Abstract Archives of the RSNA, 2008
Hansjörg Rempp MD, Presenter: Nothing to Disclose
Simone Kempf, Abstract Co-Author: Nothing to Disclose
Matthias Voigtlaender Dipl Eng, Abstract Co-Author: Employee, ERBE Elektromedizin GmbH
Stephan Clasen MD, Abstract Co-Author: Nothing to Disclose
Markus D. Enderle MD, Abstract Co-Author: Employee, ERBE Elektromedizin GmbH, Tübingen, Germany
Philippe Lucien Pereira MD, Abstract Co-Author: Nothing to Disclose
Christina Schraml, Abstract Co-Author: Nothing to Disclose
Claus Detlef Claussen MD, Abstract Co-Author: Nothing to Disclose
et al, Abstract Co-Author: Nothing to Disclose
Dehydration and carbonization limit the energy transfer of conventional radiofrequency (RF) devices. Objective of this study was to evaluate a new hybrid device combining bipolar RF applicators with internal gas-cooling and to test effective application duration and energy absorption with different parameter settings.
210 ablations were performed with an internally CO2-cooled cryo-RF applicator in a single application at ex-vivo bovine livers. Electric parameters and time to irreversible impedance increase as assessment parameter for effective application duration were digitally recorded. Gas pressure for constant cryo-cooling (500, 525, 550, 575, 600 psi and without cooling) and electric power (32-50 Watts, 2-Watt-steps) were varied independently. The series was stopped if a preselected impedance of 300 Ω was reached. Cumulative energy absorption was digitally recorded for all parameter combinations. The short axis of the white coagulation zone was macroscopically assessed.
Induced coagulations were confluent and homogeneous. For all power settings, effective application duration could be increased using higher gas pressure settings (increase 118% at 50 W to 168% at 30W, if 600 psi series are compared to 500 psi). Effective application duration varied between 2.8 minutes at 50 Watts and 500 psi and 37 minutes at 32 Watts and 600 psi. Without cooling, application time reaches only 30 % of the application time at 500 psi at 50 W. Optimal energy absorption was registered at 48 Watts and 600 psi, correspondingly this parameter combination resulted in the largest short axis with 44±1 mm.
The hybrid technology combining RF with gas-cooling leads to longer energy application duration and correspondingly to higher energy absorption with large coagulation for a single needle procedure.
The hybrid cryo-RF-device may be a promising tool for minimally invasive tumor ablation.
et al, ,
Hybrid Cryo-radiofrequency System with Gas-cooled Bipolar Applicators: An ex Vivo Application Study of Application Duration and Energy Absorption. Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6016602.html