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Andrade DLLS, Pintarelli GB, Rosa JV, Paro IB, Pagano PJT, Silva JCN, Suzuki DOH. Musa acuminata as electroporation model. Bioelectrochemistry 2023; 154:108549. [PMID: 37639773 DOI: 10.1016/j.bioelechem.2023.108549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 08/17/2023] [Accepted: 08/19/2023] [Indexed: 08/31/2023]
Abstract
Electrochemotherapy (ECT) and Irreversible electroporation (IRE) are cancer treatments based on electric field distribution in tissues. Solanum tuberosum (potato tissue) phantom is known to mimic changes in the electrical conductivity that occur in animal tissues during electroporation (EP). Electric field distribution is assessed through enzymatic staining. However, the 24-h wait for this assessment could slow agile response scenarios. We developed and validated the Musa acuminata (cavendish banana) conductivity model, which quickly evaluates EP by tissue staining. We investigated the frequency response of the tissue using impedance spectroscopy analysis, conductivity changes, and enzymatic staining. We optimized three usual EP models: adapted Gompertz, smoothed Heaviside, and the sigmoid or logistic function. We found dielectric parameters in banana tissue similar to those in potato (electrical conductivity of 0.035 S/m and relative permittivity of 4.1×104). The coefficients of determination R2 were 99.94% (Gompertz), 99.85% (Heaviside), and 99.58% (sigmoid). The sigmoid and Heaviside functions described the calibration and validation electric currents with 95% confidence. We observed the electroporated areas in bananas 3h30m after EP. Staining was significant after 450 V/cm. The conductivity model of Musa acuminata suits treatment planning, hardware development, and training scenarios. Banana phantom supports the 3Rs practice and is a reliable alternative for potato in EP studies.
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Affiliation(s)
- Daniella L L S Andrade
- Institute of Biomedical Engineering, Department of Electrical and Electronics Engineering, Federal University of Santa Catarina, Florianópolis, SC, Brazil
| | - Guilherme B Pintarelli
- Department of Control and Automation Engineering, Federal University of Santa Catarina, Blumenau, SC, Brazil
| | - Juliana V Rosa
- Institute of Biomedical Engineering, Department of Electrical and Electronics Engineering, Federal University of Santa Catarina, Florianópolis, SC, Brazil
| | - Isabela B Paro
- Institute of Biomedical Engineering, Department of Electrical and Electronics Engineering, Federal University of Santa Catarina, Florianópolis, SC, Brazil
| | - Pedro J T Pagano
- Institute of Biomedical Engineering, Department of Electrical and Electronics Engineering, Federal University of Santa Catarina, Florianópolis, SC, Brazil
| | - Julia C N Silva
- Institute of Biomedical Engineering, Department of Electrical and Electronics Engineering, Federal University of Santa Catarina, Florianópolis, SC, Brazil
| | - Daniela O H Suzuki
- Institute of Biomedical Engineering, Department of Electrical and Electronics Engineering, Federal University of Santa Catarina, Florianópolis, SC, Brazil
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Hogenes AM, Slump CH, te Riet o. g. Scholten GA, Stommel MWJ, Fütterer JJ, Verdaasdonk RM. The Effect of Partial Electrical Insulation of the Tip and Active Needle Length of Monopolar Irreversible Electroporation Electrodes on the Electric Field Line Pattern and Temperature Gradient to Improve Treatment Control. Cancers (Basel) 2023; 15:4280. [PMID: 37686556 PMCID: PMC10486353 DOI: 10.3390/cancers15174280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 08/10/2023] [Accepted: 08/21/2023] [Indexed: 09/10/2023] Open
Abstract
Unintentional local temperature effects can occur during irreversible electroporation (IRE) treatment, especially near the electrodes, and most frequently near the tip. Partial electrical insulation of the IRE electrodes could possibly control these temperature effects. This study investigated and visualized the effect of partial electrical insulation applied to the IRE electrodes on the electric field line pattern and temperature gradient. Six designs of (partial) electrical insulation of the electrode tip and/or active needle length (ANL) of the original monopolar 19G IRE electrodes were investigated. A semolina in castor oil model was used to visualize the electric field line pattern in a high-voltage static electric field. An optical method to visualize a change in temperature gradient (color Schlieren) was used to image the temperature development in a polyacrylamide gel. Computational models were used to support the experimental findings. Around the electrode tip, the highest electric field line density and temperature gradient were present. The more insulation was applied to the electrodes, the higher the resistance. Tip and ANL insulation together reduced the active area of and around the electrodes, resulting in a visually enlarged area that showed a change in temperature gradient. Electrically insulating the electrode tip together with an adjustment in IRE parameter settings could potentially reduce the uncontrollable influence of the tip and may improve the predictability of the current pathway development.
