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Faria RM, Rosa SDSRF, Nunes GAMDA, Santos KS, de Souza RP, Benavides ADI, Alves AKDO, da Silva AKA, Rosa MF, Cardoso AADA, Faria SDS, Berjano E, da Rocha AF, dos Santos Í, González-Suárez A. Particle swarm optimization solution for roll-off control in radiofrequency ablation of liver tumors: Optimal search for PID controller tuning. PLoS One 2024; 19:e0300445. [PMID: 38924000 PMCID: PMC11207125 DOI: 10.1371/journal.pone.0300445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 02/28/2024] [Indexed: 06/28/2024] Open
Abstract
The study investigates the efficacy of a bioinspired Particle Swarm Optimization (PSO) approach for PID controller tuning in Radiofrequency Ablation (RFA) for liver tumors. Ex-vivo experiments were conducted, yielding a 9th order continuous-time transfer function. PSO was applied to optimize PID parameters, achieving outstanding simulation results: 0.605% overshoot, 0.314 seconds rise time, and 2.87 seconds settling time for a unit step input. Statistical analysis of 19 simulations revealed PID gains: Kp (mean: 5.86, variance: 4.22, standard deviation: 2.05), Ki (mean: 9.89, variance: 0.048, standard deviation: 0.22), Kd (mean: 0.57, variance: 0.021, standard deviation: 0.14) and ANOVA analysis for the 19 experiments yielded a p-value ≪ 0.05. The bioinspired PSO-based PID controller demonstrated remarkable potential in mitigating roll-off effects during RFA, reducing the risk of incomplete tumor ablation. These findings have significant implications for improving clinical outcomes in hepatocellular carcinoma management, including reduced recurrence rates and minimized collateral damage. The PSO-based PID tuning strategy offers a practical solution to enhance RFA effectiveness, contributing to the advancement of radiofrequency ablation techniques.
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Affiliation(s)
- Rafael Mendes Faria
- Department of Mechanical Engineering, University of Brasilia, Brasilia, Distrito Federal, Brazil
- Department of Electrical Engineering, Federal Institute of Education, Science and Technology of Triângulo Mineiro, Paracatu, Minas Gerais, Brazil
| | - Suélia de Siqueira Rodrigues Fleury Rosa
- Department of Mechanical Engineering, University of Brasilia, Brasilia, Distrito Federal, Brazil
- Department of Biomedical Engineering, Faculty of Gama, University of Brasilia, Brasilia, Distrito Federal, Brazil
| | | | - Klériston Silva Santos
- Department of Mechanical Engineering, University of Brasilia, Brasilia, Distrito Federal, Brazil
- Department of Electrical Engineering, Federal Institute of Education, Science and Technology of Triângulo Mineiro, Paracatu, Minas Gerais, Brazil
| | - Rafael Pissinati de Souza
- Department of Mechanical Engineering, University of Brasilia, Brasilia, Distrito Federal, Brazil
- Department of Electrical Engineering, Federal Institute of Education, Science and Technology of Rondônia, Porto Velho, Rondônia, Brazil
| | | | | | | | - Mario Fabrício Rosa
- Department of Biomedical Engineering, Faculty of Gama, University of Brasilia, Brasilia, Distrito Federal, Brazil
| | | | - Sylvia de Sousa Faria
- Department of Electronic Engineering, Universitat Politècnica de València, Valencia, Spain
| | - Enrique Berjano
- Department of Electronic Engineering, Universitat Politècnica de València, Valencia, Spain
| | - Adson Ferreira da Rocha
- Department of Electrical Engineering, University of Brasilia, Brasilia, Distrito Federal, Brazil
| | - Ícaro dos Santos
- Department of Electrical Engineering and Computer Science, Milwaukee School of Engineering, Milwaukee, Wisconsin, United States of America
| | - Ana González-Suárez
- Translational Medical Device Lab, School of Medicine, University of Galway, Galway, Ireland
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Collavini S, Pérez JJ, Berjano E, Fernández-Corazza M, Oddo S, Irastorza RM. Impact of surrounding tissue-type and peri-electrode gap in stereoelectroencephalography guided (SEEG) radiofrequency thermocoagulation (RF-TC): a computational study. Int J Hyperthermia 2024; 41:2364721. [PMID: 38880496 DOI: 10.1080/02656736.2024.2364721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Accepted: 06/01/2024] [Indexed: 06/18/2024] Open
Abstract
PURPOSE To use computational modeling to provide a complete and logical description of the electrical and thermal behavior during stereoelectroencephalography-guided (SEEG) radiofrequency thermo-coagulation (RF-TC). METHODS A coupled electrical-thermal model was used to obtain the temperature distributions in the tissue during RF-TC. The computer model was first validated by an ex vivo model based on liver fragments and later used to study the impact of three different factors on the coagulation zone size: 1) the difference in the tissue surrounding the electrode (gray/white matter), 2) the presence of a peri-electrode gap occupied by cerebrospinal fluid (CSF), and 3) the energy setting used (power-duration). RESULTS The model built for the experimental validation was able to predict both the evolution of impedance and the short diameter of the coagulation zone (error < 0.01 mm) reasonably well but overestimated the long diameter by 2 - 3 mm. After adapting the model to clinical conditions, the simulation showed that: 1) Impedance roll-off limited the coagulation size but involved overheating (around 100 °C); 2) The type of tissue around the contacts (gray vs. white matter) had a moderate impact on the coagulation size (maximum difference 0.84 mm), and 3) the peri-electrode gap considerably altered the temperature distributions, avoided overheating, although the diameter of the coagulation zone was not very different from the no-gap case (<0.2 mm). CONCLUSIONS This study showed that computer modeling, especially subject- and scenario-specific modeling, can be used to estimate in advance the electrical and thermal performance of the RF-TC in brain tissue.
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Affiliation(s)
- Santiago Collavini
- Institute of Engineering and Agronomy, National University Arturo Jauretche, Buenos Aires, Argentina
- Neurosciences and Complex Systems Unit (EnyS), CONICET, Hosp. "El Cruce N. Kirchner", National University A. Jauretche (UNAJ), Buenos Aires, Argentina
| | - Juan J Pérez
- BioMIT, Departamento de Ingeniería Electrónica, Universitat Politècnica de València, València, Spain
| | - Enrique Berjano
- BioMIT, Departamento de Ingeniería Electrónica, Universitat Politècnica de València, València, Spain
| | - Mariano Fernández-Corazza
- Research Institute of Electronics, Control and Signal Processing (LEICI), National University of La Plata-CONICET, La Plata, Argentina
| | - Silvia Oddo
- Neurosciences and Complex Systems Unit (EnyS), CONICET, Hosp. "El Cruce N. Kirchner", National University A. Jauretche (UNAJ), Buenos Aires, Argentina
| | - Ramiro M Irastorza
- Institute of Engineering and Agronomy, National University Arturo Jauretche, Buenos Aires, Argentina
- Institute of Physics of Liquids and Biological Systems (IFLySiB CONICET La Plata), La Plata, Argentina
- Granular Materials Group, Department of Mechanical Engineering, La Plata Regional Faculty, National Technological University, La Plata, Argentina
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Sun Y, Zhu X, Nakamura K, Wang S. Evaluation of lesion characteristics and baseline impedance on high-power short-duration radiofrequency catheter ablation using computer simulation. Heart Vessels 2023; 38:1459-1467. [PMID: 37650926 DOI: 10.1007/s00380-023-02300-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 08/02/2023] [Indexed: 09/01/2023]
Abstract
Myocardium baseline impedance (BI) is an important factor in ablation effectiveness. This study examined the performance of low-power and long-duration (LPLD), high-power and short-duration (HPSD) ablation at different BIs by computer simulation. A 3D model of the ablation region was constructed for simulation, and in vitro experiments were performed to validate the simulation. Three ablation power and duration configurations of 30 W/30 s, 50 W/10 s, and 90 W/5 s were used for simulation with BI values of 90, 100, 110, 120, 130, and 140 Ω. Roll-off time and ablation volume were measured to evaluate ablation results. The simulation is consistent with the in vitro experiments. When BI is changed from 90 [Formula: see text] to 140 [Formula: see text], the lesion volume over 50 °C with BI of 140 [Formula: see text] was reduced by 6.3%, 6.7%, and 7.3% for 30 W/30 s, 50 W/10 s, and 90 W/5 s configurations, respectively, and the lesion volume over 100 °C was reduced by 62.8%, 49.7%, and 22.5% under 30 W/30 s, 50 W/10 s, and 90 W/5 s, respectively. Simulation results revealed that HPSD (vHPSD) and LPLD ablation were more affected by changes in BI in the lesion volumes over 50 °C and 100 °C, respectively, and demonstrated that resistive and conductive heating were the main heating effects in HPSD (vHPSD) and LPLD, respectively.
