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Cho SB, Kang SY, Lee Y, Choi M, Kim B, Ahn J. Effect of sequential delivery of 1- and 2-MHz bipolar microneedling radiofrequency energy on thermal tissue reactions in a minipig model. Skin Res Technol 2024; 30:e13898. [PMID: 39213160 PMCID: PMC11363911 DOI: 10.1111/srt.13898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2024] [Accepted: 07/15/2024] [Indexed: 09/04/2024]
Abstract
BACKGROUND Bipolar microneedling radiofrequency (RF) treatment generates different patterns of thermal reactions, depending on the skin impedance and RF treatment parameters, including the frequency, power, conduction time, settings of sub-pulse packs, and penetrating depth and type of microneedles used. We compared the effect of sequential delivery of 1- and 2-MHz bipolar RF energy to in vivo minipig skin on thermal tissue reaction. METHODS RF treatments at frequencies of 1 and 2 MHz were sequentially delivered to minipigs' skin in vivo. A histological study was performed to analyze RF-induced skin reactions at 1-h and at 3-, 7-, and 14-days post-treatment. RESULTS The skin specimens demonstrated that the two different frequencies of RF treatment generated mixed patterns of the peri-electrode coagulative necrosis (PECN) according to the experimental settings and tissue impedance. In the PECN zone, the tissue coagulation induced by the first RF treatment was surrounded by the effect of the later RF treatment at the other RF frequency. In the inter-electrode non-necrotic thermal reaction zone, the effect of the latter RF treatment was widespread and deep through the dermis, which had received RF treatment at the other frequency first. The delivery of pulsed-type RF energy at sub-pulse packs of 6 or 10 provided effective RF delivery over long conduction time without excessive thermal damage of the epidermis. Nonetheless, by sequential delivery of two different RF frequencies, RF-induced tissue reactions were found to be markedly enhanced. CONCLUSION The sequential delivery of 1- and 2-MHz RF energy induces novel histological patterns of tissue reactions, which can synergistically enhance the thermostimulatory effects of each RF setting. Moreover, variations in patterns of tissue reactions can be generated by regulating the order of frequencies and the number of sub-pulse packs of RF used.
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Affiliation(s)
- Sung Bin Cho
- Yonsei Seran Dermatology and Laser ClinicSeoulSouth Korea
| | | | - Yea‐Jin Lee
- Medical Laser Research CenterCollege of MedicineDankook UniversityCheonanSouth Korea
| | - Min Choi
- R&D CenterShenb Co., LtdSeoulSouth Korea
| | - Bora Kim
- R&D CenterShenb Co., LtdSeoulSouth Korea
| | - Jin‐Chul Ahn
- Medical Laser Research CenterCollege of MedicineDankook UniversityCheonanSouth Korea
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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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Cho SB, Lee YJ, Kang SY, Choi M, Kim B, Ahn JC. Effects of Parallel Contact Cooling on Pulsed-Type, Bipolar Radiofrequency-Induced Tissue Reactions in an in vivo Porcine Model. Clin Cosmet Investig Dermatol 2024; 17:125-135. [PMID: 38259431 PMCID: PMC10802173 DOI: 10.2147/ccid.s446814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 01/16/2024] [Indexed: 01/24/2024]
Abstract
Background Skin cooling during laser or radiofrequency (RF) treatments is a method to minimize thermal damage to the epidermis, reduce pain, and decrease post-treatment downtime. We evaluated the effect of parallel contact cooling (PCC) on RF-induced thermal reactions in minipig skin in vivo after bipolar microneedling RF treatment. Methods RF treatments were administered at frequencies of 0.5, 1, and 2 MHz with single (500 ms), six (1000 ms), and ten (5000 ms) sub-pulse packs to minipig skin with or without PCC. Subsequently, thermometric imaging and histology were used to analyze skin reactions to RF. Results Thermometric images showed that PCC promptly lowered skin temperature in the RF-treated area, with this effect persisting for over 60s. Regardless of the PCC, RF treatments lasting for 500 ms with a single pulse pack resulted in peri-electrode coagulative necrosis (PECN) zones and inter-electrode non-necrotic thermal reaction (IENT) zones in the dermis. In contrast, treatment lasting 5000 ms with 10 sub-pulse packs produced distinct IENT without notable PECN over a wide dermal area. Skin specimens obtained at 1 h and 3, 7, and 14 days after PCC-assisted RF treatments showed a higher degree of thermal tissue reactions in the deeper dermal regions compared to those after RF treatments without PCC. Conclusion PCC-assisted RF treatment, utilizing an invasive bipolar microneedling device, enhanced RF-induced skin reactions in the mid to deep dermis while preserving the epidermis and upper papillary dermis from excessive thermal tissue injury.
