A research team led by Professor Ki-Hun Jeong has developed a miniature microscope that can be attached to an endoscope to perform optical biopsies in real time. Their results were published in the online version of the world-renowned journal Optics Express on March 5.

 

This microscope, which has a diameter of just 3.2 millimeters (mm), can perform a three-dimensional scan down to a depth of 3 mm at a speed of 20 frames per second. Its resolution of 17 micrometers (μm), which is approximately one-sixth the size of a strand of hair (100 μm), enables accurate differentiation among different types of cells such as cancer cells, normal cells, and inflammatory cells. It is expected that with this technology, a biopsy that usually takes two to three days can be performed in real time, and demucosation procedures can be performed with great accuracy.

 

The key to applying novel imaging techniques in gastrointestinal endoscopes is to develop a microscope that can fit into a small space with a diameter of less than 3.5 mm. Piezoelectric elements and optical fibers have recently been used to perform a direct scan. However, existing optical fiber scanners are prone to physical interference due to their symmetrical structure. This places restrictions on the extent they can be applied clinically.

 

Professor Jeong’s team employed the use of microelectromechanical systems (MEMS) to solve this problem. They used deep reactive ion etching (DRIE) to fabricate supporting silicon structures. By combining these structures with optical fibers, the team solved the interference problem and greatly enhanced the stability of optical fiber scanners. They also developed an image retrieval method that continuously enhances image resolution with time by changing the microscope’s scan pattern. In a demonstration, it was shown that a sample’s three-dimensional structure can be detected by the microscope within 0.5 seconds.