title: Accuracy of a 3D fluoroscopic navigation system using a flat-panel detector-equipped C-arm.
abstract: OBJECTIVE
  The aim of this study was to evaluate the accuracy of a novel 3-dimensional (3D) fluoroscopic navigation system using a flat-panel detector-equipped C-arm, focusing on the influence of the distance from the center of fluoroscopic imaging on navigation accuracy.
  
  
  METHODS
  A geometric phantom was made using a Styrofoam cube with 25 markers, each consisting of a metal ball 1.5 mm in diameter, fixed in a cross arrangement at 1-cm intervals. Hip joint surgery was simulated using a set of dry pelvic and femoral bones. A total of eight markers were fixed to the acetabulum and proximal femur.
  
  
  RESULTS
  In the geometric phantom study, mean target registration error (TRE) was 0.7 mm (range: 0.1-1.5). The TRE of markers located at 5 cm from the imaging center was significantly higher than the TRE of markers located at 1 and 2 cm. However, the TRE was <1 mm in 90% of the overall trials and <1.5 mm in 100%. In the dry bone study, the mean TRE was 0.9 mm (range: 0.7-1.5) over the acetabulum and 1.0 mm (range: 0.5-1.4) over the femur. No significant difference in TRE was seen between the acetabulum and proximal femur.
  
  
  CONCLUSIONS
  The accuracy of this novel 3D fluoroscopic navigation system was considered acceptable for clinical application. A 3D C-arm equipped with a flat-panel detector could increase the feasibility of 3D fluoroscopic navigation by reducing the effects of image distortion on navigation accuracy.
authors.affiliation: Department of Orthopaedic Sugery, Osaka University Graduate School of Medicine, Japan. masaki-tko@umin.ac.jp
authors.forename: Masaki
authors.initials: M
authors.lastname: Takao
authors.forename: Kentaro
authors.initials: K
authors.lastname: Yabuta
authors.forename: Takashi
authors.initials: T
authors.lastname: Nishii
authors.forename: Takashi
authors.initials: T
authors.lastname: Sakai
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Sugano
mesh_terms: D000077:Acetabulum / Q000033:anatomy & histology*; D001863:Bone Screws; D004867:Equipment Design; D005240:Feasibility Studies; D005269:Femur / Q000033:anatomy & histology*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000295:instrumentation* / Q000379:methods; D010388:Pelvis / Q000033:anatomy & histology*; D010779:Photofluorography / Q000295:instrumentation; D018709:Statistics, Nonparametric