title: Computer-assisted access to the kidney.
abstract: OBJECTIVE
  The aim of this paper is to introduce the principles of computer-assisted access to the kidney. The system provides the surgeon with a pre-operative 3D planning on computed tomography (CT) images. After a rigid registration with space-localized ultrasound (US) data, preoperative planning can be transferred to the intra-operative conditions and an intuitive man-machine interface allows the user to perform a puncture.
  
  
  METHODS
  Both CT and US images of informed normal volunteer were obtained to perform calculation on the accuracy of registration and punctures were carried out on a kidney phantom to measure the precision of the whole of the system.
  
  
  RESULTS
  We carried out millimetric registrations on real data and guidance experiments on a kidney phantom showed encouraging results of 4.7 mm between planned and reached targets. We noticed that the most significant error was related to the needle deflection during the puncture.
  
  
  CONCLUSIONS
  Preliminary results are encouraging. Further work will be undertaken to improve efficiency and accuracy, and to take breathing into account.
authors.affiliation: Department of Urology, Pitié-Salpetriere Hospital, Pierre et Marie Curie University (Paris VI) Paris, France.
authors.forename: P
authors.initials: P
authors.lastname: Mozer
authors.forename: A
authors.initials: A
authors.lastname: Leroy
authors.forename: Y
authors.initials: Y
authors.lastname: Payan
authors.forename: J
authors.initials: J
authors.lastname: Troccaz
authors.forename: E
authors.initials: E
authors.lastname: Chartier-Kastler
authors.forename: F
authors.initials: F
authors.lastname: Richard
mesh_terms: D006801:Humans; D021621:Imaging, Three-Dimensional; D007668:Kidney / Q000000981:diagnostic imaging / Q000601:surgery*; D010347:Patient Care Planning; D019047:Phantoms, Imaging; D011677:Punctures; D015203:Reproducibility of Results; D025321:Surgery, Computer-Assisted; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography / Q000295:instrumentation; D014584:User-Computer Interface