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Fang Z, Zhang B, Moser M, Zhang E, Zhang W. Design of a Novel Electrode of Radiofrequency Ablation for Large Tumors: A Finite Element Study. ACTA ACUST UNITED AC 2017. [DOI: 10.1115/1.4038129] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The aim of the study was to design a novel radiofrequency (RF) electrode for larger and rounder ablation volumes and its ability to achieve the complete ablation of liver tumors larger than 3 cm in diameter using finite element method. A new RF expandable electrode comprising three parts (i.e., insulated shaft, changing shaft, and hooks) was designed. Two modes of this new electrode, such as monopolar expandable electrode (MEE) and hybrid expandable electrode (HEE), and a commercial expandable electrode (CEE) were investigated using liver tissue with (scenario I) and without (scenario II) a liver tumor. A temperature-controlled radiofrequency ablation (RFA) protocol with a target temperature of 95 °C and an ablation time of 15 min was used in the study. Both the volume and shape of the ablation zone were examined for all RF electrodes in scenario I. Then, the RF electrode with the best performance in scenario I and CEE were used to ablate a large liver tumor with the diameter of 3.5 cm (scenario II) to evaluate the effectiveness of complete tumor ablation of the designed RF electrode. In scenario I, the ablation volumes of CEE, HEE, and MEE were 12.11 cm3, 33.29 cm3, and 48.75 cm3, respectively. The values of sphericity index (SI) of CEE, HEE, and MEE were 0.457, 0.957, and 0.976, respectively. The best performance was achieved by using MEE. In scenario II, the ablation volumes of MEE and CEE were 71.59 cm3 and 19.53 cm3, respectively. Also, a rounder ablation volume was achieved by using MEE compared to CEE (SI: 0.978 versus 0.596). The study concluded that: (1) compared with CEE, both MEE and HEE get larger and rounder ablation volumes due to the larger electrode–tissue interface and rounder shape of hook deployment; (2) MEE has the best performance in getting a larger and rounder ablation volume; and (3) computer simulation result shows that MEE is also able to ablate a large liver tumor (i.e., 3.5 cm in diameter) completely, which has at least 0.785 cm safety margin.
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Affiliation(s)
- Zheng Fang
- Tumor Ablation Group, CISR Center, East China University of Science and Technology, Shanghai 200237, China e-mail:
| | - Bing Zhang
- Mem. ASME Division of Biomedical Engineering, University of Saskatchewan, Saskatoon, SK S7N 5A9, Canada e-mail:
| | - Michael Moser
- Department of Surgery, University of Saskatchewan, Saskatoon, SK S7N 0W8, Canada e-mail:
| | - Edwin Zhang
- Division of Vascular and Interventional Radiology, Department of Medical Imaging, University of Toronto, Toronto, ON M5T 1W7, Canada e-mail:
| | - Wenjun Zhang
- Fellow ASME Department of Mechanical Engineering, University of Saskatchewan, Saskatoon, SK S7N 5A9, Canada e-mail:
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Current Solutions for the Heat-Sink Effect of Blood Vessels with Radiofrequency Ablation: A Review and Future Work. COMMUNICATIONS IN COMPUTER AND INFORMATION SCIENCE 2017. [DOI: 10.1007/978-981-10-6370-1_12] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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