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Affiliation(s)
- Yao Sun
- Graduate School of Computer Science and Engineering, The University of Aizu, Aizuwakamatsu, Japan
| | - Xin Zhu
- Graduate School of Computer Science and Engineering, The University of Aizu, Aizuwakamatsu, Japan
| | - Keijiro Nakamura
- Division of Cardiovascular Medicine, Toho University Ohashi Medical Center, Meguro, Tokyo, 153-8515, Japan.
| | - Shuyu Wang
- Graduate School of Computer Science and Engineering, The University of Aizu, Aizuwakamatsu, Japan
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Shah IA, Seol HY, Cho Y, Ji W, Seo J, Lee C, Chon MK, Shin D, Kim JH, Choo KS, Park J, Kim J, Yoo H, Kim JH. Conversion of the bronchial tree into a conforming electrode to ablate the lung nodule in a porcine model. COMMUNICATIONS MEDICINE 2023; 3:129. [PMID: 37775526 PMCID: PMC10541426 DOI: 10.1038/s43856-023-00362-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 09/15/2023] [Indexed: 10/01/2023] Open
Abstract
BACKGROUND Radiofrequency ablation (RFA) is one of the treatment options for lung nodules. However, the need for exact delivery of the rigid metal electrode into the center of the target mass often leads to complications or suboptimal results. To overcome these limitations, a concept of conforming electrodes using a flexible material has been tested in this study. METHODS A bronchoscopy-guided RFA (CAROL) under a temperature-controlled mode was tested in in-vivo and ex-vivo porcine lungs. Gallium-based liquid metal was used for turning the bronchial tree into temporary RF electrodes. A customized bronchoscopy-guided balloon-tipped guiding catheter (CAROL catheter) was used to make the procedure feasible under fluoroscopy imaging guidance. The computer simulation was also performed to gain further insight into the ablation results. Safety was also assessed including the liquid metal remaining in the body. RESULTS The bronchial electrode injected from the CAROL catheter was able to turn the target site bronchial air pipe into a temporally multi-tined RF electrode. The mean volume of Gallium for each effective CAROL was 0.46 ± 0.47 ml. The ablation results showed highly efficacious and consistent results, especially in the peripheral lung. Most bronchial electrodes were also retrieved by either bronchoscopic suction immediately after the procedure or by natural expectoration thereafter. The liquid metal used in these experiments did not have any significant safety issues. Computer simulation also supports these results. CONCLUSION The CAROL ablation was very effective and safe in porcine lungs showing encouraging potential to overcome the conventional approaches.
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Affiliation(s)
- Izaz Ali Shah
- Department of Electronic Engineering, Hanyang University, Seoul, 04763, Republic of Korea
| | - Hee Yun Seol
- Department of Internal Medicine, School of Medicine, Pusan National University, Pusan National University Yangsan Hospital, Research Institute for Convergence of Biomedical Science and Technology, Yangsan, Republic of Korea
| | - Youngdae Cho
- Department of Electronic Engineering, Hanyang University, Seoul, 04763, Republic of Korea
| | - Wonjun Ji
- Department of Pulmonary and Critical Care Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Jaeyoung Seo
- Department of R&D Center, Tau Medical Inc, Busan, Republic of Korea
| | - Cheolmin Lee
- Department of R&D Center, Tau Medical Inc, Busan, Republic of Korea
| | - Min-Ku Chon
- Department of Cardiology, School of Medicine & Cardiovascular center, Pusan National University & Pusan National University Yangsan Hospital, Yangsan, Republic of Korea
| | - Donghoon Shin
- Department of Pathology, School of Medicine, Pusan National University & Pusan National University Yangsan Hospital, Yangsan, Republic of Korea
| | - Justin H Kim
- Department of R&D Center, Tau Medical Inc, Busan, Republic of Korea
| | - Ki-Seok Choo
- Department of Radiology, School of Medicine & Medical Research Institute, Pusan National University & Pusan National University Yangsan Hospital, Yangsan, Republic of Korea
| | - Junhui Park
- Major of Human Bioconvergence, College of Information Technology and Convergence, Pukyong National University, Busan, Republic of Korea
| | - Juhyung Kim
- Department of Physiology, University of Toronto, Toronto, Canada
| | - Hyoungsuk Yoo
- Department of Electronic Engineering, Hanyang University, Seoul, 04763, Republic of Korea.
| | - June-Hong Kim
- Department of Cardiology, School of Medicine & Cardiovascular center, Pusan National University & Pusan National University Yangsan Hospital, Yangsan, Republic of Korea.
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Tu L, Zhou YU, Wang P, Wang H, Mao LIN, Hou J, Liu Z, Song C. Minimizing thermal damage using self-cooling jaws for radiofrequency intestinal tissue fusion. MINIM INVASIV THER 2023; 32:33-41. [PMID: 36519801 DOI: 10.1080/13645706.2022.2155064] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
INTRODUCTION Radiofrequency (RF)-induced tissue fusion shows great potential in sealing intestinal tissue without foreign materials. To improve the performance of RF-induced tissue fusion, a novel self-cooling jaw has been designed to minimize thermal damage during the fusion. MATERIAL AND METHODS The prototype of self-cooling jaws was developed and manufactured. A total number of 60 mucosa-to-mucosa fusions were conducted using ex-vivo porcine intestinal segments with the proposed design and conventional bipolar jaws. The effects of intestinal fusion were evaluated based on temperature curves, burst pressure, thermal damage, and histological appearances. RESULTS The self-cooling jaws showed significant decrease in temperature during the fusion process. An optimal burst pressure (5.7 ± 0.5 kPa) and thermal damage range (0.9 ± 0.1 mm) were observed when the applied RF power was 100 W. The thermal damage range of the prototype has almost decreased 36% in comparison with the conventional bipolar jaws (1.4 ± 0.1 mm). The histological observation revealed that a decrease of thermal damage was achieved through the application of self-cooling jaws. CONCLUSIONS The self-cooling jaws were proved to be effective for reducing the thermal damage during RF-induced tissue fusion, which could potentially promote the clinical application of tissue fusion techniques in the future.