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Affiliation(s)
- Sung Bin Cho
- Yonsei Seran Dermatology and Laser Clinic, Seoul, Korea
| | - Yea-Jin Lee
- Medical Laser Research Center, College of Medicine, Dankook University, Cheonan, Korea
| | | | - Min Choi
- R&D Center, Shenb Co., Ltd, Seoul, Korea
| | - Bora Kim
- R&D Center, Shenb Co., Ltd, Seoul, Korea
| | - Jin-Chul Ahn
- Medical Laser Research Center, College of Medicine, Dankook University, Cheonan, Korea
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Dong SC, Bai DS, Wang FA, Jin SJ, Zhang C, Zhou BH, Jiang GQ. Radiofrequency ablation is an inferior option to liver resection for solitary hepatocellular carcinoma ≤ 5 cm without cirrhosis: A population-based study with stratification by tumor size. Hepatobiliary Pancreat Dis Int 2023; 22:605-614. [PMID: 35977873 DOI: 10.1016/j.hbpd.2022.08.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 08/01/2022] [Indexed: 02/05/2023]
Abstract
BACKGROUND About 10%-20% of all individuals who develop hepatocellular carcinoma (HCC) do not have cirrhosis. Comparisons are rarely reported regarding the effectiveness of radiofrequency ablation (RFA) and liver resection (LR) in survival of HCC without cirrhosis and stratification by tumor size ≤ 5 cm. METHODS We used the Surveillance, Epidemiology, and End Results (SEER) database and identified 1505 patients with a solitary HCC tumor ≤ 5 cm who underwent RFA or LR during 2004-2015. Patients were classified into non-cirrhosis and cirrhosis groups and each group was categorized into three subgroups, according to tumor size (≤ 30 mm, 31-40 mm, 41-50 mm). RESULTS In patients without cirrhosis, LR showed better 5-year HCC cancer-specific survival than RFA in all tumor size subgroups (≤ 30 mm: 82.51% vs. 56.42%; 31-40 mm: 71.31% vs. 46.83%; 41-50 mm: 74.7% vs. 37.5%; all P < 0.05). Compared with RFA, LR was an independent protective factor for HCC cancer-specific survival in multivariate Cox analysis [≤ 30 mm: hazard ratio (HR) = 0.533, 95% confidence interval (CI): 0.313-0.908; 31-40 mm: HR = 0.439, 95% CI: 0.201-0.957; 41-50 mm: HR = 0.382; 95% CI: 0.159-0.916; all P < 0.05]. In patients with cirrhosis, for both tumor size ≤ 30 mm and 31-40 mm groups, there were no significant survival differences between RFA and LR in multivariate analysis (all P > 0.05). However, in those with tumor size 41-50 mm, LR showed significantly better 5-year HCC cancer-specific survival than RFA in both univariate (54.72% vs. 23.06%; P < 0.001) and multivariate analyses (HR = 0.297; 95% CI: 0.136-0.648; P = 0.002). CONCLUSIONS RFA is an inferior treatment option to LR for patients without cirrhosis who have a solitary HCC tumor ≤ 5 cm.
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Affiliation(s)
- Song-Chen Dong
- Department of Hepatobiliary Surgery, Clinical Medical College, Yangzhou University, Yangzhou 225001, China; Department of Hepatobiliary Surgery, The First Clinical College, Dalian Medical University, Dalian 116000, China
| | - Dou-Sheng Bai
- Department of Hepatobiliary Surgery, Clinical Medical College, Yangzhou University, Yangzhou 225001, China
| | - Fu-An Wang
- Department of Interventional Radiology, Clinical Medical College, Yangzhou University, Yangzhou 225001, China
| | - Sheng-Jie Jin
- Department of Hepatobiliary Surgery, Clinical Medical College, Yangzhou University, Yangzhou 225001, China
| | - Chi Zhang
- Department of Hepatobiliary Surgery, Clinical Medical College, Yangzhou University, Yangzhou 225001, China
| | - Bao-Huan Zhou
- Department of Hepatobiliary Surgery, Clinical Medical College, Yangzhou University, Yangzhou 225001, China
| | - Guo-Qing Jiang
- Department of Hepatobiliary Surgery, Clinical Medical College, Yangzhou University, Yangzhou 225001, China.
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Dhiman M, Repaka R. Simulating radiofrequency ablation of hepatocellular carcinomas proximal to bare area of liver. MINIM INVASIV THER 2023; 32:163-174. [PMID: 37029689 DOI: 10.1080/13645706.2023.2198602] [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: 09/14/2022] [Accepted: 03/22/2023] [Indexed: 04/09/2023]
Abstract
PURPOSE To numerically assess the significance of dextrose 5% in water (D5W) thermo-protection during radiofrequency ablation (RFA) of hepatocellular carcinomas (HCCs) located near the 'bare area of liver'. MATERIAL AND METHODS This study utilises quasi-anatomical structures extracted from CT images. A multi-tine electrode, deployed inside the extracted organs and operated under temperature-controlled mode was used as the source of ablation. Geometrically, D5W was modelled around the 'bare area' and sandwiched between the liver and diaphragm. RFA at different sites relative to the 'bare area' was simulated to answer when to consider modelling D5W. RESULTS For targets near the edge of 'bare area' and at 0.5 mm gap (between the electrode and the 'bare area'), ignoring D5W and using ground conditions could result in underestimation of ablation volume by almost 25%. The importance of D5W becomes negligible for ablations near the centre of the 'bare area'. CONCLUSIONS Consideration of D5W during RFA of HCCs proximal to the 'bare area' can significantly influence the ablation outcome, especially when ablation is performed near the edge of the 'bare area'.
