The Performance of Higher Frequency Microwave Ablation in the Presence of Perfusion

Sawicki, James F.; Luyen, Hung; Mohtashami, Yahya; Shea, Jacob D.; Behdad, Nader; Hagness, Susan C.

doi:10.1109/tbme.2018.2836317

Cited by 14 publications

(11 citation statements)

References 20 publications

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“…The objective of ablation procedures is to heat the targeted tissue, consisting of the tumor and a margin of surrounding tissue, to cytotoxic temperatures. While most systems in current clinical use operate at 915 MHz or 2.45 GHz, systems operating at other frequencies in the microwave range have been proposed …”

Section: Introductionmentioning

confidence: 99%

“…While most systems in current clinical use operate at 915 MHz or 2.45 GHz, systems operating at other frequencies in the microwave range have been proposed. 2,3 Computational models are widely used to guide the design and optimization of MWA applicators, to comparatively assess the impact of energy-delivery strategies on ablation outcome, and for characterizing applicator performance in a variety of tissue types. 1,[4][5][6][7][8] Computational models are also being developed for use as treatment planning tools that may assist a physician in selecting treatment parameters that maximize the likelihood of achieving a favorable treatment outcome.…”

Section: Introductionmentioning

confidence: 99%

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Broadband lung dielectric properties over the ablative temperature range: Experimental measurements and parametric models

2019

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Purpose Computational models of microwave tissue ablation are widely used to guide the development of ablation devices, and are increasingly being used for the development of treatment planning and monitoring platforms. Knowledge of temperature‐dependent dielectric properties of lung tissue is essential for accurate modeling of microwave ablation (MWA) of the lung. Methods We employed the open‐ended coaxial probe method, coupled with a custom tissue heating apparatus, to measure dielectric properties of ex vivo porcine and bovine lung tissue at temperatures ranging between 31 and 150 ∘C, over the frequency range 500 MHz to 6 GHz. Furthermore, we employed numerical optimization techniques to provide parametric models for characterizing the broadband temperature‐dependent dielectric properties of tissue, and their variability across tissue samples, suitable for use in computational models of microwave tissue ablation. Results Rapid decreases in both relative permittivity and effective conductivity were observed in the temperature range from 94 to 108 ∘C. Over the measured frequency range, both relative permittivity and effective conductivity were suitably modeled by piecewise linear functions [root mean square error (RMSE) = 1.0952 for permittivity and 0.0650 S/m for conductivity]. Detailed characterization of the variability in lung tissue properties was provided to enable uncertainty quantification of models of MWA. Conclusions The reported dielectric properties of lung tissue, and parametric models which also capture their distribution, will aid the development of computational models of microwave lung ablation.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Broadband lung dielectric properties over the ablative temperature range: Experimental measurements and parametric models

2019

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“…Most of the MWA studies reported in the previous literature have been conducted utilizing the electromagnetic wave frequency of 915 MHz or 2.45 GHz, with a few studies also reported at higher frequencies (see e.g. (Sawicki et al, 2017, Luyen et al, 2014, Sawicki et al, 2018, Yoon et al, 2011). The electric and magnetic fields related to the time-varying transverse electromagnetic wave can be computed from the Helmholtz harmonic wave equation derived from Maxwell's equation and is given by:…”

Section: Modelling Of Heat Source For Mwa and Rfamentioning

confidence: 99%

Thermal ablation of biological tissues in disease treatment: A review of computational models and future directions

Singh

Melnik

2020

Electromagnetic Biology and Medicine

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Percutaneous thermal ablation has proved to be an effective modality for treating both benign and malignant tumors in various tissues. Among these modalities, radiofrequency ablation (RFA) is the most promising and widely adopted approach that has been extensively studied in the past decades. Microwave ablation (MWA) is a newly emerging modality that is gaining rapid momentum due to its capability of inducing rapid heating and attaining larger ablation volumes, and its lesser susceptibility to the heat sink effects as compared to RFA. Although the goal of both these therapies is to attain cell death in the target tissue by virtue of heating above 50 o C, their underlying mechanism of action and principles greatly differs. Computational modelling is a powerful tool for studying the effect of electromagnetic interactions within the biological tissues and predicting the treatment outcomes during thermal ablative therapies. Such a priori estimation can assist the clinical practitioners during treatment planning with the goal of attaining successful tumor destruction and preservation of the surrounding healthy tissue and critical structures. This review provides current state-ofthe-art developments and associated challenges in the computational modelling of thermal ablative techniques, viz., RFA and MWA, as well as touch upon several promising avenues in the modelling of laser ablation, nanoparticles assisted magnetic hyperthermia and noninvasive RFA. The application of RFA in pain relief has been extensively reviewed from modelling point of view. Additionally, future directions have also been provided to improve these models for their successful translation and integration into the hospital work flow.

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“…A variety of tissue-mimicking phantoms with tunable dielectric properties have been reported in the literature. 43,44 Measurement of the antenna’s specific absorption rate (SAR) pattern may be helpful for assessing the radiation pattern of an antenna, but neglects the effects of thermal conduction on ablation zone profiles. 45 Furthermore, SAR measurements typically do not account for the changes in antenna radiation pattern due to temperature-dependent changes in tissue dielectric properties.…”

Section: Mw Ablation Applicatorsmentioning

confidence: 99%

“…46 To account for effects of blood perfusion, which acts as a heat sink, ablation zones must be evaluated in an in vivo animal model or by emulating the perfusion using a perfusion chamber. 47,48 Ablated tissue is resected after in vivo ablations for histopathologic analysis; viability stains may assist in accurate determination of the ablation zone boundary.…”

Section: Mw Ablation Applicatorsmentioning

confidence: 99%

Antenna Designs for Microwave Tissue Ablation

Fallahi

Prakash

2018

Crit Rev Biomed Eng

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Microwave (MW) ablation has emerged as a minimally invasive therapeutic modality and is in clinical use for treatment of unresectable tumors and cardiac arrhythmias, neuromodulation, endometrial ablation, and other applications. Components of image-guided MW ablation systems include high-power MW sources, ablation applicators that deliver power from the generator to the target tissue, cooling systems, energy-delivery control algorithms, and imaging guidance systems tailored to specific clinical indications. The applicator incorporates a MW antenna that radiates MW power into the surrounding tissue. A variety of antenna designs have been developed for MW ablation with the objective of efficiently transferring MW power to tissue, with a radiation pattern well matched to the size and shape of the targeted tissue. Here, we survey advances in percutaneous, endocavitary, and endoscopic antenna designs as an integral element of MW ablation applicators for a diverse set of clinical applications.

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The Performance of Higher Frequency Microwave Ablation in the Presence of Perfusion

Cited by 14 publications

References 20 publications

Broadband lung dielectric properties over the ablative temperature range: Experimental measurements and parametric models

Broadband lung dielectric properties over the ablative temperature range: Experimental measurements and parametric models

Thermal ablation of biological tissues in disease treatment: A review of computational models and future directions

Antenna Designs for Microwave Tissue Ablation

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