title: The use of portable intraoperative computed tomography scanning for real-time image guidance: a pilot cadaver study.
abstract: BACKGROUND
  This study was performed to assess the feasibility of using intraoperative computed tomography (CT) to provide real-time updates to image guidance systems (IGSs) during surgery.
  
  
  METHODS
  The xCAT ENT portable intraoperative CT scanner (Xoran Technologies, Ann Arbor, MI) was used to acquire scans before, midway, and at the end of six cadaver dissections during the Southern States Rhinology Course, Augusta, GA, in October 2006. These scans were used to recalibrate three different IGSs used during the dissection. Time measurements were recorded and dosimetry was obtained from the cornea, sphenoid sinus (near the optic chiasm), and from the operative field during acquisition of the images. IGS accuracy was determined at the skull base and lamina papyracea. Surgeons were interviewed on benefits of real-time updates to the IGS after completion of dissections.
  
  
  RESULTS
  The xCAT ENT scanner was compatible with all three IGS platforms. The average time to update the IGS was 13 minutes. Radiation doses to the cornea were 620 mrad per scan, and optic chiasm was 800 mrad/scan. The accuracy at the anterior skull base improved from 1.58 to 0.62 mm (p=0.026). The accuracy at the posterior skull base improved from 1.46 to 0.71 mm (p=0.014). The accuracy at the lamina was not significantly changed.
  
  
  CONCLUSIONS
  Intraoperative portable CT scanning with real-time IGS updates is feasible and likely would add little additional time. Accuracy is improved at the skull base. Prospective studies on actual patients are warranted.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Medical College of Georgia, Augusta, Georgia 30912, USA.
authors.forename: Subinoy
authors.initials: S
authors.lastname: Das
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Maeso
authors.forename: Ramon E
authors.initials: RE
authors.lastname: Figueroa
authors.forename: Brent A
authors.initials: BA
authors.lastname: Senior
authors.forename: John M
authors.initials: JM
authors.lastname: Delgaudio
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Sillers
authors.forename: Rod J
authors.initials: RJ
authors.lastname: Schlosser
authors.forename: Stilianos E
authors.initials: SE
authors.lastname: Kountakis
mesh_terms: D002102:Cadaver; D003199:Computer Systems; D005240:Feasibility Studies; D006801:Humans; D007432:Intraoperative Period; D013517:Otorhinolaryngologic Surgical Procedures; D010256:Paranasal Sinuses / Q000000981:diagnostic imaging* / Q000601:surgery*; D010865:Pilot Projects; D025321:Surgery, Computer-Assisted; D015898:Tomography Scanners, X-Ray Computed; D014057:Tomography, X-Ray Computed / Q000295:instrumentation*