X-ray vision: For centuries it has been the stuff of fantasy -- and fodder for gag mail-order ads in the back of Boys' Life. But now researchers at Siemens are developing a technology that approximates the effect of seeing through walls -- or, more to the point, bones.
While current medical-imaging techniques such as ultrasound, magnetic resonance (MR), and computer tomography (CT) harvest a wealth of data from inside our bodies, the resulting images can be viewed only on light boards and computer screens. To a neurosurgeon plunging a seven-inch needle into a patient's brain, that's clearly an imperfect solution: He has to take his eye off the incision to see where he's headed.
Siemens's response, called "augmented reality," starts with a headset that overlays prerecorded ultrasound, MR, or CT images with real-time video captured by a pair of cameras just above the physician's eyes. A third infrared camera, also mounted on the headset, spatially orients the video in relation to a set of optical tracking markers placed around the patient's body. The resulting picture is projected onto two tiny screens positioned directly in front of the physician's eyes. Presto! X-ray vision -- or the next best thing.
The headset allows doctors to simultaneously view the surface and what's beneath. That, says Siemens program manager Frank Sauer, should mean less-invasive procedures that are faster, more accurate, and require less medication. Such claims already have attracted the attention of neurosurgeons, interventional radiologists, and orthopedic surgeons, many of whom have signed up to test the device in clinical trials. Dr. Stuart Silverman, a radiologist at Brigham and Women's Hospital in Boston, hopes to apply the technology in procedures such as ablation, in which a large needle is guided into a tumor and heated, chilled, or used to inject liquid, ultimately killing unwanted cells. Augmented reality, he says, could "allow us to target structures even smaller than those we do now."
Siemens projects the price of the complete augmented reality system at about $400,000. The actual cost, though, could be closer to $100,000 for the many hospitals that already have conventional imaging technology in place. Sauer has no plans to advertise in Boys' Life.