scholarly journals A Comparative Modeling Study of Thermal Mitigation Strategies in Irreversible Electroporation Treatments

2021 ◽  
Author(s):  
Kenneth N Aycock ◽  
Sabrina N. Campelo ◽  
Rafael V. Davalos
Keyword(s):  
Phase Change Materials ◽  
Thermal Damage ◽  
Irreversible Electroporation ◽  
Electrical Energy ◽  
Comparative Modeling ◽  
Pancreatic Tissue ◽  
Mitigation Strategies ◽  
Active Cooling ◽  
Focal Ablation ◽  
Thermal Mitigation

Abstract Irreversible electroporation (IRE), otherwise known as non-thermal pulsed field ablation (PFA), is an attractive focal ablation modality due to its ability to destroy aberrant cells with limited disruption of extracellular tissue architecture. Despite its non-thermal cell death mechanism, application of electrical energy results in Joule heating that, if ignored, can cause undesired thermal injury. Engineered thermal mitigation (TM) technologies including phase change materials (PCMs) and active cooling (AC) have been reported and tested in isolated preliminary studies to limit the risk of thermal damage, but their performance compared to one another is relatively unknown. Further, the effects of pulsing paradigm, electrode geometry, PCM composition, and chosen active cooling parameters have not been examined. Here, we develop a computational model of conventional bipolar and monopolar probes with solid, PCM-filled, or actively cooled cores and simulate clinical IRE treatments in pancreatic tissue. We find that probes with integrated PCM cores can be tuned to drastically limit thermal damage compared to traditional solid probes. Actively cooled probes, on the other hand, provide even more control over thermal effects within the probe vicinity and can altogether eliminate thermal damage. In practice, these differences in performance are tempered by the increased time, expense, and effort necessary to use actively cooled probes compared to traditional solid probes or those containing a PCM core.

Effect of Three-Dimensional Electric Field and Heat Conduction to Electrodes on the Temperature Rise During Irreversible Electroporation

2011 ◽  
Author(s):  
Seiji Nomura ◽  
Kosaku Kurata ◽  
Hiroshi Takamatsu
Keyword(s):  
Heat Conduction ◽  
Electric Field ◽  
Temperature Rise ◽  
Heat Conduction Equation ◽  
Thermal Damage ◽  
Irreversible Electroporation ◽  
Three Dimensional ◽  
End Effects ◽  
Abnormal Cells ◽  
Novel Method

The irreversible electroporation (IRE) is a novel method to ablate abnormal cells by applying a high voltage between two electrodes that are stuck into abnormal tissues. One of the advantages of the IRE is that the extracellular matrix (ECM) may be kept intact, which is favorable for healing. For a successful IRE, it is therefore important to avoid thermal damage of ECM resulted from the Joule heating within the tissue. A three-dimensional (3-D) analysis was conducted in this study to predict temperature rise during the IRE. The equation of electric field and the heat conduction equation were solved numerically by a finite element method. It was clarified that the highest temperature rise occurred at the base of electrodes adjacent to the insulated surface. The result was significantly different from a two-dimensional (2-D) analysis due to end effects, suggesting that the 3-D analysis is required to determine the optimal condition.

scholarly journals A Study on Nonthermal Irreversible Electroporation of the Thyroid

2019 ◽  
Vol 18 ◽  
pp. 153303381987630
Author(s):  
Yanpeng Lv ◽  
Yanfang Zhang ◽  
Jianwei Huang ◽  
Yunlong Wang ◽  
Boris Rubinsky
Keyword(s):  
Electric Fields ◽  
Thermal Damage ◽  
Irreversible Electroporation ◽  
Pulse Sequences ◽  
Cell Swelling ◽  
Tissue Type ◽  
Heterogeneous Structure ◽  
Treatment Protocols ◽  
Thyroid Ablation ◽  
Nonthermal Irreversible Electroporation

