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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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Time history of the tissue volumes undergoing IRE alone or in superposition with thermal damage. The IRE simulation used eighty pulses (50 μs) with frequencies of A) 0.5 Hz (160 s), B) 1 Hz (80 s), and C) 4 Hz (20 s). The applied voltages were 500 V, 1000 V, and 1500 V for each frequency investigated.
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Figure 9: Time history of the tissue volumes undergoing IRE alone or in superposition with thermal damage. The IRE simulation used eighty pulses (50 μs) with frequencies of A) 0.5 Hz (160 s), B) 1 Hz (80 s), and C) 4 Hz (20 s). The applied voltages were 500 V, 1000 V, and 1500 V for each frequency investigated.

Mentions: Although the volumes of tissue exposed to a minimum temperature can provide insight to the thermal effects resulting from a particular IRE protocol, they do not provide a quantitative measure of thermal damage based on established metrics in the literature [4,15,44,45]. In Figure 9 we provide plots that show the time dependence of the volume of tissue exposed to a minimum electric field of 500 V/cm, which was found to be the IRE threshold in grey matter for similar pulse parameters to those used in this study [22]. Additionally, we present the volume of tissue that undergoes thermal damage using the Arrhenius analysis presented in the methods section. Similar to the previous analysis, in Figure 9 we investigate the influence of increasing the frequency of pulse delivery in both predicted IRE treatment and thermal damage volumes. Specifically, the curves displayed in Figure 9 correspond to the IRE treated volumes with 500 V (0.293 cm3), 1000 V (0.706 - 0.732 cm3), and 1500 V (1.134 - 1.296 cm3).


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)

Time history of the tissue volumes undergoing IRE alone or in superposition with thermal damage. The IRE simulation used eighty pulses (50 μs) with frequencies of A) 0.5 Hz (160 s), B) 1 Hz (80 s), and C) 4 Hz (20 s). The applied voltages were 500 V, 1000 V, and 1500 V for each frequency investigated.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 9: Time history of the tissue volumes undergoing IRE alone or in superposition with thermal damage. The IRE simulation used eighty pulses (50 μs) with frequencies of A) 0.5 Hz (160 s), B) 1 Hz (80 s), and C) 4 Hz (20 s). The applied voltages were 500 V, 1000 V, and 1500 V for each frequency investigated.
Mentions: Although the volumes of tissue exposed to a minimum temperature can provide insight to the thermal effects resulting from a particular IRE protocol, they do not provide a quantitative measure of thermal damage based on established metrics in the literature [4,15,44,45]. In Figure 9 we provide plots that show the time dependence of the volume of tissue exposed to a minimum electric field of 500 V/cm, which was found to be the IRE threshold in grey matter for similar pulse parameters to those used in this study [22]. Additionally, we present the volume of tissue that undergoes thermal damage using the Arrhenius analysis presented in the methods section. Similar to the previous analysis, in Figure 9 we investigate the influence of increasing the frequency of pulse delivery in both predicted IRE treatment and thermal damage volumes. Specifically, the curves displayed in Figure 9 correspond to the IRE treated volumes with 500 V (0.293 cm3), 1000 V (0.706 - 0.732 cm3), and 1500 V (1.134 - 1.296 cm3).

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