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Affiliation(s)
- Liangyong Tu
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Y U Zhou
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Peiyao Wang
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Haochen Wang
- School of Mechanical Engineering, Suzhou University of Science and Technology, Suzhou, China
| | - L I N Mao
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Jian Hou
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Ziyue Liu
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Chengli Song
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
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Li N, Huber TC. Radiofrequency Ablation for Benign Thyroid Nodules: Radiology In Training. Radiology 2023; 306:54-63. [PMID: 36066365 DOI: 10.1148/radiol.220116] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Two patients, one with benign nonfunctioning nodules and one with functioning thyroid nodules, both of whom underwent radiofrequency ablation, are presented. Preprocedural evaluation, procedural considerations, and follow-up care of thyroid radiofrequency ablation, as well as published evidence on the topic, are discussed.
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Affiliation(s)
- Ningcheng Li
- From the Dotter Department of Interventional Radiology, Oregon Health and Science University, 3181 SW Sam Jackson Park Rd, Portland, OR 97239
| | - Timothy C Huber
- From the Dotter Department of Interventional Radiology, Oregon Health and Science University, 3181 SW Sam Jackson Park Rd, Portland, OR 97239
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7
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Nguyen TK, Yadav S, Truong TA, Han M, Barton M, Leitch M, Guzman P, Dinh T, Ashok A, Vu H, Dau V, Haasmann D, Chen L, Park Y, Do TN, Yamauchi Y, Rogers JA, Nguyen NT, Phan HP. Integrated, Transparent Silicon Carbide Electronics and Sensors for Radio Frequency Biomedical Therapy. ACS NANO 2022; 16:10890-10903. [PMID: 35816450 PMCID: PMC9332346 DOI: 10.1021/acsnano.2c03188] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The integration of micro- and nanoelectronics into or onto biomedical devices can facilitate advanced diagnostics and treatments of digestive disorders, cardiovascular diseases, and cancers. Recent developments in gastrointestinal endoscopy and balloon catheter technologies introduce promising paths for minimally invasive surgeries to treat these diseases. However, current therapeutic endoscopy systems fail to meet requirements in multifunctionality, biocompatibility, and safety, particularly when integrated with bioelectronic devices. Here, we report materials, device designs, and assembly schemes for transparent and stable cubic silicon carbide (3C-SiC)-based bioelectronic systems that facilitate tissue ablation, with the capability for integration onto the tips of endoscopes. The excellent optical transparency of SiC-on-glass (SoG) allows for direct observation of areas of interest, with superior electronic functionalities that enable multiple biological sensing and stimulation capabilities to assist in electrical-based ablation procedures. Experimental studies on phantom, vegetable, and animal tissues demonstrated relatively short treatment times and low electric field required for effective lesion removal using our SoG bioelectronic system. In vivo experiments on an animal model were conducted to explore the versatility of SoG electrodes for peripheral nerve stimulation, showing an exciting possibility for the therapy of neural disorders through electrical excitation. The multifunctional features of SoG integrated devices indicate their high potential for minimally invasive, cost-effective, and outcome-enhanced surgical tools, across a wide range of biomedical applications.
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Affiliation(s)
- Tuan-Khoa Nguyen
- Queensland
Micro and Nanotechnology Centre, Griffith
University, Brisbane, Queensland 4111, Australia
| | - Sharda Yadav
- Queensland
Micro and Nanotechnology Centre, Griffith
University, Brisbane, Queensland 4111, Australia
| | - Thanh-An Truong
- Queensland
Micro and Nanotechnology Centre, Griffith
University, Brisbane, Queensland 4111, Australia
- School
of Mechanical and Manufacturing Engineering, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Mengdi Han
- Department
of Biomedical Engineering, College of Future Technology, Peking University, Beijing 100871, China
| | - Matthew Barton
- School
of Nursing and Midwifery, Griffith University, Brisbane, Queensland 4111, Australia
- Menzies
Health Institute Queensland, Brisbane, Queensland 4222, Australia
| | - Michael Leitch
- School
of Nursing and Midwifery, Griffith University, Brisbane, Queensland 4111, Australia
| | - Pablo Guzman
- Queensland
Micro and Nanotechnology Centre, Griffith
University, Brisbane, Queensland 4111, Australia
| | - Toan Dinh
- Centre
for Future Materials, University of Southern
Queensland, Toowoomba, Queensland 4305, Australia
| | - Aditya Ashok
- Australian
Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Hieu Vu
- School
of Engineering and Built Environment, Griffith
University, Brisbane, Queensland 4215, Australia
| | - Van Dau
- School
of Engineering and Built Environment, Griffith
University, Brisbane, Queensland 4215, Australia
| | - Daniel Haasmann
- Queensland
Micro and Nanotechnology Centre, Griffith
University, Brisbane, Queensland 4111, Australia
| | - Lin Chen
- State
Key Laboratory for Mechanical Behavior of Materials, School of Materials
Science and Engineering, Xi’an Jiaotong
University, Xi’an 710049, Shaanxi, People’s Republic of China
| | - Yoonseok Park
- Querrey
Simpson Institute for Bioelectronics, Northwestern
University, Evanston, Illinois 60208, United States
- Department
of Advanced Materials Engineering for Information and Electronics, Kyung Hee University, Yongin 17104, Republic
of Korea
| | - Thanh Nho Do
- Graduate
School of Biomedical Engineering, The University
of New South Wales, Sydney, New South Wales 2032, Australia
| | - Yusuke Yamauchi
- Australian
Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Queensland 4072, Australia
- JST-ERATO
Yamauchi Materials Space-Tectonics Project, Kagami Memorial Research
Institute for Science and Technology, Waseda
University, Tokyo 169-0051, Japan
| | - John A. Rogers
- Querrey
Simpson Institute for Bioelectronics, Northwestern
University, Evanston, Illinois 60208, United States
- Department
of Materials Science and Engineering, Department of Mechanical Engineering,
Department of Biomedical Engineering, Departments of Electrical and
Computer Engineering and Chemistry, and Department of Neurological
Surgery, Northwestern University, Evanston, Illinois 60208, United States
| | - Nam-Trung Nguyen
- Queensland
Micro and Nanotechnology Centre, Griffith
University, Brisbane, Queensland 4111, Australia
| | - Hoang-Phuong Phan
- Queensland
Micro and Nanotechnology Centre, Griffith
University, Brisbane, Queensland 4111, Australia
- School
of Mechanical and Manufacturing Engineering, The University of New South Wales, Sydney, New South Wales 2052, Australia
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Comparisons between impedance-based and time-based switching bipolar radiofrequency ablation for the treatment of liver cancer. Comput Biol Med 2021; 134:104488. [PMID: 34020132 DOI: 10.1016/j.compbiomed.2021.104488] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 05/06/2021] [Accepted: 05/07/2021] [Indexed: 01/19/2023]
Abstract
Switching bipolar radiofrequency ablation (bRFA) is a cancer treatment technique that activates multiple pairs of electrodes alternately based on a predefined criterion. Various criteria can be used to trigger the switch, such as time (ablation duration) and tissue impedance. In a recent study on time-based switching bRFA, it was determined that a shorter switch interval could produce better treatment outcome than when a longer switch interval was used, which reduces tissue charring and roll-off induced cooling. In this study, it was hypothesized that a more efficacious bRFA treatment can be attained by employing impedance-based switching. This is because ablation per pair can be maximized since there will be no interruption to RF energy delivery until roll-off occurs. This was investigated using a two-compartment 3D computational model. Results showed that impedance-based switching bRFA outperformed time-based switching when the switch interval of the latter is 100 s or higher. When compared to the time-based switching with switch interval of 50 s, the impedance-based model is inferior. It remains to be investigated whether the impedance-based protocol is better than the time-based protocol for a switch interval of 50 s due to the inverse relationship between ablation and treatment efficacies. It was suggested that the choice of impedance-based or time-based switching could ultimately be patient-dependent.
