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A parametric study delineating irreversible electroporation from thermal damage based on a minimally invasive intracranial procedure.

Garcia PA, Rossmeisl JH, Neal RE, Ellis TL, Davalos RV - Biomed Eng Online (2011)

Bottom Line: We developed numerical simulations of typical protocols based on a previously published computed tomographic (CT) guided in vivo procedure.We confirm that determining an IRE treatment protocol requires incorporating all the physical effects of electroporation, and that these effects may have significant implications in treatment planning and outcome assessment.The goal of the manuscript is to provide the reader with the numerical methods to assess multiple-pulse electroporation treatment protocols in order to isolate IRE from thermal damage and capitalize on the benefits of a non-thermal mode of tissue ablation.

View Article: PubMed Central - HTML - PubMed

Affiliation: Bioelectromechanical Systems Laboratory, School of Biomedical Engineering and Sciences, Virginia Tech-Wake Forest University, Blacksburg, VA, USA.

ABSTRACT

Background: Irreversible electroporation (IRE) is a new minimally invasive technique to kill undesirable tissue in a non-thermal manner. In order to maximize the benefits from an IRE procedure, the pulse parameters and electrode configuration must be optimized to achieve complete coverage of the targeted tissue while preventing thermal damage due to excessive Joule heating.

Methods: We developed numerical simulations of typical protocols based on a previously published computed tomographic (CT) guided in vivo procedure. These models were adapted to assess the effects of temperature, electroporation, pulse duration, and repetition rate on the volumes of tissue undergoing IRE alone or in superposition with thermal damage.

Results: Nine different combinations of voltage and pulse frequency were investigated, five of which resulted in IRE alone while four produced IRE in superposition with thermal damage.

Conclusions: The parametric study evaluated the influence of pulse frequency and applied voltage on treatment volumes, and refined a proposed method to delineate IRE from thermal damage. We confirm that determining an IRE treatment protocol requires incorporating all the physical effects of electroporation, and that these effects may have significant implications in treatment planning and outcome assessment. The goal of the manuscript is to provide the reader with the numerical methods to assess multiple-pulse electroporation treatment protocols in order to isolate IRE from thermal damage and capitalize on the benefits of a non-thermal mode of tissue ablation.

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Electric field, conductivity, temperature and thermal damage distributions at the conclusion of an 80 s IRE treatment simulation. A model of eighty 50 μs pulses with an applied voltage of 1000 V at a repetition rate of 1 Hz is presented. The grid resolution in the distributions is 1.0 mm. For this specific simulation, the tissue was treated only with IRE since thermal damage occurs when Ω > 0.53.
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Figure 6: Electric field, conductivity, temperature and thermal damage distributions at the conclusion of an 80 s IRE treatment simulation. A model of eighty 50 μs pulses with an applied voltage of 1000 V at a repetition rate of 1 Hz is presented. The grid resolution in the distributions is 1.0 mm. For this specific simulation, the tissue was treated only with IRE since thermal damage occurs when Ω > 0.53.

Mentions: Figure 6 is a representation of the results from the simulated IRE treatments in brain. This figure displays the electric field, conductivity, temperature, and thermal damage distributions at the end of an entire IRE protocol. The electric field and temperature distributions are critical since they allow for the numerical integration of the electric field (Figure 6A) to determine volumes of IRE and temperature (Figure 6C) to assess thermal effects including thermal damage, respectively (Figure 6D). We provide these distributions for one time point (80 s) and treatment parameter set (e.g. eighty 50-μs pulses at 1000 V delivered at 1 Hz), but could readily report any of the other simulated protocols. Figure 6A displays the electric field distribution on the tissue treated with IRE. Figure 6B shows the distribution of the electrical conductivity of the tissue as given by Equation 2. Figure 6C presents the temperatures at the completion of the pulse delivery. Figure 6D uses the temperature data throughout the treatment delivery to assess the presence of thermal damage. The maximum temperature reached was 47.8°C, with a thermal damage value, Ω, of 0.38. The increase in temperature during this simulation did not generate any tissue death by thermal modes since Ω was below the 0.53 threshold needed for thermal damage.


