title: Rotational encoding of C-arm fluoroscope with tilt sensing accelerometer.
abstract: OBJECTIVE
  Accurate, practical, and affordable joint encoding on legacy C-arm fluoroscopes is a major technical challenge. Conventional pose tracking methods, like optical cameras and radiographic fiducials, are hampered by significant shortcomings.
  
  
  METHODS
  We propose to retrofit legacy C-arms with a tilt sensing accelerometer for rotation encoding. Our experimental setup consists of affixing an accelerometer to a full scale C-arm with a webcam as an alternative to X-ray imaging for this feasibility research. Ground-truth C-arm poses were obtained from the webcam that tracked a checkerboard plate. From these we constructed a series of angle and structural correction equations that can properly relate the accelerometer angle readings to C-arm pose during surgery and compensate for systematic structural C-arm deformations, such as sagging and bending.
  
  
  RESULTS
  Real-time tracking of the primary and secondary angle rotations of the C-arm showed an accuracy and precision of less than 0.5 degrees in the entire range of interest.
authors.affiliation: Queen's University, Kingston, ON, Canada v.grzeda@queensu.ca
authors.forename: Victor
authors.initials: V
authors.lastname: Grzeda
authors.forename: Gabor
authors.initials: G
authors.lastname: Fichtinger
mesh_terms: D000054:Acceleration; D004867:Equipment Design; D019544:Equipment Failure Analysis; D011856:Radiographic Image Enhancement / Q000295:instrumentation* / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000295:instrumentation* / Q000379:methods*; D015203:Reproducibility of Results; D012399:Rotation; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000295:instrumentation*; D014159:Transducers