title: Assessment of a needle-tracking system for bipolar radiofrequency ablation.
abstract: OBJECTIVE
  The purpose of this study was to assess the accuracy and efficacy of a needle-tracking system in phantom and clinical studies using bipolar electrodes.
  
  
  METHODS
  To observe the tip of the electrode, a needle-tracking system with a volume navigation system was used. In the phantom study, the electrode was inserted at various angles and the error was verified. In the clinical study, 21 nodules close to extrahepatic organs or major vessels were enrolled between May and October 2014. After puncturing with the needle-tracking system, computed tomography (CT) was performed. The distances between the electrode tip and extrahepatic organs or major vessels were measured on both B-mode ultrasound (US) and CT. By comparing these distances, the accuracy of this system was evaluated.
  
  
  RESULTS
  In the phantom study, the deviation between the tip of the electrode and the virtual tip of the electrode was analyzed. The median values were within 2 mm at each puncture angle. In the clinical study, the difference between B-mode US and CT was less (mean value 1.17 ± 1.76 mm; range 0-3.5 mm).
  
  
  CONCLUSIONS
  The needle-tracking system is an accurate and useful system for bipolar radiofrequency ablation.
authors.affiliation: Department of Gastroenterology and Metabology, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, 791-0295, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Hirooka
authors.affiliation: Department of Gastroenterology and Metabology, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, 791-0295, Japan.
authors.forename: Yohei
authors.initials: Y
authors.lastname: Koizumi
authors.affiliation: Department of Gastroenterology and Metabology, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, 791-0295, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Imai
authors.affiliation: Department of Gastroenterology and Metabology, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, 791-0295, Japan.
authors.forename: Hironori
authors.initials: H
authors.lastname: Ochi
authors.affiliation: Department of Gastroenterology and Metabology, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, 791-0295, Japan.
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Nakamura
authors.affiliation: Department of Gastroenterology and Metabology, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, 791-0295, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Yoshida
authors.affiliation: Department of Gastroenterology and Metabology, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, 791-0295, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Hiraoka
authors.affiliation: Department of Gastroenterology and Metabology, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, 791-0295, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Tokumoto
authors.affiliation: Department of Gastroenterology and Metabology, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, 791-0295, Japan.
authors.forename: Masanori
authors.initials: M
authors.lastname: Abe
authors.affiliation: Department of Gastroenterology and Metabology, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, 791-0295, Japan. hiasa@m.ehime-u.ac.jp.
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Hiasa
mesh_terms: D055011:Ablation Techniques / Q000295:instrumentation / Q000379:methods*; D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging / Q000601:surgery*; D004566:Electrodes; D004867:Equipment Design; D005260:Female; D006801:Humans; D008099:Liver / Q000000981:diagnostic imaging / Q000601:surgery; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D009339:Needles; D019047:Phantoms, Imaging; D000078702:Radiofrequency Therapy; D025321:Surgery, Computer-Assisted / Q000295:instrumentation / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods; D014463:Ultrasonography / Q000295:instrumentation / Q000379:methods*
keywords: Hepatocellular carcinoma; Liver tumor; Navigation; Radiofrequency ablation