US engineers have demonstrated an endoscope as thin as a human hair that has four times the resolution of similar devices.
The researchers from Stanford University developed the micro-endoscope, which can show objects about 2.5 microns in size, by working out how to unscramble the light signals that travel through multiple paths within the endoscope’s optical fibre.
The technology could help doctors see much more detail inside the body than normally possible with traditional endoscopes, opening new imaging methods in fields such as neurology and early cancer detection.
‘[We] wanted to know if it would it be possible to send light through a single hair-thin fibre, form a bright spot inside the body and scan it to record images of living tissue,’ said project leader Prof Joseph Kahn, in a statement.
To do this they used multimode fibres that allow light to carry complex information by travelling through multiple paths (modes), but which tend to scramble the signals.
Kahn devised a way to undo the scrambling of information using a miniature liquid crystal display called a spatial light modulator and an algorithm that turns measurements of the power of the reflected light into an image.
Using random patterns of light enabled the researchers to speed up the image recording, as had previously been done in magnetic resonance imaging (MRI) systems.
But this also increased the number of modes in the fibre and so increased the amount of information that could be captured, giving the device a resolution four times higher than that of similar micro-endoscopes.
Kahn and his team have created a prototype of a rigid fibre with their technology, which could be used for a range of microscopic imaging techniques, from analyzing neuronal cellular biology in brain tissue to studying muscle physiology and disease.
But they also want to find a way to put their technology into a flexible endoscope that could reach deeper into the body. ‘No one knows if a flexible single-fibre endoscope is even possible, but we’re going to try,’ said Kahn.