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Wang B, Zang L, Lu Y, Zhan M, Sun T, Zhou Y, Song C. Simulation-guided development of advanced PID control algorithm for skin cooling in radiofrequency lipolysis. Biomed Mater Eng 2024; 35:303-321. [PMID: 38517766 DOI: 10.3233/bme-230185] [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] [Indexed: 03/24/2024]
Abstract
BACKGROUND The clinical outcomes of bipolar radiofrequency (RF) lipolysis, a prevalent non-invasive fat reduction procedure, hinge on the delicate balance between effective lipolysis and patient safety, with skin overheating and subsequent tissue damage as primary concerns. OBJECTIVE This study aimed to investigate a novel bipolar radiofrequency lipolysis technique, safeguarding the skin through an innovative PID temperature control algorithm. METHODS Utilizing COMSOL Multiphysics simulation software, a two-dimensional fat and skin tissue model was established, simulating various PID temperature control schemes. The crux of the simulation involved a comparative analysis of different PID temperatures at 45 °C, 50 °C, and 55 °C and constant power strategies, assessing their implications on skin temperature. Concurrently, a custom bipolar radiofrequency lipolysis device was developed, with ex vivo experiments conducted using porcine tissue for empirical validation. RESULTS The findings indicated that with PID settings of Kp = 7, Ki = 2, and Kd = 0, and skin temperature control at 45 °C or 50 °C, the innovative PID-based epidermal temperature control strategy successfully maintained the epidermal temperature within a safe range. This maintenance was achieved without compromising the effectiveness of RF lipolysis, significantly reducing the risk of thermal damage to the skin layers. CONCLUSION Our research confirms the substantial practical utility of this advanced PID-based bipolar RF lipolysis technique in clinical aesthetic procedures, enhancing patient safety during adipose tissue ablation therapies.
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Affiliation(s)
- Binyu Wang
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Lianru Zang
- Center for Biomedical Engineering, School of Information Science and Technology, Fudan University, Shanghai, China
- National Heart and Lung Institute, Imperial College London, London, United Kingdom of Great Britain and Northern Ireland
| | - Yingxi Lu
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Mengying Zhan
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Tingting Sun
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Yu Zhou
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Chengli Song
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
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2
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Ma Y, Wang N, Li K, Liang H, Bai J, Ji X. Effect of geometric parameters of electrodes on skin heating for the design of non-ablative radiofrequency device. Skin Res Technol 2023; 29:e13472. [PMID: 37881053 PMCID: PMC10560826 DOI: 10.1111/srt.13472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Accepted: 09/07/2023] [Indexed: 10/27/2023]
Abstract
BACKGROUND Non-ablative radiofrequency (RF) has been widely used in clinical and at-home cosmetics devices. RF electrode geometry can influence the heat distribution in the tissue. This study analyzes the influence of geometric parameters of the electrode on the heat distribution in the layered tissue. MATERIALS & METHODS The finite element simulation of the electrothermal coupling field was performed to obtain the three-dimensional (3D) temperature distribution of the four-layer tissue. The electrode geometric parameters including the inter-electrode spacing (5-12 mm), width (1-3 mm), length (3-10 mm), shapes (bar, dot and circle), and the coupling gel's electrical conductivity (0.2-1.5 S/m) were simulated. The maximum temperature at 2 mm depth (T-2 mm ) and the temperature difference (Tdiff ) between the maximum skin surface temperature and T-2 mm were obtained to evaluate the effectiveness and safety. RESULTS The effect of geometric parameters on the effectiveness and safety was mixed. The maximum T-2 mm occurred with the 5 mm inter-electrode spacing, 3 mm width, 10 mm length, the circle-shaped electrode, and the 1.5 S/m coupling gel's electrical conductivity. The ratio of inter-electrode spacing to width at around four can achieve rapid temperature rise and skin surface temperature protection. The electrode shape influenced the area of temperature rise in the tissue's cross-section. The coupling gel's electrical conductivity should be close to that of the skin to avoid energy accumulation on the skin surface. CONCLUSION The electrode's geometric parameters affect the effectiveness and safety of the RF product. This study has provided the simulation procedure for the electrode design.
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Affiliation(s)
- Yiyou Ma
- School of Biomedical EngineeringShanghai Jiao Tong UniversityShanghaiChina
| | - Nianou Wang
- School of Biomedical EngineeringShanghai Jiao Tong UniversityShanghaiChina
- Shenzhen Accompany Tech co., ltdShenzhenChina
| | - Ke Li
- Shenzhen Accompany Tech co., ltdShenzhenChina
| | - Huan Liang
- Shenzhen Accompany Tech co., ltdShenzhenChina
| | - Jingfeng Bai
- School of Biomedical EngineeringShanghai Jiao Tong UniversityShanghaiChina
| | - Xiang Ji
- School of Biomedical EngineeringShanghai Jiao Tong UniversityShanghaiChina
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Torres F, Basaran AC, Schuller IK. Thermal Management in Neuromorphic Materials, Devices, and Networks. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2205098. [PMID: 36067752 DOI: 10.1002/adma.202205098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 08/30/2022] [Indexed: 06/15/2023]
Abstract
Machine learning has experienced unprecedented growth in recent years, often referred to as an "artificial intelligence revolution." Biological systems inspire the fundamental approach for this new computing paradigm: using neural networks to classify large amounts of data into sorting categories. Current machine-learning schemes implement simulated neurons and synapses on standard computers based on a von Neumann architecture. This approach is inefficient in energy consumption, and thermal management, motivating the search for hardware-based systems that imitate the brain. Here, the present state of thermal management of neuromorphic computing technology and the challenges and opportunities of the energy-efficient implementation of neuromorphic devices are considered. The main features of brain-inspired computing and quantum materials for implementing neuromorphic devices are briefly described, the brain criticality and resistive switching-based neuromorphic devices are discussed, the energy and electrical considerations for spiking-based computation are presented, the fundamental features of the brain's thermal regulation are addressed, the physical mechanisms for thermal management and thermoelectric control of materials and neuromorphic devices are analyzed, and challenges and new avenues for implementing energy-efficient computing are described.
