title: Innovative technique of transbronchial radiofrequency ablation for intrapulmonary tumors: a preliminary study in a rabbit model.
abstract: BACKGROUND
  : Radiofrequency ablation (RFA) has emerged as a potential alternative for surgery in clinical oncology. This animal experiment was conducted to evaluate the feasibility, safety, and effectiveness of transbronchial RFA in the treatment of lung tumor.
  
  
  METHODS
  : VX2 lung cancer model was established in Japanese white rabbits by transbronchial injection of tissue clot suspension. After waiting for tumor growth to approximately 10 to 20 mm in diameter, transbronchial RFA was performed on VX2 tumors using the Celon-ProCurve microprobe with a 12 mm active tip, a diameter of 1.3 mm, without cooled-tip electrode under the guidance of biplane x-ray scanning. At first, the power of delivery of RFA was increased in a stepwise manner beginning at 1 W/min up to a maximum of 4 W/min, to seek appropriate power deposition. Next, the extent of ablation under determined power deposition was examined for various time periods. The therapeutic efficacy was evaluated by grossly and pathologically 1 week after transbronchial RFA.
  
  
  RESULTS
  : All rabbits tolerated the experimental procedures well. Transbronchial RFA at 2 W/min for 20 minute was the most effective setting in this study. Application of more than 2 W/min was not technically feasible using this equipment, leading to destruction of the probe due to high resistance. In transbronchial RFA at 2 W/min condition, the extent of ablation depended on the duration of ablation.
  
  
  CONCLUSIONS
  : This study demonstrates the potential of transbronchial RFA therapy for treatment of lung tumors. Probe improvement and additional study will be required for further progress.
authors.affiliation: *Department of Thoracic Surgery, Graduate School of Medicine †Department of Thoracic Surgery, Tokyo Women's Medical University, Yachiyo Medical Center ‡Research Center for Frontier Medical Engineering, Chiba University, Chiba, Japan.
authors.forename: Hidemi
authors.initials: H
authors.lastname: Suzuki
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Sekine
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Saito
authors.forename: Takahiro
authors.initials: T
authors.lastname: Nakajima
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Sakairi
authors.forename: Shigetoshi
authors.initials: S
authors.lastname: Yoshida
authors.forename: Ichiro
authors.initials: I
authors.lastname: Yoshino