Background: Nonthermal irreversible electroporation is a minimally invasive surgery technology that employs high and brief electric fields to ablate undesirable tissues. Nonthermal irreversible electroporation can ablate only cells while preserving intact functional properties of the extracellular structures. Therefore, nonthermal irreversible electroporation can be used to ablate tissues safely near large blood vessels, the esophagus, or nerves. This suggests that it could be used for thyroid ablation abutting the esophagus. This study examines the feasibility of using nonthermal irreversible electroporation for thyroid ablation. Methods: Rats were used to evaluate the effects of nonthermal irreversible electroporation on the thyroid. The procedure entails the delivery of high electric field pulses (1-3 kV/cm, 100 microseconds) between 2 surface electrodes bracing the thyroid. The right lobe was treated with various nonthermal irreversible electroporation pulse sequences, and the left was the control. After 24 hours of the nonthermal irreversible electroporation treatment, the thyroid was examined with hemotoxylin and eosin histological analysis. Mathematical models of electric fields and the Joule heating-induced temperature raise in the thyroid were developed to examine the experimental results. Results: Treatment with nonthermal irreversible electroporation leads to follicular cells damage, associated with cell swelling, inflammatory cell infiltration, and cell ablation. Nonthermal irreversible electroporation spares the trachea structure. Unusually high electric fields, for these types of tissue, 3000 V/cm, are needed for thyroid ablation. The mathematical model suggests that this may be related to the heterogeneous structure of the thyroid-induced distortion of local electric fields. Moreover, most of the tissue does not experience thermal damage inducing temperature elevation. However, the heterogeneous structure of the thyroid may cause local hot spots with the potential for local thermal damage. Conclusion: Nonthermal irreversible electroporation with 3000 V/cm can be used for thyroid ablation. Possible applications are treatment of hyperthyroidism and thyroid cancer. The highly heterogeneous structure of the thyroid distorts the electric fields and temperature distribution in the thyroid must be considered when designing treatment protocols for this tissue type.

Adapting the Cassini Curve to Approximate In Vivo Irreversible Electroporation Ablations in Porcine Liver

2013 ◽  
Author(s):  
Paulo A. Garcia ◽  
Christopher B. Arena ◽  
Robert E. Neal ◽  
S. Nahum Goldberg ◽  
Eliel Ben-David ◽  
...  
Keyword(s):  
Cell Death ◽  
Transmembrane Potential ◽  
Tumor Tissue ◽  
Irreversible Electroporation ◽  
Low Energy ◽  
Porcine Liver ◽  
Electric Pulses ◽  
Focal Ablation ◽  
Increase Membrane Permeability

Irreversible electroporation (IRE) is a new minimally invasive non-thermal focal ablation technique that has been used for the treatment of spontaneous tumors in canine and human patients [1, 2]. The procedure typically involves placing two electrodes into or around a tumor and delivering a series of low energy electric pulses to kill tumor tissue with sub-millimeter resolution. The pulses generate an electric field that alters the resting transmembrane potential (TMP) of the cells. Depending on the magnitude of the induced TMP, the electric pulses can have no effect, reversibly increase membrane permeability, or cause cell death in the case of IRE.

In Vivo Validation of Irreversible Electroporation Electric Field Threshold for Prostate Tissue

2013 ◽  
Author(s):  
Robert E. Neal ◽  
Helen Kavnoudias ◽  
Franklin Rosenfeldt ◽  
Ruchong Ou ◽  
James Marron ◽  
...  
Keyword(s):  
Thermal Ablation ◽  
Conventional Treatment ◽  
Irreversible Electroporation ◽  
Blood Perfusion ◽  
Complete Regression ◽  
Safety Study ◽  
Electric Pulses ◽  
Transmembrane Potentials ◽  
Focal Ablation

Irreversible electroporation (IRE) is a non-thermal focal ablation technique that uses needle electrodes to deliver a series of brief (100μs duration) electric pulses into the targeted region. These alter cellular transmembrane potentials, destabilizing the membranes in a manner that kills the cells while sparing major vasculature and other sensitive structures. IRE can therefore be used in regions ineligible for surgical resection or thermal ablation. Treatments result in rapid lesion creation and resolution [1], are unaffected by the blood perfusion “heat sink”, can be planned with numerical modeling [2], and its effects can be readily monitored with various imaging modalities [3]. Therapeutic ire has proven effective in the treatment of experimental [4] and clinical tumors. A human safety study attained complete regression in 46 of 69 tumors ineligible or unresponsive to conventional treatment [5], and veterinary case studies convey its utility in large difficult tumors [6, 7].