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Affiliation(s)
- Felipe Torres
- Physics Department, Faculty of Science, University of Chile, 653, Santiago, 7800024, Chile
- Center of Nanoscience and Nanotechnology (CEDENNA), Av. Ecuador 3493, Santiago, 9170124, Chile
| | - Ali C Basaran
- Department of Physics and Center for Advanced Nanoscience, University of California San Diego, La Jolla, CA, 92093, USA
| | - Ivan K Schuller
- Department of Physics and Center for Advanced Nanoscience, University of California San Diego, La Jolla, CA, 92093, USA
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4
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Cosma C, Apostu D, Vilau C, Popan A, Oltean-Dan D, Balc N, Tomoaie G, Benea H. Finite Element Analysis of Different Osseocartilaginous Reconstruction Techniques in Animal Model Knees. MATERIALS (BASEL, SWITZERLAND) 2023; 16:2546. [PMID: 37048840 PMCID: PMC10095518 DOI: 10.3390/ma16072546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 03/09/2023] [Accepted: 03/14/2023] [Indexed: 06/19/2023]
Abstract
Lesions of the articular cartilage are frequent in all age populations and lead to functional impairment. Multiple surgical techniques have failed to provide an effective method for cartilage repair. The aim of our research was to evaluate the effect of two different compression forces on three types of cartilage repair using finite element analysis (FEA). Initially, an in vivo study was performed on sheep. The in vivo study was prepared as following: Case 0-control group, without cartilage lesion; Case 1-cartilage lesion treated with macro-porous collagen implants; Case 2-cartilage lesion treated with collagen implants impregnated with bone marrow concentrate (BMC); Case 3-cartilage lesion treated with collagen implants impregnated with adipose-derived stem cells (ASC). Using the computed tomography (CT) data, virtual femur-cartilage-tibia joints were created for each Case. The study showed better results in bone changes when using porous collagen implants impregnated with BMC or ASC stem cells for the treatment of osseocartilaginous defects compared with untreated macro-porous implant. After 7 months postoperative, the presence of un-resorbed collagen influences the von Mises stress distribution, total deformation, and displacement on the Z axis. The BMC treatment was superior to ASC cells in bone tissue morphology, resembling the biomechanics of the control group in all FEA simulations.
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Affiliation(s)
- Cosmin Cosma
- Department of Manufacturing Engineering, Technical University of Cluj-Napoca, 400641 Cluj-Napoca, Romania; (C.C.)
| | - Dragos Apostu
- Department of Orthopedics and Traumatology, Iuliu Haţieganu University of Medicine and Pharmacy, 400132 Cluj-Napoca, Romania
| | - Cristian Vilau
- Department of Material Resistance, Technical University of Cluj-Napoca, 400641 Cluj-Napoca, Romania
| | - Alexandru Popan
- Department of Manufacturing Engineering, Technical University of Cluj-Napoca, 400641 Cluj-Napoca, Romania; (C.C.)
| | - Daniel Oltean-Dan
- Department of Orthopedics and Traumatology, Iuliu Haţieganu University of Medicine and Pharmacy, 400132 Cluj-Napoca, Romania
| | - Nicolae Balc
- Department of Manufacturing Engineering, Technical University of Cluj-Napoca, 400641 Cluj-Napoca, Romania; (C.C.)
| | - Gheorghe Tomoaie
- Department of Orthopedics and Traumatology, Iuliu Haţieganu University of Medicine and Pharmacy, 400132 Cluj-Napoca, Romania
- Academy of Romanian Scientists, 050044 Bucharest, Romania
| | - Horea Benea
- Department of Orthopedics and Traumatology, Iuliu Haţieganu University of Medicine and Pharmacy, 400132 Cluj-Napoca, Romania
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Temperature Dependence of Thermal Properties of Ex Vivo Porcine Heart and Lung in Hyperthermia and Ablative Temperature Ranges. Ann Biomed Eng 2023; 51:1181-1198. [PMID: 36656452 PMCID: PMC10172290 DOI: 10.1007/s10439-022-03122-9] [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: 07/31/2022] [Accepted: 12/25/2022] [Indexed: 01/20/2023]
Abstract
This work proposes the characterization of the temperature dependence of the thermal properties of heart and lung tissues from room temperature up to > 90 °C. The thermal diffusivity (α), thermal conductivity (k), and volumetric heat capacity (Cv) of ex vivo porcine hearts and deflated lungs were measured with a dual-needle sensor technique. α and k associated with heart tissue remained almost constant until ~ 70 and ~ 80 °C, accordingly. Above ~ 80 °C, a more substantial variation in these thermal properties was registered: at 94 °C, α and k respectively experienced a 2.3- and 1.5- fold increase compared to their nominal values, showing average values of 0.346 mm2/s and 0.828 W/(m·K), accordingly. Conversely, Cv was almost constant until 55 °C and decreased afterward (e.g., Cv = 2.42 MJ/(m3·K) at 94 °C). Concerning the lung tissue, both its α and k were characterized by an exponential increase with temperature, showing a marked increment at supraphysiological and ablative temperatures (at 91 °C, α and k were equal to 2.120 mm2/s and 2.721 W/(m·K), respectively, i.e., 13.7- and 13.1-fold higher compared to their baseline values). Regression analysis was performed to attain the best-fit curves interpolating the measured data, thus providing models of the temperature dependence of the investigated properties. These models can be useful for increasing the accuracy of simulation-based preplanning frameworks of interventional thermal procedures, and the realization of tissue-mimicking materials.
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Sebek J, Park WKC, Geimer S, Van Citters DW, Farah A, Dupuy DE, Meaney PM, Prakash P. Computational modeling of microwave ablation with thermal accelerants. Int J Hyperthermia 2023; 40:2255755. [PMID: 37710404 DOI: 10.1080/02656736.2023.2255755] [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: 03/30/2023] [Revised: 08/30/2023] [Accepted: 08/31/2023] [Indexed: 09/16/2023] Open
Abstract
PURPOSE To develop a computational model of microwave ablation (MWA) with a thermal accelerant gel and apply the model toward interpreting experimental observations in ex vivo bovine and in vivo porcine liver. METHODS A 3D coupled electromagnetic-heat transfer model was implemented to characterize thermal profiles within ex vivo bovine and in vivo porcine liver tissue during MWA with the HeatSYNC thermal accelerant. Measured temperature dependent dielectric and thermal properties of the HeatSYNC gel were applied within the model. Simulated extents of MWA zones and transient temperature profiles were compared against experimental measurements in ex vivo bovine liver. Model predictions of thermal profiles under in vivo conditions in porcine liver were used to analyze thermal ablations observed in prior experiments in porcine liver in vivo. RESULTS Measured electrical conductivity of the HeatSYNC gel was ∼83% higher compared to liver at room temperature, with positive linear temperature dependency, indicating increased microwave absorption within HeatSYNC gel compared to tissue. In ex vivo bovine liver, model predicted ablation zone extents of (31.5 × 36) mm with the HeatSYNC, compared to (32.9 ± 2.6 × 40.2 ± 2.3) mm in experiments (volume differences 4 ± 4.1 cm3). Computational models under in vivo conditions in porcine liver suggest approximating the HeatSYNC gel spreading within liver tissue during ablations as a plausible explanation for larger ablation zones observed in prior in vivo studies. CONCLUSION Computational models of MWA with thermal accelerants provide insight into the impact of accelerant on MWA, and with further development, could predict ablations with a variety of gel injection sites.
