Dan Stoianovici: Robot does not affect MRI magnets.

Dan Stoianovici and colleagues have created a new kind of motor — a marvel, made of plastic, ceramic, glass and rubber. It has no metal and uses no electricity; instead, it runs on puffs of air, with fiber-optic sensors. Just by itself, this motor, which took three years to design, is big news in the engineering world. As complicated as our technology has gotten, everything is still powered by just a handful of different types of motors. But the new motor, called PneuStep, is only half the story: It wasn’t created as an academic exercise, but to fill a pressing need — to power a new robot that can work within the magnetic field of MRI.

Why a robot? MRI requires the patient to lie inside a big tube; there’s not room for the doctor to be in there, too.

MRI (magnetic resonance imaging) technology is so good these days that it can show the prostate clearly, with great detail. It has the potential to offer the most accurate placement yet of radioactive seeds to kill prostate cancer, except for one big problem: Conventional motors won’t work with MRI, because they are made of metal, and they interfere with the strong magnets in the machines. Because the PneuStep motor is metal-free, it can operate inside the scanner. (A robot is necessary because MRI requires the patient to lie inside a big tube; there’s not room for the doctor to be in there, too.) Recently, Stoianovici and colleagues demonstrated that this robot can place seeds with remarkable accuracy. Their work, which was funded by the National Institutes of Health, was published in the journal, Radiology.

In animal studies, the scientists made tiny targets, put needles in them, and then inserted dummy seeds through these needles, placing the seeds exactly where they wanted them to go. These were early tests, and more work is needed before the new robot, and the motor that drives it, can be used to help men with prostate cancer.But it’s a highly promising beginning.

“Another exciting aspect of the robot is that we designed it with a modular structure,”
says Stoianovici, the R. Christian B. Evensen Scholar. Like a high-tech LEGO system, its parts can be interchanged. “It is easy to exchange the current seed-placing end with one designed for a different procedure.

We can design alternative end pieces to perform biopsies, inject liquid agents, and insert cryotherapy or radiofrequency probes. We believe our robotic system will be able to improve the performance of a number of procedures to treat and diagnose prostate disease.”