title: Internally gas-cooled radiofrequency applicators as an alternative to conventional radiofrequency and microwave ablation devices: an in vivo comparison.
abstract: OBJECTIVE
  To test the efficacy of internally CO2-cooled radiofrequency (RF) ablation in vivo and to compare its effectiveness to a standard water-cooled RF probe and to a gas-cooled microwave (MW) device.
  
  
  METHODS
  49 ablations were performed on 15 pigs under general anesthesia using 15G monopolar CO2-cooled RF applicators, 17G monopolar water-cooled RF applicators and 15G internally CO2-cooled microwave devices. The power of the MW device was 45W, the current of the gas-cooled RF device was 1200-1600mA. At the water-cooled RF probe, maximum power of 200W was set. Ablation time was 15min. The short and long axes of the ablation zone were measured. Histological analyses and NADH-staining were performed. The diameters and the ablation volumes were compared using an analysis of variance.
  
  
  RESULTS
  No spots of untreated tissue were observed close to the cooled needle track in any of the ablation zones. The largest short axis diameter was 3.4±0.5cm achieved with the gas-cooled monopolar applicator. With the water-cooled applicators, short axis diameter was significantly smaller, reaching 2.5±0.4cm. Gas-cooled MW probes achieved 2.9±1.0cm. The largest ablation volume was 31.5±12ml (gas-cooled RF), and the smallest was 12.7±4ml (water-cooled RF). Short/long axis ratio was largest for gas-cooled RF probes with 0.73±0.08 versus 0.64±0.04 for the water-cooled probes and 0.49±0.25 for the microwave applicator.
  
  
  CONCLUSIONS
  Gas-cooled RF applicators may have a higher potential for effective destruction of liver lesions than comparable water-cooled RF systems, and may be an alternative to standard RF and MW ablation devices.
authors.affiliation: Eberhard Karls University of Tübingen, Tübingen University Hospital, Department of Diagnostic and Interventional Radiology, Hoppe-Seyler-Straße 3, Tübingen 72076, Germany. Hansjoerg.rempp@med.uni-tuebingen.de
authors.forename: Hansjörg
authors.initials: H
authors.lastname: Rempp
authors.forename: Matthias
authors.initials: M
authors.lastname: Voigtländer
authors.forename: Martin
authors.initials: M
authors.lastname: Schenk
authors.forename: Markus D
authors.initials: MD
authors.lastname: Enderle
authors.forename: Marcus
authors.initials: M
authors.lastname: Scharpf
authors.forename: Tim O
authors.initials: TO
authors.lastname: Greiner
authors.forename: Alexander
authors.initials: A
authors.lastname: Neugebauer
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Hoffmann
authors.forename: Claus D
authors.initials: CD
authors.lastname: Claussen
authors.forename: Stephan
authors.initials: S
authors.lastname: Clasen
mesh_terms: D000818:Animals; D017115:Catheter Ablation / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005260:Female; D005740:Gases / Q000627:therapeutic use; D006498:Hepatectomy / Q000295:instrumentation*; D006801:Humans; D006979:Hyperthermia, Induced / Q000295:instrumentation*; D008099:Liver / Q000473:pathology* / Q000601:surgery*; D008297:Male; D008872:Microwaves / Q000627:therapeutic use*; D013552:Swine; D016896:Treatment Outcome
chemical_list: D005740:Gases