Engineers have developed a new lens-free ultra-miniaturized endoscope — the width of a few human hairs in size — that is less invasive and produces high quality images when inserted into the body.
The conundrum for engineers designing endoscopes earlier was that they had to either sacrifice size or image quality in the manufacturing process. Since the quality of images was critical to medical prognosis, endoscopes ended up being bigger than optimal instruments.
Now engineers at Johns Hopkins University in the United States have developed a microendoscope capable of examining neurons firing off in the brains of animals such as mice and rats. An ideal microendoscope should be small to minimize brain tissue damage yet powerful enough to produce a clear image.
Currently, standard microendoscopes are about half a millimeter to a few millimeters in diameter, and require larger, more invasive lenses for better imaging. While lensless microendoscopes exist, the optical fiber within that scans an area pixel by pixel frequently bends and loses imaging ability when moved.
Scientists behind the new development created a lens-free ultra-miniaturized microendoscope that, compared to a conventional lens-based microendoscope, increases the amount researchers can see and improves image quality with an instrument that is less than half the size in width of existing microendoscopes.
The researchers achieved this by using a coded aperture, or a flat grid that randomly blocks light creating a projection in a known pattern akin to randomly poking a piece of aluminum foil and letting light through all of the small holes. This creates a messy image, but one that provides a bounty of information about where the light originates, and that information can be computationally reconstructed into a clearer image.
Additionally, the new microendoscope does not require movement to focus on objects at different depths; they use computational refocusing to determine where the light originated from in 3 dimensions. This allows the endoscope to be much smaller than a traditional one that requires moving the endoscope around to focus.
