When pressed to explain the value of 3-D virtual holography, Dave Chavez, CTO of holographic computing firm zSpace, gave a surprising answer: it's because we have two eyes.

In fact, most complex organisms have two eyes, which begs the question — why not just one eye? Why not three? "Two eyes is exactly the right number to deal with the spatial environment in which we live," Chavez explained.

"It allows us to navigate, process and interact with the world in front of us in a much more powerful and efficient way. It's worth the extra energy and complexity to have that second eye."

Though we're biologically programmed to interact with a three-dimensional, spatially complex world, most of us spend the majority of our days staring at a flat screen — a disparity that may have real implications for the medical profession, which requires advanced spatial skills and processing.

Madeleine Keehner, a research scientist for the Educational Testing Service and director of the Spatial Cognition Laboratory at the University of Dundee in Scotland, studies the role of spatial cognition and image processing in medicine.

Her research argues that because 2-D pictures are essentially an artificial representation of a 3-D object, interpreting images is a cognitively intensive process for physicians.

Under the right circumstances, she says, 3-D computer visualization tools can help enhance learning and cognition.

"You would look at that data completely differently. Since you're wired to deal with the info, you don't have to interact with an artificial representation of these planes — you can see additional anomalies and details," says Chavez.

Virtual surgery

Because the technology is so new, there's a relative dearth of research around the benefits around 3-D virtual holography for pedagogical purposes, but nevertheless, interest is still high: zSpace is now helping first year medical students at Touro College dissect virtual bodies without ever having to touch a cadaver.

Using a large screen, glasses and a pointer, students can interact with and manipulate 3-D images, including examining it from all angles and zooming in and out.

The advantages of this technology are, first and foremost, practical: while holographs can't entirely replace the need for real cadavers, they are expensive and time-consuming to prepare for dissection. By using holographic technology, medical schools can aid students in spatial learning without the economic constraints of buying and using real bodies.

Furthermore, they can customize the virtual surgeries, planting certain kinds of tumors or presenting certain challenges for the students to learn. And if the students cut into the cadaver in the wrong way or make a mistake, they can just start over.

Floating hearts

But virtual holography isn't just making inroads with medical education — new technology developed by Royal Philips and Israeli firm RealView Imaging Ltd. may help physicians performing interventional procedures better visualize the patient's heart.

The two firms have announced this week that they have completed a pilot study that tested out interactive, real-time 3-D holographic visualization technology with eight patients in collaboration with the Schneider Children's Medical Center in Petach Tikva, Israel.

The technology, the first of its kind, uses Philips' interventional imaging technology to recreate a 3-D holographic representation of the patient's heart that floats in space without the need for screens or eyewear.

In addition, doctors can manipulate the heart by touching the projected holographic model.

"It's as if you have a real life-size heart under your eyes. You can use an object like a stent and hold that into the hologram and see if it fits in the coronary artery to see if it's the right size stent," explained Bert van Meurs, senior vice president at Philips HealthCare.

Using this technology, he said, physicians can measure and accurately analyze the heart as if they were looking at the real thing. "It's almost like you're doing an open surgery rather than having it on a display," he said.

As interventional procedures have grown more complicated, there's been a corresponding rise in demand for better, more accurate imaging techniques. It's no surprise, then, that Philips is investigating the use of virtual holography to visualize anatomy.

But what the measurable clinical benefits would be are still unclear. In fact, Meurs himself questioned whether virtual holography would bring more benefit to doctors than a 2-D image. "Quite honestly, at first I was myself even a bit skeptical — do you really get more information?" he said. However, he changed his mind after he saw the technology in action.

"The benefit is in accuracy and measurement — having access to even more information," he said. While he said the results are promising, he also stressed that the technology is far from being market-ready yet. The firm plans to engage in further clinical studies to develop the technology into a practical and clinical product.