WPI's MR-compatible robots

We are very proud of our friends from WPI for the amazing job they do regarding system design and development. Their MR-compatible robots--being under clinical trials--were featured recently in the IEEE Spectrum Magazine. Well done!

"Researchers at Worcester Polytechnic Institute (WPI) are developing a MRI-compatible robotic surgery tool that can overcome those limitations. Their system isn’t made of metal, but instead has plastic parts and ceramic piezoelectric motors that allow it to work safely inside an MRI.

The tool is now being tested on human patients undergoing prostate biopsies at Boston’s Brigham and Women’s Hospital. The radiologists can use real-time MRI images to guide the movement of their robotic assistant, which they believe will provide unprecedented accuracy. (If you’re wondering how it works, here’s a descriptive line from a journal article the researchers published last year: “The patient lies inside the MRI scanner . . . and the robot accesses the prostate through the perineal wall.”) 

The robot, developed by WPI in collaboration with Brigham and Johns Hopkins University, also boasts a low-noise control system that doesn’t cause electrical interference. “Essentially, we made a device that can move around the MRI bore without affecting image quality,” says Gregory Fischer, a professor of mechanical engineering at WPI whose Automation and Interventional Medicine Robotics Lab led the research.  

So far, a dozen men have participated in a clinical trial assessing the feasibility and safety of robot-assisted prostate biopsies. The count should reach 20 by the end of July.

The typical biopsy that doctors perform to check a man for prostate cancer is far from a precise procedure, says the trial’s principle investigator Clare Tempany, a radiologist and director of the National Center for Image Guided Therapy at Brigham. Typically a physician targets the prostate, which is the size of “a small peach or plum,” she says, by placing a grid guide between the patient’s legs. Then the doctor inserts needles through the skin and into each quadrant to get tissue samples. “This is somewhat disparagingly called ‘the blind biopsy,’ ” says Tempany. “There’s no lesion targeted, it’s just: ‘Let’s push a bunch of needles in and see what we get.’ ”

These biopsies are sometimes aided by ultrasound imaging, which requires inserting a ultrasound wand into the patient’s rectum. Because ultrasound doesn’t provide clear enough images, doctors aren’t able to make precision strikes with their needles, says Tempany. They often end up taking 10 to 50 core samples, she says, and each needle stick carries the risk of infection.

This clinical trial literally shows a better way. Looking at real-time MRI images, the doctor can identify parts of the prostate that look suspicious, and direct the robotic tool to those spots. “In our procedure, a small little robot places the needle on the skin’s surface and says, ‘This is the spot where you need to push, and in five or six centimeters you’ll hit your target,’ ” Tempany explains. In the current trial the doctor takes the actual step of inserting the needle, and typically takes samples in just four locations. “It’s a smarter biopsy,” she says."

Source: IEEE Spectrum