multiprobe rf ablation: a feasibility study
DESCRIPTION
Multiprobe RF ablation: A Feasibility Study. Fred T. Lee Jr., MD Dieter Haemmerich, MS Andrew S. Wright, MD David M. Mahvi, MD John G. Webster, PhD. University of Wisconsin Depts. Of Radiology, Bioengineering, Surgery. Why multiprobe RF?. Why multiprobe RF?. Why multiprobe RF?. - PowerPoint PPT PresentationTRANSCRIPT
Multiprobe RF ablation: A Feasibility Study
Fred T. Lee Jr., MDDieter Haemmerich, MSAndrew S. Wright, MDDavid M. Mahvi, MDJohn G. Webster, PhD
University of Wisconsin Depts. Of Radiology, Bioengineering, Surgery
Why multiprobe RF?
Why multiprobe RF?
Why multiprobe RF?
Why multiprobe RF?
• Simultaneous ablations– Increase lesion number– Multiple probes in large tumor
• Decrease ablation time• Improve temperature distribution in lesion
(make ablation more effective)• Control lesion (bigger not always better)
Current RF systems
• Multiple prongs run at same voltage
RITA
RTC
Radionics
Faraday Effect
Faraday Effect
Electrodes at same voltage
Faraday Effect
Probes at different voltage=bipolar Current flows between probes
Faraday Effect
Electrically independent probes
How independent probes created
• Rapid switching between probes• Temperature in tissue changes much
slower than switching• Temperature/impedance feedback
algorithm
How independent probes created
Prototype dual probe unit
Prototype dual probe unit
Ex vivo results: Dual probes in pig liver at same temperature
In vivo results
• Domestic pigs (n=3, mean wt=35 kg)• 13 RF lesions
– 3 single control lesions– 10 dual (5 pairs created simultaneously)
RITA Model 150 generator (150 W), Starburst electrode deployed to 3.0 cm. 10 minute ablation, 100° C.
In vivo results
vs
Single Simultaneous dual RF
Note: same scale
In vivo results
• Time to temperature (100°C)single: 2.7 minutes (162
seconds)dual: 3.4 minutes (204 seconds)
In vivo results:volume of necrosis
• Single: 10.7 cc• Dual (each individual lesion): 17.3ccTherefore, 34.6 cc ablation obtained in
approximately same time as 10.7 cc ablation
In vivo results:max diameter
• Single: 3.3 cm• Dual (each individual lesion): 3.8 cm
Conclusions
• Feasible to create multiple simultaneous burns with a single generator
• No lesion size penalty• Slight increase in time to
temperature
What’s next?
• Increase # of probes (?4)• Will require increased generator power• Many technical factors involved with rapid
switching (mechanical electrical)• Cluster probes in close proximity to
increase lesion size, temperature