Electric field computation and measurements in the electroporation of inhomogeneous samples

Bernardis, Alessia; Bullo, M.; Campana, Luca Giovanni; Barba, Paolo Di; Dughiero, Fabrizio; Forzan, Michele; Mognaschi, Maria Evelina; Sgarbossa, Paolo; Sieni, Elisabetta

doi:10.1515/phys-2017-0092

Cited by 21 publications

(24 citation statements)

References 24 publications

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“…Both the treatment electrodes and the dormant electrodes were used to measure tissue impedance changes. This process was conducted on potato tuber tissue, a model commonly used for electroporation studies since the electroporated area becomes dark, which makes it is easy to define the ablation boundary [ 16 – 22 ]. First, the two diagonal electrodes in a four-needle setup were used to apply electroporation-inducing pulses to potato tissues.…”

Section: Introductionmentioning

confidence: 99%

Ablation outcome of irreversible electroporation on potato monitored by impedance spectrum under multi-electrode system

Zhao

Bhonsle

et al. 2018

BioMed Eng OnLine

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BackgroundIrreversible electroporation (IRE) therapy relies on pulsed electric fields to non-thermally ablate cancerous tissue. Methods for evaluating IRE ablation in situ are critical to assessing treatment outcome. Analyzing changes in tissue impedance caused by electroporation has been proposed as a method for quantifying IRE ablation. In this paper, we assess the hypothesis that irreversible electroporation ablation outcome can be monitored using the impedance change measured by the electrode pairs not in use, getting more information about the ablation size in different directions.MethodsUsing a square four-electrode configuration, the two diagonal electrodes were used to electroporate potato tissue. Next, the impedance changes, before and after treatment, were measured from different electrode pairs and the impedance information was extracted by fitting the data to an equivalent circuit model. Finally, we correlated the change of impedance from various electrode pairs to the ablation geometry through the use of fitted functions; then these functions were used to predict the ablation size and compared to the numerical simulation results.ResultsThe change in impedance from the electrodes used to apply pulses is larger and has higher deviation than the other electrode pairs. The ablation size and the change in resistance in the circuit model correlate with various linear functions. The coefficients of determination for the three functions are 0.8121, 0.8188 and 0.8691, respectively, showing satisfactory agreement. The functions can well predict the ablation size under different pulse numbers, and in some directions it did even better than the numerical simulation method, which used different electric field thresholds for different pulse numbers.ConclusionsThe relative change in tissue impedance measured from the non-energized electrodes can be used to assess ablation size during treatment with IRE according to linear functions.

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Section: Introductionmentioning

confidence: 99%

Ablation outcome of irreversible electroporation on potato monitored by impedance spectrum under multi-electrode system

Zhao

Bhonsle

et al. 2018

BioMed Eng OnLine

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“…40 This way simulation and potato with gel experiment appear to be a useful model to compare experimental data and simulation results, since electrical properties of gel and potato could be known in an easy way like in the study by Bernardis et al . 43 …”

Section: Discussionmentioning

confidence: 99%

Effect of Tissue Inhomogeneity in Soft Tissue Sarcomas: From Real Cases to Numerical and Experimental Models

Campana

Bullo

Barba

et al. 2018

Technol Cancer Res Treat

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Electrochemotherapy is an established treatment option for patients with superficially metastatic tumors, mainly malignant melanoma and breast cancer. Based on preliminary experiences, electrochemotherapy has the potential to be translated in the treatment of larger and deeper neoplasms, such as soft tissue sarcomas. However, soft tissue sarcomas are characterized by tissue inhomogeneity and, consequently, by variable electrical characteristic of tumor tissue. The inhomogeneity in conductivity represents the cause of local variations in the electric field intensity. Crucially, this fact may hamper the achievement of the electroporation threshold during the electrochemotherapy procedure. In order to evaluate the effect of tissue inhomogeneity on the electric field distribution, we first performed ex vivo analysis of some clinical cases to quantify the inhomogeneity area. Subsequently, we performed some simulations where the electric field intensity was evaluated by means of finite element analysis. The results of the simulation models are finally compared to an experimental model based on potato and tissue mimic materials. Tissue mimic materials are materials where the conductivity can be suitably designed. The coupling of computation and experimental results could be helpful to show the effect of the inhomogeneity in terms of variation in electric field distribution and characteristics.

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“…In this research, the effect of the presence of inhomogeneous area between the needles used to apply the electric field is studied by means of numerical simulations and experiments on phantoms. The phantoms are built using potato tissue that becomes dark if electroporated, and a tissue mimic material (TMM), the resistivity of which can be suitably designed . This technique of approaching materials with different electrical properties was used in order to simulate, in a laboratory phantom, the inhomogeneities encountered in real tissues .…”

Section: Introductionmentioning

confidence: 99%

“…The phantoms are built using potato tissue that becomes dark if electroporated, and a tissue mimic material (TMM), the resistivity of which can be suitably designed. [27][28][29][30][31] This technique of approaching materials with different electrical properties was used in order to simulate, in a laboratory phantom, the inhomogeneities encountered in real tissues. 26 For this purpose, a pair of needles, with a 2-cm gap, was used to apply the electric field.…”

Section: Introductionmentioning

confidence: 99%

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Electric field distribution study in inhomogeneous biological tissues

Sieni

Sgarbossa

Mognaschi

et al. 2019

Int J Numerical Modelling

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Most solid tumors are inhomogeneous, because of the different types of cells present, different tissues and fat, etc, along with irregular vascularization, pH variation, and heterogeneous oxygen concentration. It is of interest to study the electric field distribution when electrochemotherapy is administered. The variations in the physical and hence the electrical properties, such as the resistance (or conductance), will vary, and parts of the tumor might not get the same electric field and hence will not have the required or the desired efficacy. In this study, the effect of tissue inhomogeneity is explored using potato and apple tissue samples. For this purpose, agar gel and other tissue mimic materials are used to create the inhomogeneity and pulsed to study the effect of electrical pulses. In addition, the electric field distribution is studied using a numerical model to evaluate the effect of tissue inhomogeneity in terms of electric field distribution when electroporation is applied to permeabilize cells, for enhanced drug uptake. The electric field is evaluated by means of finite element analysis and is compared with the distribution found in a phantom model. Good correlation is obtained between the experimental and simulation results. This research has the potential to study the real tumor inhomogeneity conditions.

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Electric field computation and measurements in the electroporation of inhomogeneous samples

Cited by 21 publications

References 24 publications

Ablation outcome of irreversible electroporation on potato monitored by impedance spectrum under multi-electrode system

Ablation outcome of irreversible electroporation on potato monitored by impedance spectrum under multi-electrode system

Effect of Tissue Inhomogeneity in Soft Tissue Sarcomas: From Real Cases to Numerical and Experimental Models

Electric field distribution study in inhomogeneous biological tissues

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