Microwave Ablation of Hepatic Tumors: Simultaneous Use of Multiple Probes Results in Large Areas of

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Microwave Ablation of Hepatic Tumors
Simultaneous Use of Multiple Probes Results in
Large Areas of Tissue Necrosis

• Andrew Wright MD, Chris Johnson, Fred Lee Jr. MD,
  and David Mahvi MD

Departments of Radiology and Surgery University
of Wisconsin Hospital
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Multiple Probe Ablation

• Microwave Ablation
• Goals
• Increase lesion size
• Increase control and customization of lesion size
  and shape
• Decrease treatment time
• Allow for treatment of multiple tumors

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Hypothesis

• Multiple probe hepatic ablation will result in
  synergistically larger lesion sizes by shielding
  lesion center from blood-flow mediated cooling

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Methods

• Microwave Ablation System

Vivant Medical 13g, 15cm dipole antenna
60W, 915MHz generator 8 channels Fiberoptic
temperature monitor
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Methods

• Microwave Protocol
• Domestic Swine
• 10 minute ablation, 40 Watts
• Single Probe Ablation
• Multiple Probe Ablation
• 3 parallel probes in triangular array
• Separation between probes varied from 0.5 to 3.5cm

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Methods

• Microwave Protocol

Single Probe
Multiple Probe
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Assessment

• Lesion dimensions calculated
• Multiple Probe lesions scored for shape

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Results
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Results
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Results
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Results

• Size by Separation

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Results

• Lesion Shape

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Results

• Lesion Shape

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Results

• Temperature

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Results
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Results

• 5 Probes

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Conclusions

• Microwave ablation may be performed with
  multiple, simultaneous probes
• Microwave ablation with three probes results in
  lesions four times larger than single probe
  microwave ablation
• Confluent lesions may be produced with probe
  separations of 1.6cm or less

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Summary

• Microwave ablation has several theoretical
  advantages over RF ablation
• Multiple probe microwave ablation may allow for
  treatment of larger, more complex tumors as well
  as simultaneous treatment of multiple tumors
• Multiple probe ablation may improve treatment of
  tumors near blood vessels