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Affiliation(s)
- Manoj Dhiman
- Department of Mechanical Engineering, Indian Institute of Technology Ropar, Rupnagar, India
| | - Ramjee Repaka
- Department of Mechanical Engineering, Indian Institute of Technology Ropar, Rupnagar, India
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Choi M, Lee HS, Cho SB. Effect of Pulse Widths and Cycles on Invasive, Bipolar, and Gated Radiofrequency-Induced Thermal Reactions in ex vivo Bovine Liver Tissue. Clin Cosmet Investig Dermatol 2023; 16:87-97. [PMID: 36660189 PMCID: PMC9844106 DOI: 10.2147/ccid.s395072] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 01/10/2023] [Indexed: 01/15/2023]
Abstract
Background Radiofrequency (RF) oscillations generate thermal tissue reactions, the patterns of which vary depending on the mode and efficiency of energy delivery. The aim of our study was to analyze patterns of RF-induced thermal tissue reactions according to the modes of RF delivery, including continuous and gated modes, using an alternating current, invasive bipolar RF device. Methods RF energies at frequencies of 1 and 2 MHz were delivered at respective experimental settings into ex vivo bovine liver tissue at a 0.5-mm microneedle penetration depth. The tissue samples were then evaluated thermometrically. A histologic study was performed to evaluate RF-induced thermal tissue reactions at a 3.0-mm microneedle penetration depth. Results Thermal imaging study revealed homogenous, well-demarcated, square-shaped zones of RF-induced thermal reactivity on the treated area. Multivariate linear regression analysis revealed that higher temperature elevations immediately after RF treatment (∆T1) were positively associated with RF frequency, power, conduction time/pulse pack, and off-time between pulse packs and negatively associated with total off time. In the 1-MHz experimental setting, higher ∆T1 showed a positive association with power, conduction time/pulse pack, and off-time between pulse packs and a negative association with the number of pulse packs. In the 2-MHz setting, however, higher ∆T1 was positively associated with only total treatment time. Conclusion Thermometric effects during bipolar and gated RF treatments are significantly associated with the frequency, power, and pulse widths and cycles of pulse packs.
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Affiliation(s)
- Min Choi
- R&D Center, Shenb Co., Ltd, Seoul, Korea
| | - Hye Sun Lee
- Department of Biostatistics, Yonsei University College of Medicine, Seoul, Korea
| | - Sung Bin Cho
- Yonsei Seran Dermatology and Laser Clinic, Seoul, Korea,Correspondence: Sung Bin Cho, Yonsei Seran Dermatology and Laser Clinic, Geumcheon REMAIN CITY 6F, 224 Siheung-daero, Geumcheon-gu, Seoul, 08628, Korea, Tel +82.2-2135-1375, Fax +82.70-8250-1375, Email
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Kim HK, Kim HJ, Kim JY, Ban MJ, Son J, Hwang Y, Cho SB. Immediate and Late Effects of Pulse Widths and Cycles on Bipolar, Gated Radiofrequency-Induced Tissue Reactions in in vivo Rat Skin. Clin Cosmet Investig Dermatol 2023; 16:721-729. [PMID: 37008192 PMCID: PMC10053894 DOI: 10.2147/ccid.s404631] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 03/21/2023] [Indexed: 04/04/2023]
Abstract
Background Single to multiple pulse packs of bipolar, alternating current radiofrequency (RF) oscillations have been used for various medical purposes using invasive microneedle electrodes. This study was designed to evaluate the effects of pulse widths and cycles of RF pulse packs on immediate and delayed thermal tissue reactions in in vivo rat skin. Methods RF energy at the frequency of 1 MHz and power of 70 W was delivered at each experimental setting into in vivo rat skin at 1.5-mm microneedle penetration, and then, tissue samples were obtained after 1 h and 3, 7, 14, and 21 days and histologically analyzed. Results A single-pulse-pack RF treatment generated coagulative necrosis zones in the dermal peri-electrode area and zones of non-necrotic thermal reactions in the dermal inter-electrode area. Multiple pulse-pack, RF-treated rat skin specimens revealed that the number and size of peri-electrode coagulative necrosis were markedly decreased by increasing the number of pulse packs and accordingly decreasing the conduction time of each pulse pack. The microscopic changes in RF-induced non-necrotic thermal reaction in the inter-electrode area were more remarkable in specimens treated with RF of 7 or 10 pulse packs than in specimens treated with RF of 1-4 pulse packs. Conclusion The gated delivery of multiple RF pulse packs using a bipolar, alternating current, 1-MHz RF system using insulated microneedle electrodes efficiently generates non-necrotic thermal tissue reactions over the upper, mid, and deep dermis and subcutaneous fat in the inter-electrode areas.
