A Closed-loop MRI-powered Actuator for Robotic Interventions

Introduction Robotically-assisted MR-guided interventions are becoming increasingly important in the clinical community. Surgical robots offer precision, accuracy, speed, and the potential for remote operation, while the MRI offers superior soft tissue contrast and a well-defined 3D coordinate system. The synergy of both systems results in robotically assisted MR-guided interventional procedures that can target lesions more accurately and more efficiently. Recently, an MR-powered and controlled actuator technology has been proposed for needle guidance of biopsies or interventional therapies. The principle of operation is based on one or more small ferromagnetic bodies embedded in the actuator that serves to convert the electromagnetic energy of the MR gradients into mechanical energy [1]. A prototype was constructed to show that the actuator can drive a needle and successfully puncture a swine heart under open-loop control. In order to improve actuator performance as well as to automate the puncturing procedure, a closed-loop MRI-controlled actuator is developed.