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Affiliation(s)
- Jan Sebek
- Department of Electrical and Computer Engineering, Kansas State University, Manhattan, Kansas, USA
| | | | - Shireen Geimer
- Expeditionary School at Black River, Ludlow, Vermont, USA
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
| | | | | | | | - Paul M Meaney
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
| | - Punit Prakash
- Department of Electrical and Computer Engineering, Kansas State University, Manhattan, Kansas, USA
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Fabrication and characterization of synthesized hydroxyapatite/ethanolamine for bone tissue engineering application. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.129591] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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8
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Murugarren N, Roig‐Sanchez S, Antón‐Sales I, Malandain N, Xu K, Solano E, Reparaz JS, Laromaine A. Highly Aligned Bacterial Nanocellulose Films Obtained During Static Biosynthesis in a Reproducible and Straightforward Approach. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2201947. [PMID: 35861401 PMCID: PMC9475533 DOI: 10.1002/advs.202201947] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 06/21/2022] [Indexed: 06/15/2023]
Abstract
Bacterial nanocellulose (BNC) is usually produced as randomly-organized highly pure cellulose nanofibers films. Its high water-holding capacity, porosity, mechanical strength, and biocompatibility make it unique. Ordered structures are found in nature and the properties appearing upon aligning polymers fibers inspire everyone to achieve highly aligned BNC (A-BNC) films. This work takes advantage of natural bacteria biosynthesis in a reproducible and straightforward approach. Bacteria confined and statically incubated biosynthesized BNC nanofibers in a single direction without entanglement. The obtained film is highly oriented within the total volume confirmed by polarization-resolved second-harmonic generation signal and Small Angle X-ray Scattering. The biosynthesis approach is improved by reusing the bacterial substrates to obtain A-BNC reproducibly and repeatedly. The suitability of A-BNC as cell carriers is confirmed by adhering to and growing fibroblasts in the substrate. Finally, the thermal conductivity is evaluated by two independent approaches, i.e., using the well-known 3ω-method and a recently developed contactless thermoreflectance approach, confirming a thermal conductivity of 1.63 W mK-1 in the direction of the aligned fibers versus 0.3 W mK-1 perpendicularly. The fivefold increase in thermal conductivity of BNC in the alignment direction forecasts the potential of BNC-based devices outperforming some other natural polymer and synthetic materials.
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Affiliation(s)
- Nerea Murugarren
- Institut Ciencia de Materials de Barcelona (ICMAB‐CSIC)Campus UABBellaterra08193Spain
| | - Soledad Roig‐Sanchez
- Institut Ciencia de Materials de Barcelona (ICMAB‐CSIC)Campus UABBellaterra08193Spain
| | - Irene Antón‐Sales
- Institut Ciencia de Materials de Barcelona (ICMAB‐CSIC)Campus UABBellaterra08193Spain
| | - Nanthilde Malandain
- Institut Ciencia de Materials de Barcelona (ICMAB‐CSIC)Campus UABBellaterra08193Spain
| | - Kai Xu
- Institut Ciencia de Materials de Barcelona (ICMAB‐CSIC)Campus UABBellaterra08193Spain
| | - Eduardo Solano
- NCD‐SWEET beamlineALBA Synchrotron Light SourceCarrer de la Llum 2−26Cerdanyola del VallèsBarcelona08290Spain
| | | | - Anna Laromaine
- Institut Ciencia de Materials de Barcelona (ICMAB‐CSIC)Campus UABBellaterra08193Spain
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9
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Ren Y, Yan Y, Qi H. Photothermal conversion and transfer in photothermal therapy: From macroscale to nanoscale. Adv Colloid Interface Sci 2022; 308:102753. [PMID: 36007283 DOI: 10.1016/j.cis.2022.102753] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 08/08/2022] [Accepted: 08/10/2022] [Indexed: 12/17/2022]
Abstract
Photothermal therapy (PTT) is a promising alternative therapy for benign or even malignant tumors. To improve the selective heating of tumor cells, target-specific photothermal conversion agents are often included, especially nanoparticles. Meanwhile, some indirect methods by manipulating the radiation and heat delivery are also adopted. Therefore, to gain a clear understanding of the mechanism, and to improve the controllability of PTT, a few issues need to be clarified, including bioheat and radiation transfer, localized and collective heating of nanoparticles, etc. In this review, we provide an introduction to the typical bioheat transfer and radiation transfer models along with the dynamic thermophysical properties of biological tissue. On this basis, we reviewed the most recent advances in the temperature control methods in PTT from macroscale to nanoscale. Most importantly, a comprehensive introduction of the localized and collective heating effects of nanoparticle clusters is provided to give a clear insight into the mechanism for PPT from the microscale and nanoscale point of view.
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Affiliation(s)
- Yatao Ren
- Faculty of Engineering, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom; School of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001, PR China
| | - Yuying Yan
- Faculty of Engineering, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom.
| | - Hong Qi
- School of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001, PR China.
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10
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Sánchez-Muñoz EJ, Berjano E, González-Suárez A. Computer simulations of consecutive radiofrequency pulses applied at the same point during cardiac catheter ablation: Implications for lesion size and risk of overheating. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 220:106817. [PMID: 35468542 DOI: 10.1016/j.cmpb.2022.106817] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 04/12/2022] [Accepted: 04/14/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND AND OBJECTIVES To study temperature distribution and lesion size during two repeated radiofrequency (RF) pulses applied at the same point in the context of RF cardiac ablation (RFCA). METHODS An in-silico RFCA model accounting for reversible and irreversible changes in myocardium electrical properties due to RF-induced heating. Arrhenius damage model to estimate lesion size during the application of two 20 W pulses at intervals (INT) of from 5 to 70 s. We considered two pulse durations: 20 s and 30 s. RESULTS INT has a significant effect on lesion size and maximum tissue temperature (TMAX). The shorter the INT the greater the increase in lesion size after the second pulse but also the greater the TMAX. If the second pulse is applied almost immediately (INT=5 s), depth increases 1.4 mm and 1.5 mm for pulses of 20 s and 30 s, respectively. If INT is longer than 30 s it increases 1.1 mm and 1.3 mm for pulses of 20 s and 30 s, respectively. While a single 20 s pulse causes TMAX=79 ºC, a second pulse produces values of from 92 to 96 ºC (the higher the temperature the shorter the INT). For 30 s pulses, TMAX=93 ºC for a single pulse, and varied from 98 to 104 ºC for a second pulse. CONCLUSIONS Applying a second RF pulse at the same ablation site increases lesion depth by 1 - 1.5 mm more than a single pulse and could lead to higher temperatures (up to 17 ºC). Both lesion depth and maximum tissue temperature increased at shorter inter-pulse intervals, which could cause clinical complications from overheating such as steam pops.