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Tucci C, Trujillo M, Berjano E, Iasiello M, Andreozzi A, Vanoli GP. Pennes' bioheat equation vs. porous media approach in computer modeling of radiofrequency tumor ablation. Sci Rep 2021; 11:5272. [PMID: 33674658 PMCID: PMC7970869 DOI: 10.1038/s41598-021-84546-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 02/15/2021] [Indexed: 12/28/2022] Open
Abstract
The objective of this study was to compare three different heat transfer models for radiofrequency ablation of in vivo liver tissue using a cooled electrode and three different voltage levels. The comparison was between the simplest but less realistic Pennes' equation and two porous media-based models, i.e. the Local Thermal Non-Equilibrium (LTNE) equations and Local Thermal Equilibrium (LTE) equation, both modified to take into account two-phase water vaporization (tissue and blood). Different blood volume fractions in liver were considered and the blood velocity was modeled to simulate a vascular network. Governing equations with the appropriate boundary conditions were solved with Comsol Multiphysics finite-element code. The results in terms of coagulation transverse diameters and temperature distributions at the end of the application showed significant differences, especially between Pennes and the modified LTNE and LTE models. The new modified porous media-based models covered the ranges found in the few in vivo experimental studies in the literature and they were closer to the published results with similar in vivo protocol. The outcomes highlight the importance of considering the three models in the future in order to improve thermal ablation protocols and devices and adapt the model to different organs and patient profiles.
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Affiliation(s)
- Claudio Tucci
- Dipartimento Di Medicina E Scienze Della Salute "Vincenzo Tiberio", Università del Molise, Via Francesco De Sanctis 1, 86100, Campobasso, Italy.
| | - Macarena Trujillo
- BioMIT, Department of Applied Mathematics, Universitat Politècnica de València, 46022, Camino de Vera, Valencia, Spain
| | - Enrique Berjano
- BioMIT, Department of Electronic Engineering, Universitat Politècnica de València, 46022, Camino de Vera, Valencia, Spain
| | - Marcello Iasiello
- Dipartimento Di Ingegneria Industriale, Università Degli Studi Di Napoli Federico II, P.le Tecchio 80, 80125, Napoli, Italy
| | - Assunta Andreozzi
- Dipartimento Di Ingegneria Industriale, Università Degli Studi Di Napoli Federico II, P.le Tecchio 80, 80125, Napoli, Italy
| | - Giuseppe Peter Vanoli
- Dipartimento Di Medicina E Scienze Della Salute "Vincenzo Tiberio", Università del Molise, Via Francesco De Sanctis 1, 86100, Campobasso, Italy
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10
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Yap S, Ooi EH, Foo JJ, Ooi ET. Bipolar radiofrequency ablation treatment of liver cancer employing monopolar needles: A comprehensive investigation on the efficacy of time-based switching. Comput Biol Med 2021; 131:104273. [PMID: 33631495 DOI: 10.1016/j.compbiomed.2021.104273] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 02/09/2021] [Accepted: 02/10/2021] [Indexed: 12/16/2022]
Abstract
Radiofrequency ablation (RFA) is a thermal ablative treatment method that is commonly used to treat liver cancer. However, the thermal coagulation zone generated using the conventional RFA system can only successfully treat tumours up to 3 cm in diameter. Switching bipolar RFA has been proposed as a way to increase the thermal coagulation zone. Presently, the understanding of the underlying thermal processes that takes place during switching bipolar RFA remains limited. Hence, the objective of this study is to provide a comprehensive understanding on the thermal ablative effects of time-based switching bipolar RFA on liver tissue. Five switch intervals, namely 50, 100, 150, 200 and 300 s were investigated using a two-compartment 3D finite element model. The study was performed using two pairs of RF electrodes in a four-probe configuration, where the electrodes were alternated based on their respective switch interval. The physics employed in the present study were verified against experimental data from the literature. Results obtained show that using a shorter switch interval can improve the homogeneity of temperature distribution within the tissue and increase the rate of temperature rise by delaying the occurrence of roll-off. The coagulation volume obtained was the largest using switch interval of 50 s, followed by 100, 150, 200 and 300 s. The present study demonstrated that the transient thermal response of switching bipolar RFA can be improved by using shorter switch intervals.
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Affiliation(s)
- Shelley Yap
- School of Engineering, Monash University Malaysia, Jalan Lagoon Selatan, 47500 Bandar Sunway, Selangor, Malaysia
| | - Ean H Ooi
- School of Engineering, Monash University Malaysia, Jalan Lagoon Selatan, 47500 Bandar Sunway, Selangor, Malaysia; Advanced Engineering Platform, Monash University Malaysia, Jalan Lagoon Selatan, 47500 Bandar Sunway, Selangor, Malaysia.
| | - Ji J Foo
- School of Engineering, Monash University Malaysia, Jalan Lagoon Selatan, 47500 Bandar Sunway, Selangor, Malaysia
| | - Ean T Ooi
- School of Engineering and Information Technology, Faculty of Science and Technology, Federation University, VIC, 3350, Australia
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Parametric evaluation of impedance curve in radiofrequency ablation: A quantitative description of the asymmetry and dynamic variation of impedance in bovine ex vivo model. PLoS One 2021; 16:e0245145. [PMID: 33449951 PMCID: PMC7810295 DOI: 10.1371/journal.pone.0245145] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 12/22/2020] [Indexed: 01/03/2023] Open
Abstract
Radiofrequency ablation (RFA) is a treatment for liver tumors with advantages over the traditional treatment of surgical resection. This procedure has the shortest recovery time in early stage tumors. The objective of this study is to parameterize the impedance curve of the RFA procedure in an ex vivo model by defining seven parameters (t1/2, tminimum, tend, Zinitial, Z1/2, Zminimum and Zend). Based on these parameters, three performance indices are defined: one to identify the magnitude of impedance curve asymmetry (δ), one Drop ratio (DR) describing the percentage of impedance decrease until the minimum impedance point is reached, and Ascent Ratio (AR) describing the magnitude of increase in impedance from the minimum impedance point to its maximum point. Fifty ablations were performed in a bovine ex vivo model to measure and evaluate the proposed parameters and performance index. The results show that the groups had an average δ of 29.02%, DR of 22.41%, and AR of 545.33% for RFA without the use of saline or deionized solutions. The saline solution and deionized water-cooled groups indicated the correlation of performance indices δ, DR, and AR with the obtained final ablation volume. Therefore, by controlling these parameters and indices, lower recurrence is achieved.
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Castro-López DL, Berjano E, Romero-Mendez R. Radiofrequency ablation combined with conductive fluid-based dopants (saline normal and colloidal gold): computer modeling and ex vivo experiments. Biomed Eng Online 2021; 20:4. [PMID: 33407532 PMCID: PMC7788784 DOI: 10.1186/s12938-020-00842-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 12/15/2020] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND The volume of the coagulation zones created during radiofrequency ablation (RFA) is limited by the appearance of roll-off. Doping the tissue with conductive fluids, e.g., gold nanoparticles (AuNPs) could enlarge these zones by delaying roll-off. Our goal was to characterize the electrical conductivity of a substrate doped with AuNPs in a computer modeling study and ex vivo experiments to investigate their effect on coagulation zone volumes. METHODS The electrical conductivity of substrates doped with normal saline or AuNPs was assessed experimentally on agar phantoms. The computer models, built and solved on COMSOL Multiphysics, consisted of a cylindrical domain mimicking liver tissue and a spherical domain mimicking a doped zone with 2, 3 and 4 cm diameters. Ex vivo experiments were conducted on bovine liver fragments under three different conditions: non-doped tissue (ND Group), 2 mL of 0.9% NaCl (NaCl Group), and 2 mL of AuNPs 0.1 wt% (AuNPs Group). RESULTS The theoretical analysis showed that adding normal saline or colloidal gold in concentrations lower than 10% only modifies the electrical conductivity of the doped substrate with practically no change in the thermal characteristics. The computer results showed a relationship between doped zone size and electrode length regarding the created coagulation zone. There was good agreement between the ex vivo and computational results in terms of transverse diameter of the coagulation zone. CONCLUSIONS Both the computer and ex vivo experiments showed that doping with AuNPs can enlarge the coagulation zone, especially the transverse diameter and hence enhance sphericity.
