Andreas Velten: Taking imaging to new extremes

Unlike many of us, Andreas Velten loves working in windowless rooms. His research tools are shrouded in sealed black boxes to keep out unwanted light. He’s been known to cover red building exit signs to extinguish any trace of visual noise.

Andreas Velten

Velten’s research world revolves around precisely controlling and manipulating light — and unwanted light is about as welcome as a radio blaring during a symphony. His light performs unusual tasks such as bouncing off tissue, bending around corners and dousing organisms in an explosion of color.

Velten, a Morgridge Institute Affiliate with the Medical Engineering Group and assistant scientist with UW–Madison Laboratory of Optical and Computational Instrumentation, is developing useful new tools in optical imaging with a plethora of applications, from basic research labs to operating rooms. Many of the tools in development are pushing imaging speeds to new limits, since greater speed corresponds to sharper resolution.

“Among all the ways we collect medical information, optical imaging holds a special place,” Velten says. “Light is sensitive to the biochemical processes in our cells and bodies that make life possible. Light is also special because of the extraordinary amount of information it provides, but we only know how to use a fraction of that information.”

Velten is most known for a project he worked on as a postdoc at the MIT Media Lab, a unique trillion-frame per second camera that has the capability of “seeing” around corners. “The camera sends a sharp pulse of light into a room, which bounces off the wall and scatters throughout the room,” Velten says. “That scattered light is then recaptured to compute the three-dimensional structure of objects in the room.”

Such a camera could help, for example, law enforcement detect suspects in nearby rooms, or help firefighters locate survivors in an active blaze. At Morgridge, Velten is investigating whether the technology could be used in medicine to image visually challenging spaces, such as lungs or arteries.

“We’re trying to transfer this process to a wavelength that would scatter off tissue,” he says. “The problem now is the light we’re using is not reflected well by tissue. If we can bounce it off, we could give surgeons 3D views of the areas they are working on.”

Another medical imaging idea of Velten is called transient lighting, a form of lighting for operating rooms that would be invisible to the extremely sensitive detectors and sensors needed for surgery. He developed a pulsing light system that flashes one millisecond of light for every nine milliseconds of darkness. The naked eye sees only normal-state lighting with no flicker, but the light-sensitive equipment operates as if in complete darkness.

A patent is filed on this application, which could help surgeons use fluorescence in real-time during surgeries, to precisely define operating targets, he says.

Perhaps Velten’s most visually striking advance is his hyperspectral imaging microscope, which captures images across 15 primary colors. This imaging allows scientists to look at numerous fluorescent labels at the same time within an organism, which can illuminate growth and development, cell biology and interactions and the spread of disease.

Hyperspectral imaging has been used by UW–Madison scientists to track the interplay between immune system cells and bacteria in a zebrafish model. The team has developed movies that follow the immune cells tracking down and absorbing bacteria, changing colors in the process. Another project illuminates the process of cell division in frog eggs, showing the cutting and pulling apart of chromosomes in vivid colors.

These new techniques may provide a more powerful way for medicine to harness light — one of the most minimally invasive and functional tools available. “Future imaging devices will be able to create optical images from deep inside the body and find signs of disease before then become detectable by other means,” he says.