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Affiliation(s)
| | - Enrique Berjano
- BioMIT, Department of Electronic Engineering, Universitat Politècnica de València, Valencia, Spain
| | - Ana González-Suárez
- Electrical and Electronic Engineering, National University of Ireland Galway, Ireland; Translational Medical Device Lab, National University of Ireland Galway, Ireland.
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Li S, Dai Z, Li L, Padture NP, Guo P. Time-resolved vibrational-pump visible-probe spectroscopy for thermal conductivity measurement of metal-halide perovskites. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:053003. [PMID: 35649796 DOI: 10.1063/5.0083763] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Understanding thermal transport at the microscale to the nanoscale is crucially important for a wide range of technologies ranging from device thermal management and protection systems to thermal-energy regulation and harvesting. In the past decades, non-contact optical methods, such as time-domain and frequency-domain thermoreflectance, have emerged as extremely powerful and versatile thermal metrological techniques for the measurement of material thermal conductivities. Here, we report the measurement of thermal conductivity of thin films of CH3NH3PbI3 (MAPbI3), a prototypical metal-halide perovskite, by developing a time-resolved optical technique called vibrational-pump visible-probe (VPVP) spectroscopy. The VPVP technique relies on the direct thermal excitation of MAPbI3 by femtosecond mid-infrared optical pump pulses that are wavelength-tuned to a vibrational mode of the material, after which the time dependent optical transmittance across the visible range is probed in the ns to the μs time window using a broadband pulsed laser. Using the VPVP method, we determine the thermal conductivities of MAPbI3 thin films deposited on different substrates. The transducer-free VPVP method reported here is expected to permit spectrally resolving and spatiotemporally imaging of the dynamic lattice temperature variations in organic, polymeric, and hybrid organic-inorganic semiconductors.
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Affiliation(s)
- Shunran Li
- Department of Chemical and Environmental Engineering, Yale University, 9 Hillhouse Avenue, New Haven, Connecticut 06520, USA
| | - Zhenghong Dai
- School of Engineering, Brown University, Providence, Rhode Island 02912, USA
| | - Linda Li
- Department of Chemical and Environmental Engineering, Yale University, 9 Hillhouse Avenue, New Haven, Connecticut 06520, USA
| | - Nitin P Padture
- School of Engineering, Brown University, Providence, Rhode Island 02912, USA
| | - Peijun Guo
- Department of Chemical and Environmental Engineering, Yale University, 9 Hillhouse Avenue, New Haven, Connecticut 06520, USA
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12
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The Role of Hyperthermia in the Treatment of Peritoneal Surface Malignancies. Curr Oncol Rep 2022; 24:875-887. [PMID: 35325402 DOI: 10.1007/s11912-022-01275-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/15/2022] [Indexed: 11/03/2022]
Abstract
PURPOSE OF REVIEW Hyperthermia is used to treat peritoneal surface malignancies (PSM), particularly during hyperthermic intraperitoneal chemotherapy (HIPEC). This manuscript provides a focused update of hyperthermia in the treatment of PSM. RECENT FINDINGS The heterogeneous response to hyperthermia in PSM can be explained by tumor and treatment conditions. PSM tumors may resist hyperthermia via metabolic and immunologic adaptation. The thermodynamics of HIPEC are complex and require computational fluid dynamics (CFD). The clinical evidence supporting the benefit of hyperthermia is largely observational. Continued research will allow clinicians to characterize and predict the individual response of PSM to hyperthermia. The application of hyperthermia in current HIPEC protocols is mostly empirical. Thus, modeling heat transfer with CFD is a necessary task if we are to achieve consistent and reproducible hyperthermia. Although observational evidence suggests a survival benefit of hyperthermia, no clinical trial has tested the individual role of hyperthermia in PSM.
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Fang Y, Zheng W, Peng Y, Liu J, Gao J, Tu Y, Sun S, Huang X, She J, Chen C, Xu S, Yue Y. Differentiate Thermal Property of Mammary Glands for Precise Photothermal Therapy. ADVANCED THERAPEUTICS 2022. [DOI: 10.1002/adtp.202100216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Yuxin Fang
- Key Laboratory of Hydraulic Machinery Transients (MOE) School of Power and Mechanical Engineering Wuhan University Wuhan 430072 China
| | - Weijie Zheng
- Department of Breast and Thyroid Surgery Renmin Hospital of Wuhan University Wuhan 430060 China
| | - Yuxuan Peng
- Key Laboratory of Hydraulic Machinery Transients (MOE) School of Power and Mechanical Engineering Wuhan University Wuhan 430072 China
| | - Jianhua Liu
- Department of Breast and Thyroid Surgery Renmin Hospital of Wuhan University Wuhan 430060 China
| | - Jianshu Gao
- Key Laboratory of Hydraulic Machinery Transients (MOE) School of Power and Mechanical Engineering Wuhan University Wuhan 430072 China
| | - Yi Tu
- Department of Breast and Thyroid Surgery Renmin Hospital of Wuhan University Wuhan 430060 China
| | - Shengrong Sun
- Department of Breast and Thyroid Surgery Renmin Hospital of Wuhan University Wuhan 430060 China
| | - Xiaona Huang
- Key Laboratory of Hydraulic Machinery Transients (MOE) School of Power and Mechanical Engineering Wuhan University Wuhan 430072 China
| | - Jinjuan She
- Department of Mechanical and Manufacturing Engineering Miami University Ohio 45056 USA
| | - Chuang Chen
- Department of Breast and Thyroid Surgery Renmin Hospital of Wuhan University Wuhan 430060 China
| | - Shen Xu
- School of Mechanical and Automotive Engineering Shanghai University of Engineering Science Shanghai 201620 China
| | - Yanan Yue
- Key Laboratory of Hydraulic Machinery Transients (MOE) School of Power and Mechanical Engineering Wuhan University Wuhan 430072 China
- Department of Mechanical and Manufacturing Engineering Miami University Ohio 45056 USA
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14
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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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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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16
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Campbell-Staton SC, Walker RH, Rogers SA, De León J, Landecker H, Porter W, Mathewson PD, Long RA. Physiological costs of undocumented human migration across the southern United States border. Science 2021; 374:1496-1500. [PMID: 34914507 DOI: 10.1126/science.abh1924] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Shane C Campbell-Staton
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA.,Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, USA.,Institute for Society and Genetics, University of California, Los Angeles, CA, USA
| | - Reena H Walker
- Department of Fish and Wildlife Sciences, University of Idaho, Moscow, ID, USA
| | - Savannah A Rogers
- Bioinformatics and Computational Biology, University of Idaho, Moscow, ID, USA
| | - Jason De León
- Department of Anthropology and Chicana, Chicano, and Central American Studies, University of California, Los Angeles, CA, USA
| | - Hannah Landecker
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, USA.,Sociology Department, University of California, Los Angeles, CA, USA
| | - Warren Porter