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Affiliation(s)
- Hee Kyung Kim
- Department of Pathology, Soonchunhyang University Bucheon Hospital, Bucheon, Korea
| | | | - Jae Yun Kim
- Department of Dermatology, Soonchunhyang University Hospital, Cheonan, Korea
| | - Myung Jin Ban
- Department of Otorhinolaryngology-Head and Neck Surgery, Soonchunhyang University Hospital, Cheonan, Korea
| | - Jiwon Son
- Soonchunhyang Institute of Medi-Bio Science (SIMS), Soonchunhyang University, Cheonan, Korea
| | - Yongsung Hwang
- Soonchunhyang Institute of Medi-Bio Science (SIMS), Soonchunhyang University, Cheonan, Korea
- Department of Integrated Biomedical Science, Soonchunhyang University, Cheonan, Korea
| | - Sung Bin Cho
- Yonsei Seran Dermatology and Laser Clinic, Seoul, Korea
- Correspondence: Sung Bin Cho, Yonsei Seran Dermatology and Laser Clinic, Geumcheon REMAIN CITY 6F, 224 Siheung-daero, Geumcheon-gu, Seoul, 08628, Korea, Tel +82 2-2135-1375, Fax +82 70-8250-1375, Email
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Moll X, Fondevila D, García-Arnas F, Burdio F, Trujillo M, Irastorza RM, Berjano E, Andaluz A. Comparison of two radiofrequency-based hemostatic devices: saline-linked bipolar vs. cooled-electrode monopolar. Int J Hyperthermia 2022; 39:1397-1407. [DOI: 10.1080/02656736.2022.2140840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Xavier Moll
- Departament de Medicina i Cirurgia Animals, Facultat de Veterinària, Universitat Autònoma de Barcelona, Barcelona, Spain
- Fundació Hospital Clínic Veterinari, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Dolors Fondevila
- Departament de Medicina i Cirurgia Animals, Facultat de Veterinària, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Félix García-Arnas
- Departament de Medicina i Cirurgia Animals, Facultat de Veterinària, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Fernando Burdio
- Department of Surgery, Division of Hepato-Biliary and Pancreatic Surgery, Hospital del Mar, Barcelona, Spain; Hospital del Mar Medical Research Institute (IMIM), Barcelona, Spain
| | - Macarena Trujillo
- Department of Applied Mathematics, BioMIT, Universitat Politècnica de València, Valencia, Spain
| | - Ramiro M. Irastorza
- Instituto de Física de Líquidos y Sistemas Biológicos (CONICET), La Plata, Argentina
- Departamento de Ingeniería Mecánica, Universidad Tecnológica Nacional, Facultad Regional La Plata, La Plata, Argentina
| | - Enrique Berjano
- Department of Electronic Engineering, BioMIT, Universitat Politècnica de València, Valencia, Spain
| | - Anna Andaluz
- Departament de Medicina i Cirurgia Animals, Facultat de Veterinària, Universitat Autònoma de Barcelona, Barcelona, Spain
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Radiofrequency ablation for liver tumors abutting complex blood vessel structures: treatment protocol optimization using response surface method and computer modeling. Int J Hyperthermia 2022; 39:733-742. [PMID: 35610101 DOI: 10.1080/02656736.2022.2075567] [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: 10/18/2022] Open
Abstract
OBJECTIVE To achieve a result of a large tumor ablation volume with minimal thermal damage to the surrounding blood vessels by designing a few clinically-adjustable operating parameters in radiofrequency ablation (RFA) for liver tumors abutting complex vascular structures. METHODS Response surface method (RSM) was employed to correlate the ablated tumor volume (Ra) and thermal damage to blood vessels (Dt) based on RFA operating parameters: ablation time, electrode position, and insertion angle. A coupled electric-thermal-fluid RFA computer model was created as the testbed for RSM to simulate RFA process. Then, an optimal RFA protocol for the two conflicting goals, namely (1) large tumor ablation and (2) small thermal damage to the surrounding blood vessels, has been achieved under a specific ablation environment. RESULTS Linear regression analysis confirmed that the RFA protocol significantly affected Ra and Dt (the adjusted coefficient of determination Radj2 = 93.61% and 95.03%, respectively). For a proposed liver tumor scenario (liver tumor with a dimension of 4×3×2.9 cm3 abutting a complex vascular structure), an optimized RFA protocol was found based on the regression results in RSM. Compared with a reference RFA protocol, in which the electrode was centered in the tumor with a 12-min ablation time, the optimized RFA protocol has increased Ra from 98.1% to 99.6% and decreased Dt from 4.1% to 0.4%, achieving nearly the complete ablation of proposed liver tumor and ignorable thermal damages to vessels. CONCLUSION This work showed that it is possible to design a few clinically-adjustable operating parameters of RFA for achieving a large tumor ablation volume while minimizing thermal damage to the surrounding blood vessels.
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Zhang S, Li C, Cao L, Moser MAJ, Zhang W, Qian Z, Zhang B. Modeling and ex vivo experimental validation of liver tissue carbonization with laser ablation. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 217:106697. [PMID: 35180678 DOI: 10.1016/j.cmpb.2022.106697] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 01/26/2022] [Accepted: 02/08/2022] [Indexed: 06/14/2023]
Abstract
OBJECTIVE The purpose of this study was to model the process of liver tissue carbonization with laser ablation (LA). METHODS A dynamic heat source model was proposed and combined with the light distribution model as well as bioheat transfer model to predict the development of tissue carbonization with laser ablation (LA) using an ex vivo porcine liver tissue model. An ex vivo laser ablation experiment with porcine liver tissues using a custom-made 1064 nm bare fiber was then used to verify the simulation results at 3, 5, and 7 W laser administrations for 5 min. The spatiotemporal temperature distribution was monitored by measuring the temperature changes at three points close the fiber during LA. Both the experiment and simulation of the temperature, tissue carbonization zone, and ablation zone were then compared. RESULTS Four stages were recognized in the development of liver tissue carbonization during LA. The growth of the carbonization zone along the fiber axial and radial directions were different in the four stages. The carbonization zone along the fiber axial direction (L2) grew in the four stages with a sharp increase in the initial period and a minor increase in Stage 4. However, the change in the carbonization zone along the fiber radial direction (D2) increased dramatically (Stage 1) to a long-time plateau (Stages 2 and 3) followed by a slow growth in Stage 4. An acceptable agreement between the computer simulation and ex vivo experiment in the temperature changes at the three points was found at all three testing laser administrations. A similar result was also obtained for the dimensions of coagulation zone and ablation zone between the computer simulation and ex vivo experiment (carbonization zone: 2.99± 0.10 vs. 2.78 mm2, 67.39± 0.09 vs. 63.53 mm2, and 90.53± 0.11 vs. 85.15 mm2; ablation zone: 68.95± 0.28 vs. 65.29 mm2, 182.11± 0.24 vs. 213.81 mm2, and 244.80± 0.06 vs. 251.79 mm2 at 3, 5, and 7 W, respectively). CONCLUSION This study demonstrates that the proposed dynamic heat source model combined with the light distribution model as well as bioheat transfer model can predict the development of liver tissue carbonization with an acceptable accuracy. This study contributes to an improved understanding of the LA process in the treatment of liver tumors.
