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Autonomous Shrapnel Remover

Surgical robots moved into the limelight with the Da Vinci, but that is essentially a laparoscopic waldo. It has no brain, no intelligence, it just obeys the surgeon's hands. A true robotic surgeon would be able to operate at its own discretion, making its own decisions about what to cut, and what to remove.

We are still a long way from an autonomous robot surgeon in general surgery, but perhaps not as far removed as it was believed. Bioengineers at Duke University have developed a laboratory robot that can successfully locate tiny pieces of metal within flesh and guide a needle to its exact location, without any human assistance.

Its not to the point of operating on humans yet of course, but it is an impressive step in the right direction.

The robot uses stereoscopic vision that's a bit different from normal. Its 'eyes use ultrasound to build up an image. Twin emitters creating a 3D effect that allows it to gauge depth accurately. This information is then used to guide the robot's arm as it isolates material that does not belong, by use of a small electromagnet. The magnet causes the metal to vibrate, allowing the robot to lock in on it.

The machine sets about finding the least damaging path to removing it, cutting through minimal flesh. Of course, at the current stage of development, the robot cannot tell muscle from nerve, and so does not understand how it might be better to cut more muscle rather than a few nerves, but that is mostly a matter of sensor technology.

It is only a small step from current tests to replacing the needle on the arm with tools able of making micro incisions, and removing metallic fragments. With this proof of concept available, the researchers have stated a belief that in the relatively near future it will be possible for very simple procedures to be carried out by a robot, rather than a human surgeon. A robot does not tire, and continually operates at the height of precision.

In the latest experiments, the robot successfully performed its main task: locating a tiny piece of metal in a water bath, then directing a needle on the end of the robotic arm to it. The researchers had previously used this approach to detect micro-calcifications in simulated breast tissue.

The robot used in these experiments is a tabletop version capable of moving in three axes. For the next series of tests, the Duke researchers plan to use a robotic arm with six-axis capability.

The results of the experiments were published early online in the July 2009 issue of the journal IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.


Autonomous Surgical Robot Detects Shrapnel

3-D Ultrasound Guidance of Autonomous Robot for Location of Ferrous Shrapnel (PDF)

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