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Affiliation(s)
- Dora Luz Castro-López
- Facultad de Ingeniería, Universidad Autónoma de San Luis Potosí, San Luis Potosí, SLP 78290, México
| | - Enrique Berjano
- BioMIT, Department of Electronic Engineering, Universitat Politècnica de València, 46018, Valencia, Spain
| | - Ricardo Romero-Mendez
- Facultad de Ingeniería, Universidad Autónoma de San Luis Potosí, San Luis Potosí, SLP 78290, México.
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Deng H, Zhang T, Jiang X, Huang S, Jiang NN, Lau WY, Jinhua H. Comparison of hydrochloric acid infusion radiofrequency ablation with microwave ablation in an ex vivo liver model. Int J Hyperthermia 2020; 37:600-607. [PMID: 32484363 DOI: 10.1080/02656736.2020.1772995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
Objectives: To compare sizes and shapes of ablation zones resulting from hydrochloric acid infusion radiofrequency ablation (HRFA) and microwave ablation (MWA), using normal saline infusion radiofrequency ablation (NSRFA) as a control, at a variety of matched power settings and ablation durations, in an ex vivo bovine liver model.Methods: A total of 90 ablation procedures were performed, using each of three modalities: NSRFA, HRFA, and MWA. For each modality, five ablation procedures were performed for each combination of power (80 W, 100 W, or 120 W) and duration (5, 10, 20, 30, 45, or 60 min). The size of ablation zones were compared using ANOVA, the Kruskal-Wallis test, or generalized linear regression.Results: For ablation durations up to 30 min, mean transverse diameter (TD) after HRFA and MWA did not differ significantly (β = 0.13, p = .20). For ablation durations greater than 30 min, mean TD was significantly larger after HRFA than after MWA (β = 1.657, p < .001). The largest TD (9.46 cm) resulted from HRFA performed with 100 W power for 60 min.Conclusions: Compared to MWA, monopolar HRFA with power settings of 80 W-120 W and durations of less than 30 min showed no significant difference. When duration of more than 30 min, HRFA created larger ablation zones than MWA.
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Affiliation(s)
- Hanxia Deng
- Department of Minimally Invasive Interventional Radiology, Sun Yat-sen University Cancer Center, Guangzhou, China.,State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China
| | - Tianqi Zhang
- Department of Minimally Invasive Interventional Radiology, Sun Yat-sen University Cancer Center, Guangzhou, China.,State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China
| | - Xiongying Jiang
- Department of Interventional Radiology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Senmiao Huang
- Department of Oncology, Panyu Central Hospital, Guangzhou, People's Republic of China
| | - Nan Nancy Jiang
- Department of Diagnostic Radiology, Hamilton Health Sciences, McMaster University, Hamilton, Canada
| | - Wan-Yee Lau
- Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong Special Administrative Region, Hong Kong, PR China
| | - Huang Jinhua
- Department of Minimally Invasive Interventional Radiology, Sun Yat-sen University Cancer Center, Guangzhou, China.,State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China
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Cheong JKK, Yap S, Ooi ET, Ooi EH. A computational model to investigate the influence of electrode lengths on the single probe bipolar radiofrequency ablation of the liver. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2019; 176:17-32. [PMID: 31200904 DOI: 10.1016/j.cmpb.2019.04.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 04/14/2019] [Accepted: 04/25/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND AND OBJECTIVES Recently, there have been calls for RFA to be implemented in the bipolar mode for cancer treatment due to the benefits it offers over the monopolar mode. These include the ability to prevent skin burns at the grounding pad and to avoid tumour track seeding. The usage of bipolar RFA in clinical practice remains uncommon however, as not many research studies have been carried out on bipolar RFA. As such, there is still uncertainty in understanding the effects of the different RF probe configurations on the treatment outcome of RFA. This paper demonstrates that the electrode lengths have a strong influence on the mechanics of bipolar RFA. The information obtained here may lead to further optimization of the system for subsequent uses in the hospitals. METHODS A 2D model in the axisymmetric coordinates was developed to simulate the electro-thermophysiological responses of the tissue during a single probe bipolar RFA. Two different probe configurations were considered, namely the configuration where the active electrode is longer than the ground and the configuration where the ground electrode is longer than the active. The mathematical model was first verified with an existing experimental study found in the literature. RESULTS Results from the simulations showed that heating is confined only to the region around the shorter electrode, regardless of whether the shorter electrode is the active or the ground. Consequently, thermal coagulation also occurs in the region surrounding the shorter electrode. This opened up the possibility for a better customized treatment through the development of RF probes with adjustable electrode lengths. CONCLUSIONS The electrode length was found to play a significant role on the outcome of single probe bipolar RFA. In particular, the length of the shorter electrode becomes the limiting factor that influences the mechanics of single probe bipolar RFA. Results from this study can be used to further develop and optimize bipolar RFA as an effective and reliable cancer treatment technique.
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Affiliation(s)
- Jason K K Cheong
- School of Engineering, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway 47500, Selangor, Malaysia
| | - Shelley Yap
- School of Engineering, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway 47500, Selangor, Malaysia
| | - Ean T Ooi
- School of Engineering and Information Technology, Faculty of Science and Technology, Federation University, VIC 3350, Australia
| | - Ean H Ooi
- School of Engineering, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway 47500, Selangor, Malaysia; Advanced Engineering Platform, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway 47500, Selangor, Malaysia.
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15
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Ooi EH, Lee KW, Yap S, Khattab MA, Liao IY, Ooi ET, Foo JJ, Nair SR, Mohd Ali AF. The effects of electrical and thermal boundary condition on the simulation of radiofrequency ablation of liver cancer for tumours located near to the liver boundary. Comput Biol Med 2019; 106:12-23. [DOI: 10.1016/j.compbiomed.2019.01.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 01/04/2019] [Accepted: 01/05/2019] [Indexed: 01/12/2023]
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da Fonseca RD, Monteiro MS, Marques MP, Motta BC, Guimaraes GDA, do Santos PR, Jacobi RP, Rosa SDSRF. Roll-Off Displacement in Ex Vivo Experiments of RF Ablation With Refrigerated Saline Solution and Refrigerated Deionized Water. IEEE Trans Biomed Eng 2018; 66:1390-1401. [PMID: 30281435 DOI: 10.1109/tbme.2018.2873141] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE The recurrence rate in the treatment of liver tumors using radio frequency ablation (RFA) is often related to incomplete tissue necrosis and consequently the limitation in the ablation volume. This paper proposes an ablation protocol combined with the infusion of saline solution and deionized water aiming at achieving a time displacement in the roll-off occurrence and consequently increasing the volume of ablation. METHODS An infusion of saline solution and deionized water at 5 and 23 °C was performed to evaluate the influence of these liquids on the RFA procedure in ex vivo bovine liver pieces. The obtained results were used to propose a mathematical model of the roll-off phenomenon by means of the system identification techniques. RESULTS The RFA combined with the infusion of saline solution 0.9% at 5 °C presented optimal results, with a time delay of the roll-off occurrence in 27.8% compared to pure RFA ( p = 0.002) and an increase in the necrotic volume of 51.2% ( p = 0.0002). Two Box-Jenkins models were obtained to describe the roll-off phenomenon: 1) pure RFA; and 2) RFA combined with the saline solution 0.9% at 5 °C. CONCLUSION The RFA therapy combined with the saline solution 0.9% at 5 °C increases the time range to the roll-off occurrence, leading to higher necrosis volumes in ex vivo bovine liver samples. The development of a mathematical model to describe the roll-off behavior demonstrated that the transient response is improved by the infusion of the saline solution 0.9% at 5 °C.
