Gastrointestinal and bowel conditions are typically diagnosed after an inspection via endoscopy. Researchers from The Optical Society designed a new endoscope device that combines fluorescent and photoacoustic imaging.
The study was recently published in the journal Biomedical Optics Express. The new device measures the width of a single strand of hair, making it a minimally-invasive endoscope.
A traditional endoscope is made of a flexible tube with optical cables. The optical fibers are made of either plastic or glass, usually about 1/5 an inch in diameter.
One or two tubes are inserted into the patient's body via the esophagus - one light and one camera. The doctor can then inspect the stomach and intestines for signs of an illness such as inflammation as the live feed is viewed on a monitor.
Modern endoscopes have evolved into being used to carry out medical procedures such as minor surgeries. Newer versions of the tube may have biopsy forceps or use precision lasers to make accurate incisions during an endoscopy.
New Endoscopy Technique
The newly developed device measures at only 250 by 125 microns (µm), containing "an ultra-sensitive fiber-optic ultrasound sensor for photoacoustic detection placed next to the fiber" alongside a photodetector. The combination enabled the team to capture fluorescence and photoacoustic images via a single laser that shoots per pixel. The resulting images are two-dimensional imaging of fluorescent beads and red blood cells, wrote the authors.
Fluorescent signals are useful in identifying specific tissue, which is made when a fluorescent marker absorbs light then emits it with a different wavelength. At the same time, photoacoustic images are the product of acoustic waves produced after the light is absorbed, which would be useful for tracking blood cells.
Emmanuel Bossy from the Université Grenobe Alpes Laboratoire Interdisciplinaire de Physique shared that "combining these imaging modalities could" provide new data on brain structure and behavior associated with neurological conditions or the result of drug-targeting treatment. As a result, the device creates minimal tissue damage during an endoscopy.
Pixel by Pixel Imaging
"Light propagating into a multi-mode fiber is scrambled, making it impossible to see through the fiber," said Bossy. Since the new device is much smaller than traditional fiber optics, it can be applied to various medical endoscopic devices.
The addition of an optical fiber sensitive to sound, the photoacoustic signals help the fluorescent light signals focus on a particular area, explained Bossy, allowing the team to build images pixel by pixel. On the other hand, "commercial fiber optic acoustic sensors would have required many laser pulses." The team successfully detected red blood cells six microns in size and one-micron fluorescent microspheres.
The team's new microendoscopy technique is called optical wavefront shaping. Someday, the scientists hope that their research can provide a way for neural activity and blood dynamics, like red blood cell activity, to be measured simultaneously.
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