Hyperspectral Imaging Coming to Medical Applications

Hyperspectral imaging (HSI) is a technique that analyzes a wide spectrum of light coming into a camera. Instead of assigning individual pixels to primary colors (usually red, green, and blue), the light coming into individual pixels is broken down into many more bands, providing more information of what’s being observed. Hyperspectral imaging has particularly been useful for satellites monitoring the environment on Earth, but now researchers at the National Institute of Standards and Technology (NIST) are working on bringing this technology to image the human body for disease.

Until now the problem has been calibrating an HSI device so that it spots the specific color signature of whatever is being looked for. The NIST team developed a method, which uses something called a microarrayer, to do this calibration by depositing substances that have the precise color they’re looking for and calibrating the HSI device against that.

More info from NIST’s press release:

“Because diseased tissues and cells also have distinct spectra, scientists have been trying to use HSI for medical applications as well,” says NIST physicist Jeeseong Hwang. “But any time you tell a machine to scan for something, you need to be sure it is actually looking for what you want, and you have to make sure that the image analysis algorithm extracts the correct color information out of a complex multicolor data set. We decided to create a way to calibrate an HSI device and to test its algorithm as well.”

Matthew Clarke, a former National Research Council-supported postdoctoral fellow in Hwang’s group who is currently working in the National Gallery of Art in Washington, D.C., wrote new software for a device called a microarrayer, so named because it is capable of laying down hundreds of tiny sample droplets in specific places on a microscope slide’s surface. Normally a microarrayer creates DNA arrays for genetic research, but the team remade it into an artistic tool, programming it to select chemicals of different hues and lay them down on the slide’s surface.

The results, which look a bit like dot-matrix printing, can be used to calibrate medical HSI devices and image analysis algorithms. When combined with HSI in a medical imaging application, this effort could allow a surgeon to look for cells with a specific chemical makeup, as determined by the cells’ color.

Press release: NIST Effort Could Improve High-Tech Medical Scanners…

Abstract in Biomedical Optics Express: Designing microarray phantoms for hyperspectral imaging validation