Ivan Fomin*, Robert Odenbach, Enrico Pannicke, Bennet Hensen, Frank Wacker, Georg Rose μRIGS – Ultra-light Micropositioning Robotics for Universal MRI Guided Interventions Abstract: Performing minimal invasive interventions under real-time image guidance proves problematic in a closed-bore magnetic resonance imaging scanner. To enable better usability in MRI guided interventions, robotic systems could be used for additional assistance. However, the integration of such devices into the clinical workflow relates to many technical challenges in order to increase precision of the procedure while ensuring the overall safety. In this work, an MR compatible, compact, ultra-light and remotely controllable micropositioning system called μRIGS is presented. The instrument positioning unit can be operated in a 5-DoF range within a working volume of 2100 cm  with an instrument feed of 120 mm. The kinematics are actuated with a combination of non-metallic Bowden cables and electric stepper motors from a safe distance inside the scanner room, while their control is initiated from the control room via a custom-fitted GUI. Thereby, the precision of the positioning reproducibility of the respective DoF can be achieved with a mean deviation of 0.12 °. Furthermore, a feed force of 14 N can be provided to puncture various soft tissue. Keywords: MR compatible, Ultra-light, Patient-mounted, Robot, Manipulator, Positioning system, Image-guided surgery, MRI guided Intervention 1 Introduction Compared to sonography (US) or computed tomography (CT), magnetic resonance imaging (MRI) offers high soft tissue contrast as well as real-time multiplanar imaging capabilities for navigation. In addition, MRI has the unique ability to measure temperature distribution non-invasively. These aspects form the basis for performing MRI guided diagnostic procedures (e.g. biopsy) and minimally invasive therapeutic interventions (e.g. tumor ablation, pain therapy and brachytherapy). [1–3] Despite many advantages, some disadvantages complicate the application in clinical practice, such as the constricted space in the MR bore or the non-standardized workflows, which currently limit interventional MRI (iMRI) to relatively small number of cases in specialized centers [1]. In particular, positioning and continuously holding the ______ *Corresponding author: Ivan Fomin, Research Campus STIMULATE, Otto-von-Guericke University, Magdeburg, Germany, E-Mail: ivan.fomin@ovgu.de Ivan Fomin, Robert Odenbach, Enrico Pannicke and Georg Rose, Institute for Medical Engineering, Otto-von-Guericke University, Magdeburg, Germany Bennet Hensen and Frank Wacker, Institute of Diagnostic and Interventional Radiology, Medical School, Hannover, Germany Enrico Pannicke, Bennet Hensen, Frank Wacker and Georg Rose, Research Campus STIMULATE, Otto-von-Guericke University, Magdeburg, Germany Figure 1: μRIGS exemplary in the clinical setup for performing an MRI guided liver puncture with an 3 T Skyra System (A). The Instrument positioning unit (B) with 5-DoFs can be remotely controlled from the control room via Bowden cables (C) and the drive unit installed on a mobile and MR safe trolley (D). (E) 18 G puncture needle. DE GRUYTER Current Directions in Biomedical Engineering 2021;7(1): 20211120 https://doi.org/10.1515/cdbme-2021-1018