A parametric study delineating irreversible electroporation from thermal damage based on a minimally invasive intracranial procedure.

Garcia PA, Rossmeisl JH, Neal RE, Ellis TL, Davalos RV - Biomed Eng Online (2011)

Electric field, conductivity, temperature and thermal damage distributions at the conclusion of an 80 s IRE treatment simulation. A model of eighty 50 μs pulses with an applied voltage of 1000 V at a repetition rate of 1 Hz is presented. The grid resolution in the distributions is 1.0 mm. For this specific simulation, the tissue was treated only with IRE since thermal damage occurs when Ω > 0.53.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3108916&req=5

Figure 6: Electric field, conductivity, temperature and thermal damage distributions at the conclusion of an 80 s IRE treatment simulation. A model of eighty 50 μs pulses with an applied voltage of 1000 V at a repetition rate of 1 Hz is presented. The grid resolution in the distributions is 1.0 mm. For this specific simulation, the tissue was treated only with IRE since thermal damage occurs when Ω > 0.53.
Mentions: Figure 6 is a representation of the results from the simulated IRE treatments in brain. This figure displays the electric field, conductivity, temperature, and thermal damage distributions at the end of an entire IRE protocol. The electric field and temperature distributions are critical since they allow for the numerical integration of the electric field (Figure 6A) to determine volumes of IRE and temperature (Figure 6C) to assess thermal effects including thermal damage, respectively (Figure 6D). We provide these distributions for one time point (80 s) and treatment parameter set (e.g. eighty 50-μs pulses at 1000 V delivered at 1 Hz), but could readily report any of the other simulated protocols. Figure 6A displays the electric field distribution on the tissue treated with IRE. Figure 6B shows the distribution of the electrical conductivity of the tissue as given by Equation 2. Figure 6C presents the temperatures at the completion of the pulse delivery. Figure 6D uses the temperature data throughout the treatment delivery to assess the presence of thermal damage. The maximum temperature reached was 47.8°C, with a thermal damage value, Ω, of 0.38. The increase in temperature during this simulation did not generate any tissue death by thermal modes since Ω was below the 0.53 threshold needed for thermal damage.

Bottom Line: We developed numerical simulations of typical protocols based on a previously published computed tomographic (CT) guided in vivo procedure.We confirm that determining an IRE treatment protocol requires incorporating all the physical effects of electroporation, and that these effects may have significant implications in treatment planning and outcome assessment.The goal of the manuscript is to provide the reader with the numerical methods to assess multiple-pulse electroporation treatment protocols in order to isolate IRE from thermal damage and capitalize on the benefits of a non-thermal mode of tissue ablation.

View Article: PubMed Central - HTML - PubMed

Affiliation: Bioelectromechanical Systems Laboratory, School of Biomedical Engineering and Sciences, Virginia Tech-Wake Forest University, Blacksburg, VA, USA.

ABSTRACT

Background: Irreversible electroporation (IRE) is a new minimally invasive technique to kill undesirable tissue in a non-thermal manner. In order to maximize the benefits from an IRE procedure, the pulse parameters and electrode configuration must be optimized to achieve complete coverage of the targeted tissue while preventing thermal damage due to excessive Joule heating.

Methods: We developed numerical simulations of typical protocols based on a previously published computed tomographic (CT) guided in vivo procedure. These models were adapted to assess the effects of temperature, electroporation, pulse duration, and repetition rate on the volumes of tissue undergoing IRE alone or in superposition with thermal damage.

Results: Nine different combinations of voltage and pulse frequency were investigated, five of which resulted in IRE alone while four produced IRE in superposition with thermal damage.

Conclusions: The parametric study evaluated the influence of pulse frequency and applied voltage on treatment volumes, and refined a proposed method to delineate IRE from thermal damage. We confirm that determining an IRE treatment protocol requires incorporating all the physical effects of electroporation, and that these effects may have significant implications in treatment planning and outcome assessment. The goal of the manuscript is to provide the reader with the numerical methods to assess multiple-pulse electroporation treatment protocols in order to isolate IRE from thermal damage and capitalize on the benefits of a non-thermal mode of tissue ablation.

Show MeSH
Related in: MedlinePlus