Three-dimensional finite element analysis of current density and temperature distributions during radio-frequency ablation

Panescu, Dorin; Whayne, James G.; Fleischman, S.D.; Mirotznik, Mark S.; Swanson, David K.; Webster, John G.

doi:10.1109/10.412649

Cited by 182 publications

(148 citation statements)

References 13 publications

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“…However, to our knowledge, the majority of the numerical models of RF heating using an active electrode include only a limited fragment of biological tissue and active electrode [17,19,22,26,[36][37][38][39]. Computer simulations have been carried out in all these cases in order to determine the appropriate model dimensions.…”

Section: H Electrical Conductivity Dispersionmentioning

confidence: 99%

Radio-frequency heating of the cornea: theoretical model and in vitro experiments

Berjano

Sáiz

Ferrero

2002

IEEE Trans. Biomed. Eng.

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We present a theoretical model for the study of cornea heating with radiofrequency currents. This technique is used to reshape the cornea to correct refractive disorders. Our numerical model has allowed the study of the temperature distributions in the cornea and to estimate the dimensions of the lesion. The model incorporates a fragment of cornea, aqueous humor and the active electrode placed on the cornea surface. The finite element method has been used to calculate the temperature distribution in the cornea by solving a coupled electric-thermal problem. We analyzed by means of computer simulations the effect of: a) temperature influence on the tissue electrical conductivity, b) the dispersion of the biological characteristics, c) the anisotropy of the cornea thermal conductivity, d) the presence of the tear film, and e) the insertion depth of the active electrode in the cornea, and the results suggest that these effects have a significant influence on the temperature distributions and thereby on the lesion dimensions. However, the cooling of the aqueous humor in the endothelium or the realistic value of the cornea curvature did not have a significant effect on the temperature distributions.An experimental model based on the lesions created in rabbit eyes has been used in order to compare the theoretical and experimental results. There is a tendency towards the agreement between experimental and theoretical results, although we have observed that the theoretical model overestimates the lesion dimension.

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Section: H Electrical Conductivity Dispersionmentioning

confidence: 99%

Radio-frequency heating of the cornea: theoretical model and in vitro experiments

Berjano

Sáiz

Ferrero

2002

IEEE Trans. Biomed. Eng.

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“…Panescu et al [5]). This approach, though theoretically accurate, suffers from a high computational cost because of the required fine volume mesh on the surface of the very thin probe tips.…”

Section: (C) Electrical Heating Modelmentioning

confidence: 99%

“…The classical bio-heat equation, the Pennes model, has been widely used in the literature to model the electrical-thermal heating process during the ablation procedure [4][5][6]. However, the convective heat-transfer term between tissue and blood in the equation is oversimplified, assuming the blood to be a volumetric heat sink and one that is uniformly distributed throughout the tissue [7].…”

Section: (A) Bio-heat Modelmentioning

confidence: 99%

Image-based multi-scale modelling and validation of radio-frequency ablation in liver tumours

Payne

Flanagan²,

Pollari

et al. 2011

Phil. Trans. R. Soc. A.

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The treatment of cancerous tumours in the liver remains clinically challenging, despite the wide range of treatment possibilities, including radio-frequency ablation (RFA), highintensity focused ultrasound and resection, which are currently available. Each has its own advantages and disadvantages. For non-or minimally invasive modalities, such as RFA, considered here, it is difficult to monitor the treatment in vivo. This is particularly problematic in the liver, where large blood vessels act as heat sinks, dissipating delivered heat and shrinking the size of the lesion (the volume damaged by the heat treatment) locally; considerable experience is needed on the part of the clinician to optimize the heat treatment to prevent recurrence. In this paper, we outline our work towards developing a simulation tool kit that could be used both to optimize treatment protocols in advance and to train the less-experienced clinicians for RFA treatment of liver tumours. This tool is based on a comprehensive mathematical model of bio-heat transfer and cell death. We show how simulations of ablations in two pigs, based on individualized imaging data, compare directly with experimentally measured lesion sizes and discuss the likely sources of error and routes towards clinical implementation. This is the first time that such a 'loop' of mathematical modelling and experimental validation in vivo has been performed in this context, and such validation enables us to make quantitative estimates of error.

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“…Future studies should be conducted to investigate all the factors which are known to influence tissue temperature during RF ablation, such as the angle between the electrode and cardiac surface [Panescu et al 1995], distance between electrode and cooling balloon [Berjano et al 2005b], pressure of the electrode on the cardiac surface (i.e. insertion depth of the electrode into the tissue) [Tungjitkusolmun et al 2001], and blood flow on electrode and cardiac surface [Cao et al 2001].…”

Section: )mentioning

confidence: 99%

A cooled water-irrigated intraesophageal balloon to prevent thermal injury during cardiac ablation: experimental study based on an agar phantom

Lequerica¹,

Berjano²,

Herrero³

et al. 2008

Phys. Med. Biol.

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Lequerica, JL.; Berjano, E.; Herrero, M.; Melecio, L.; Hornero, F. (2008). Cooled waterirrigated intraesophageal balloon to prevent thermal injury during cardiac ablation: Experimental study based on an agar phantom. Physics in AbstractA great deal of current research is directed to finding a way to minimize thermal injury in the esophagus during radiofrequency (RF) catheter ablation of the atrium. A recent clinical study employing a cooling intraesophageal balloon reported a reduction of the temperature in the esophageal lumen. However, it could not be determined whether the deeper muscular layer of the esophagus was cooled enough to prevent injury. We built a model based on an agar phantom in order to experimentally study the thermal behavior of this balloon by measuring the temperature not only on the balloon, but also at a hypothetical point between the esophageal lumen and myocardium (2 mm distant).Controlled temperature (55ºC) ablations were conducted for 120 s. The results showed that: 1) The cooling balloon provides a reduction in the final temperature reached, both on the balloon surface and at a distance of 2 mm; 2) Coolant temperature has a significant effect on the temperature measured at 2 mm from the esophageal lumen (it has less effect on the temperature measured on the balloon surface); and 3) The precooling period has a significant effect on the temperature measured on the balloon surface (the effect on the temperature measured 2 mm away is small). The results were in good agreement with those obtained in a previous clinical study. The study suggests that that the cooling balloon gives thermal protection to the esophagus when a minimum pre-cooling period of 2 minutes is programmed at a coolant temperature of 5ºC or less.

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Three-dimensional finite element analysis of current density and temperature distributions during radio-frequency ablation

Cited by 182 publications

References 13 publications

Radio-frequency heating of the cornea: theoretical model and in vitro experiments

Radio-frequency heating of the cornea: theoretical model and in vitro experiments

Image-based multi-scale modelling and validation of radio-frequency ablation in liver tumours

A cooled water-irrigated intraesophageal balloon to prevent thermal injury during cardiac ablation: experimental study based on an agar phantom

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