Effect of electrode contact on lesion growth during temperature controlled radio frequency ablation

Jain, M.K.; Wolf, Peter

doi:10.1109/iembs.1998.745886

Cited by 8 publications

(13 citation statements)

References 6 publications

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“…During the last 10 years, another two groups became interested in theoretical RF ablation modeling. The Duke University group [ 41 - 46 ] developed interesting three-dimensional RF cardiac ablation models to assess the effect of different factors on the temperature distributions in the tissue. This group focused mainly on increasing the realism of the modeling of blood flow [ 44 ], and conducted excellent experiments to validate their models [ 44 , 45 , 47 ].…”

Section: Introductionmentioning

confidence: 99%

Theoretical modeling for radiofrequency ablation: state-of-the-art and challenges for the future

2006

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Radiofrequency ablation is an interventional technique that in recent years has come to be employed in very different medical fields, such as the elimination of cardiac arrhythmias or the destruction of tumors in different locations. In order to investigate and develop new techniques, and also to improve those currently employed, theoretical models and computer simulations are a powerful tool since they provide vital information on the electrical and thermal behavior of ablation rapidly and at low cost. In the future they could even help to plan individual treatment for each patient. This review analyzes the state-of-the-art in theoretical modeling as applied to the study of radiofrequency ablation techniques. Firstly, it describes the most important issues involved in this methodology, including the experimental validation. Secondly, it points out the present limitations, especially those related to the lack of an accurate characterization of the biological tissues. After analyzing the current and future benefits of this technique it finally suggests future lines and trends in the research of this area.

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Section: Introductionmentioning

confidence: 99%

Theoretical modeling for radiofrequency ablation: state-of-the-art and challenges for the future

2006

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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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“…The temperature thresholds that have been used to predict lesion size and define thermal injury are well documented in the literature . The most common temperatures used are 43°C [22,23], 48°C [24,25], 50°C [9,13,14], and 59°C [12]. While some of this variation is attributable to differences in tissue *Address correspondence to this author at the U.S. Food and Drug Administration, White Oak, MD 20993, USA; E-mail: Isaac.Chang@fda.hhs.gov type (i.e.…”

Section: Introductionmentioning

confidence: 99%

Considerations for Thermal Injury Analysis for RF Ablation Devices

Chang¹

2010

TOBEJ

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Abstract:Background: The estimation of lesion size is an integral part of treatment planning for the clinical applications of radiofrequency ablation. However, to date, studies have not directly evaluated the impact of different computational estimation techniques for predicting lesion size. In this study, we focus on three common methods used for predicting tissue injury: (1) iso-temperature contours, (2) Cumulative equivalent minutes, (3) Arrhenius based thermal injury. Methods:We created a geometric model of a multi-tyne ablation electrode and simulated thermal and tissue injury profiles that result from three calculation methods after 15 minutes exposure to a constant RF voltage source. A hybrid finite element technique was used to calculate temperature and tissue injury. Time-temperature curves were used in the assessment of iso-temperature thresholds and the method of cumulative equivalent minutes. An Arrhenius-based formulation was used to calculate sequential and recursive thermal injury to tissues. Results: The data demonstrate that while iso-temperature and cumulative equivalent minute contours are similar in shape, these two methodologies grossly over-estimate the amount of tissue injury when compared to recursive thermal injury calculations, which have previously been shown to correlate closely with in vitro pathologic lesion volume measurement. In addition, Arrhenius calculations that do not use a recursive algorithm result in a significant underestimation of lesion volume. The data also demonstrate that lesion width and depth are inadequate means of characterizing treatment volume for multi-tine ablation devices. Conclusions: Recursive thermal injury remains the most physiologically relevant means of computationally estimating lesion size for hepatic tumor applications. Iso-thermal and cumulative equivalent minute approaches may produce significant errors in the estimation of lesion size.

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Effect of electrode contact on lesion growth during temperature controlled radio frequency ablation

Cited by 8 publications

References 6 publications

Theoretical modeling for radiofrequency ablation: state-of-the-art and challenges for the future

Theoretical modeling for radiofrequency ablation: state-of-the-art and challenges for the future

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

Considerations for Thermal Injury Analysis for RF Ablation Devices

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