A new instrument could one day help surgeons more easily identify cancerous tissue

Researchers have developed a novel bio-inspired medical endoscope that can simultaneously acquire 3D visible-light and near-infrared fluorescence images. It features an optical design that combines the high-resolution 3D imaging of human vision with the mantis shrimp’s ability to simultaneously detect multiple wavelengths of light.

Endoscopes with 3D imaging capability can help surgeons precisely locate diseased tissue. The addition of fluorescence imaging can illuminate cancerous tissue for easier removal or highlight critical parts of anatomy that should be avoided during surgery.

In the journal The Optical Society (OSA) Express Optics, Chenyoung Shi of the Chinese Academy of Sciences and colleagues describe and demonstrate the new multimodal endoscope. Although this is a first demonstration, the new endoscope is designed to directly replace existing endoscopes without requiring clinicians to learn how to use a new instrument.

“Existing 3D fluorescence endoscopes require surgeons to switch working modes during the operation to see the fluorescence images,” Shi said. “Because our 3D endoscope can simultaneously acquire visible and fluorescent 3D images, it not only provides more visual information, but also can significantly shorten operation time and reduce risk during surgery.”

Help with robotic surgery

Although it can be used for any endoscopic procedure, researchers have designed the new multimodal endoscope for robotic surgery systems. These systems help increase the precision and accuracy of minimally invasive procedures and can help surgeons perform complex tasks in confined areas of the body. For robotic surgery, the improved visual information provided by the new endoscope could help a surgeon who may be in a different room from the patient to clearly distinguish between various tissue types in the operating field.

“Although today’s robotic surgical systems require the surgeon to be nearby, robotic surgery based on this multimodal 3D endoscope could one day allow surgeons to perform procedures remotely in remote locations,” said Shi. “It could help solve the problem of unequal distribution of medical resources and benefit people who live in areas with relatively poor medical conditions.”

The new multimodal endoscope achieves high-resolution 3D imaging by using two optical systems to form a binocular design very similar to that of human eyes. However, in this case, the optical design can accommodate both visible light like human eyes and the near-infrared wavelengths required for fluorescence imaging. This light is detected by a sensor inspired by the compound eyes of the mantis shrimp, which not only detects multispectral information but also recognizes polarized light. The sensor detects multiple parts of the electromagnetic spectrum using pixels with different spectral and polarization responses.

To obtain high quality 3D images, the binocular optical system must have two optical systems with exactly the same parameters. “It places strict demands on the processing accuracy of optical components,” Shi said. “We were able to achieve this accuracy by using precision optical processing and combined it with on-chip spectroscopy technology to make this multimodal 3D endoscope possible.”

Combination of visible and fluorescence images

To test the new endoscope, researchers analyzed its resolution, fluorescence imaging capability, and ability to simultaneously obtain 3D images with near-infrared and visible color information. The endoscope performed well and achieved resolution as high as 7 line pairs per millimeter with visible light – the same as the best 3D endoscopes in use today – and 4 line pairs per millimeter under near infrared light. .

They then used the endoscope to acquire visible color and near-infrared fluorescence images of three concentrations of indocyanine green. This near-infrared fluorescent tag is FDA approved and used to label tumor tissue. Although the three samples could not be distinguished by the human eye, they could be clearly distinguished using the multimodal 3D endoscope. The researchers also tested the endoscope’s 3D imaging performance by using it to image a toy with many intersecting parts. The endoscope was able to produce 3D images that did not cause eye fatigue even after a long period of observation.

The researchers plan to use the 3D endoscope to perform additional biological and clinical imaging. They also plan to incorporate more wavelengths and the ability to detect polarization to provide even more visual information.

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Material provided by The Optical Society. Note: Content may be edited for style and length.

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