- Department of Integrative Biology, University of Wisconsin, Madison, WI, USA
| | - Paul D Mathewson
- Department of Integrative Biology, University of Wisconsin, Madison, WI, USA
| | - Ryan A Long
- Department of Fish and Wildlife Sciences, University of Idaho, Moscow, ID, USA
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17
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Chang CF, Kuo HY, Lee JP. AC measurements and simulations of hepatic radiofrequency ablation. Int J Hyperthermia 2021; 38:1322-1332. [PMID: 34477032 DOI: 10.1080/02656736.2021.1971779] [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: 10/20/2022] Open
Abstract
INTRODUCTION The radiofrequency ablation (RFA) of liver cancer is a desirable treatment option, as it is minimally invasive. An accurate numerical simulation can greatly help physicians better plan their surgical protocols. Previously, the displacement current in the RFA process was considered negligible, and therefore RFA simulation was modeled as a direct current (DC) system instead of an alternating current (AC) system. Our study investigated the hypothesis that the displacement current in the RFA process should not always be considered negligible. METHODS AC measurements of ex vivo bovine liver ablation were performed, and numerical simulations were also conducted to test the hypothesis that the relative permittivity would significantly decrease after the liver tissue reached a high temperature. RESULTS The displacement current was observed to be a sizable fraction of the conduction current, especially before the onset of the first pause. The simulation results indicated that the relative permittivity is likely to decrease to several hundred or lower at elevated temperatures. CONCLUSIONS Our study results suggest that the DC model may be inadequate, especially before the first roll-off and that additional information could be available during RFA treatment by considering the AC nature of RFA, which could lead to improved numerical simulation. Additional measurements of tissue parameters are needed to reach the full potential of the AC model for further development of ablation control.
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Affiliation(s)
- Chieh-Feng Chang
- Biomedical Technology and Device Research Laboratories, Industrial Technology Research Institute, Chutung, Taiwan
| | - Hsuan-Yu Kuo
- Biomedical Technology and Device Research Laboratories, Industrial Technology Research Institute, Chutung, Taiwan
| | - Jo-Ping Lee
- Biomedical Technology and Device Research Laboratories, Industrial Technology Research Institute, Chutung, Taiwan
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18
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Payne A, Chopra R, Ellens N, Chen L, Ghanouni P, Sammet S, Diederich C, Ter Haar G, Parker D, Moonen C, Stafford J, Moros E, Schlesinger D, Benedict S, Wear K, Partanen A, Farahani K. AAPM Task Group 241: A medical physicist's guide to MRI-guided focused ultrasound body systems. Med Phys 2021; 48:e772-e806. [PMID: 34224149 DOI: 10.1002/mp.15076] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 04/28/2021] [Accepted: 06/21/2021] [Indexed: 11/07/2022] Open
Abstract
Magnetic resonance-guided focused ultrasound (MRgFUS) is a completely non-invasive technology that has been approved by FDA to treat several diseases. This report, prepared by the American Association of Physicist in Medicine (AAPM) Task Group 241, provides background on MRgFUS technology with a focus on clinical body MRgFUS systems. The report addresses the issues of interest to the medical physics community, specific to the body MRgFUS system configuration, and provides recommendations on how to successfully implement and maintain a clinical MRgFUS program. The following sections describe the key features of typical MRgFUS systems and clinical workflow and provide key points and best practices for the medical physicist. Commonly used terms, metrics and physics are defined and sources of uncertainty that affect MRgFUS procedures are described. Finally, safety and quality assurance procedures are explained, the recommended role of the medical physicist in MRgFUS procedures is described, and regulatory requirements for planning clinical trials are detailed. Although this report is limited in scope to clinical body MRgFUS systems that are approved or currently undergoing clinical trials in the United States, much of the material presented is also applicable to systems designed for other applications.
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Affiliation(s)
- Allison Payne
- Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, USA
| | - Rajiv Chopra
- Department of Radiology, UT Southwestern Medical Center, Dallas, TX, USA
| | | | - Lili Chen
- Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA, USA
| | - Pejman Ghanouni
- Department of Radiology, Stanford University, Stanford, CA, USA
| | - Steffen Sammet
- Department of Radiology, University of Chicago, Chicago, IL, USA
| | - Chris Diederich
- Department of Radiation Oncology, University of California San Francisco, San Francisco, CA, USA
| | | | - Dennis Parker
- Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, USA
| | - Chrit Moonen
- Imaging Division, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jason Stafford
- Department of Imaging Physics, MD Anderson Cancer Center, Houston, TX, USA
| | - Eduardo Moros
- Department of Radiation Oncology, Moffitt Cancer Center, Tampa, FL, USA
| | - David Schlesinger
- Department of Radiation Oncology, University of Virginia, Charlottesville, VA, USA
| | | | - Keith Wear
- U.S. Food and Drug Administration, Silver Spring, MD, USA
| | | | - Keyvan Farahani
- National Cancer Institute, National Institutes of Health, Rockville, MD, USA
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19
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Mohammadi A, Bianchi L, Korganbayev S, De Landro M, Saccomandi P. Thermomechanical Modeling of Laser Ablation Therapy of Tumors: Sensitivity Analysis and Optimization of Influential Variables. IEEE Trans Biomed Eng 2021; 69:302-313. [PMID: 34181533 DOI: 10.1109/tbme.2021.3092889] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
In cancer treatment, laser ablation is a promising technique used to induce localized thermal damage. Different variables influence the temperature distribution in the tissue and the resulting therapy efficacy; thus, the optimal therapy settings are required for obtaining the desired clinical outcome. In this work, thermomechanical modeling of contactless laser ablation was implemented to analyze the sensitivity of independent variables on the optimal treatment conditions. The Finite Element Method was utilized to solve the governing equations, i.e., the bioheat, mechanical deformation, and the Navier-Stokes equations. Validation of the model was evaluated by comparing experimental and simulated temperatures, which indicated high accuracy for estimating temperature. In particular, the results showed that the model is capable of estimating temperature with a good correlation factor (R=0.98) and low Mean Absolute Error (3.9 C). A sensitivity analysis based on laser irradiation time, power, beam distribution, and the blood vessel depth on temperature distribution and fraction of necrotic tissue was performed. Based on the most significant variables i.e., laser irradiation time and power, an optimization process was performed. This resulted into an indication of the optimal therapy settings for achieving maximum procedure efficiency i.e., the required fraction of necrotic tissue within the target volume, constituted by tumor and safety margins around it.
