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Onyekanne CE, Salifu AA, Obayemi JD, Ani CJ, Ashouri Choshali H, Nwazojie CC, Onwudiwe KC, Oparah JC, Ezenwafor TC, Ezeala CC, Odusanya OS, Rahbar N, Soboyejo WO. Laser-induced heating of polydimethylsiloxane-magnetite nanocomposites for hyperthermic inhibition of triple-negative breast cancer cell proliferation. J Biomed Mater Res B Appl Biomater 2022; 110:2727-2743. [PMID: 35799416 DOI: 10.1002/jbm.b.35124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 03/23/2022] [Accepted: 06/08/2022] [Indexed: 12/15/2022]
Abstract
This paper presents the results of an experimental and computational study of the effects of laser-induced heating provided by magnetite nanocomposite structures that are being developed for the localized hyperthermic treatment of triple-negative breast cancer. Magnetite nanoparticle-reinforced polydimethylsiloxane (PDMS) nanocomposites were fabricated with weight percentages of 1%, 5%, and 10% magnetite nanoparticles. The nanocomposites were exposed to incident Near Infrared (NIR) laser beams with well-controlled powers. The laser-induced heating is explored in: (i) heating liquid media (deionized water and cell growth media [Leibovitz L15+]) to characterize the photothermal properties of the nanocomposites, (ii) in vitro experiments that explore the effects of localized heating on triple-negative breast cancer cells, and (iii) experiments in which the laser beams penetrate through chicken tissue to heat up nanocomposite samples embedded at different depths beneath the chicken skin. The resulting plasmonic laser-induced heating is explained using composite theories and heat transport models. The results show that the laser/nanocomposite interactions decrease the viability of triple-negative breast cancer cells (MDA-MB-231) at temperatures in the hyperthermia domain between 41 and 44°C. Laser irradiation did not cause any observed physical damage to the chicken tissue. The potential in vivo performance of the PDMS nanocomposites was also investigated using computational finite element models of the effects of laser/magnetite nanocomposite interactions on the temperatures and thermal doses experienced by tissues that surround the nanocomposite devices. The implications of the results are then discussed for the development of implantable nanocomposite devices for localized treatment of triple-negative breast cancer tissue via hyperthermia.
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Affiliation(s)
- Chinyerem E Onyekanne
- Department of Materials Science and Engineering, Biomaterials Lab, African University of Science and Technology, Abuja, Federal Capital Territory, Nigeria
| | - Ali A Salifu
- Department of Mechanical Engineering, Worcester Polytechnic Institute, Worcester, Massachusetts, USA.,Department of Biomedical Engineering, Worcester Polytechnic Institute, Worcester, Massachusetts, USA
| | - John D Obayemi
- Department of Mechanical Engineering, Worcester Polytechnic Institute, Worcester, Massachusetts, USA.,Department of Biomedical Engineering, Worcester Polytechnic Institute, Worcester, Massachusetts, USA
| | - Chukwuemeka J Ani
- Department of Physics, Nile University of Nigeria, Abuja, Federal Capital Territory, Nigeria
| | - Habibeh Ashouri Choshali
- Department of Civil and Environmental Engineering, Worcester Polytechnic Institute, Worcester, Massachusetts, USA
| | - Chukwudalu C Nwazojie
- Department of Materials Science and Engineering, Biomaterials Lab, African University of Science and Technology, Abuja, Federal Capital Territory, Nigeria
| | - Killian C Onwudiwe
- Department of Materials Science and Engineering, Biomaterials Lab, African University of Science and Technology, Abuja, Federal Capital Territory, Nigeria
| | - Josephine C Oparah
- Department of Materials Science and Engineering, Biomaterials Lab, African University of Science and Technology, Abuja, Federal Capital Territory, Nigeria
| | - Theresa C Ezenwafor
- Department of Materials Science and Engineering, Biomaterials Lab, African University of Science and Technology, Abuja, Federal Capital Territory, Nigeria
| | - Chukwudi C Ezeala
- Department of Materials Science and Engineering, Biomaterials Lab, African University of Science and Technology, Abuja, Federal Capital Territory, Nigeria
| | - Olushola S Odusanya