Irreversible Electroporation for Focal Ablation at the Porta Hepatis

2012 ◽  
Vol 35 (6) ◽  
pp. 1531-1534 ◽  
Author(s):  
Veeru Kasivisvanathan ◽  
Ankur Thapar ◽  
Youssof Oskrochi ◽  
John Picard ◽  
Edward L. S. Leen
Keyword(s):  
Irreversible Electroporation ◽  
Porta Hepatis ◽  
Focal Ablation

scholarly journals The Effect of Conductivity Changes on Temperature Rise During Irreversible Electroporation

2020 ◽  
Author(s):  
Amir Khorasani
Keyword(s):  
Electrical Conductivity ◽  
Cell Death ◽  
Electric Field ◽  
Electric Field Intensity ◽  
Thermal Damage ◽  
Pulse Sequence ◽  
Irreversible Electroporation ◽  
Tissue Temperature ◽  
Comsol Multiphysics ◽  
Simulation Results

Purpose: Irreversible electroporation is a physical process which is used for killing the cancer cells. The process that leads to cell death in this method is a unique process. Thermal damage does not exist in this process. However, the temperature of the tissue also increases during the electroporation. In this study, we aim to investigate the effect of conductivity changes on tissue temperature increase during the irreversible electroporation process. Materials and Methods: To perform simulations and solve equations, COMSOL MultiPhysics has been used. Standard electroporation pulse sequence (8 pulses with different electric field intensities) was used as a pulse sequence in the simulation. Results: During the electroporation process, the electrical conductivity and the temperature of the tissue were increased. Changes in the tissue temperature in the simulation with variable electrical conductivity are more than in the simulation with constant electrical conductivity during the electroporation process. This difference for pulses with more vigorous electric field intensity and points closer to the electrodes has been achieved more. Conclusion: To more accurately estimate and calculate the temperature and thermal damage inside the tissue during the irreversible electroporation process, it is suggested to consider the effect of conductivity changes during this process.

scholarly journals Performance Evaluation of a Solar PV/T Water Heater Integrated with Inorganic Salt Based Energy Storage Medium

2020 ◽  
Vol 23 (3) ◽  
pp. 213-220
Author(s):  
R Prakash ◽  
B Meenakshipriya ◽  
S Vijayan ◽  
R Kumaravelan
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Phase Change Materials ◽  
Electrical Energy ◽  
Electrical Performance ◽  
Back Side ◽  
Solar Pv ◽  
Storage Medium ◽  
Pv Module ◽  
Mixture Phase

Thermal and Electrical performance of solar PV/T hybrid water heating system using salt mixture phase change materials in storage tank is analyzed in this study. Compare to all conventional type heaters, the solar PV/T hybrid module collector has ability to produces both electrical energy from PV module and utilizes incident solar energy to heat the water. The sheet and tube type absorber is used to heat up the tube which is attached at the back side of PV module and transfer the heat to flowing water and the electrical energy is tested by connecting the DC load on the PV terminals under glazed and unglazed modes respectively. To enhance the thermal performance, energy storage medium is used as phase change materials at good proportion in the tank. The thermo physical properties of PCM are analyzed by Differential Scanning Calorimetry. This experimental testing is conducted from 8.00 to 17.00 IST in various sunny days and results are compared for glazed and unglazed conditions. The results shows that the average water temperature easily reaches 38-45°C and the final temperature of water never dropped below 34°, the temperature of PCM is 45.6oC, which is 5oC higher than outlet. The amount of heat stored using PCM in tank is 16.86% greater than no-PCM in the tank for constant 0.01 kg/s mass flow rate. The daily average electrical efficiency is 6.4% under glazed mode and 8.8% under unglazed conditions.

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