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20
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Mohammadi A, Bianchi L, Asadi S, Saccomandi P. Measurement of Ex Vivo Liver, Brain and Pancreas Thermal Properties as Function of Temperature. SENSORS (BASEL, SWITZERLAND) 2021; 21:4236. [PMID: 34205567 PMCID: PMC8235733 DOI: 10.3390/s21124236] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 06/04/2021] [Accepted: 06/17/2021] [Indexed: 12/11/2022]
Abstract
The ability to predict heat transfer during hyperthermal and ablative techniques for cancer treatment relies on understanding the thermal properties of biological tissue. In this work, the thermal properties of ex vivo liver, pancreas and brain tissues are reported as a function of temperature. The thermal diffusivity, thermal conductivity and volumetric heat capacity of these tissues were measured in the temperature range from 22 to around 97 °C. Concerning the pancreas, a phase change occurred around 45 °C; therefore, its thermal properties were investigated only until this temperature. Results indicate that the thermal properties of the liver and brain have a non-linear relationship with temperature in the investigated range. In these tissues, the thermal properties were almost constant until 60 to 70 °C and then gradually changed until 92 °C. In particular, the thermal conductivity increased by 100% for the brain and 60% for the liver up to 92 °C, while thermal diffusivity increased by 90% and 40%, respectively. However, the heat capacity did not significantly change in this temperature range. The thermal conductivity and thermal diffusivity were dramatically increased from 92 to 97 °C, which seems to be due to water vaporization and state transition in the tissues. Moreover, the measurement uncertainty, determined at each temperature, increased after 92 °C. In the temperature range of 22 to 45 °C, the thermal properties of pancreatic tissue did not change significantly, in accordance with the results for the brain and liver. For the three tissues, the best fit curves are provided with regression analysis based on measured data to predict the tissue thermal behavior. These curves describe the temperature dependency of tissue thermal properties in a temperature range relevant for hyperthermia and ablation treatments and may help in constructing more accurate models of bioheat transfer for optimization and pre-planning of thermal procedures.
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Affiliation(s)
| | | | | | - Paola Saccomandi
- Department of Mechanical Engineering, Politecnico di Milano, 20156 Milan, Italy; (A.M.); (L.B.); (S.A.)
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21
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Lianru Z, Yu Z, Jia K, Yinmin X, ChengLi S. A Computational and Experimental Study to Compare the Effectiveness of Bipolar Mode With Phase-Shift Angle Mode in Radiofrequency Fat Dissolution on Subcutaneous Tissue. Lasers Surg Med 2021; 53:1395-1412. [PMID: 34036607 DOI: 10.1002/lsm.23420] [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: 10/09/2020] [Revised: 04/02/2021] [Accepted: 05/09/2021] [Indexed: 11/08/2022]
Abstract
BACKGROUND AND OBJECTIVES Radiofrequency (RF) energy exposure refers to a popular non-invasive method employed to generate heat in cutaneous and subcutaneous tissues. RF thermal stimulation of adipose tissue has been considered to cause adipocyte metabolism and enzymatic degradation of triglycerides into free fatty acids and glycerol. Bipolar mode (BM) has achieved extensive applications in clinical studies on RF fat dissolution, whereas BM has a less penetration depth than monopolar, result in a higher RF voltage that may be required to increase power to the deeper fat layer of the subcutaneous tissue, and improper power control may easily cause the skin layer to be thermally damaged. To tackle down the mentioned defect, a novel phase-shift angle mode (PM) was proposed in this study based on double-channel bipolar RF. By employing the finite element method (FEM) and performing the ex vivo experiment, the effectiveness of BM was compared with that of PM in RF fat dissolution on subcutaneous tissue. In addition, this study attempted to develop reasonable phase-shift angles capable of achieving fat dissolution effects, while the RF energy of which would not cause the skin layer to be thermally damaged. STUDY DESIGN/MATERIALS AND METHODS Two electrode spacings (1 and 2 cm) were applied in BM (BM-1 cm and BM-2 cm, respectively), and six phase-shift angles (i.e., 30°, 60°, 90°, 120°, 150°, and 180°) were set in PM (i.e., PM-30°, PM-60°, PM-90°, PM-120°, PM-150°, and PM-180°). In addition, COMSOL was adopted to conduct a finite element analysis for achieving thermoelectric coupling. Ex vivo experiments were performed with a self-developed double-channel bipolar RF device, through which up to two adjustable phase-shift angle sinusoidal voltages could be generated. Such a device was isolated with a transformer and then connected to four electrodes with a 5 mm diameter contacting the ex vivo porcine abdominal tissue. RESULTS Under the RF voltage amplitude of 30 V, and after 1800 seconds of RF heating, no thermally damaged area was formed in the tissue in BM-1 cm and BM-2 cm; in PM-30°, PM-60°, and PM-90°, thermally damaged areas were formed in the fat layer, while the skin layer was not located in the thermally damaged area. Moreover, the temperature in the thermally damaged area attributed to the mentioned three conditions may satisfy the requirement of fat dissolution temperature. CONCLUSIONS Under the identical RF voltage and heating time, PM is easier to cause the fat layer of the subcutaneous tissue to be thermally damaged as compared with BM. Accordingly, PM may be enabled to achieve the fat dissolution effect under a relatively low RF voltage as opposed to BM, thus avoiding the possibility of thermal damage of the skin layer attributed to the use of higher RF voltage. In PM, different phase-shift angle significantly affects the electrical and thermal properties of RF energy applied on subcutaneous tissue; the phase-shift angle of RF voltage is likely to be regulated for fat dissolution effect, while the RF energy of which will not cause the skin layer to be thermally damaged.© 2021 Wiley Periodicals LLC.
