title: Spatial calibration of a 2D/3D ultrasound using a tracked needle.
abstract: OBJECTIVE
  Spatial calibration between a 2D/3D ultrasound and a pose tracking system requires a complex and time-consuming procedure. Simplifying this procedure without compromising the calibration accuracy is still a challenging problem.
  
  
  METHODS
  We propose a new calibration method for both 2D and 3D ultrasound probes that involves scanning an arbitrary region of a tracked needle in different poses. This approach is easier to perform than most alternative methods that require a precise alignment between US scans and a calibration phantom.
  
  
  RESULTS
  Our calibration method provides an average accuracy of 2.49 mm for a 2D US probe with 107 mm scanning depth, and an average accuracy of 2.39 mm for a 3D US with 107 mm scanning depth.
  
  
  CONCLUSIONS
  Our method proposes a unified calibration framework for 2D and 3D probes using the same phantom object, work-flow, and algorithm. Our method significantly improves the accuracy of needle-based methods for 2D US probes as well as extends its use for 3D US probes.
authors.affiliation: Centre for Medical Image Computing, UCL, London, UK. f.vasconcelos@ucl.ac.uk.
authors.forename: Francisco
authors.initials: F
authors.lastname: Vasconcelos
authors.affiliation: Department of Obstetrics and Gynecology, UCL, London, UK.
authors.forename: Donald
authors.initials: D
authors.lastname: Peebles
authors.affiliation: Centre for Medical Image Computing, UCL, London, UK.
authors.forename: Sebastien
authors.initials: S
authors.lastname: Ourselin
authors.affiliation: Centre for Medical Image Computing, UCL, London, UK.
authors.forename: Danail
authors.initials: D
authors.lastname: Stoyanov
mesh_terms: D000465:Algorithms; D002138:Calibration; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D009339:Needles; D019047:Phantoms, Imaging; D014463:Ultrasonography / Q000379:methods*
keywords: 3D Ultrasound; Calibration; Instrument Tracking