- Department of Materials Science and Engineering, Biomaterials Lab, African University of Science and Technology, Abuja, Federal Capital Territory, Nigeria.,Biotechnology and Genetic Engineering Advanced Laboratory, Sheda Science and Technology Complex, Abuja, Federal Capital Territory, Nigeria
| | - Nima Rahbar
- Department of Civil and Environmental Engineering, Worcester Polytechnic Institute, Worcester, Massachusetts, USA
| | - Winston O Soboyejo
- Department of Materials Science and Engineering, Biomaterials Lab, African University of Science and Technology, Abuja, Federal Capital Territory, Nigeria.,Department of Mechanical Engineering, Worcester Polytechnic Institute, Worcester, Massachusetts, USA.,Department of Biomedical Engineering, Worcester Polytechnic Institute, Worcester, Massachusetts, USA
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González-Suárez A, Pérez JJ, Irastorza RM, D'Avila A, Berjano E. Computer modeling of radiofrequency cardiac ablation: 30 years of bioengineering research. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 214:106546. [PMID: 34844766 DOI: 10.1016/j.cmpb.2021.106546] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 11/08/2021] [Accepted: 11/15/2021] [Indexed: 06/13/2023]
Abstract
This review begins with a rationale of the importance of theoretical, mathematical and computational models for radiofrequency (RF) catheter ablation (RFCA). We then describe the historical context in which each model was developed, its contribution to the knowledge of the physics of RFCA and its implications for clinical practice. Next, we review the computer modeling studies intended to improve our knowledge of the biophysics of RFCA and those intended to explore new technologies. We describe the most important technical details of the implementation of mathematical models, including governing equations, tissue properties, boundary conditions, etc. We discuss the utility of lumped element models, which despite their simplicity are widely used by clinical researchers to provide a physical explanation of how RF power is absorbed in different tissues. Computer model verification and validation are also discussed in the context of RFCA. The article ends with a section on the current limitations, i.e. aspects not yet included in state-of-the-art RFCA computer modeling and on future work aimed at covering the current gaps.
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Affiliation(s)
- Ana González-Suárez
- Electrical and Electronic Engineering, National University of Ireland Galway, Ireland; Translational Medical Device Lab, National University of Ireland Galway, Ireland
| | - Juan J Pérez
- Department of Electronic Engineering, BioMIT, Universitat Politècnica de València, Valencia, Spain
| | - Ramiro M Irastorza
- Instituto de Física de Líquidos y Sistemas Biológicos (CONICET), La Plata, Argentina; Instituto de Ingeniería y Agronomía, Universidad Nacional Arturo Jauretche, Florencio Varela, Argentina
| | - Andre D'Avila
- Division of Cardiovascular Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
| | - Enrique Berjano
- Department of Electronic Engineering, BioMIT, Universitat Politècnica de València, Valencia, Spain.
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Key factors behind autofluorescence changes caused by ablation of cardiac tissue. Sci Rep 2020; 10:15369. [PMID: 32958843 PMCID: PMC7506017 DOI: 10.1038/s41598-020-72351-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 08/25/2020] [Indexed: 11/30/2022] Open
Abstract
Radiofrequency ablation is a commonly used clinical procedure that destroys arrhythmogenic sources in patients suffering from atrial fibrillation and other types of cardiac arrhythmias. To improve the success of this procedure, new approaches for real-time visualization of ablation sites are being developed. One of these promising methods is hyperspectral imaging, an approach that detects lesions based on changes in the endogenous tissue autofluorescence profile. To facilitate the clinical implementation of this approach, we examined the key variables that can influence ablation-induced spectral changes, including the drop in myocardial NADH levels, the release of lipofuscin-like pigments, and the increase in diffuse reflectance of the cardiac muscle beneath the endocardial layer. Insights from these experiments suggested simpler algorithms that can be used to acquire and post-process the spectral information required to reveal the lesion sites. Our study is relevant to a growing number of multilayered clinical targets to which spectral approaches are being applied.
