Researchers take optical coherence tomography to the next level

Researchers take optical coherence tomography to the next level

Researchers have developed an improved version of OCT that can image biomedical samples with higher contrast and resolution across a wider field of view in 3D than was previously possible. They used the new method for imaging the zebrafish larva. Credit: Kevin Zhou, Duke University

Researchers have developed an improved version of optical coherence tomography (OCT) that can image biomedical samples with higher contrast and resolution across a wider 3D field of view than previously possible. The new 3D microscope could be useful for biomedical research and eventually enable more accurate imaging of medical diagnoses.

in optics Periodically, researchers from Duke University describe the new technology, which they call 3-D refractive tomography (3D OCRT). Using different biological samples, they show that 3D OCRT produces highly detailed images that reveal features that are difficult to observe with conventional OCT.

OCT uses light to provide high-resolution 3D images without the need for any contrast agents or labels. Although commonly used in ophthalmological applications, the imaging method can also be used to image many other parts of the body such as the skin, the inside of the ears, the mouth, the arteries, and the gastrointestinal tract.

First author Kevin C. “We have developed an exciting new extension, featuring new hardware combined with a new 3D image reconstruction computational algorithm to address some of the well-known limitations of imaging technology.”

“We envision this approach to be applied in a variety of biomedical imaging applications, such as in vivo Diagnostic imaging of the human eye or skin,” said research team co-leader Joseph A. Isaat. The devices we designed to perform this technology can also be easily miniaturized into small probes or endoscopes for easy access to Digestive and other parts of the body.

Researchers take optical coherence tomography to the next level

The new method produces highly detailed images that reveal features that are difficult to observe using conventional OCT as shown in these images of the Drosophila head. Credit: Kevin Zhou, Duke University

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Although OCT has proven useful in both clinical and biomedical research, it is difficult to obtain high-resolution OCT images over a wide field of view in all directions simultaneously due to the fundamental limitations imposed by optical beam propagation. Another challenge is that OCT images contain high levels of random noise, called spots, that can obscure biomedically important details.

To address these limitations, the researchers used an optical design that includes a parabolic mirror. This type of mirror is commonly found in non-figurative applications, such as flashlights, where Light To direct the light in one direction. The researchers used an optical setup in which light is sent the other way, with the sample placed where the light bulb would be in a flashlight.

This design made it possible to photograph the specimen from multiple perspectives across a very wide range of angles. They have developed a complex algorithm to combine the renderings into a single, high-quality 3D image that corrects distortions, noise, and other defects.

The work was published in optics Our previous research extends by overcoming significant engineering challenges, in both hardware and software, to allow OCRT to operate in 3D and make it more widely applicable,” said Sina Farcio, co-leader of the research team. Because our system generates tens to hundreds of gigabytes of data, we had to develop a new algorithm based on modern computational tools that have recently matured in the machine learning community. “







The video shows a comparison between 3D OCRT and conventional OCT of a zebrafish larva. Credit: Kevin Zhou, Duke University

Get a wider view

The researchers demonstrated the method’s versatility and broad applicability by using it to image various biological samples including zebrafish and Drosophila, which are important model organisms for behavioral, developmental and neurobiological studies. They also imaged tissue samples from mice from the trachea and esophagus to demonstrate the potential for medical diagnostic imaging. Using 3D OCRT, they obtained 3D fields of view of up to ±75° without moving the sample.

“In addition to reducing noise defects and correcting sample-generated distortions, OCRT technology is inherently capable of creating computational contrast from tissue properties that are less evident in conventional OCT,” Chu said. “For example, we show that it is sensitive to oriented structures such as fiber-like tissue.”

Researchers are now exploring ways to shrink the system down and make it faster for live imaging by taking advantage of recent advances in faster OCT system technologies and advances in deep learning that can speed up or improve data processing.


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more information:
Kevin Zhou et al., 3D computational microscopy with optical refractive tomography, optics (2022). DOI: 10.1364 / OPTICA.454860

the quote: Researchers Take Optical Coherence Tomography to the Next Level (2022, June 2) Retrieved June 3, 2022 from https://phys.org/news/2022-06-optical-coherence-tomography.html

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