title: A clinically applicable laser-based image-guided system for laparoscopic liver procedures.
abstract: OBJECTIVE
  Laser range scanners (LRS) allow performing a surface scan without physical contact with the organ, yielding higher registration accuracy for image-guided surgery (IGS) systems. However, the use of LRS-based registration in laparoscopic liver surgery is still limited because current solutions are composed of expensive and bulky equipment which can hardly be integrated in a surgical scenario.
  
  
  METHODS
  In this work, we present a novel LRS-based IGS system for laparoscopic liver procedures. A triangulation process is formulated to compute the 3D coordinates of laser points by using the existing IGS system tracking devices. This allows the use of a compact and cost-effective LRS and therefore facilitates the integration into the laparoscopic setup. The 3D laser points are then reconstructed into a surface to register to the preoperative liver model using a multi-level registration process.
  
  
  RESULTS
  Experimental results show that the proposed system provides submillimeter scanning precision and accuracy comparable to those reported in the literature. Further quantitative analysis shows that the proposed system is able to achieve a patient-to-image registration accuracy, described as target registration error, of [Formula: see text].
  
  
  CONCLUSIONS
  We believe that the presented approach will lead to a faster integration of LRS-based registration techniques in the surgical environment. Further studies will focus on optimizing scanning time and on the respiratory motion compensation.
authors.affiliation: Artorg Center for Biomedical Engineering Research, IGT, University of Bern, Bern, Switzerland. matteo.fusaglia@artorg.unibe.ch.
authors.forename: Matteo
authors.initials: M
authors.lastname: Fusaglia
authors.affiliation: Artorg Center for Biomedical Engineering Research, IGT, University of Bern, Bern, Switzerland.
authors.forename: Hanspeter
authors.initials: H
authors.lastname: Hess
authors.affiliation: Artorg Center for Biomedical Engineering Research, IGT, University of Bern, Bern, Switzerland.
authors.forename: Marius
authors.initials: M
authors.lastname: Schwalbe
authors.affiliation: Artorg Center for Biomedical Engineering Research, IGT, University of Bern, Bern, Switzerland.
authors.forename: Matthias
authors.initials: M
authors.lastname: Peterhans
authors.affiliation: Department of Visceral Surgery, University Hospital of Bern, Bern, Switzerland.
authors.forename: Pascale
authors.initials: P
authors.lastname: Tinguely
authors.affiliation: Artorg Center for Biomedical Engineering Research, IGT, University of Bern, Bern, Switzerland.
authors.forename: Stefan
authors.initials: S
authors.lastname: Weber
authors.affiliation: Artorg Center for Biomedical Engineering Research, IGT, University of Bern, Bern, Switzerland.
authors.forename: Huanxiang
authors.initials: H
authors.lastname: Lu
mesh_terms: D006801:Humans; D010535:Laparoscopy / Q000295:instrumentation / Q000379:methods*; D007834:Lasers; D008099:Liver / Q000000981:diagnostic imaging / Q000601:surgery*; D009038:Motion; D019047:Phantoms, Imaging; D025321:Surgery, Computer-Assisted / Q000295:instrumentation / Q000379:methods*
keywords: Image-guided surgery; Laparoscopic liver surgery; Laser range scanner; Surface registration