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Affiliation(s)
- Shiguang Zhang
- Intelligent Energy-based Tumor Ablation Laboratory, School of Mechatronic Engineering and Automation, Shanghai University, Shanghai, 200444, China; School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai, 200237, China
| | - Chunlei Li
- Shanghai Advanced Research Institute, Chinese Academy of Science, Shanghai, 201024, China
| | - Lin Cao
- Department of Automatic Control and Systems Engineering, the University of Sheffield, Sheffield, UK
| | - Michael A J Moser
- Department of Surgery, University of Saskatchewan, Saskatoon, Canada
| | - Wenjun Zhang
- Department of Mechanical Engineering, University of Saskatchewan, Saskatoon, Canada
| | - Zhiqin Qian
- School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai, 200237, China.
| | - Bing Zhang
- Intelligent Energy-based Tumor Ablation Laboratory, School of Mechatronic Engineering and Automation, Shanghai University, Shanghai, 200444, China.
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Bianchi L, Cavarzan F, Ciampitti L, Cremonesi M, Grilli F, Saccomandi P. Thermophysical and mechanical properties of biological tissues as a function of temperature: a systematic literature review. Int J Hyperthermia 2022; 39:297-340. [DOI: 10.1080/02656736.2022.2028908] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- Leonardo Bianchi
- Department of Mechanical Engineering, Politecnico di Milano, Milan, Italy
| | - Fabiana Cavarzan
- Department of Mechanical Engineering, Politecnico di Milano, Milan, Italy
| | - Lucia Ciampitti
- Department of Mechanical Engineering, Politecnico di Milano, Milan, Italy
| | - Matteo Cremonesi
- Department of Mechanical Engineering, Politecnico di Milano, Milan, Italy
| | - Francesca Grilli
- Department of Mechanical Engineering, Politecnico di Milano, Milan, Italy
| | - Paola Saccomandi
- Department of Mechanical Engineering, Politecnico di Milano, Milan, Italy
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Zhang B, Liu F, Fang Z, Ding L, Moser MAJ, Zhang W. An in vivo study of a custom-made high-frequency irreversible electroporation generator on different tissues for clinically relevant ablation zones. Int J Hyperthermia 2021; 38:593-603. [PMID: 33853496 DOI: 10.1080/02656736.2021.1912417] [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] [Indexed: 10/21/2022] Open
Abstract
PURPOSE To examine the ablation zone, muscle contractions, and temperature increases in both rabbit liver and kidney models in vivo for a custom-made high-frequency irreversible electroporation (H-FIRE) generator. MATERIALS AND METHODS A total of 18 New Zealand white rabbits were used to investigate five H-FIRE protocols (n = 3 for each protocol) and an IRE protocol (n = 3) for the performance of the designed H-FIRE device in both liver and kidney tissues. The ablation zone was determined by using histological analysis 72 h after treatment. The extent of muscle contractions and temperature change during the application of pulse energy were measured by a commercial accelerometer attached to animals and fiber optic temperature probe inserted into organs with IRE electrodes, respectively. RESULTS All H-FIRE protocols were able to generate visible ablation zones without muscle contractions, for both liver and kidney tissues. The area of ablation zone generated in H-FIRE pulse protocols (e.g., 0.3-1 μs, 2000 V, and 90-195 bursts) appears similar to that of IRE protocol (100 μs, 1000 V, and 90 pulses) in both liver and kidney tissues. No significant temperature increase was noticed except for the protocol with the highest pulse energy (e.g., 1 μs, 2000 V, and 180 bursts). CONCLUSION Our work serves to complement the current H-FIRE pulse waveforms, which can be optimized to significantly improve the quality of ablation zone in terms of precision for liver and kidney tumors in clinical setting.
