Microwave Ablation with Triaxial Antennas Tuned for Lung: Results in an in Vivo Porcine Model

Durick, Nathan A.; Laeseke, Paul F.; Broderick, Lynn S.; Lee, Fred T.; Sampson, Lisa A.; Frey, Tina M.; Warner, Thomas F.; Fine, Jason P.; Weide, Daniel W. van der; Brace, Christopher L.

doi:10.1148/radiol.2471062123

Cited by 57 publications

(56 citation statements)

References 36 publications

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“…30,31 While microwave tumor ablation has historically been performed most frequently in the liver, it is emerging as a treatment option for tumors in the kidney, lung, and bone as well. The properties of normal kidney are similar to liver, but normal lung and bone are characterized by very different relative permittivity and effective conductivity values.…”

Section: Discussionmentioning

confidence: 99%

Dual‐slot antennas for microwave tissue heating: Parametric design analysis and experimental validation

Brace

2011

Medical Physics

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Purpose: Design and validate an efficient dual-slot coaxial microwave ablation antenna that produces an approximately spherical heating pattern to match the shape of most abdominal and pulmonary tumor targets. Methods: A dual-slot antenna geometry was utilized for this study. Permutations of the antenna geometry using proximal and distal slot widths from 1 to 10 mm separated by 1-20 mm were analyzed using finite-element electromagnetic simulations. From this series, the most optimal antenna geometry was selected using a two-term sigmoidal objective function to minimize antenna reflection coefficient and maximize the diameter-to-length aspect ratio of heat generation. Sensitivities to variations in tissue properties and insertion depth were also evaluated in numerical models. The most optimal dual-slot geometry of the parametric analysis was then fabricated from semirigid coaxial cable. Antenna reflection coefficients at various insertion depths were recorded in ex vivo bovine livers and compared to numerical results. Ablation zones were then created by applying 50 W for 2-10 min in simulations and ex vivo livers. Mean zone diameter, length, aspect ratio, and reflection coefficients before and after heating were then compared to a conventional monopole antenna using ANOVA with post-hoc t-tests. Statistical significance was indicated for P < 0.05. Results: Antenna performance was highly sensitive to dual-slot geometry. The best-performing designs utilized a proximal slot width of 1 mm, distal slot width of 4 mm 6 1 mm and separation of 8 mm 6 1 mm. These designs were characterized by an active choking mechanism that focused heating to the distal tip of the antenna. A dual-band resonance was observed in the most optimal design, with a minimum reflection coefficient of À20.9 dB at 2.45 and 1.25 GHz. Total operating bandwidth was greater than 1 GHz, but the desired heating pattern was achieved only near 2.45 GHz. As a result, antenna performance was robust to changes in insertion depth and variations in relative permittivity of the surrounding tissue medium. In both simulations and ex vivo liver, the dual-slot antenna created ablations greater in diameter than a coaxial monopole (35 mm 6 2 mm versus 31 mm 6 2 mm; P < 0.05), while also shorter in length (49 mm 6 2 mm versus 60 mm 6 6 mm; P < 0.001) after 10 min. Similar results were obtained after 2 and 5 min as well. Conclusions: Dual-slot antennas can produce more spherical ablation zones while retaining low reflection coefficients. These benefits are obtained without adding to the antenna diameter. Further evaluation for clinical microwave ablation appears warranted.

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Section: Discussionmentioning

confidence: 99%

Dual‐slot antennas for microwave tissue heating: Parametric design analysis and experimental validation

Brace

2011

Medical Physics

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“…Many antennae produce an elongated ablation zone (as long as 6 cm) that may increase the risk for burns to the body wall and other structures, so newer designs aim for more rounded and forward-weighted heating that is amenable to treating smaller tumors (Fig 3) (26,27). Some systems also include antenna designs to transfer energy more optimally to different organ types, such as the lungs (28). As with other ablation modalities, multiple antennae can also be used in concert to create larger, more conformal and confluent ablation zones (29,30).…”

Section: Heat-based Ablationmentioning

confidence: 99%

“…Adequately powered 915-MHz and 2.45-GHz systems can create relatively large ablation zones, but the longer wavelength at 915 MHz typically results in a longer ablation zone (28,34,(36)(37)(38). In general, the greatest heating from any system occurs within 1 cm of the antenna.…”

Section: Heat-based Ablationmentioning

confidence: 99%

“…Cryoablation can effectively ablate tumors in the lung and has the advantage of being relatively resistant to the cold-sink effects of ventilation, compared with RF ablation (83,84). The effect has not been studied in microwave ablation as of yet, but according to animal studies, microwave ablation seems to be less susceptible to these effects and creates a larger and more confluent zone of ablation compared with RF ablation and cryoablation (28). Another advantage of cryoablation is seen with tumors that are relatively central or closely adjacent to or invasive into the mediastinum or chest wall (Fig 13).…”

Section: Organ-specific Considerationsmentioning

confidence: 99%

“…Microwave ablation has the advantage of creating predictable and large ablation zones, even in the setting of aerated lung (28). The advantage of a faster procedure is also true in the lungs-most ablations require approximately 5 minutes after antenna placement.…”

Section: Organ-specific Considerationsmentioning

confidence: 99%

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Percutaneous Tumor Ablation Tools: Microwave, Radiofrequency, or Cryoablation—What Should You Use and Why?

Hinshaw¹,

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Nanoscale Metal‐Organic Frameworks: Synthesis, Biocompatibility, Imaging Applications, and Thermal and Dynamic Therapy of Tumors

Tan

Meng

2020

Adv Funct Materials

130

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Nanoscale metal‐organic frameworks (NMOFs) have attracted increasing attention for biomedical applications due to their large specific surface area, good biocompatibility, adjustable structures, and diverse functions. By choosing appropriate metal ions and ligands, NMOFs can be synthesized and regulated to assist the diagnosis and treatment of cancer, acting as imaging agents, drug carriers, and cancer therapeutic agents. This review summarizes the recent advances of NMOFs in synthesis, biocompatibility, imaging, and applications in cancer therapies. Among these, the term “biocompatibility” is used to outline their various biological characteristics, and it is mainly discussed from the aspects of size and surface properties of NMOFs. The imaging section mainly emphasizes the application advantages of NMOFs as imaging agents in magnetic resonance, computed tomography, and fluorescence imaging. The applications of NMOFs in four cancer therapies, including phototherapy, radiotherapy, microwave therapy, and ultrasonic therapy, are addressed, especially for thermal and dynamic therapy. Finally, the prospects and challenges of NMOFs in imaging and cancer therapies are also discussed.

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Microwave Ablation with Triaxial Antennas Tuned for Lung: Results in an in Vivo Porcine Model

Abstract: A 17-gauge triaxial microwave ablation system tuned for lung tissue yielded large circular zones of coagulation in vivo in porcine lungs. The coagulation zones created with bronchial occlusion and multiple antennas were significantly larger than those created with one antenna.

Cited by 57 publications

References 36 publications

Dual‐slot antennas for microwave tissue heating: Parametric design analysis and experimental validation

Dual‐slot antennas for microwave tissue heating: Parametric design analysis and experimental validation

Percutaneous Tumor Ablation Tools: Microwave, Radiofrequency, or Cryoablation—What Should You Use and Why?

Nanoscale Metal‐Organic Frameworks: Synthesis, Biocompatibility, Imaging Applications, and Thermal and Dynamic Therapy of Tumors

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