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Guillot AJ, Cordeiro AS, Donnelly RF, Montesinos MC, Garrigues TM, Melero A. Microneedle-Based Delivery: An Overview of Current Applications and Trends. Pharmaceutics 2020; 12:pharmaceutics12060569. [PMID: 32575392 PMCID: PMC7355570 DOI: 10.3390/pharmaceutics12060569] [Citation(s) in RCA: 113] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 06/13/2020] [Accepted: 06/16/2020] [Indexed: 12/18/2022] Open
Abstract
Microneedle arrays (MNA) are considered as one of the most promising resources to achieve systemic effects by transdermal delivery of drugs. They are designed as a minimally invasive, painless system which can bypass the stratum corneum, overcoming the potential drawbacks of subcutaneous injections and other transdermal delivery systems such as chemical enhancers, nano and microparticles, or physical treatments. As a trendy field in pharmaceutical and biomedical research, its applications are constantly evolving, even though they are based on very well-established techniques. The number of molecules administered by MNA are also increasing, with insulin and vaccines administration being the most investigated. Furthermore, MNA are being used to deliver cells and applied in other organs and tissues like the eyes and buccal mucosae. This review intends to offer a general overview of the current state of MNA research, focusing on the strategies, applications, and types of molecules delivered recently by these systems. In addition, some information about the materials and manufacturing processes is presented and safety data is discussed.
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Affiliation(s)
- Antonio José Guillot
- Department of Pharmacy and Pharmaceutical Technology and Parasitology, Faculty of Pharmacy, University of Valencia, Avda. Vincent Andrés Estellés s/n, 46100 Burjassot, Spain; (A.J.G.); (A.M.)
| | - Ana Sara Cordeiro
- School of Pharmacy, Queen’s University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast BT9 7BL, UK; (A.S.C.); (R.F.D.)
| | - Ryan F. Donnelly
- School of Pharmacy, Queen’s University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast BT9 7BL, UK; (A.S.C.); (R.F.D.)
| | - M. Carmen Montesinos
- Department of Pharmacology, Faculty of Pharmacy, University of Valencia, Avda. Vincent Andrés Estellés s/n, 46100 Burjassot, Spain
- Center of Molecular Recognition and Technological Development (IDM), 46100 Burjassot, Spain
- Correspondence: (M.C.M.); (T.M.G.)
| | - Teresa M. Garrigues
- Department of Pharmacy and Pharmaceutical Technology and Parasitology, Faculty of Pharmacy, University of Valencia, Avda. Vincent Andrés Estellés s/n, 46100 Burjassot, Spain; (A.J.G.); (A.M.)
- Correspondence: (M.C.M.); (T.M.G.)
| | - Ana Melero
- Department of Pharmacy and Pharmaceutical Technology and Parasitology, Faculty of Pharmacy, University of Valencia, Avda. Vincent Andrés Estellés s/n, 46100 Burjassot, Spain; (A.J.G.); (A.M.)
