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Temperature modulation of electric fields in biological matter.

Daniels CS, Rubinsky B - PLoS ONE (2011)

Bottom Line: This second study demonstrates that in this probe configuration the temperature induced changes in electrical properties of tissue substantially reduce the electric fields in the cooled regions.This novel treatment can potentially be used to protect sensitive tissues from the effect of the PEF.Perhaps the most important conclusion of this investigation is that temperature is a powerful and accessible mechanism to modulate and control electric fields in biological tissues and can therefore be used to optimize and control PEF treatments.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Engineering, University of California, Berkeley, California, United States of America. daniels.charlotte@gmail.com

ABSTRACT
Pulsed electric fields (PEF) have become an important minimally invasive surgical technology for various applications including genetic engineering, electrochemotherapy and tissue ablation. This study explores the hypothesis that temperature dependent electrical parameters of tissue can be used to modulate the outcome of PEF protocols, providing a new means for controlling and optimizing this minimally invasive surgical procedure. This study investigates two different applications of cooling temperatures applied during PEF. The first case utilizes an electrode which simultaneously delivers pulsed electric fields and cooling temperatures. The subsequent results demonstrate that changes in electrical properties due to temperature produced by this configuration can substantially magnify and confine the electric fields in the cooled regions while almost eliminating electric fields in surrounding regions. This method can be used to increase precision in the PEF procedure, and eliminate muscle contractions and damage to adjacent tissues. The second configuration considered introduces a third probe that is not electrically active and only applies cooling boundary conditions. This second study demonstrates that in this probe configuration the temperature induced changes in electrical properties of tissue substantially reduce the electric fields in the cooled regions. This novel treatment can potentially be used to protect sensitive tissues from the effect of the PEF. Perhaps the most important conclusion of this investigation is that temperature is a powerful and accessible mechanism to modulate and control electric fields in biological tissues and can therefore be used to optimize and control PEF treatments.

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Schematic of the positioning of the cooling probe and electrodes in the different variations of Case 2.
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pone-0020877-g006: Schematic of the positioning of the cooling probe and electrodes in the different variations of Case 2.

Mentions: The configuration examined in the second half of this study is illustrated schematically in Figure 6. In Case 2, the effect of cooling delivered by a probe that is not electrically active on a typical irreversible electroporation protocol is investigated. The PEFs were delivered by two electrodes of 1 mm diameter, separated by 2 cm. The 3.4 mm diameter cold probe was placed at various locations from the center along the axial line connecting the centers of the PEF electrodes. The protocol consisted of 2000 seconds of cooling applied by the cold probe at 0°C, followed by ten, 2500 V pulses (1 Hz, 50 µs length) applied by the PEF electrodes. The cooling probe was electrically insulated. In the control case, ten 2500 V pulses (1 Hz, 50 µs length) applied by the PEF electrodes without using the cooling probe. Full bioheat parameters were utilized to simulate tissue.


Temperature modulation of electric fields in biological matter.

Daniels CS, Rubinsky B - PLoS ONE (2011)

Schematic of the positioning of the cooling probe and electrodes in the different variations of Case 2.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3113852&req=5

pone-0020877-g006: Schematic of the positioning of the cooling probe and electrodes in the different variations of Case 2.
Mentions: The configuration examined in the second half of this study is illustrated schematically in Figure 6. In Case 2, the effect of cooling delivered by a probe that is not electrically active on a typical irreversible electroporation protocol is investigated. The PEFs were delivered by two electrodes of 1 mm diameter, separated by 2 cm. The 3.4 mm diameter cold probe was placed at various locations from the center along the axial line connecting the centers of the PEF electrodes. The protocol consisted of 2000 seconds of cooling applied by the cold probe at 0°C, followed by ten, 2500 V pulses (1 Hz, 50 µs length) applied by the PEF electrodes. The cooling probe was electrically insulated. In the control case, ten 2500 V pulses (1 Hz, 50 µs length) applied by the PEF electrodes without using the cooling probe. Full bioheat parameters were utilized to simulate tissue.

Bottom Line: This second study demonstrates that in this probe configuration the temperature induced changes in electrical properties of tissue substantially reduce the electric fields in the cooled regions.This novel treatment can potentially be used to protect sensitive tissues from the effect of the PEF.Perhaps the most important conclusion of this investigation is that temperature is a powerful and accessible mechanism to modulate and control electric fields in biological tissues and can therefore be used to optimize and control PEF treatments.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Engineering, University of California, Berkeley, California, United States of America. daniels.charlotte@gmail.com

ABSTRACT
Pulsed electric fields (PEF) have become an important minimally invasive surgical technology for various applications including genetic engineering, electrochemotherapy and tissue ablation. This study explores the hypothesis that temperature dependent electrical parameters of tissue can be used to modulate the outcome of PEF protocols, providing a new means for controlling and optimizing this minimally invasive surgical procedure. This study investigates two different applications of cooling temperatures applied during PEF. The first case utilizes an electrode which simultaneously delivers pulsed electric fields and cooling temperatures. The subsequent results demonstrate that changes in electrical properties due to temperature produced by this configuration can substantially magnify and confine the electric fields in the cooled regions while almost eliminating electric fields in surrounding regions. This method can be used to increase precision in the PEF procedure, and eliminate muscle contractions and damage to adjacent tissues. The second configuration considered introduces a third probe that is not electrically active and only applies cooling boundary conditions. This second study demonstrates that in this probe configuration the temperature induced changes in electrical properties of tissue substantially reduce the electric fields in the cooled regions. This novel treatment can potentially be used to protect sensitive tissues from the effect of the PEF. Perhaps the most important conclusion of this investigation is that temperature is a powerful and accessible mechanism to modulate and control electric fields in biological tissues and can therefore be used to optimize and control PEF treatments.

Show MeSH
Related in: MedlinePlus