MRI/fMRI-compatible robotic system with force feedback for interaction with human motion

This paper presents a robotic system that is compatible with anatomical magnetic resonance imaging (MRI) as well as with the more sensitive functional MRI (fMRI), and can safely and smoothly interact with human motion during the imaging. The system takes advantage of the electromagnetic shield that encloses the MR room by placing the interfering or sensitive components outside the shield, in the control room. This eliminates the need for extensive compatibility testing before each use. The concept is based on a conventional actuator placed outside the scanner room and a hydrostatic connection to transmit force and motion to an MR-compatible slave placed next to or inside the MR scanner. A force sensor, based on reflected light intensity measurement over optical fibers, measures interaction forces with the human subject. A robotic interface for wrist motion demonstrates the MR compatibility of this concept and the possibility to interact with various dynamic environments during functional imaging. This technology provides a basis for applications such as assistive devices for interventional MRI and haptic interfaces for neuroscience investigations.