Point of Care Microscope Helps Identify Cancer Cells

A handheld miniature microscope could examine tissues at the cellular level right in the operating room, helping surgeons determine the extent of tumor resection.

Developed by researchers at the University of Washington (UW; Seattle, USA), Memorial Sloan-Kettering Cancer Center (MSKCC; New York, NY, USA), and other institutions, the microelectromechanical systems (MEMS) line-scanned (LS) dual-axis confocal (DAC) microscope has a 12-mm diameter distal tip specifically developed for clinical point-of-care (POC) pathology examination. The dual-axis architecture surpasses conventional, single-axis confocal configuration by reducing the background noise generated by out-of-focus images and scattered light.

The use of line scanning enables scan rates of at least 16 frames per second (FPS), which helps mitigate motion artifacts common when using hand-held devices. The researcher also developed a method to actively align the illumination and collection beams in a DAC microscope through the use of a pair of rotatable alignment mirrors. Finally, the incorporation of a custom objective lens with a small form factor enables the device to achieve an optical-sectioning thickness of 2 micrometers with a lateral resolution of just 1.1 micrometers.

The researchers successfully demonstrated that the miniature POC microscope has sufficient resolution to see subcellular details, comparable to those produced from a multi-day process at a clinical pathology lab, which is the current gold standard for identifying cancerous cells. They hope that after testing the microscope’s performance as a human cancer-screening tool in vivo, it could be used during surgeries or other clinical procedures within the next 2-4 years. The study describing the development process was published in the January 2016 issue of Biomedical Optics Express.

“Surgeons don’t have a very good way of knowing when they’re done cutting out a tumor. They’re using their sense of sight, their sense of touch, preoperative images of the brain, and oftentimes it’s pretty subjective,” said senior author Jonathan Liu, PHD, a UW assistant professor of mechanical engineering. “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.”

“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,” added study coauthor Milind Rajadhyaksha, MD, of MSKCC. “So there’s a need for creating much more miniaturized microscopes. 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.”

Related Links:
University of Washington
Memorial Sloan-Kettering Cancer Center
Stanford University