Safe, Nonmagnetic Fluidic Actuator for MRI-Guided Interventions

Achievement date: 

Researchers affiliated with the Center for Compact and Efficient Fluid Power (CCEFP), an NSF-funded Engineering Research Center (ERC) headquartered at the University of Minnesota, have taken a significant step toward using fluid-power solutions for health care. Specifically, the researchers recently invented a fluid-powered actuator for interventions guided by magnetic resonance imaging (MRI).


Fluid power is an ideal form of robotic actuation inside the scanner’s magnetic field because actuators can be designed free of magnetic and electrical components. However, there are no fluid-power actuators readily available that offer the safety, sterilizability, and precision performance required for medical robotic systems. The CCEFP researchers’ work represents a major movement to overcome this transformational barrier.



MRI offers many benefits to image-guided interventions. These benefits include excellent soft tissue distinction, little to no repositioning of the patient, and zero radiation exposure. However, the closed, narrow bore of a high-field MRI scanner limits clinician access to the patient, so an MRI-compatible robot is essentially required for many potential interventions. With a compact design made possible by additive manufacturing, a first prototype was made (see figure). Employing inchworm-like behavior, the device is intrinsically safe. The linear actuator can advance or retract a needle in small, discrete steps. The device’s pneumatic bellows and pinching mechanism are hermetically sealed for clean performance in sterile environments.