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Jiang XY, Zhang TQ, Li G, Gu YK, Gao F, Yao W, Zhang YY, Huang JH. Increasing radiofrequency ablation volumes with the use of internally cooled electrodes and injected hydrochloric acid in ex vivo bovine livers. Int J Hyperthermia 2018; 35:37-43. [PMID: 29807444 DOI: 10.1080/02656736.2018.1472305] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
PURPOSE We used an impedance-controlled generator with an internally cooled electrode to perform radiofrequency ablation (RFA) in ex vivo bovine livers, with a single injection of either 38.5% sodium chloride (NaCl) or 10% hydrochloric acid (HCl), to determine the relative effects of these two solutions on tissue impedance, temperature and ablation volume. MATERIALS AND METHODS We performed 10 ablations each with injections of NaCl (NaCl-RFA), HCl (HCl-RFA) or nothing (RFA-alone), with a power setting of 200 W for 15 minutes. We recorded tissue impedance before and after injection. We logged temperatures obtained from thermocouple probes positioned 5, 10, 15 and 20 mm from the internally cooled RF electrode. After ablation, we measured ablation zone longitudinal and transverse diameters, and we calculated a spherical ratio (SR) for each ablation. RESULTS Mean post-injection impedance of 30.3 (standard deviation [SD] 2.5) ohms for HCl was significantly lower than that of 55.4 (SD 3.5) ohms for NaCl (p < .001). Mean maximum temperatures recorded at each respective distance from the RFA electrode were all highest for HCl-RFA and lowest for RFA-alone (p < .001). Mean longitudinal and transverse diameters after HCl-RFA (5.50 [SD 0.25] cm and 5.28 [SD 0.22] cm, respectively) were significantly larger than those after NaCl-RFA (4.24 [SD 0.35] cm and 3.55 [SD 0.43] cm, respectively) and after RFA-alone (3.60 [SD 0.10] cm and 2.70 [SD 0.13] cm, respectively) (p < .001). Mean SR after HCl-RFA (0.93, SD 0.02) was significantly higher than mean SR after NaCl-RFA (0.76, SD 0.06) and RFA-alone (0.72, SD 0.04) (p < .001). CONCLUSION Monopolar, impedance-controlled RFA, with an internally cooled electrode and a single 10% HCl injection may allow larger tumors to be treated, potentially resulting in improved patient outcomes.
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Affiliation(s)
- Xiong-Ying Jiang
- a Department of Minimally Invasive Interventional Radiology , Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine , Guangzhou , P. R. China.,b Department of Interventional Radiology , Sun Yat-sen Memorial Hospital, Sun Yat-sen University , Guangzhou , Guangdong , P. R. China
| | - Tian-Qi Zhang
- a Department of Minimally Invasive Interventional Radiology , Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine , Guangzhou , P. R. China
| | - Guo Li
- c Department of Radiotherapy , Cancer Center of Guangzhou Medical University , Guangzhou , Guangdong , P. R. China
| | - Yang-Kui Gu
- a Department of Minimally Invasive Interventional Radiology , Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine , Guangzhou , P. R. China
| | - Fei Gao
- a Department of Minimally Invasive Interventional Radiology , Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine , Guangzhou , P. R. China
| | - Wang Yao
- a Department of Minimally Invasive Interventional Radiology , Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine , Guangzhou , P. R. China.,d Department of Interventional Oncology , Sun Yat-sen University First Affiliated Hospital , Guangzhou , P. R. China
| | - Yan-Yang Zhang
- a Department of Minimally Invasive Interventional Radiology , Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine , Guangzhou , P. R. China.,e Department of Interventional Radiology , Sun Yat-sen University Third Affiliated Hospital , Guangzhou , P. R. China
| | - Jin-Hua Huang
- a Department of Minimally Invasive Interventional Radiology , Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine , Guangzhou , P. R. China
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18
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Trujillo M, Bon J, Berjano E. Computational modelling of internally cooled wet (ICW) electrodes for radiofrequency ablation: impact of rehydration, thermal convection and electrical conductivity. Int J Hyperthermia 2017; 33:624-634. [DOI: 10.1080/02656736.2017.1303751] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Affiliation(s)
- Macarena Trujillo
- Biomedical Synergy, Department of Applied Mathematics, Universitat Politècnica de València, Valencia, Spain
| | - Jose Bon
- Food Technology Department, Universitat Politècnica de València, Valencia, Spain
| | - Enrique Berjano
- Biomedical Synergy, Department of Electronic Engineering, Universitat Politècnica de València, Valencia, Spain
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19
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Zhang B, Moser MAJ, Zhang EM, Luo Y, Zhang W. A new approach to feedback control of radiofrequency ablation systems for large coagulation zones. Int J Hyperthermia 2016; 33:367-377. [DOI: 10.1080/02656736.2016.1263365] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Affiliation(s)
- Bing Zhang
- CISR Lab, East China University of Science and Technology, Shanghai, China
- Division of Biomedical Engineering, University of Saskatchewan, Saskatoon, Canada
| | | | - Edwin M. Zhang
- Division of Vascular & Interventional Radiology, Department of Medical Imaging, University of Toronto, Toronto, Canada
| | - Yigang Luo
- Department of Surgery, University of Saskatchewan, Saskatoon, Canada
| | - Wenjun Zhang
- CISR Lab, East China University of Science and Technology, Shanghai, China
- Division of Biomedical Engineering, University of Saskatchewan, Saskatoon, Canada
- Department of Mechanical Engineering, University of Saskatchewan, Saskatoon, Canada
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20
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A review of radiofrequency ablation: Large target tissue necrosis and mathematical modelling. Phys Med 2016; 32:961-71. [PMID: 27461969 DOI: 10.1016/j.ejmp.2016.07.092] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2015] [Revised: 06/06/2016] [Accepted: 07/18/2016] [Indexed: 12/15/2022] Open
Abstract
Radiofrequency ablation (RFA) is an effective clinical method for tumour ablation with minimum intrusiveness. However, the use of RFA is mostly restricted to small tumours, especially those <3cm in diameter. This paper discusses the state-of-the-art of RFA, drawn from experimental and clinical results, for large tumours (i.e. ⩾3cm in diameter). In particular, the paper analyses clinical results related to target tissue necrosis (TTN) and mathematical modelling of the RFA procedure to understand the mechanism whereby the TTN is limited to under 3cm with RFA. This paper also discusses a strategy of controlling of the temperature of target tissue in the RFA procedure with the state-of-art device, which has the potential to increase the size of TTN. This paper ends with a discussion of some future ideas to solve the so-called 3-cm problem with RFA.