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Yap S, Cheong JKK, Ooi EH, Liao IY, Foo JJ, Nair SR, Mohd Ali AF. A numerical study on the no-touch bipolar radiofrequency ablation .. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020; 2019:2887-2890. [PMID: 31946494 DOI: 10.1109/embc.2019.8857816] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The commonly used radiofrequency ablation (RFA) technique for treating liver cancer is in the monopolar mode. This requires the insertion of the RF electrode directly into the tumor tissue, which increases the risks of tumor track seeding (TTS). One way to overcome TTS is by employing the bipolar RFA, implemented in the no-touch mode. In the no-touch mode, two RF electrodes are inserted into the healthy tissue that surrounds the tumor. The distance between the electrodes and the tumor is defined as the no-touch gap. The ability of the no-touch bipolar RFA to overcome TTS has been demonstrated in laboratory studies; however, little is known about the thermo-physiological responses of the tissue during the ablation process of the no-touch procedure. This will be investigated numerically in the present study. A 3D model of the liver tissue is developed and the no-touch bipolar RFA implemented using a pair of RF electrodes is simulated using the finite element method. In particular, the effects of the no-touch gap on the treatment outcome of the RFA procedure are investigated. Results show that a larger no-touch gap may result incomplete tumor destruction due to the central region of the tumor not being directly affected by the Joule heating phenomenon that is more prominent around the electrodes. This suggests that an improperly selected no-touch gap may result in a reduced efficiency of the no-touch bipolar RFA.
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Possebon R, Jiang Y, Mulier S, Wang C, Chen F, Feng Y, Ni Y. A piecewise function of resistivity of liver: determining parameters with finite element analysis of radiofrequency ablation. Med Biol Eng Comput 2017; 56:385-394. [DOI: 10.1007/s11517-017-1699-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 07/23/2017] [Indexed: 01/29/2023]
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Gil DA, Swift LM, Asfour H, Muselimyan N, Mercader MA, Sarvazyan NA. Autofluorescence hyperspectral imaging of radiofrequency ablation lesions in porcine cardiac tissue. JOURNAL OF BIOPHOTONICS 2017; 10:1008-1017. [PMID: 27545317 PMCID: PMC5511096 DOI: 10.1002/jbio.201600071] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2016] [Revised: 06/21/2016] [Accepted: 07/29/2016] [Indexed: 05/22/2023]
Abstract
Radiofrequency ablation (RFA) is a widely used treatment for atrial fibrillation, the most common cardiac arrhythmia. Here, we explore autofluorescence hyperspectral imaging (aHSI) as a method to visualize RFA lesions and interlesional gaps in the highly collagenous left atrium. RFA lesions made on the endocardial surface of freshly excised porcine left atrial tissue were illuminated by UV light (365 nm), and hyperspectral datacubes were acquired over the visible range (420-720 nm). Linear unmixing was used to delineate RFA lesions from surrounding tissue, and lesion diameters derived from unmixed component images were quantitatively compared to gross pathology. RFA caused two consistent changes in the autofluorescence emission profile: a decrease at wavelengths below 490 nm (ascribed to a loss of endogenous NADH) and an increase at wavelengths above 490 nm (ascribed to increased scattering). These spectral changes enabled high resolution, in situ delineation of RFA lesion boundaries without the need for additional staining or exogenous markers. Our results confirm the feasibility of using aHSI to visualize RFA lesions at clinically relevant locations. If integrated into a percutaneous visualization catheter, aHSI would enable widefield optical surgical guidance during RFA procedures and could improve patient outcome by reducing atrial fibrillation recurrence.