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Affiliation(s)
- Bing Zhang
- Energy-based Tumor Ablation Laboratory, School of Mechatronic Engineering and Automation, Shanghai University, Shanghai, China
| | - Fanning Liu
- Energy-based Tumor Ablation Laboratory, School of Mechatronic Engineering and Automation, Shanghai University, Shanghai, China
| | - Zheng Fang
- Energy-based Tumor Ablation Laboratory, School of Mechatronic Engineering and Automation, Shanghai University, Shanghai, China
| | - Lujia Ding
- Energy-based Tumor Ablation Laboratory, School of Mechatronic Engineering and Automation, Shanghai University, Shanghai, China
| | - Michael A J Moser
- Department of Surgery, University of Saskatchewan, Saskatoon, Canada
| | - Wenjun Zhang
- Division of Biomedical Engineering, University of Saskatchewan, Saskatoon, Canada
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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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14
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Dhiman M, Kumawat AK, Ramjee Repaka. Directional ablation in radiofrequency ablation using a multi-tine electrode functioning in multipolar mode: An in-silico study using a finite set of states. Comput Biol Med 2020; 126:104007. [PMID: 32987201 DOI: 10.1016/j.compbiomed.2020.104007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 09/04/2020] [Accepted: 09/06/2020] [Indexed: 01/26/2023]
Abstract
PURPOSE To analyse the feasibility of directional ablation using a multi-tine electrode. METHODS A multi-tine electrode capable of operating in multipolar mode has been used to study the directional ablation. In addition to the basic design, similar to commercially available FDA approved multi-tine electrode, tines have been insulated from each other inside the probe base and tip using a thin insulating material of thickness 0.25 mm. A cylindrical single-compartment model of size 6 cm × 6 cm has been used to model normal liver tissue. The temperature-controlled radiofrequency ablation has been employed to maintain the tine-tips at different temperatures. Electro-thermal simulations have been performed by using a commercial multi-physics software package based on finite element methods. To make this study feasible a new approach to predict the ablations have been proposed and used in this study. RESULTS Asymmetric ablation zone with up to 5 mm difference in ablation boundary between the intended and non-intended direction has been observed along the transverse direction. Reduction in ablation up to 5 mm along the axial direction in comparison to the monopolar mode has also been observed. CONCLUSION Multi-tine electrode modified to operate in multipolar mode can create directional ablations of different shapes and can be used to target position and shape specific tumours.
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Affiliation(s)
- Manoj Dhiman
- Department of Mechanical Engineering, Indian Institute of Technology Ropar, Rupnagar, Punjab, India
| | - Aakash Kumar Kumawat
- Department of Mechanical Engineering, Indian Institute of Technology Ropar, Rupnagar, Punjab, India
| | - Ramjee Repaka
- Department of Mechanical Engineering, Indian Institute of Technology Ropar, Rupnagar, Punjab, India.
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15
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Cheong JKK, Ooi EH, Ooi ET. Thermal and thermal damage responses during switching bipolar radiofrequency ablation employing bipolar needles: A computational study on the effects of different electrode configuration, input voltage and ablation duration. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2020; 36:e3374. [PMID: 32519516 DOI: 10.1002/cnm.3374] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 04/30/2020] [Accepted: 05/19/2020] [Indexed: 06/11/2023]
Abstract
Recent studies have demonstrated the effectiveness of switching bipolar radiofrequency ablation (bRFA) in treating liver cancer. Nevertheless, the clinical use of the treatment remains less common than conventional monopolar RFA - likely due to the lack of understanding of how the tissues respond thermally to the switching effect. The problem is exacerbated by the numerous possible switching combinations when bRFA is performed using bipolar needles, thus making theoretical deduction and experimental studies difficult. This article addresses this issue via computational modelling by examining if significant variation in the treatment outcome exists amongst six different electrode configurations defined by the X-, C-, U-, N-, Z- and O-models. Results indicated that the tissue thermal and thermal damage responses varied depending on the electrode configuration and the operating conditions (input voltage and ablation duration). For a spherical tumour, 30 mm in diameter, complete ablation could not be attained in all configurations with 70 V input voltage and 5 minutes ablation duration. Increasing the input voltage to 90 V enlarged the coagulation zone in the X-model only. With the other configurations, extending the ablation duration to 10 minutes was found to be the better at enlarging the coagulation zone.
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Affiliation(s)
- Jason K K Cheong
- School of Engineering, Monash University Malaysia, Bandar Sunway, Malaysia
| | - Ean H Ooi
- School of Engineering, Monash University Malaysia, Bandar Sunway, Malaysia
- Advanced Engineering Platform, Monash University Malaysia, Bandar Sunway, Malaysia
| | - Ean T Ooi
- School of Engineering and Information Technology, Faculty of Science and Technology, Federation University, Ballarat, Victoria, Australia
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16
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Singh S, Melnik R. Thermal ablation of biological tissues in disease treatment: A review of computational models and future directions. Electromagn Biol Med 2020; 39:49-88. [PMID: 32233691 DOI: 10.1080/15368378.2020.1741383] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Percutaneous thermal ablation has proven to be an effective modality for treating both benign and malignant tumours in various tissues. Among these modalities, radiofrequency ablation (RFA) is the most promising and widely adopted approach that has been extensively studied in the past decades. Microwave ablation (MWA) is a newly emerging modality that is gaining rapid momentum due to its capability of inducing rapid heating and attaining larger ablation volumes, and its lesser susceptibility to the heat sink effects as compared to RFA. Although the goal of both these therapies is to attain cell death in the target tissue by virtue of heating above 50°C, their underlying mechanism of action and principles greatly differs. Computational modelling is a powerful tool for studying the effect of electromagnetic interactions within the biological tissues and predicting the treatment outcomes during thermal ablative therapies. Such a priori estimation can assist the clinical practitioners during treatment planning with the goal of attaining successful tumour destruction and preservation of the surrounding healthy tissue and critical structures. This review provides current state-of-the-art developments and associated challenges in the computational modelling of thermal ablative techniques, viz., RFA and MWA, as well as touch upon several promising avenues in the modelling of laser ablation, nanoparticles assisted magnetic hyperthermia and non-invasive RFA. The application of RFA in pain relief has been extensively reviewed from modelling point of view. Additionally, future directions have also been provided to improve these models for their successful translation and integration into the hospital work flow.