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Trujillo M, Bon J, José Rivera M, Burdío F, Berjano E. Computer modelling of an impedance-controlled pulsing protocol for RF tumour ablation with a cooled electrode. Int J Hyperthermia 2016; 32:931-939. [PMID: 27452352 DOI: 10.1080/02656736.2016.1190868] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
PURPOSE To develop computer models to mimic the impedance-controlled pulsing protocol implemented in radiofrequency (RF) generators used for clinical practice of radiofrequency ablation (RFA), and to assess the appropriateness of the models by comparing the computer results with those obtained in previous experimental studies. METHODS A 12-min RFA was modelled using a cooled electrode (17G, 3 cm tip) inserted in hepatic tissue. The short (transverse) diameter of the coagulation zone was assessed under in vivo (with blood perfusion (BP) and considering clamping) and ex vivo (at 21 °C) conditions. The computer results obtained by programming voltage pulses were compared with current pulses. RESULTS The differences between voltage and current pulses were noticeable: using current instead of voltage allows larger coagulation zones to be created, due to the higher energy applied by current pulses. If voltage pulses are employed the model can accurately predict the number of roll-offs, although the waveform of the applied power is clearly not realistic. If current voltages are employed, the applied power waveform matches well with those reported experimentally, but there are significantly fewer roll-offs. Our computer results were overall into the ranges of experimental ones. CONCLUSIONS The proposed models reproduce reasonably well the electrical-thermal performance and coagulation zone size obtained during an impedance-controlled pulsing protocol.
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Affiliation(s)
- Macarena Trujillo
- a Instituto Universitario de Matemática Pura y Aplicada, Universitat Politècnica de València , Spain
| | - Jose Bon
- b Food Technology Department , Universitat Politècnica de València , Spain
| | - María José Rivera
- c Applied Mathematics Department , Universitat Politècnica de València , Spain
| | - Fernando Burdío
- d Department of Surgery , Hospital del Mar , Barcelona , Spain
| | - Enrique Berjano
- e Biomedical Synergy, Department of Electronic Engineering , Universitat Politècnica de València , Spain
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Lopez Molina JA, Rivera MJ, Berjano E. Electrical-thermal analytical modeling of monopolar RF thermal ablation of biological tissues: determining the circumstances under which tissue temperature reaches a steady state. MATHEMATICAL BIOSCIENCES AND ENGINEERING : MBE 2016; 13:281-301. [PMID: 27105984 DOI: 10.3934/mbe.2015003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
It has been suggested that during RF thermal ablation of biological tissue the thermal lesion could reach an equilibrium size after 1-2 minutes. Our objective was to determine under which circumstances of electrode geometry (needle-like vs. ball-tip), electrode type (dry vs. cooled) and blood perfusion the temperature will reach a steady state at any point in the tissue. We solved the bioheat equation analytically both in cylindrical and spherical coordinates and the resultant limit temperatures were compared. Our results demonstrate mathematically that tissue temperature reaches a steady value in all cases except for cylindrical coordinates without the blood perfusion term, both for dry and cooled electrodes, where temperature increases infinitely. This result is only true when the boundary condition far from the active electrode is considered to be at infinitum. In contrast, when a finite and sufficiently large domain is considered, temperature reaches always a steady state.
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Affiliation(s)
- J A Lopez Molina
- Applied Mathematics Department, Universitat Politècnica de València, Camino de Vera 46022 Valencia, Spain.
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Romão J, Mul G. Substrate Specificity in Photocatalytic Degradation of Mixtures of Organic Contaminants in Water. ACS Catal 2016. [DOI: 10.1021/acscatal.5b02015] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Joana Romão
- Photocatalytic Synthesis
Group, MESA+ Institute for Nanotechnology, Faculty of Science and
Technology, University of Twente, Meander 229, P.O.
Box 217, 7500 AE Enschede, The Netherlands
| | - Guido Mul
- Photocatalytic Synthesis
Group, MESA+ Institute for Nanotechnology, Faculty of Science and
Technology, University of Twente, Meander 229, P.O.
Box 217, 7500 AE Enschede, The Netherlands
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Zhang B, Moser MAJ, Zhang EM, Luo Y, Zhang W. Numerical analysis of the relationship between the area of target tissue necrosis and the size of target tissue in liver tumours with pulsed radiofrequency ablation. Int J Hyperthermia 2015; 31:715-25. [PMID: 26360111 DOI: 10.3109/02656736.2015.1058429] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
PURPOSE Radiofrequency ablation (RFA) is currently restricted to the treatment of target tissues with a small size (<3 cm in diameter). To overcome this problem with RFA, some phenomena need to be understood first. The study presented in this paper investigated the relationship between the area of target tissue necrosis (TTN) and the size of target tissue in pulsed radiofrequency ablation (PRFA). MATERIALS AND METHODS Liver tumour, one of the common targets of RFA in clinical practice, was used as the target tissue in this study. Two types of pulsed RF power supply methods (half-square and half-sine) and three target tissues with different sizes (25 mm, 30 mm and 35 mm in diameter) were studied using finite element modelling. The finite element model (FEM) was validated by using an in vitro experiment with porcine liver tissue. The first roll-off occurrence or 720 s, whichever occurs first, was chosen as the ablation termination criterion in this study. RESULTS For each target tissue size, the largest TTN area was obtained using the maximum voltage applied (MVA) without roll-off occurrence. In this study, target tissues with a 25 mm diameter can be ablated cleanly but target tissues with 30-mm and 35-mm failed to be ablated. CONCLUSIONS The half-square PRFA could achieve a larger TTN area than the half-sine PRFA. The MVA decreases with an increase in the target tissue diameter in both the half-square PRFA and the half-sine PRFA. The findings of this study are in agreement with the clinical results that lesions (≥ 3 cm in diameter) have less favourable results from RFA.
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Affiliation(s)
- Bing Zhang
- a Division of Biomedical Engineering , University of Saskatchewan , Saskatoon , Canada
| | - Michael A J Moser
- b Department of Surgery , University of Saskatchewan , Saskatoon , Canada
| | - Edwin M Zhang
- c Department of Radiology and Diagnostic Imaging , University of Alberta , Edmonton , Canada
| | - Yigang Luo
- b Department of Surgery , University of Saskatchewan , Saskatoon , Canada
| | - Wenjun Zhang
- a Division of Biomedical Engineering , University of Saskatchewan , Saskatoon , Canada .,d Complex and Intelligent Systems Centre, School of Mechanical and Power Engineering, East China University of Science and Technology , Shanghai , China , and.,e Department of Mechanical Engineering , University of Saskatchewan , Saskatoon , Saskatchewan , Canada
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25
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Zhang B, Moser MAJ, Zhang EM, Luo Y, Zhang H, Zhang W. Study of the relationship between the target tissue necrosis volume and the target tissue size in liver tumours using two-compartment finite element RFA modelling. Int J Hyperthermia 2015; 30:593-602. [PMID: 25430990 DOI: 10.3109/02656736.2014.984000] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
PURPOSE The aim of this study was to investigate the relationship between the target tissue necrosis volume and the target tissue size during the radiofrequency ablation (RFA) procedure. MATERIALS AND METHODS The target tissues with four different sizes (dxy = 20, 25, 30 and 35 mm) were modelled using a two-compartment radiofrequency ablation model. Different voltages were applied to seek the maximum target tissue necrosis volume for each target tissue size. The first roll-off occurrence or the standard ablation time (12 min) was taken as the sign for the termination of the RFA procedure. RESULTS Four different maximum voltages without the roll-off occurrence were found for the four different sizes of target tissues (dxy = 20, 25, 30 and 35 mm), and they were 36.6, 35.4, 33.9 and 32.5 V, respectively. The target tissues with diameters of 20, 25 mm can be cleanly ablated at their own maximum voltages applied (MVA) but the same finding was not found for the 35-mm target tissue. For the target tissue with diameter of 30 mm, the 50 °C isothermal contour (IT50) result showed that the target tissue can be cleanly ablated, but the same result did not show in the Arrhenius damage model result. Furthermore, two optimal RFA protocols with a minimal thermal damage to the healthy tissues were found for the target tissues with diameters of 20 and 25 mm, respectively. CONCLUSIONS The study suggests that target tissues of different sizes should be treated with different RFA protocols. The maximum target tissue volume was achieved with the MVA without the roll-off occurrence for each target tissue size when a constant RF power supply was used.
