Shrapnel-Detecting Robot

Advances in precision: Rogers with aotonomous robots. Jon Gardiner

Bioengineers at Duke have developed a laboratory robot that can locate tiny pieces of metal within flesh and guide a needle to its exact location—all without human assistance.

The experiments led the researchers to believe that such a robot could not only help treat shrapnel injuries on the battlefield, but might also be used for such medical procedures as placing and removing radioactive "seeds" used in the treatment of prostate and other cancers.

The engineers started with a rudimentary robot whose "eyes" are a novel 3-D ultrasound technology developed at Duke. An artificial-intelligence program served as the robot's "brain," taking the real-time 3-D information, processing it, and giving the robot specific commands to perform. The researchers used tiny pieces of magnetic needle as a stand-in for shrapnel.

"We attached an electromagnet to our 3-D probe, which caused the shrapnel to vibrate just enough that its motion could be detected," says A.J. Rogers B.S.E. '09, who worked on the research project as an undergraduate. "Once the shrapnel's coordinates were established by the computer, it successfully guided a needle to the site."

Advances in ultrasound technology made these latest experiments possible by generating detailed, 3-D moving images from traditional 2-D scans. Since inventing the technique at Duke in 1991, the team has used it to develop specialized catheters and endoscopes for real-time imaging of blood vessels in the heart and brain.

Researchers say it would simply be a matter of replacing the needle probe with a tiny tool, such as a grabber, to make the robot ready for action.

"We showed that, in principle, the system works," says lead author Stephen W. Smith Ph.D. '75, professor of biomedical engineering and director of the Duke University Ultrasound Transducer Group. "It can be very difficult using conventional means to detect small pieces of shrapnel, especially in the field. The military has an extensive program of exploring the use of surgical robots in the field, and this advance could play a role."