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Affiliation(s)
- Sundeep Singh
- MS2Discovery Interdisciplinary Research Institute, Wilfrid Laurier University, Waterloo, Ontario, Canada
| | - Roderick Melnik
- MS2Discovery Interdisciplinary Research Institute, Wilfrid Laurier University, Waterloo, Ontario, Canada.,BCAM - Basque Center for Applied Mathematics, Bilbao, Spain
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17
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Kho ASK, Foo JJ, Ooi ET, Ooi EH. Shape-shifting thermal coagulation zone during saline-infused radiofrequency ablation: A computational study on the effects of different infusion location. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2020; 184:105289. [PMID: 31891903 DOI: 10.1016/j.cmpb.2019.105289] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 12/07/2019] [Accepted: 12/19/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND AND OBJECTIVE The majority of the studies on radiofrequency ablation (RFA) have focused on enlarging the size of the coagulation zone. An aspect that is crucial but often overlooked is the shape of the coagulation zone. The shape is crucial because the majority of tumours are irregularly-shaped. In this paper, the ability to manipulate the shape of the coagulation zone following saline-infused RFA by altering the location of saline infusion is explored. METHODS A 3D model of the liver tissue was developed. Saline infusion was described using the dual porosity model, while RFA was described using the electrostatic and bioheat transfer equations. Three infusion locations were investigated, namely at the proximal end, the middle and the distal end of the electrode. Investigations were carried out numerically using the finite element method. RESULTS Results indicated that greater thermal coagulation was found in the region of tissue occupied by the saline bolus. Infusion at the middle of the electrode led to the largest coagulation volume followed by infusion at the proximal and distal ends. It was also found that the ability to delay roll-off, as commonly associated with saline-infused RFA, was true only for the case when infusion is carried out at the middle. When infused at the proximal and distal ends, the occurrence of roll-off was advanced. This may be due to the rapid and more intense heating experienced by the tissue when infusion is carried out at the electrode ends where Joule heating is dominant. CONCLUSION Altering the location of saline infusion can influence the shape of the coagulation zone following saline-infused RFA. The ability to 'shift' the coagulation zone to a desired location opens up great opportunities for the development of more precise saline-infused RFA treatment that targets specific regions within the tissue.
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Affiliation(s)
- Antony S K Kho
- School of Engineering, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway 47500, Selangor, Malaysia
| | - Ji J Foo
- 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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18
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Fang Z, Moser MAJ, Zhang EM, Zhang W, Zhang B. A Novel Method to Increase Tumor Ablation Zones With RFA by Injecting the Cationic Polymer Solution to Tissues: In Vivo and Computational Studies. IEEE Trans Biomed Eng 2019; 67:1787-1796. [PMID: 31634120 DOI: 10.1109/tbme.2019.2947292] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE This study aims to examine, for the first time, the introduction of cationic polymer solutions to improve radiofrequency ablation (RFA) in terms of a potentially enlarged ablation zone. METHODS By using in vivo and computational RFA studies, two cationic polymers, Chitooligosaccharides (COS) and carboxymethyl chitosan (CMC), diluted in deionized water, were injected into tissues separately surrounding the RF bipolar electrode prior to power application. A total of 9 rabbits were used to 1) measure the increase in electrical conductivity of tissues injected with the cationic polymer solutions, and 2) explore the enhancement of the ablation performance in RFA trials. A computer model of RFA comprising a model of the solution diffusion with an RF thermal ablation model was also built, validated by the in vivo experiment, to quantitatively study the effect of cationic polymer solutions on ablation performances. RESULTS Compared to the control group, the electrical conductivity of rabbit liver tissues was increased by 42.20% (0.282 ± 0.006 vs. 0.401 ± 0.048 S/m, P = 0.001) and 43.97% (0.282 ± 0.006 vs. 0.406 ± 0.042 S/m, P = 0.001) by injecting the COS and CMC solution at the concentration of 100 mg/mL into the tissues, denoted COSDW100 and CMCDW100, respectively. Consequently, the in vivo experiments show that the ablation zone was enlarged by 95% (47.6 ± 6.3 vs. 92.6 ± 11.5 mm2, P < 0.001) and 87% (47.6± 6.3 vs. 88.8 ± 9.6 mm2, P < 0.001) by COSDW100 and CMCDW100, respectively. The computer simulation shows that the ablation zone was enlarged by 71% (51.9 vs. 88.7 mm2) and 63% (51.9 vs. 84.7 mm2) by COSDW100 and CMCDW100, respectively. CONCLUSION The injection of the cationic solution can greatly improve the performance of RFA treatment in terms of enlarging the ablation zone, which is due to the increase in the electrical conductivity of liver tissues surrounding the RF electrode. SIGNIFICANCE This study contributes to the improvement of RFA in the treatment of large tumors.