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Affiliation(s)
- Annemiek M. Hogenes
- Department of Medical Imaging, Radboud University Medical Center, P.O. Box 9101 (766), 6500 HB Nijmegen, The Netherlands
| | - Cornelis H. Slump
- Department of Robotics and Mechatronics, University of Twente, 7522 NB Enschede, The Netherlands
| | | | - Martijn W. J. Stommel
- Department of Surgery, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Jurgen J. Fütterer
- Department of Medical Imaging, Radboud University Medical Center, P.O. Box 9101 (766), 6500 HB Nijmegen, The Netherlands
- Department of Robotics and Mechatronics, University of Twente, 7522 NB Enschede, The Netherlands
| | - Rudolf M. Verdaasdonk
- Department of Health Technology Implementation, TechMed Center, University of Twente, 7522 NB Enschede, The Netherlands
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Sugrue A, Maor E, Del-Carpio Munoz F, Killu AM, Asirvatham SJ. Cardiac ablation with pulsed electric fields: principles and biophysics. Europace 2022; 24:1213-1222. [PMID: 35426908 DOI: 10.1093/europace/euac033] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 02/24/2022] [Indexed: 01/04/2023] Open
Abstract
Pulsed electric fields (PEFs) have emerged as an ideal cardiac ablation modality. At present numerous clinical trials in humans are exploring PEF as an ablation strategy for both atrial and ventricular arrhythmias, with early data showing significant promise. As this is a relatively new technology there is limited understanding of its principles and biophysics. Importantly, PEF biophysics and principles are starkly different to current energy modalities (radiofrequency and cryoballoon). Given the relatively novel nature of PEFs, this review aims to provide an understanding of the principles and biophysics of PEF ablation. The goal is to enhance academic research and ultimately enable optimization of ablation parameters to maximize procedure success and minimize risk.
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Affiliation(s)
- Alan Sugrue
- Division of Heart Rhythm Services, Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
- Division of Cardiovascular Medicine, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Elad Maor
- Division of Heart Rhythm Services, Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
- Chaim Sheba Medical Center and Sackler School of Medicine, Tel Aviv University, Israel
| | - Freddy Del-Carpio Munoz
- Division of Heart Rhythm Services, Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
| | - Ammar M Killu
- Division of Heart Rhythm Services, Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
| | - Samuel J Asirvatham
- Division of Heart Rhythm Services, Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
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Zhao Y, McKillop IH, Davalos RV. Modeling of a single bipolar electrode with tines for irreversible electroporation delivery. Comput Biol Med 2022; 142:104870. [PMID: 35051854 PMCID: PMC10037907 DOI: 10.1016/j.compbiomed.2021.104870] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 08/24/2021] [Accepted: 09/12/2021] [Indexed: 01/07/2023]
Abstract
Irreversible electroporation (IRE) is a non-thermal tumor ablation technology employed to treat solid tumors not amenable to resection or thermal ablation. The IRE systems currently in clinical use deliver electrical pulses via multiple monopolar electrodes. This approach can present significant technical challenges due to the requirement for accurate placement of multiple electrodes and maintenance of parallel electrode alignment during pulse delivery. In this study, we sought to evaluate a novel IRE electrode configuration consisting of a single bipolar electrode with deployable tines. Using commercial finite element software predicted ablation outcomes, thermal damage, ablation sphericity, and energy delivery were calculated for existing monopolar and bipolar electrodes, and bipolar electrodes with either 4 or 8 deployable tines. The bipolar electrodes with tines generated larger predicted ablations compared to existing monopolar (>100%) and bipolar (>10%) arrangements, and the ablation shape using bipolar electrodes with tines were more spherical than those modeled for bipolar electrodes. Thermal damage modeled for bipolar electrodes and bipolar electrodes with tines was less than that of monopolar electrodes (using identical pulse parameters), and bipolar electrodes with tines delivered less energy than monopolar or bipolar electrodes. These studies using a single point of device insertion suggest the potential for developing alternative IRE delivery techniques, and may simplify clinical use and increase the predicted ablation shape/volume.
