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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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Related in: MedlinePlus

Results for Case 1.a) and b) Temperature and electric field distribution, respectively, at a transection along the diameter of the domain. c) and d) Temperature and electric field surface plots, respectively, in the domain. Plots reflect results after 2000 seconds of cooling at 0°C followed by ten 2500 V pulses (1 Hz, 50 µs) with full bioheat parameters considered.
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pone-0020877-g003: Results for Case 1.a) and b) Temperature and electric field distribution, respectively, at a transection along the diameter of the domain. c) and d) Temperature and electric field surface plots, respectively, in the domain. Plots reflect results after 2000 seconds of cooling at 0°C followed by ten 2500 V pulses (1 Hz, 50 µs) with full bioheat parameters considered.

Mentions: The temperature distribution after the cooling and PEF procedure is illustrated in Figure 3a. The temperature distribution, as expected, increases from the low temperatures at the cold probe surface to body temperature at the outer boundary. The corresponding electric field is demonstrated in Figure 3b. It is clear from these two graphs that the electric field and temperature distribution are inversely proportional. This relationship is a result of the temperature dependence of electrical conductivity, demonstrated by Equation 2. As a result, the highest electric fields occur in the regions of lowest temperature. It can be seen clearly that the electric field is confined within the low temperature region, and reaches zero nearly everywhere else.


Temperature modulation of electric fields in biological matter.

Daniels CS, Rubinsky B - PLoS ONE (2011)

Results for Case 1.a) and b) Temperature and electric field distribution, respectively, at a transection along the diameter of the domain. c) and d) Temperature and electric field surface plots, respectively, in the domain. Plots reflect results after 2000 seconds of cooling at 0°C followed by ten 2500 V pulses (1 Hz, 50 µs) with full bioheat parameters considered.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0020877-g003: Results for Case 1.a) and b) Temperature and electric field distribution, respectively, at a transection along the diameter of the domain. c) and d) Temperature and electric field surface plots, respectively, in the domain. Plots reflect results after 2000 seconds of cooling at 0°C followed by ten 2500 V pulses (1 Hz, 50 µs) with full bioheat parameters considered.
Mentions: The temperature distribution after the cooling and PEF procedure is illustrated in Figure 3a. The temperature distribution, as expected, increases from the low temperatures at the cold probe surface to body temperature at the outer boundary. The corresponding electric field is demonstrated in Figure 3b. It is clear from these two graphs that the electric field and temperature distribution are inversely proportional. This relationship is a result of the temperature dependence of electrical conductivity, demonstrated by Equation 2. As a result, the highest electric fields occur in the regions of lowest temperature. It can be seen clearly that the electric field is confined within the low temperature region, and reaches zero nearly everywhere else.

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