VISE SUMMER SEMINAR SERIES Intraoperative Digitization and Image-to-Physical Registration Dr. Amber Simpson Research Assistant Professor Biomedical Engineering ACKNOWLEDGEMENTS Diagrams, photos, and inspiration ... Queen’s University Gabor Fichtinger, PhD Manuella Kunz, PhD Vanderbilt University Jessica Burgner, PhD Bob Galloway, PhD Ankur Kumar, MS Thomas Pheiffer, MS Pathfinder Therapeutics Inc. SURGIC AL NAVIGATION measurement system image (or model) object registration reference system preoperative procedure intraoperative procedure LOC ALIZATION INTRAOPERATIVE TRACKING Coordinate Measurement Acoustic Inertial Mechanical Magnetic/RF Optical More details on July 26 MECHANICAL LOCALIZATION Advantages: simple concept, no • line of site issues, reliable, repeatable, accurate Disadvantages: clumsy, confined • range, single reference frame, error propagation/aggregation, each joint requires calibration, head ring is very invasive Source: Gabor Fichtinger, Queen’s University ARTICULATED ARM IN SURGERY Media Source: Bob Galloway MAGNETIC/RF LOC ALIZATION Flock of Birds, Ascension (now NDI) Aurora, NDI Fastrak, Polhemus G4, Polhemus AURORA SYSTEM • SCU powers field generator – field generator produces a series of varying magnetic fields, creating a known volume of varying magnetic flux. Source: Aurora User Guide, Northern Digital Inc. ELECTROMAGNETIC TRACKING • Sensor coils are connected to SCU via SIU. • Sensor coils inside measurement volume = voltage induced in them • Characteristic of induced voltage: depends on sensor coil position and orientation in measurement volume and strength and phase of varying magnetic field • SIU converts the voltage into digital data and sends it to the SCU • SCU calculates position and orientation of coil and Measurement Volume sends result to host computer