title: A whole-body registration-free navigation system for image-guided surgery and interventional radiology.
abstract: OBJECTIVE
  To develop and test an image-guided navigation system in which the base of reference is taken from the imaging modality, here, a helical CT scanner.
  
  
  METHODS
  An optical digitizer together with a calibration device is used to measure the transformation matrix between the digitizer reference system and a CT reference system. During intervention, it tracks radiological and surgical tools with tool references. A specific software visually integrates the current tool position with the corresponding image information. In vitro accuracy tests were performed.
  
  
  RESULTS
  With helical CT, freehand positioning accuracy was 1.9 +/- 1.1 mm (mean +/- SD) in vitro (n = 718).
  
  
  CONCLUSIONS
  The navigation system developed by the authors appears to be feasible for radiological interventions as well as for minimally invasive surgery. It is not limited to a certain procedure, can be used in every region of the body, and is functional after imaging. Intraprocedural scans can be integrated immediately.
authors.affiliation: Department of Radiology, University Hospital, Basel, Switzerland. AL@Jacob.ac
authors.forename: A L
authors.initials: AL
authors.lastname: Jacob
authors.forename: P
authors.initials: P
authors.lastname: Messmer
authors.forename: A
authors.initials: A
authors.lastname: Kaim
authors.forename: N
authors.initials: N
authors.lastname: Suhm
authors.forename: P
authors.initials: P
authors.lastname: Regazzoni
authors.forename: B
authors.initials: B
authors.lastname: Baumann
mesh_terms: D004867:Equipment Design; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation*; D015642:Radiology, Interventional; D015203:Reproducibility of Results; D012984:Software; D013514:Surgical Procedures, Operative; D013813:Therapy, Computer-Assisted; D014057:Tomography, X-Ray Computed / Q000295:instrumentation*