High-Tech Medical Scanners

The technique, called hyperspectral imaging (HSI), has frequently been used in satellites because of its superior ability to identify objects by colour. While many other visual surveying methods can scan only for a single colour, HSI is able to distinguish the full colour spectrum in each pixel, which allows it to perceive the unique colour "signatures" of individual objects. Well-calibrated HSI sensors have been able to discern problems from diseases in coral reefs to pollution in the atmosphere as determined by the distinct spectral signature at a location.

"Because diseased tissues and cells also have distinct spectra, scientists have been trying to use HSI for medical applications as well," says 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 colour information out of a complex multicolour data set. We decided to create a way to calibrate an HSI device and to test its algorithm as well."

Matthew Clarke 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' colour.

"Scientists and engineers can create a custom slide with the exact colours representing the chemical makeup they want the HSI devices to detect," Hwang says. "It could be a good way to make sure the HSI devices for medical imaging perform correctly so that surgeons are able to see all of a tumour or diseased tissue when operating on a patient."

COMPAMED.de; Source: National Institute of Standards and Technology (NIST)