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Affiliation(s)
- Daniel A. Gil
- Department of Pharmacology & Physiology, George Washington University School of Medicine and Health Sciences, 2300 Eye Street NW, Washington DC, USA
- Department of Biomedical Engineering, Vanderbilt University, 5824 Stevenson Center, PMB 351631, 2301 Vanderbilt Place, Nashville, TN, USA
| | - Luther M. Swift
- Department of Pharmacology & Physiology, George Washington University School of Medicine and Health Sciences, 2300 Eye Street NW, Washington DC, USA
| | - Huda Asfour
- Department of Pharmacology & Physiology, George Washington University School of Medicine and Health Sciences, 2300 Eye Street NW, Washington DC, USA
| | - Narine Muselimyan
- Department of Pharmacology & Physiology, George Washington University School of Medicine and Health Sciences, 2300 Eye Street NW, Washington DC, USA
| | - Marco A. Mercader
- Division of Cardiology, George Washington University Medical Faculty Associates, 2150 Pennsylvania Avenue NW, Suite 4-417, Washington DC, USA
| | - Narine A. Sarvazyan
- Department of Pharmacology & Physiology, George Washington University School of Medicine and Health Sciences, 2300 Eye Street NW, Washington DC, USA
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Li Y, Sun C, Kuang J, Ji C, Feng S, Wu J, You H. An In Vitro and Numerical Study of Moxibustion Therapy on Biological Tissue. IEEE Trans Biomed Eng 2017. [PMID: 28650805 DOI: 10.1109/tbme.2017.2719633] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Moxibustion therapy achieves satisfactory therapeutic effects largely depending on the heat stimulation of burning moxa. Understanding the thermal characteristics of heating process is an effective way to reveal the underlying mechanisms of moxibustion therapy. METHODS This paper performs experimental study on temperature distributions of burning moxa sticks and fresh in vitro porcine abdominal tissue using an infrared camera and thermocouples. Meanwhile, a moxibustion model incorporating moxa stick burning model and tissue heat transfer model was established with consideration of radiation propagation and water evaporation. RESULTS The burning features of moxa sticks were acquired and the radiation energy generated by the burning moxa stick was absorbed and scattered in biological tissue, resulting in a large temperature gradient in the skin layer. And the water evaporation led to a mass loss and reduced skin surface temperature. The numerical model was verified by experimental results and the effects of moxibustion treatment distance and duration can be quantified based on model calculation. CONCLUSION The detailed heat transfer process of moxibustion was obtained experimentally and numerically. During moxibustion, the radiation attenuation and water evaporation have a significant influence on the energy transport in biological tissue which cannot be ignored. The treatment distance of 3 cm is the recommended value to achieve the treatment efficacy without thermal damage and pain. SIGNIFICANCE This research would reveal the underlying mechanisms of moxibustion therapy. Besides, the developed models are expected to establish a guideline for moxibustion clinical treatment.
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Liu D, Brace CL. Numerical simulation of microwave ablation incorporating tissue contraction based on thermal dose. Phys Med Biol 2017; 62:2070-2086. [PMID: 28151729 DOI: 10.1088/1361-6560/aa5de4] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Tissue contraction plays an important role during high temperature tumor ablation, particularly during device characterization, treatment planning and imaging follow up. We measured such contraction in 18 ex vivo bovine liver samples during microwave ablation by tracking fiducial motion on CT imaging. Contraction was then described using a thermal dose dependent model and a negative thermal expansion coefficient based on the empirical data. FEM simulations with integrated electromagnetic wave propagation, heat transfer, and structural mechanics were evaluated using temperature-dependent dielectric properties and the negative thermal expansion models. Simulated temperature and displacement curves were then compared with the ex vivo experimental results on different continuous output powers. The optimized thermal dose model indicated over 50% volumetric contraction occurred at the temperature over 102.1 °C. The numerical simulation results on temperature and contraction-induced displacement showed a good agreement with experimental results. At microwave powers of 55 W, the mean errors on temperature between simulation and experimental results were 8.25%, 2.19% and 5.67% at 5 mm, 10 mm and 20 mm radially from the antenna, respectively. The simulated displacements had mean errors of 16.60%, 14.08% and 23.45% at the same radial locations. Compared to the experimental results, the simulations at the other microwave powers had larger errors with 10-40% mean errors at 40 W, and 10-30% mean errors at 25 W. The proposed model is able to predict temperature elevation and simulate tissue deformation during microwave ablation, and therefore may be incorporated into treatment planning and clinical translation from numerical simulations.
