging modality with micrometer scale axial resolution and up to multi-GigaVoxel/s imaging speed. However, the imaging range of high speed OCT has been limited [to depths of a few centimeters],” James G. Fujimoto, PhD, from the department of electrical engineering and computer science and research laboratory of electronics at MIT, and colleagues wrote.

OCT was invented in the 1990s by Fujimoto’s group and collaborators. Today, OCT is the standard technology used in ophthalmic clinical imaging procedures and is rapidly gaining acceptance in cardiology, dermatology and gastroenterology.

The researchers were able to perform high speed, 3-D OCT imaging with 15-micron resolution over a 1.5-meter area. This advancement of OCT capabilities has the potential for many new industrial, manufactural and medical applications due to its ability to deliver information to clinicians on material composition, subsurface structure, coatings, surface roughness, as well as many other properties that are usually challenging to acquire.

“Our study demonstrates world-record results in cubic meter volume imaging, with at least an order of magnitude larger depth range and volume compared to previous demonstrations of 3-D OCT,” Fujimoto said in a related press release. “These results provide a proof-of-principle demonstration for using OCT in this new regime.”

This new technique would improve medical imaging by enabling clinicians to obtain 3-D images and measures for procedures, such as laparoscopy, or mapping structures of complex anatomic structures, such as the upper airway.

In addition, Acacia developed a new silicon photonics coherent optical receiver that was used to replace several large components of OCT with a tiny, low-cost, single chip photonic integrated circuit (PIC) embedded with integrated optics. The PIC receiver doubles the OCT imaging range for a specified speed for data acquisition through quadrature detection.

“As PIC technology continues to advance, one can realistically expect full OCT systems on a single chip within the next 5 years, dramatically lowering the size and cost,” Chris Doerr, coauthor of the paper from Acacia Communications, said in the release. “This would allow more people all over the world to benefit from OCT and open up new applications.”

The advancements are a part of ongoing efforts to develop even more low-cost, high-speed components for OCT that would accelerate data acquisition and processing steps, potentially generating real-time OCT imaging using customized integrated circuit chips, according to the researchers.

“The results suggest that it is a viable imaging and profiling technology that promises to enable a wide range of new industrial, research, and medical applications,” Fujimoto and colleagues concluded. – by Alaina Tedesco

Disclosure: The researchers report funding by the National Institutes of Health and Air Force Office of Scientific Research.