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Affiliation(s)
- Yajun Zhao
- College of Electrical Engineering and Control Science, Nanjing Tech. University, Nanjing, 211816, China; Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA, 24061, USA.
| | - Iain H McKillop
- Department of Surgery, Atrium Health, 1000 Blythe Boulevard, Charlotte, NC, 28203, USA
| | - Rafael V Davalos
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA, 24061, USA
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Guo F, Deng H, Qian K, Li X. Characterization of dispersion and anisotropic-conductivity in tissue model during electroporation pulses. Bioelectrochemistry 2021; 144:108029. [PMID: 34894430 DOI: 10.1016/j.bioelechem.2021.108029] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 11/22/2021] [Accepted: 11/28/2021] [Indexed: 12/15/2022]
Abstract
Electroporation occurs when biological cells are exposed to intensive, short-duration pulses, which can be used to ablate biological tumor tissues. Based on the traditional numerical models, the isotropic conductivity model with the non-dispersion effect (ICND), the anisotropic conductivity model with the dispersion effect (ACD) is developed in this study. The second-order Debye function is introduced to manifest the dielectric relaxation effect, and the two-dimensional Cartesian conductivity matrix is applied to describe the anisotropy of the tissue conductivity during the electroporation process. A monopolar pulse and a monopolar burst are applied to the breast tumor model through the two-needle electrodes configuration. The results show that taking the dispersion into account can increase the total electroporated area more than 2.31%. Considering the conductivity anisotropy, the total electroporated area increases, but the irreversible electroporation (IRE) area decreases by more than 3.99%. The ACD model can achieve a larger electroporated area but a relatively smaller IRE area than those of the ICND model, and comparably minor maximum thermal damage is evaluated in the ACD model. Our model analyzes the effects of the dielectric dispersion and anisotropic conductivity of tissue, which have strong guiding significance for making the treatment planning before clinical practice.
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Affiliation(s)
- Fei Guo
- Institute of Ecological Safety, Chongqing University of Posts and Telecommunications, Chongqing 400065, China.
| | - Hao Deng
- Institute of Ecological Safety, Chongqing University of Posts and Telecommunications, Chongqing 400065, China
| | - Kun Qian
- Institute of Ecological Safety, Chongqing University of Posts and Telecommunications, Chongqing 400065, China
| | - Xin Li
- Institute of Ecological Safety, Chongqing University of Posts and Telecommunications, Chongqing 400065, China
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Lorenzo MF, Bhonsle SP, Arena CB, Davalos RV. Rapid Impedance Spectroscopy for Monitoring Tissue Impedance, Temperature, and Treatment Outcome During Electroporation-Based Therapies. IEEE Trans Biomed Eng 2021; 68:1536-1546. [PMID: 33156779 PMCID: PMC8127872 DOI: 10.1109/tbme.2020.3036535] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Electroporation-based therapies (EBTs) employ high voltage pulsed electric fields (PEFs) to permeabilize tumor tissue; this results in changes in electrical properties detectable using electrical impedance spectroscopy (EIS). Currently, commercial potentiostats for EIS are limited by impedance spectrum acquisition time ( ∼ 10 s); this timeframe is much larger than pulse periods used with EBTs ( ∼ 1 s). In this study, we utilize rapid EIS techniques to develop a methodology for characterizing electroporation (EP) and thermal effects associated with high-frequency irreversible EP (H-FIRE) in real-time by monitoring inter-burst impedance changes. METHODS A charge-balanced, bipolar rectangular chirp signal is proposed for rapid EIS. Validation of rapid EIS measurements against a commercial potentiostat was conducted in potato tissue using flat-plate electrodes and thereafter for the measurement of impedance changes throughout IRE treatment. Flat-plate electrodes were then utilized to uniformly heat potato tissue; throughout high-voltage H-FIRE treatment, low-voltage inter-burst impedance measurements were used to continually monitor impedance change and to identify a frequency at which thermal effects are delineated from EP effects. RESULTS Inter-burst impedance measurements (1.8 kHz - 4.93 MHz) were accomplished at 216 discrete frequencies. Impedance measurements at frequencies above ∼ 1 MHz served to delineate thermal and EP effects in measured impedance. CONCLUSION We demonstrate rapid-capture ( 1 s) EIS which enables monitoring of inter-burst impedance in real-time. For the first time, we show impedance analysis at high frequencies can delineate thermal effects from EP effects in measured impedance. SIGNIFICANCE The proposed waveform demonstrates the potential to perform inter-burst EIS using PEFs compatible with existing pulse generator topologies.
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