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Affiliation(s)
- Zang Lianru
- Shanghai Institute for Minimally Invasive Therapy, University of Shanghai for Science and Technology, 516 Jungong Road, 200082, Shanghai, China
| | - Zhou Yu
- Shanghai Institute for Minimally Invasive Therapy, University of Shanghai for Science and Technology, 516 Jungong Road, 200082, Shanghai, China
| | - Kang Jia
- Shanghai Institute for Minimally Invasive Therapy, University of Shanghai for Science and Technology, 516 Jungong Road, 200082, Shanghai, China
| | - Xue Yinmin
- Shanghai Institute for Minimally Invasive Therapy, University of Shanghai for Science and Technology, 516 Jungong Road, 200082, Shanghai, China
| | - Song ChengLi
- Shanghai Institute for Minimally Invasive Therapy, University of Shanghai for Science and Technology, 516 Jungong Road, 200082, Shanghai, China
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22
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Wardhana G, Almeida JP, Abayazid M, Fütterer JJ. Development of a thermal model for irreversible electroporation: an approach to estimate and optimize the IRE protocols. Int J Comput Assist Radiol Surg 2021; 16:1325-1334. [PMID: 34032965 PMCID: PMC8295143 DOI: 10.1007/s11548-021-02403-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 05/07/2021] [Indexed: 11/27/2022]
Abstract
Purpose Irreversible electroporation (IRE) is an emerging technique that has drawn attention in the field of cancer treatment. IRE uses non-thermal electric pulses to induce death of cancerous cells. However, recent studies have shown that the application of this technique may result in heating of the tissue. There is still room for improving its efficiency and defining better treatment protocols. This study investigates the optimal IRE protocols that avoiding the thermal damage during the IRE treatment. Methods Electrode and pulse parameter are investigated. Finite element models are created to evaluate the ablation area and the temperature changes in the tissue. The model is validated experimentally in bovine liver tissue, while the parameters were optimized using response surface method (RSM). Results From analysis of variance, the parameter of electrode distance and input voltage has significant effect to the temperature rise in the IRE treatment of bovine liver (P = 0.020 and P = 0.003 respectively). Meanwhile, only the input voltage significantly affects the ablation area (P < 0.001). The optimal result from RSM showed that for maximum ablation area 250.82mm2 with no thermal damage, the IRE protocol consisted of an active electrode length of 10 mm, a distance between electrodes of 10 mm, and the delivery of 50 pulses of 41.21 µs and 3000 V. Conclusions The approach presented in this study allows the optimization of the IRE protocols. An optimal IRE protocol that maximizes the ablation area was successfully calculated which can be applied with no risk of thermal damage to the tissue.
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Affiliation(s)
- Girindra Wardhana
- Department of Robotics and Mechatronics, The Faculty of Electrical Engineering, Mathematics and Computer Science, Technical Medical Centre, University of Twente, 7522 NB, Enschede, The Netherlands.
| | - João Pedro Almeida
- Department of Robotics and Mechatronics, The Faculty of Electrical Engineering, Mathematics and Computer Science, Technical Medical Centre, University of Twente, 7522 NB, Enschede, The Netherlands
| | - Momen Abayazid
- Department of Robotics and Mechatronics, The Faculty of Electrical Engineering, Mathematics and Computer Science, Technical Medical Centre, University of Twente, 7522 NB, Enschede, The Netherlands
| | - Jurgen J Fütterer
- Department of Robotics and Mechatronics, The Faculty of Electrical Engineering, Mathematics and Computer Science, Technical Medical Centre, University of Twente, 7522 NB, Enschede, The Netherlands
- Department of Medical Imaging, Radboud University Medical Center Nijmegen, Geert Grooteplein Zuid 10, 6525 GA, Nijmegen, The Netherlands
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23
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Veloso SR, Andrade RG, Castanheira EM. Review on the advancements of magnetic gels: towards multifunctional magnetic liposome-hydrogel composites for biomedical applications. Adv Colloid Interface Sci 2021; 288:102351. [PMID: 33387893 DOI: 10.1016/j.cis.2020.102351] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 12/18/2020] [Accepted: 12/19/2020] [Indexed: 12/11/2022]
Abstract
Magnetic gels have been gaining great attention in nanomedicine, as they combine features of hydrogels and magnetic nanoparticles into a single system. The incorporation of liposomes in magnetic gels further leads to a more robust multifunctional system enabling more functions and spatiotemporal control required for biomedical applications, which includes on-demand drug release. In this review, magnetic gels components are initially introduced, as well as an overview of advancements on the development, tuneability, manipulation and application of these materials. After a discussion of the advantages of combining hydrogels with liposomes, the properties, fabrication strategies and applications of magnetic liposome-hydrogel composites (magnetic lipogels or magnetolipogels) are reviewed. Overall, the progress of magnetic gels towards smart multifunctional materials are emphasized, considering the contributions for future developments.
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24
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Dong H, Liu G, Tong X. Influence of temperature-dependent acoustic and thermal parameters and nonlinear harmonics on the prediction of thermal lesion under HIFU ablation. MATHEMATICAL BIOSCIENCES AND ENGINEERING : MBE 2021; 18:1340-1351. [PMID: 33757188 DOI: 10.3934/mbe.2021070] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
According to the traditional method of high intensity focused ultrasound (HIFU) treatment, the acoustic and thermal characteristic parameters of constant temperature (room temperature or body temperature) are used to predict thermal lesion. Based on the nonlinear spherical beam equation (SBE) and Pennes bio-heat transfer equation, and a new acoustic-thermal coupled model is proposed. The constant and temperature-dependent acoustic and thermal characteristic parameters are used to predict thermal lesion, and the predicted lesion area are compared with each other. Moreover, the relationship between harmonic amplitude ratio (P2/P1) and thermal lesion is studied. Combined with the known experimental data of acoustic and thermal characteristic parameters of biological tissue and data fitting method, the relationship between acoustic and thermal characteristic parameters and temperature is obtained; and the thermal lesion simulation calculation is carried out by using the acoustic and thermal characteristic parameters under constant temperature and temperature- dependent acoustic and thermal characteristic parameters, respectively. The simulation results show that under the same irradiation condition, the thermal lesion predicted by temperature-dependent acoustic and thermal characteristic parameters is larger than that predicted by traditional method, and the thermal lesion increases with the decrease of harmonic amplitude ratio.
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Affiliation(s)
- Hu Dong
- School of Information Science and Engineering, Changsha Normal University, Changsha 410100, China
| | - Gang Liu
- School of Physics and Electronics, Central South University, Changsha 410083, China
| | - Xin Tong
- School of Information Science and Engineering, Changsha Normal University, Changsha 410100, China
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25
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Mercado M, Leung L, Gallagher M, Shah S, Kulstad E. Modeling esophageal protection from radiofrequency ablation via a cooling device: an analysis of the effects of ablation power and heart wall dimensions. Biomed Eng Online 2020; 19:77. [PMID: 33046057 PMCID: PMC7552446 DOI: 10.1186/s12938-020-00821-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 09/24/2020] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Esophageal thermal injury can occur after radiofrequency (RF) ablation in the left atrium to treat atrial fibrillation. Existing methods to prevent esophageal injury have various limitations in deployment and uncertainty in efficacy. A new esophageal heat transfer device currently available for whole-body cooling or warming may offer an additional option to prevent esophageal injury. We sought to develop a mathematical model of this process to guide further studies and clinical investigations and compare results to real-world clinical data. RESULTS The model predicts that the esophageal cooling device, even with body-temperature water flow (37 °C) provides a reduction in esophageal thermal injury compared to the case of the non-protected esophagus, with a non-linear direct relationship between lesion depth and the cooling water temperature. Ablation power and cooling water temperature have a significant influence on the peak temperature and the esophageal lesion depth, but even at high RF power up to 50 W, over durations up to 20 s, the cooling device can reduce thermal impact on the esophagus. The model concurs with recent clinical data showing an 83% reduction in transmural thermal injury when using typical operating parameters. CONCLUSIONS An esophageal cooling device appears effective for esophageal protection during atrial fibrillation, with model output supporting clinical data. Analysis of the impact of ablation power and heart wall dimensions suggests that cooling water temperature can be adjusted for specific ablation parameters to assure the desired myocardial tissue ablation while keeping the esophagus protected.
