Consideration of geometric constraints regarding MR-compatible interventional robotic devices

The design of MR-compatible robotic systems is a challenging task given the magnetic nature of the scanning environment but also the limitations imposed by the geometric characteristics of the imaging modality. The latter issue is often referred to as geometric MR-compatibility and was treated through image-based analyses as part of the design of a new interventional robotic device. Examinations on geometric MR-compatibility focused on ways to quantify the available space inside a cylindrical scanner, considerations regarding the effective field-of-view of an MR scanner, representations of the attainable anatomical region as defined for needle targeting applications, and computer simulations using three-dimensional digital models representing the patient. Geometric considerations are relevant both to the design of an MR-compatible robotic device but also its operation, as for example when using patient-specific data for intervention planning purposes. A preoperative planning procedure developed for the new robotic device will also be described.