BACKGROUND: The advantages of surgical robots and manipulators are wellrecognized in the clinical and technical community. Precision, accuracy and the potential for telesurgeryare the prime motivations in applying advanced robot technology in surgery. In this paper critical interactionsbetween Magnetic Resonance Imaging equipment and mechatronic devices are discussed and a novel MagneticResonance compatible surgical robot is described.
MATERIAL AND METHODS: Experimental results of the effectsfrom several passive (metallic materials) and active (ultrasound motors) mechanical elements are demonstrated.The design principles for Magnetic Resonance compatible robots are established and the compatibilityof the proposed robot is assessed by comparing images taken with and without the robot's presence withinSigna SP/I GE Medical Systems scanner.
RESULTS: The results showed that, in principle, it is possibleto construct precision mechatronic devices intended to operate inside MR scanner. Use of such a devicewill not cause image shift or significant degradation of signal-to-noise-ratio. An MR compatible surgicalassist robot was designed and constructed. The robot is not affected by the presence of strong magneticfields and is able to manoeuvre during imaging without compromising the quality of images. A novel image-guidedrobot control scheme was proposed. As a part of the control scheme, biomechanics-based organ deformationmodel was constructed and validated by in-vivo experiment. It has been recognised that for robust controlof an image guided surgical robot the precise knowledge of the mechanical properties of soft organs operatedon must be known. As an illustration, results in mathematical modelling and computer simulation of braindeformation are given.
CONCLUSION: The novel MR compatible robot was designed to position and directan axisymmetric tool, such as a laser pointer or a biopsy catheter. New Robot control system based onthe prediction of soft organ deformation was proposed.

Keywords: magnetic resonance compatibility, surgical robot, mechanical properties, finite element method