title: Microwave ablation: results with double 915 MHz antennae in ex vivo bovine livers.
abstract: OBJECTIVE
  To investigate the settings for the optimal microwave ablation geometry with the simultaneous application of double 915 MHz antennae in ex vivo bovine livers, so as to provide the technical basis for treating large liver tumor in one ablation session.
  
  
  METHODS
  MWAs were performed on ex vivo bovine livers by simultaneously application of double 915 MHz internally cooled-shaft antennae. Four power settings (50, 60, 70 and 80 W) were used during MWAs, while application time was fixed at 10 min. Three inter-antenna distances (2.0, 2.5 and 3.0 cm) were used. Diameters and shapes of the coagulation zones were observed on gross specimens.
  
  
  RESULTS
  (1) The coagulation shape was related to the inter-antenna distance, which was most spherical at an inter-antenna distance of 2.0 cm. A recess of the coagulation zone was observed at an inter-antenna distances of 2.5 and 3.0 cm. (2) The long-axis and short-axis coagulation diameter enlarged with increasing power output. However, there were no significant differences in the coagulation diameters between 70 and 80 W (P>0.05). More desirable coagulation geometry could be obtained by simultaneous application of double antennae at 70 W for 10 min with an inter-antenna distance of 2.0 cm, the long-axis and short-axis coagulation diameter were 6.95 ± 0.32 cm and 5.30 ± 0.22 cm, respectively.
  
  
  CONCLUSIONS
  Simultaneous application of double 915 MHz antennae can generate large coagulation zones with desirable shape which may be advantageous for treating large liver tumor in one ablation session.
authors.affiliation: Department of Interventional Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, Beijing 100853, China.
authors.forename: Wenyuan
authors.initials: W
authors.lastname: Shi
authors.forename: Ping
authors.initials: P
authors.lastname: Liang
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhu
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Yu
authors.forename: Qiujie
authors.initials: Q
authors.lastname: Shao
authors.forename: Tong
authors.initials: T
authors.lastname: Lu
authors.forename: Yang
authors.initials: Y
authors.lastname: Wang
authors.forename: Baowei
authors.initials: B
authors.lastname: Dong
mesh_terms: D000818:Animals; D017115:Catheter Ablation / Q000295:instrumentation*; D002417:Cattle; D004867:Equipment Design; D066298:In Vitro Techniques; D008099:Liver / Q000601:surgery*; D008872:Microwaves / Q000627:therapeutic use*