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19
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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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20
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Zhang B, Yang Y, Ding L, Moser MAJ, Zhang EM, Zhang W. Tumor Ablation Enhancement by Combining Radiofrequency Ablation and Irreversible Electroporation: An In Vitro 3D Tumor Study. Ann Biomed Eng 2018; 47:694-705. [PMID: 30565007 DOI: 10.1007/s10439-018-02185-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 12/06/2018] [Indexed: 02/08/2023]
Abstract
We hypothesized and demonstrated for the first time that significant tumor ablation enhancement can be achieved by combining radiofrequency ablation (RFA) and irreversible electroporation (IRE) using a 3D cervical cancer cell model. Three RFA (43, 50, and 60 °C for 2 min) and IRE protocols (350, 700, and 1050 V/cm) were used to study the combining effect in the 3D tumor cell model. The in vitro experiment showed that both RFA enhanced IRE and IRE enhanced RFA can lead to a significant increase in the size of the ablation zone compared to IRE and RFA alone. It was also noted that the sequence of applying ablation energy (RFA → RE or IRE → RFA) affected the efficacy of tumor ablation enhancement. The electrical conductivity of 3D tumor was found to be increased after preliminary RFA or IRE treatment. This increase in tumor conductivity may explain the enhancement of tumor ablation. Another explanation might be that there is repeat injury to the transitional zone of the first treatment by the second one. The promising results achieved in the study can provide us useful clues about the treatment of large tumors abutting large vessels or bile ducts.
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Affiliation(s)
- Bing Zhang
- Tumor Ablation Group, Biomedical Science and Technology Research Center, School of Mechatronic Engineering and Automation, Shanghai University, 99 Shangda Road, Baoshan, Shanghai, 200444, China.
| | - Yongji Yang
- School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai, 200237, China
| | - Lujia Ding
- School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai, 200237, China
| | - Michael A J Moser
- Department of Surgery, University of Saskatchewan, Saskatoon, SK, S7N 0W8, Canada
| | - Edwin M Zhang
- Division of Vascular & Interventional Radiology, Department of Medical Imaging, University of Toronto, Toronto, ON, M5T 1W7, Canada
| | - Wenjun Zhang
- Tumor Ablation Group, Biomedical Science and Technology Research Center, School of Mechatronic Engineering and Automation, Shanghai University, 99 Shangda Road, Baoshan, Shanghai, 200444, China.,Department of Mechanical Engineering, University of Saskatchewan, Saskatoon, SK, S7N 5A9, Canada
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21
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Zhang K, Zou J, He K, Xu L, Liu P, Li W, Zhang A, Xu LX. Study of enhanced radiofrequency heating by pre-freezing tissue. Int J Hyperthermia 2018; 35:79-89. [PMID: 29865914 DOI: 10.1080/02656736.2018.1476984] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
In our previous animal model study, we found that radiofrequency (RF) ablation of pre-frozen tumor resulted in improved therapeutic effects. To understand the underlying mechanisms and optimize the treatment protocol, the RF heating pattern in pre-frozen tissue was studied in this paper. Both ex vivo and in vivo experiments were conducted to compare the temperature profiles of RF heating with or without pre-freezing. Results showed that the heating rate of in vivo tissues was significantly higher with pre-freezing. However, little difference was observed in the heating rate of ex vivo tissues with or without pre-freezing. In the histopathologic analysis of in vivo tissues, both a larger ablation area and a wider transitional zone were found in the tissue with pre-freezing. To investigate the cause for the enhancement in RF heating, the parameters affecting the tissue temperature rise were studied. It was found that the electrical conductivity of in vivo tissue with pre-freezing was much higher at low frequencies, but little difference was found at the 460 kHz frequency commonly used in clinical applications. A finite element model for RF heating was developed and validated to fit the thermal conductivity of in vivo tissue including effects of pre-freezing and the associated blood perfusion rate. Results showed that the enhancement of the heating rate was primarily attributed to the decreased blood perfusion rate in the tissue with vascular damage caused by pre-freezing. The ablation volume was increased by 104% due to the reduced heat dissipation.
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Affiliation(s)
- Kangwei Zhang
- a School of Biomedical Engineering , Shanghai Jiao Tong University , Shanghai , China
| | - Jincheng Zou
- a School of Biomedical Engineering , Shanghai Jiao Tong University , Shanghai , China
| | - Kun He
- a School of Biomedical Engineering , Shanghai Jiao Tong University , Shanghai , China
| | - Lichao Xu
- b Fudan University Shanghai Cancer Center , Shanghai , China.,c Department of Oncology , Shanghai Medical College, Fudan University , Shanghai , China
| | - Ping Liu
- a School of Biomedical Engineering , Shanghai Jiao Tong University , Shanghai , China
| | - Wentao Li
- b Fudan University Shanghai Cancer Center , Shanghai , China.,c Department of Oncology , Shanghai Medical College, Fudan University , Shanghai , China
| | - Aili Zhang
- a School of Biomedical Engineering , Shanghai Jiao Tong University , Shanghai , China
| | - Lisa X Xu
- a School of Biomedical Engineering , Shanghai Jiao Tong University , Shanghai , China.,d Med-X Research Institute , Shanghai Jiao Tong University , Shanghai , China
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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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