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Affiliation(s)
- Dong Liu
- Department of Radiology and Biomedical Engineering, University of Wisconsin-Madison, 1111 Highland Ave, Madison WI 53705, United States of America
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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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CONSIGLIERI LUISA. ANALYTICAL SOLUTIONS IN THE MODELING OF THE LOCAL RF ABLATION. J MECH MED BIOL 2016. [DOI: 10.1142/s0219519416500718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Coupled mathematical models for the radiofrequency (RF) ablation performed in biomedical sciences have been developed based on the bioheat transfer theory. The heat exchange problem is important to be analytically studied in order to control the size of the necrosis zone caused by RF ablation. This lesion size in the tissue may be predicted by the knowledge of the internal tissue temperature. We propose an analytical solution for the Pennes heat transfer equation in bi- and tri-region domains, applicable to the RF ablation of cancerigeneous tissue — a clinical relevant problem. The model consists of two partial differential equations describing the spatio-temporal interactions between the electric and thermic effects. The aim is to find simple algebraic expressions of analytical solutions that may allow to generate quantitative results which in turn may be interpreted (including uncertainties). The dependence of the temperature as function of the electrothermal parameters in both diseased and surrounding healthy tissues is pointed out. Two cases, namely the tumor–tissue and tumor–tissue–skin systems, are graphically computed, and important findings include the fact that the presence of tissue with smaller value parameters protects somehow healthy cells. Moreover, the graphical representations are conducted to highlight the link of the profile of current density distribution in the physiological problem with the (neither oval nor circular) shape of the temperature isoclinic lines.
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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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Wang Z, Luo H, Coleman S, Cuschieri A. Bi-component conformal electrode for radiofrequency sequential ablation and circumferential separation of large tumours in solid organs: development and in-vitro evaluation. IEEE Trans Biomed Eng 2016; 64:699-705. [DOI: 10.1109/tbme.2016.2573043] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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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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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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Liu D, Brace CL. CT imaging during microwave ablation: analysis of spatial and temporal tissue contraction. Med Phys 2015; 41:113303. [PMID: 25370671 DOI: 10.1118/1.4897381] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
PURPOSE To analyze the spatial distribution and temporal development of liver tissue contraction during high-temperature ablation by using intraprocedural computed tomography (CT) imaging. METHODS A total of 46 aluminum fiducial markers were positioned in a 60 × 45 mm grid, in a single plane, around a microwave ablation antenna in each of six ex vivo bovine liver samples. Ablations were performed for 10 min at 100 W. CT data of the liver sample were acquired every 30 s during ablation. Fiducial motion between acquisitions was tracked in postprocessing and used to calculate measures of tissue contraction and contraction rates. The spatial distribution and temporal evolution of contraction were analyzed. RESULTS Fiducial displacement indicated that the zone measured postablation was 8.2 ± 1.8 mm (∼20%) smaller in the radial direction and 7.1 ± 1.0 mm (∼10%) shorter in the longitudinal direction than the preablation tissue dimension. Therefore, the total ablation volume was reduced from its preablation value by approximately 45%. Very little longitudinal contraction was noted in the distal portion of the ablation zone. Central tissues contracted more than 60%, which was near an estimated limit of ∼70% based on initial water content. More peripheral tissues contracted only 15% in any direction. Contraction rates peaked during the first 60 s of heating with a roughly exponential decay over time. CONCLUSIONS Ablation zones measured posttreatment are significantly smaller than the pretreatment tissue dimensions. Tissue contraction is spatially dependent, with the greatest effect occurring in the central ablation zone. Contraction rate peaks early and decays over time.
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Affiliation(s)
- Dong Liu
- Departments of Radiology and Biomedical Engineering, University of Wisconsin, Madison, Wisconsin 53705
| | - Christopher L Brace
- Departments of Radiology and Biomedical Engineering, University of Wisconsin, Madison, Wisconsin 53705
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Mulier S, Jiang Y, Jamart J, Wang C, Feng Y, Marchal G, Michel L, Ni Y. Bipolar radiofrequency ablation with 2 × 2 electrodes as a building block for matrix radiofrequency ablation:Ex vivoliver experiments and finite element method modelling. Int J Hyperthermia 2015; 31:649-65. [DOI: 10.3109/02656736.2015.1046194] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
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