New Process Helps Find Cancerous Cells During Surgery

A handheld miniature microscope has the potential to identify cancerous cells during an operation, a recent study found.

In a study published in Biomedical Optics Express, mechanical engineers at the University of Washington developed a pen-sized microscope that allows surgeons to see cancer at a cellular level. As of now surgeons, don’t have a definitive way to determine which brain cells are cancerous and which are not while operating to remove a tumor.

"Surgeons don't have a very good way of knowing when they're done cutting out a tumor," said senior author Jonathan Liu. "They're using their sense of sight, their sense of touch, pre-operative images of the brain -- and oftentimes it's pretty subjective.

"Being able to zoom and see at the cellular level during the surgery would really help them to accurately differentiate between tumor and normal tissues and improve patient outcomes.”

It can also be used in a dental and dermatological clinical setting to assess whether a lesion or mole has cancerous cells without performing a biopsy.

Although smaller microscopes typically have to sacrifice image quality or resolution, field of view, depth, and imaging contrast of processing speed, the tiny microscope can deliver high-quality images at a faster rate.

The microscope uses what they call “dual-axis confocal microscopy” to see the opaque tissue more clearly. It is also able to capture details that are up to a half a millimeter below the tissue surface where some cancer cells originate.

“We feel like this device does one of the best jobs ever -- compared to existing commercial devices and previous research devices -- of balancing all those tradeoffs," Liu said. "Trying to see beneath the surface of tissue is like trying to drive in a thick fog with your high beams on - you really can't see much in front of you. But there are tricks we can play to see more deeply into the fog, like a fog light that illuminates from a different angle and reduces the glare."

When using a hand-held device, there needs to be fast image delivery because of human movements. Otherwise if the image rate is too slow, the images turn out blurry. In order to combat this, the new microscope uses a technique called line scanning, which speeds up the image collection process.

By using micro-electrical mechanical (MEMS) mirrors that directs an optical beam to scan the tissue, it’s able to do line-by-line scanning with great speed.

Researchers were able to show that the microscope has a high enough resolution to be able to see subcellular details. The images that were taken from the mouse tissue held up in comparison with the multi-day process at a clinical pathology lab.

The researchers expect for the handheld microscope to be tested as a cancer screening tool in a clinical setting next year, and hope that afterwards it can be introduced into surgeries or other procedures in the next 2 to 4 years.

"For brain tumor surgery, there are often cells left behind that are invisible to the neurosurgeon. This device will really be the first to let you identify these cells during the operation and determine exactly how much further you can reduce this residual," said project collaborator Nader Sanai. "That's not possible to do today."