A microscope the size of a pen could help surgeons with difficult-to-remove tumors and cancers.
A new pen-sized microscope could give surgeons, especially those removing brain tumors and oral cancers, a tool they need to peer below the surface of an opaque tissue and see in real-time at a cellular level.
Jonathan Liu, an assistant professor of mechanical engineering at the University of Washington, hopes his device will eventually help surgeons and other doctors spot cancer cells and remove them without damaging the healthy tissue around them. That would solve two of the main challenges cancer surgeons face.
To remove a tumor, surgeons typically use sight, touch, and pre-operative images to determine when to stop cutting, Liu said. They can then send excised tissue samples to a pathology lab to distinguish between cancerous and healthy tissue, but that often takes days. In practice, this means that surgeons rely on their subjective clinical judgment. As a result, they sometimes miss cancerous tissue, which can lead to recurrence, or cut out too much healthy tissue, which can damage vital organs.
“There’s no good, real-time method for diagnosing tissues,” Liu said.
To give them one, Liu designed his microscope to overcome some of the technical problems of previous mini-microscopes, which achieved a compact size at the cost of imaging speed and quality, resolution, contrast, and field of view.
Liu’s biggest engineering challenge was trying to align the tiny mirrors, lenses, and other components in such a small device. He directed micromirrors with an optical beam to scan tissue line by line. This allows the device to quickly compose an image, which reduces jitter-induced blur and could help a surgeon see clearly.
The microscope also deploys a technology called dual-axis confocal microscopy that makes otherwise opaque tissue visible, enabling surgeons to see details up to one-half millimeter beneath its surface.
Liu and his colleagues described their microscope in Biomedical Optical Express.
Combined, the technologies produce high enough contrast and resolution to reveal subcellular details that distinguish cancer cells from healthy tissue. The device could lead to new standardized, automated diagnostic approaches, especially for skin cancers and mouth, throat, and other oral cancers, the authors wrote.
Liu expects the microscope—developed with Memorial Sloan Kettering Cancer Center in New York City, Stanford University and the Barrow Neurological Institute in Phoenix—to undergo clinical feasibility studies later this year.
Jeff O’Heir is an independent writer