Optimization and characterization of a novel internally-cooled radiofrequency ablation system with optimized pulsing algorithm in an ex-vivo bovine liver
Purpose: To prospectively characterize and optimize radiofrequency energy deposition to determine ideal parameters for achieving large ablation zones. Materials and methods: An internally-cooled RF system was used to perform 214 ablations in 72 ex-vivo bovine livers. Tip exposure (1–5 cm), electrode...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Taylor & Francis Group
2019-10-01
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| Series: | International Journal of Hyperthermia |
| Subjects: | |
| Online Access: | http://dx.doi.org/10.1080/02656736.2019.1617901 |
| _version_ | 1818482123839897600 |
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| author | Eliel Ben-David Isaac Nissenbaum Svetlana Gurevich Eric R. Cosman S. Nahum Goldberg |
| author_facet | Eliel Ben-David Isaac Nissenbaum Svetlana Gurevich Eric R. Cosman S. Nahum Goldberg |
| author_sort | Eliel Ben-David |
| collection | DOAJ |
| description | Purpose: To prospectively characterize and optimize radiofrequency energy deposition to determine ideal parameters for achieving large ablation zones. Materials and methods: An internally-cooled RF system was used to perform 214 ablations in 72 ex-vivo bovine livers. Tip exposure (1–5 cm), electrode current (400–2500 mA), and application duration (3–15 min) were systematically varied. A pulsing algorithm optimized efficiency of RF deposition, including initial automatic ramping followed by adjustment in current, in response to changes in tissue impedance. Following the procedure ablation diameter and length were measured, sphericity calculated, and correlated with parameters of energy deposition and tissue temperatures. Results: Increasing electrode exposure from 1–5 cm produced linear increases in ablation diameter from 1.4 ± 0.1 to 5.3 ± 0.1 cm (y = 1.1x–0.5; R2 = 0.93), and length (y = 1.18x + 0.34; R2 = 0.92). A sphericity index >0.85 was noted at optimal energy setting for electrode exposures of 1–4 cm. Maximum temperatures post-ablation increased with active tip length from 68.5 ± 4.9 °C to 91.3 ± 1.5 °C in a logarithmic (y = 0.94ln(x)−2.75; R2 = 0.90) or power relationship between temperature and the resultant ablation diameter (y = 0.27e0.0295x; R2 = 0.76). A tight exponential relationship (y = 0.28x0.38; R2 = 0.97) was also observed between total energy deposition and ablation diameter. Finally, a multifactor relationship of the diameter of ablation to electrode tip exposure and the time to first impedance rise was successfully modeled, with a root mean squared error of 1.9 mm and R2 = 0.95. Conclusion: Large, reproducible, and spherical ablation areas can be achieved with the novel system described, with efficient delivery of RF energy deposited into tissue. These findings may have important clinical relevance in regards to the clinical utility of RF ablation compared to other competitive forms of thermal tumor ablation. |
| first_indexed | 2024-12-10T11:44:04Z |
| format | Article |
| id | doaj.art-e25a5cf53cbe42b1b9bc245dcbf736af |
| institution | Directory Open Access Journal |
| issn | 0265-6736 1464-5157 |
| language | English |
| last_indexed | 2024-12-10T11:44:04Z |
| publishDate | 2019-10-01 |
| publisher | Taylor & Francis Group |
| record_format | Article |
| series | International Journal of Hyperthermia |
| spelling | doaj.art-e25a5cf53cbe42b1b9bc245dcbf736af2022-12-22T01:50:10ZengTaylor & Francis GroupInternational Journal of Hyperthermia0265-67361464-51572019-10-01362818810.1080/02656736.2019.16179011617901Optimization and characterization of a novel internally-cooled radiofrequency ablation system with optimized pulsing algorithm in an ex-vivo bovine liverEliel Ben-David0Isaac Nissenbaum1Svetlana Gurevich2Eric R. Cosman3S. Nahum Goldberg4Shaare Zedek Medical CenterHadassah Hebrew University Medical CenterHadassah Hebrew University Medical CenterCambridge InterventionalHadassah Hebrew University Medical CenterPurpose: To prospectively characterize and optimize radiofrequency energy deposition to determine ideal parameters for achieving large ablation zones. Materials and methods: An internally-cooled RF system was used to perform 214 ablations in 72 ex-vivo bovine livers. Tip exposure (1–5 cm), electrode current (400–2500 mA), and application duration (3–15 min) were systematically varied. A pulsing algorithm optimized efficiency of RF deposition, including initial automatic ramping followed by adjustment in current, in response to changes in tissue impedance. Following the procedure ablation diameter and length were measured, sphericity calculated, and correlated with parameters of energy deposition and tissue temperatures. Results: Increasing electrode exposure from 1–5 cm produced linear increases in ablation diameter from 1.4 ± 0.1 to 5.3 ± 0.1 cm (y = 1.1x–0.5; R2 = 0.93), and length (y = 1.18x + 0.34; R2 = 0.92). A sphericity index >0.85 was noted at optimal energy setting for electrode exposures of 1–4 cm. Maximum temperatures post-ablation increased with active tip length from 68.5 ± 4.9 °C to 91.3 ± 1.5 °C in a logarithmic (y = 0.94ln(x)−2.75; R2 = 0.90) or power relationship between temperature and the resultant ablation diameter (y = 0.27e0.0295x; R2 = 0.76). A tight exponential relationship (y = 0.28x0.38; R2 = 0.97) was also observed between total energy deposition and ablation diameter. Finally, a multifactor relationship of the diameter of ablation to electrode tip exposure and the time to first impedance rise was successfully modeled, with a root mean squared error of 1.9 mm and R2 = 0.95. Conclusion: Large, reproducible, and spherical ablation areas can be achieved with the novel system described, with efficient delivery of RF energy deposited into tissue. These findings may have important clinical relevance in regards to the clinical utility of RF ablation compared to other competitive forms of thermal tumor ablation.http://dx.doi.org/10.1080/02656736.2019.1617901Radiofrequency ablationinternally-cooledoptimizationcharacterizationmodeling |
| spellingShingle | Eliel Ben-David Isaac Nissenbaum Svetlana Gurevich Eric R. Cosman S. Nahum Goldberg Optimization and characterization of a novel internally-cooled radiofrequency ablation system with optimized pulsing algorithm in an ex-vivo bovine liver International Journal of Hyperthermia Radiofrequency ablation internally-cooled optimization characterization modeling |
| title | Optimization and characterization of a novel internally-cooled radiofrequency ablation system with optimized pulsing algorithm in an ex-vivo bovine liver |
| title_full | Optimization and characterization of a novel internally-cooled radiofrequency ablation system with optimized pulsing algorithm in an ex-vivo bovine liver |
| title_fullStr | Optimization and characterization of a novel internally-cooled radiofrequency ablation system with optimized pulsing algorithm in an ex-vivo bovine liver |
| title_full_unstemmed | Optimization and characterization of a novel internally-cooled radiofrequency ablation system with optimized pulsing algorithm in an ex-vivo bovine liver |
| title_short | Optimization and characterization of a novel internally-cooled radiofrequency ablation system with optimized pulsing algorithm in an ex-vivo bovine liver |
| title_sort | optimization and characterization of a novel internally cooled radiofrequency ablation system with optimized pulsing algorithm in an ex vivo bovine liver |
| topic | Radiofrequency ablation internally-cooled optimization characterization modeling |
| url | http://dx.doi.org/10.1080/02656736.2019.1617901 |
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