University of Washington mechanical engineers and collaborators have developed a handheld microscope to help doctors and dentists distinguish between healthy and cancerous cells in an office setting or operating room. (credit: Dennis Wise/University of Washington)
The new technology is intended to solve a critical problem in brain surgery: to definitively distinguish between cancerous and normal brain cells, during an operation, neurosurgeons would have stop the operation and send tissue samples to a pathology lab — where they are typically frozen, sliced, stained, mounted on slides and investigated under a bulky microscope.
Developed in collaboration with Memorial Sloan Kettering Cancer Center, Stanford University and the Barrow Neurological Institute, the new microscope is outlined in an
«Surgeons don’t have a very good way of knowing when they’re done cutting out a tumor," said senior author Jonathan Liu, UW assistant professor of mechanical engineering. «They’re using their sense of sight, their sense of touch, and
The handheld microscope, roughly the size of a pen, combines technologies in a novel way to deliver
It also has other uses in medicine and dentistry. For instance, dentists who find a
That process subjects patients to an invasive procedure and overburdens pathology labs. A miniature microscope with high enough resolution to detect changes at a cellular level could be used in dental or dermatological clinics to better assess which lesions or moles are normal and which ones need to be biopsied.
Key technologies: dual-axis confocal microscopy and line scanning
«The microscope technologies that have been developed over the last couple of decades are expensive and still pretty large, about the size of a hair dryer or a small dental
Making microscopes smaller, however, usually requires sacrificing some aspect of image quality or performance such as resolution, field of view, depth, imaging contrast or processing speed.
«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," said Liu.
The miniature microscope uses an innovative approach called «
In the video below, for instance, researchers produced images of fluorescent blood vessels in a mouse ear at various depths ranging from 0.075 to 0.125 millimeters deep.
«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," Liu said. «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.»
The microscope also employs a technique called line scanning to speed up the
Imaging speed is particularly important for a handheld device, which has to contend with motion jitter from the human using it. If the imaging rate is too slow, the images will be blurry.
In the paper, the researchers demonstrate that the miniature microscope has sufficient resolution to see subcellular details. Images taken of mouse tissues compare well with those produced from a
The researchers hope that after testing the microscope’s performance as a
«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, professor of neurosurgery at the Barrow Neurological Institute in Phoenix. «That’s not possible to do today.»
The research was funded by the National Institutes of Health through its National Institute of Dental and Craniofacial Research and National Cancer Institute.
Abstract of Miniature in vivo MEMS-based line-scanned dual-axis confocal microscope for point-of-care pathology
There is a need for miniature
