title: Comparison of microwave ablation and multipolar radiofrequency ablation in vivo using two internally cooled probes.
abstract: OBJECTIVE
  The objective of our study was to compare the effectiveness of microwave ablation (MWA) and multipolar radiofrequency ablation (RFA) in vivo using two internally cooled probes.
  
  
  METHODS
  MWA (n=24) was performed by simultaneous application of double internally cooled-shaft antennae. Three power settings (60, 70, and 80 W) were used. Multipolar RFA (n=16) was also performed by simultaneously using two internally cooled bipolar applicators (lengths: 3-cm T30 and 4-cm T40) at 60 and 80 W. Probe spacing was 2 cm. Each power setting was applied for eight ablations with a 10-minute duration for each. The cooled-shaft probes were inserted approximately 7 cm into the liver parenchyma of seven adult Wuzhishan pigs under ultrasound guidance, and ablations were performed in various segments of porcine liver. The long-axis diameter (Dl), short-axis diameter (Ds) and the ratio Ds/Dl for each ablation was measured. Temperature curves at 0, 2, and 3 cm from the middle of the two probes and the time to reach 60°C at 0 cm from the parallel central line between the two probes were recorded.
  
  
  RESULTS
  The long-axis diameter and short-axis diameter for all the power settings of MWA were significantly larger than that of both kinds of multipolar RFA (p<0.05). The rates of temperature rise to 60°C at 0 cm from the parallel central line between the two probes for all MWA power settings were significantly faster compared with RFA.
  
  
  CONCLUSIONS
  MWA, by the simultaneous application of double antennae, can generate a larger ablation zone, in vivo, compared with multipolar RFA.
authors.affiliation: Department of Medical Imaging and Interventional Radiology, Cancer Center and State Key Laboratory of Oncology in South China, Sun Yat-sen University, No. 651 Dongfeng East Rd, Guangzhou, Guangdong Province, 510060, China. fanweijun1964@126.com
authors.forename: WeiJun
authors.initials: W
authors.lastname: Fan
authors.forename: Xin
authors.initials: X
authors.lastname: Li
authors.forename: Liang
authors.initials: L
authors.lastname: Zhang
authors.forename: Hua
authors.initials: H
authors.lastname: Jiang
authors.forename: JianLei
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000818:Animals; D017115:Catheter Ablation / Q000295:instrumentation*; D003080:Cold Temperature; D008099:Liver / Q000601:surgery*; D008872:Microwaves / Q000627:therapeutic use*; D000078702:Radiofrequency Therapy; D013552:Swine