title: Image-guided robotic neurosurgery--an in vitro and in vivo point accuracy evaluation experimental study.
abstract: BACKGROUND
  We describe the development of a prototype neurosurgical robotic system called NISS. The aim is to implement a robotic system capable of achieving accurate registration of robotic coordinate systems based on CT images, so that it can be used in clinical application. This system has been refined with a better level of predictability, reliability, and robustness sufficient for animal trial evaluation in stereotactic biopsy of brain lesions.
  
  
  METHODS
  Point accuracy evaluation of NISS began with an in vitro study. The in vitro robotic application accuracy result was 0.1 +/- 0.05 mm and absolute needle-to-target deviation was 0.3 +/- 0.2 mm. An in vivo experiment approach of using steel balls of 1.56-mm-diameter as targets inside the brain of an anaesthetized dog was used to evaluate the performance accuracy of NISS stereotactic probe placement. Five dogs underwent surgical insertion of steel balls into the brain, and the steel balls were served as targets to be reached by a core needle (1.56-mm-diameter). The experiment was carried out by precise manipulation of the needle to reach the steel ball using frameless stereotactic localization principles.
  
  
  RESULTS
  A total of 9 needle results were collected from procedures involving 5 dogs. In the first 5 procedures on 3 dogs, the results were less than 1.9 mm, with an average of 1.3 +/- 0.5 mm. The remaining 4 procedures on 2 dogs yielded results of less than 0.7 mm, with an average of 0.3 +/- 0.2 mm.
  
  
  CONCLUSIONS
  The in vitro and in vivo studies represent the first approach toward evaluating targeting accuracy of a robotic surgery system by using stereotactics biopsy application in a living subject.
authors.affiliation: Advanced Integrated Medical Systems Laboratory, National Neuroscience Institute, Singapore 308433, Singapore. chee_fatt_chan@nni.com.sg
authors.forename: Frank
authors.initials: F
authors.lastname: Chan
authors.forename: Irwan
authors.initials: I
authors.lastname: Kassim
authors.forename: Charles
authors.initials: C
authors.lastname: Lo
authors.forename: Chi Long
authors.initials: CL
authors.lastname: Ho
authors.forename: David
authors.initials: D
authors.lastname: Low
authors.forename: Beng Ti
authors.initials: BT
authors.lastname: Ang
authors.forename: Ivan
authors.initials: I
authors.lastname: Ng