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Affiliation(s)
- Bing Zhang
- Complex and Intelligent Systems Centre, School of Mechanical and Power Engineering, East China University Science and Technology , Shanghai , China
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Hall SK, Ooi EH, Payne SJ. Cell death, perfusion and electrical parameters are critical in models of hepatic radiofrequency ablation. Int J Hyperthermia 2015; 31:538-50. [PMID: 26000972 PMCID: PMC4776731 DOI: 10.3109/02656736.2015.1032370] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Purpose: A sensitivity analysis has been performed on a mathematical model of radiofrequency ablation (RFA) in the liver. The purpose of this is to identify the most important parameters in the model, defined as those that produce the largest changes in the prediction. This is important in understanding the role of uncertainty and when comparing the model predictions to experimental data. Materials and methods: The Morris method was chosen to perform the sensitivity analysis because it is ideal for models with many parameters or that take a significant length of time to obtain solutions. A comprehensive literature review was performed to obtain ranges over which the model parameters are expected to vary, crucial input information. Results: The most important parameters in predicting the ablation zone size in our model of RFA are those representing the blood perfusion, electrical conductivity and the cell death model. The size of the 50 °C isotherm is sensitive to the electrical properties of tissue while the heat source is active, and to the thermal parameters during cooling. Conclusions: The parameter ranges chosen for the sensitivity analysis are believed to represent all that is currently known about their values in combination. The Morris method is able to compute global parameter sensitivities taking into account the interaction of all parameters, something that has not been done before. Research is needed to better understand the uncertainties in the cell death, electrical conductivity and perfusion models, but the other parameters are only of second order, providing a significant simplification.
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Affiliation(s)
- Sheldon K Hall
- Institute of Biomedical Engineering, University of Oxford , UK and
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Tosi D, Macchi EG, Braschi G, Cigada A, Gallati M, Rossi S, Poeggel S, Leen G, Lewis E. Fiber-optic combined FPI/FBG sensors for monitoring of radiofrequency thermal ablation of liver tumors: ex vivo experiments. APPLIED OPTICS 2014; 53:2136-2144. [PMID: 24787172 DOI: 10.1364/ao.53.002136] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 02/25/2014] [Indexed: 06/03/2023]
Abstract
We present a biocompatible, all-glass, 0.2 mm diameter, fiber-optic probe that combines an extrinsic Fabry-Perot interferometry and a proximal fiber Bragg grating sensor; the probe enables dual pressure and temperature measurement on an active 4 mm length, with 40 Pa and 0.2°C nominal accuracy. The sensing system has been applied to monitor online the radiofrequency thermal ablation of tumors in liver tissue. Preliminary experiments have been performed in a reference chamber with uniform heating; further experiments have been carried out on ex vivo porcine liver, which allowed the measurement of a steep temperature gradient and monitoring of the local pressure increase during the ablation procedure.
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Zhu Q, Shen Y, Zhang A, Xu LX. Numerical study of the influence of water evaporation on radiofrequency ablation. Biomed Eng Online 2013; 12:127. [PMID: 24325296 PMCID: PMC3904760 DOI: 10.1186/1475-925x-12-127] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 11/26/2013] [Indexed: 01/30/2023] Open
Abstract
Background Radiofrequency ablation is a promising minimal invasive treatment for tumor. However, water loss due to evaporation has been a major issue blocking further RF energy transmission and correspondently eliminating the therapeutic outcome of the treatment. Method A 2D symmetric cylindrical mathematical model coupling the transport of the electrical current, heat, and the evaporation process in the tissue, has been developed to simulate the treatment process and investigate the influence of the excessive evaporation of the water on the treatment. Results Our results show that the largest specific absorption rate (QSAR) occurs at the edge of the circular surface of the electrode. When excessive evaporation takes place, the water dehydration rate in this region is the highest, and after a certain time, the dehydrated tissue blocks the electrical energy transmission in the radial direction. It is found that there is an interval as long as 65 s between the beginning of the evaporation and the increase of the tissue impedance. The model is further used to investigate whether purposely terminating the treatment for a while allowing diffusion of the liquid water into the evaporated region would help. Results show it has no obvious improvement enlarging the treatment volume. Treatment with the cooled-tip electrode is also studied. It is found that the cooling conditions of the inside agent greatly affect the water loss pattern. When the convection coefficient of the cooling agent increases, excessive evaporation will start from near the central axis of the tissue cylinder instead of the edge of the electrode, and the coagulation volume obviously enlarges before a sudden increase of the impedance. It is also found that a higher convection coefficient will extend the treatment time. Though the sudden increase of the tissue impedance could be delayed by a larger convection coefficient; the rate of the impedance increase is also more dramatic compared to the case with smaller convection coefficient. Conclusion The mathematical model simulates the water evaporation and diffusion during radiofrequency ablation and may be used for better clinical design of radiofrequency equipment and treatment protocol planning.
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Affiliation(s)
| | | | - Aili Zhang
- State Key Laboratory of Oncogenes and Related Genes, School of Biomedical Engineering, Med-X Research Institute, Shanghai Jiao Tong University, Shanghai, China.
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Trujillo M, Berjano E. Review of the mathematical functions used to model the temperature dependence of electrical and thermal conductivities of biological tissue in radiofrequency ablation. Int J Hyperthermia 2013; 29:590-7. [PMID: 23841882 DOI: 10.3109/02656736.2013.807438] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
PURPOSE Although theoretical modelling is widely used to study different aspects of radiofrequency ablation (RFA), its utility is directly related to its realism. An important factor in this realism is the use of mathematical functions to model the temperature dependence of thermal (k) and electrical (σ) conductivities of tissue. Our aim was to review the piecewise mathematical functions most commonly used for modelling the temperature dependence of k and σ in RFA computational modelling. MATERIALS AND METHODS We built a hepatic RFA theoretical model of a cooled electrode and compared lesion dimensions and impedance evolution with combinations of mathematical functions proposed in previous studies. We employed the thermal damage contour D63 to compute the lesion dimension contour, which corresponds to Ω = 1, Ω being local thermal damage assessed by the Arrhenius damage model. RESULTS The results were very similar in all cases in terms of impedance evolution and lesion size after 6 min of ablation. Although the relative differences between cases in terms of time to first roll-off (abrupt increase in impedance) were as much as 12%, the maximum relative differences in terms of the short lesion (transverse) diameter were below 3.5%. CONCLUSIONS The findings suggest that the different methods of modelling temperature dependence of k and σ reported in the literature do not significantly affect the computed lesion diameter.
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Affiliation(s)
- Macarena Trujillo
- Instituto Universitario de Matemática Pura y Aplicada, Universitat Politècnica de València, Spain.
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Trujillo M, Castellví Q, Burdío F, Sánchez Velazquez P, Ivorra A, Andaluz A, Berjano E. Can electroporation previous to radiofrequency hepatic ablation enlarge thermal lesion size? A feasibility study based on theoretical modelling andin vivoexperiments. Int J Hyperthermia 2013; 29:211-8. [DOI: 10.3109/02656736.2013.777854] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
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