title: Accuracy of 3-d needle navigation in interstitial brachytherapy in various body regions.
abstract: BACKGROUND
  Precise immobilisation of a patient during extracranial stereotactic 3-D navigation is essential in order to minimize the patient's movement during CT data recording and needle application. In this paper we report the first results of needle positioning accuracy in various body regions, using a 3-D navigation system for brachytherapy and a new patient immobilisation system.
  
  
  METHODS
  Six patients with different manifestations of neoplastic diseases were immobilized by a special vacuum system and treated with stereotactic 3-D navigational interstitial brachytherapy.
  
  
  RESULTS
  The comparison of the simulated stereotactic needle positions with the actual needle positions resulted in a mean positioning deviation varying from 3.4 to 6.5 mm for 29 needles. The maximum positioning deviation lay between 5.7 and 13 mm.
  
  
  CONCLUSIONS
  The results of our study show that, despite effective patient immobilisation, an increase in needle positioning accuracy is limited by the method of stereotactic 3-D navigation. Effects such as modification of body shape caused by the needle application morphologic alterations, and inherent inaccuracies within the navigation system have an important influence upon accuracy, which it is not yet possible to calculate.
authors.affiliation: Department of Radio-Oncology, University of Marburg, Germany. strassma@med.uni-marburg.de
authors.forename: Gerd
authors.initials: G
authors.lastname: Strassmann
authors.forename: Reinhard
authors.initials: R
authors.lastname: Heyd
authors.forename: Rita
authors.initials: R
authors.lastname: Cabillic-Engenhart
authors.forename: Cristos
authors.initials: C
authors.lastname: Kolotas
authors.forename: Stefan
authors.initials: S
authors.lastname: Walter
authors.forename: Georg
authors.initials: G
authors.lastname: Sakas
authors.forename: Detlef
authors.initials: D
authors.lastname: Richter
authors.forename: Nikos
authors.initials: N
authors.lastname: Zamboglou
mesh_terms: D001918:Brachytherapy / Q000295:instrumentation*; D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000295:instrumentation*; D007103:Immobilization; D008297:Male; D008875:Middle Aged; D009339:Needles; D009367:Neoplasm Staging; D009369:Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D010043:Outcome and Process Assessment, Health Care; D011880:Radiotherapy Planning, Computer-Assisted / Q000295:instrumentation*; D011881:Radiotherapy, Computer-Assisted / Q000295:instrumentation*; D014057:Tomography, X-Ray Computed / Q000295:instrumentation*