The Duke team combined a “souped-up” version of an existing robot arm with an ultrasound system of its own design. The ultrasound serves as the robot’s “eyes” by collecting data from its scan and locating its target. The robot is “controlled” not by a physician, but by an artificial intelligence program that takes the real-time 3-D information, processes it and gives the robot specific commands to perform. The robot arm has a mechanical “hand” that can manipulate the same biopsy plunger device that physicians use to reach a lesion and take samples.

In the latest series of experiments, the robot guided the plunger to eight different locations on the simulated prostate tissue in 93 percent of its attempts. This is important because multiple samples can also determine the extent of any lesion, said Stephen Smith, director of the Duke University Ultrasound Transducer Group at the Pratt School of Engineering.

Duke University researchers have been busy in this specialized area of medical robotics. Engineers created a prototype tabletop robot surgery device as well as a Shrapnel-Locating Autonomous Robot.

Science fiction fans of course remember the robot surgeon from Isaac Asimov's 1976 classic The Bicentennial Man:

Andrew Martin studied the robot's right hand, his cutting hand, as it lay motionless on the desk. The fingers were long and were shaped into artistically metallic, looping curves so -graceful and appropriate that one could imagine a scalpel fitting them and becoming, temporarily, one piece with them. There would be no hesitation in his work, no stumbling, no quivering, no mistakes. That confidence came with specialization, of course, a specialization so fiercely desired by humanity that few robots were, any longer, independently brained. A surgeon, of course, would have to be.
(Read more about Asimov's robot surgeon)

Earlier still, Philip K. Dick wrote about a similar idea in his 1955 short story War Veteran; a robot surgeon-hand that could be detached and would work autonomously. In this instance, the robotic hand was doing double-duty as an escape device:

From time to time V-Stephens examined his wristwatch and then turned his attention back to the object crawling up and down the sealed edges of the entrance-lock.

The object moved slowly and cautiously. It had been exploring the lock for twenty-nine hours straight; it had traced down the power leads that kept the heavy plate fused in place... During the last hour it had cut its way throught the rexeroid surface to within an inch of the terminals. The crawling, exploring object was V-Stephen's surgeon-hand, a self-contained robot of precision quality usually joined to his right wrist.

It wasn't joined there now. He had detached it and sent it up the face of the cube to find a way out. The metal fingers clung precariously to the smooth dull surface, as the cutting-thumb laboriously dug its way in...

The forefinger of the surgeon-hand reached the anode terminal and paused questioningly. All four fingers rose erect and waved like insect antennae. One by one they fitted themselves into the cut slot and probed for the nearby cathode lead.
(Read more about Dick's autonomous robot surgeon-hand)