Virtual Tools Offer 3-D Access to Organs

Aug. 23, 2006 — As many as 98,000 people die in hospitals each year as a result of medical errors that could have been prevented, according to two major studies from the Institute of Medicine of the National Academies in Washington, DC.

Now, two new technologies being developed at separate universities could help make surgery safer and, perhaps in some cases, unnecessary.

The first is a program that instantly produces three-dimensional images of a person's anatomy. The software tool, called Live Surface, is designed to allow need for exploratory surgery.

"We'd just as soon make things as less invasive as possible," said professor William Barrett, who created the program along with graduate student Chris Armstrong at Brigham Young University in Provo, Utah.

The data to create the three-dimensional images comes from existing CT scans, MRIs or 3-D ultrasounds. But identifying the structures of interest, extracting that information and rendering it rapidly is a challenge that researchers have been trying to overcome for decades.

Other software either requires a technician to render the structure manually or takes tens to hundreds of seconds to display the image automatically.

"If you are doing bone surgery, you would like to identify bones in the data and display them in a way that you would see during surgery," said Ron Kikinis, Director of the Surgical Planning Laboratory at Brigham and Women's Hospital in Boston.

"Dr. Barrett's approach is a more effective way to do this kind of segmentation."

Kikinis is not associated with Barrett's research.

With Live Surface, the user clicks on the intended object with a computer mouse and the program extracts the image in half a second.

A doctor could use the image as part of a diagnosis to, for example, locate a hidden tumor or as a graphical guide during surgery.

If the images show that surgery is needed, the doctor may then want to practice the procedure on a surgery simulator being developed in an unrelated project led by Rensselaer Polytechnic Institute in Troy, NY.

The simulator combines the sense of touch with three-dimensional computer models of organs. This lends an immersive experience of performing an operation without ever cutting into real tissue.

The simulator could allow both unexperienced and veteran surgeons to hone their skills on new or rare procedures.

"The whole point of this simulation is to allow surgeons to practice on materials at absolutely no risk," said Suvranu De, director of the Advanced Computational Research Lab at Rensselaer.

Currently, surgeons-in-training practice their technique on cadavers or pigs. But pig organs are not human organs and neither situation lends itself to simulating complications that can arise during surgery.

De's simulator uses tactile information gathered during surgeries on pigs. De and his team use a device that is able to measure how much force a surgical instrument puts on different kinds of tissue to penetrate and cut.

Another tool is able to measure how the tissue responds to such forces. Video is also compiled during such a procedure to serve as a visual aid.

All this data is fed into a computer model, which is able to produce a visual and haptic experience of specific surgeries.

The team is currently working to simulate surgeries, including gastric bypass or gastric banding, which are typically performed on obese patients.

The idea, said De, is to create simulations for a wide variety of surgeries, giving doctors the chance to hone their motor skills and refine their technique before ever stepping into the operating room.