title: Accuracy of 3D fluoroscopy in cranial stereotactic surgery: a comparative study in phantoms and patients.
abstract: BACKGROUND
  To assess the precision and accuracy of 3D fluoroscopy (XT) in phantoms and patients compared to computed tomography (CT) in localizing stereotactic probes.
  
  
  METHODS
  Approval was obtained from the institutional research ethics board. The prospective phantom study was compared to a retrospective patient cohort. Accuracy was assessed by the mean error and precision by the mean dispersion between XT and CT with a cubic or a skull phantom containing metallic spheres installed on plates or along trajectories. Significance was assessed by Friedman's and Levene's test. Secondary endpoints were Euclidean error, other influences e.g. installed frame and radiation exposure.
  
  
  RESULTS
  A total of 3,342 distances were assessed in 17 XT and 13 CT phantom scans. The cubic phantom showed mean distance errors of 0.33 mm (SD + -0.46 mm) for XT compared to 0.19 mm (SD + -0.83 mm) for CT scans (p = 0.0004) and a dispersion of 0.22 mm (XT) and 0.70 mm (CT). The dispersion was 0.36 mm with and 0.63 mm without a stereotactic frame (p < 0.0001). The mean Euclidean error was 0.72 mm (SD + -0.59 mm) in the skull phantom and 1.34 mm (SD + -0.82 mm) in the patient cohort. The effective dose was 0.65 mSv for the XT and 1.12 mSv for the CT.
  
  
  CONCLUSIONS
  The accuracy of XT imaging in phantoms revealed a slightly lower accuracy but higher precision than the CT. The overall accuracy of XT was higher than that of the stereotactic frame allowing stereotactic localization with about half of the effective dose of a CT-scan.
authors.affiliation: Department of Neurosurgery, Goethe University Frankfurt, Schleusenweg 2-16, 60528, Frankfurt, Germany, lutz.weise@med.uni-frankfurt.de.
authors.forename: Lutz M
authors.initials: LM
authors.lastname: Weise
authors.forename: Sebastian
authors.initials: S
authors.lastname: Eibach
authors.forename: Matthias
authors.initials: M
authors.lastname: Setzer
authors.forename: Volker
authors.initials: V
authors.lastname: Seifert
authors.forename: Eva
authors.initials: E
authors.lastname: Herrmann
authors.forename: Elke
authors.initials: E
authors.lastname: Hattingen
mesh_terms: D046690:Deep Brain Stimulation; D004566:Electrodes; D005471:Fluoroscopy; D005917:Globus Pallidus / Q000000981:diagnostic imaging*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D016343:Monitoring, Intraoperative / Q000379:methods*; D009069:Movement Disorders / Q000628:therapy; D019047:Phantoms, Imaging; D011446:Prospective Studies; D016634:Radiosurgery / Q000379:methods*; D012189:Retrospective Studies; D020531:Subthalamic Nucleus / Q000000981:diagnostic imaging*; D025321:Surgery, Computer-Assisted / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods; D020651:Ventral Thalamic Nuclei / Q000000981:diagnostic imaging*