New York: Scientists, including one of Indian-origin, are developing a handheld microscope, roughly the size of a pen, which could allow brain cancer surgeons to "see" at a cellular level in the operating room if tumour cells have been successfully removed.
"Surgeons don't have a very good way of knowing when they're done cutting out a tumour," said senior author Jonathan Liu, assistant professor at University of Washington. "They are using their sense of sight, their sense of touch, pre-operative images of the brain and oftentimes it is pretty subjective," Liu said.
"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," said Liu.
The handheld microscope combines technologies in a novel way to deliver high-quality images at faster speeds than existing devices. Dentists who find a suspicious-looking lesion in a patient's mouth often wind up cutting it out and sending it to a lab to be biopsied for oral cancer.
Most come back benign. That process subjects patients to an invasive procedure and overburdens pathology labs, researchers said. 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.
"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 x-ray machine," said co-author Milind Rajadhyaksha, associate
faculty member at the Memorial Sloan Kettering Cancer Center.
Making microscopes smaller 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 trade-offs," said Liu.
The miniature microscope uses an innovative approach called "dual-axis confocal microscopy" to illuminate and more clearly see through opaque tissue. It can capture details up to a half millimetre beneath the tissue surface, where some types of cancerous cells originate.
The microscope also employs a technique called line scanning to speed up the image-collection process. It uses micro-electrical-mechanical also known as
MEMS mirrors to direct an optical beam which scans the tissue, line by line, and quickly builds an image.
Imaging speed is particularly important for a handheld device, which has to contend with motion jitter from the human using it, the researchers said. They demonstrated that the miniature microscope has sufficient resolution to see sub-cellular details. The study was published in the journal Biomedical Optics
Express.