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Affiliation(s)
- Marcela Mercado
- Bioengineering Department, Engineering Faculty, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellin, Colombia.
| | - Lisa Leung
- St. George's University Hospitals NHS Foundation Trust, St. George's, University of London, Cranmer Terrace, Tooting, London, SW17 0RE, UK
| | - Mark Gallagher
- St. George's University Hospitals NHS Foundation Trust, St. George's, University of London, Cranmer Terrace, Tooting, London, SW17 0RE, UK
| | | | - Erik Kulstad
- Southwestern Medical Center, University of Texas, Dallas, TX, USA
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26
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Ramaraju H, Ul-Haque A, Verga AS, Bocks ML, Hollister SJ. Modulating nonlinear elastic behavior of biodegradable shape memory elastomer and small intestinal submucosa(SIS) composites for soft tissue repair. J Mech Behav Biomed Mater 2020; 110:103965. [PMID: 32957256 DOI: 10.1016/j.jmbbm.2020.103965] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 06/17/2020] [Accepted: 06/29/2020] [Indexed: 01/08/2023]
Abstract
Structural repair of soft tissue for regenerative therapies can be advanced by developing biocompatible and bioresorbable materials with mechanical properties similar to the tissue targeted for therapy. Developing new materials modeling soft tissue mechanics can mitigate many limitations of material based therapies, specifically concerning the mechanical stress and deformation the material imposes on surrounding tissue structures. However, many elastomeric materials used in soft tissue repair lack the ability to be delivered through minimally invasive surgical (MIS) or transcatheter routes and require open surgical approaches for placement and application. We have developed a biocompatible and fully biodegradable shape memory elastomer, poly-(glycerol dodecanedioate) (PGD), which fulfills the requirements for hyperelasticity and exhibits shape memory behavior to serve as a novel substrate material for regenerative therapy in minimally invasive clinical procedures. Our previous work demonstrated control over the tangent modulus at 12.5% compressive strain between 1 and 3 MPa by increasing the crosslinking density in the polymer. In order to improve control over a broader range of mechanical properties, nonlinear behavior, and toughness, we 1) varied PGD physical crosslink density, 2) incorporated sheets of porcine small intestinal submucosa (SIS, Cook Biotech, Inc.) with varying thickness, and 3) mixed lyophilized SIS particulates into PGD at different weight percentages. Tensile testing (ASTM D412a) revealed PGD containing SIS sheets of were stiffer than controls (p < 0.01). Incorporating lyophilized SIS particulates into PGD increased the strain to failure (p < 0.001) compared to PGD controls. Test specimens with 1 ply sheets had greater tear strength (ASTM D624c) compared to PGD tear specimens prepared control specimens (p < 0.001). However, incorporating SIS particulates decreased tear strength of PGD-SIS 0.5 wt% particulate composites (p < 0.01) compared to PGD controls. Incorporating 2 ply and 4 ply sheets and 0.5 wt% particulates into PGD decreased the fixity and recovery of composite materials compared to controls (p < 0.01). Nonlinear modeling of stress strain curves under uniaxial tension demonstrated tunability of PGD-SIS composite materials to model various nonlinear soft tissues. These findings support the use of shape memory PGD-SIS composite materials towards the design of implantable devices for a variety of soft tissue regeneration applications by minimally invasive surgery.
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Affiliation(s)
- Harsha Ramaraju
- Georgia Institute of Technology, Wallace H. Coulter Department of Biomedical Engineering, Atlanta, GA, USA.
| | - Anum Ul-Haque
- Georgia Institute of Technology, Wallace H. Coulter Department of Biomedical Engineering, Atlanta, GA, USA
| | - Adam S Verga
- Georgia Institute of Technology, Wallace H. Coulter Department of Biomedical Engineering, Atlanta, GA, USA
| | - Martin L Bocks
- Case Western Reserve University, School of Medicine, Cleveland, OH, USA
| | - Scott J Hollister
- Georgia Institute of Technology, Wallace H. Coulter Department of Biomedical Engineering, Atlanta, GA, USA
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27
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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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Hierarchical biofabrication of biomimetic collagen-elastin vascular grafts with controllable properties via lyophilisation. Acta Biomater 2020; 112:52-61. [PMID: 32525053 DOI: 10.1016/j.actbio.2020.06.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Revised: 05/28/2020] [Accepted: 06/02/2020] [Indexed: 12/19/2022]
Abstract
This article describes the development of a hierarchical biofabrication technique suitable to create large but complex structures, such as vascular mimicking grafts, using facile lyophilisation technology amenable to multiple other biomaterial classes. The combination of three fabrication techniques together, namely solvent evaporation, lyophilisation, and crosslinking together allows highly tailorable structures from the microstructure up to the macrostructure, and with the ability to independently crosslink each layer it allows great flexibility to match desired native mechanical properties independently of the micro/macrostructure. We have demonstrated the flexibility of this biofabrication technique by independently optimising each of the layers to create a multi-layered arterial structure with tailored architectural and biophysical/biochemical properties using a collagen-elastin composite. Taken together, the facile biofabrication methodology developed has led to the development of a biomimetic bilayered scaffold suitable for use as a tissue engineered vascular graft (for haemodialysis access or peripheral/coronary bypass), or as an in vitro test platform to examine disease progression, pharmacological toxicity, or cardiovascular medical device testing. STATEMENT OF SIGNIFICANCE: The ability to grow large complex tissues such as blood vessels for transplantation is often hampered by the limitations of the selected biofabrication technique. Here, we sought to overcome some of the fabrication limitations for naturally occurring cardiovascular polymers (collagen/elastin) via a hierarchical approach to fabrication where each layer is built upon the previous. This approach enabled the flexibility to modify and tailor each layer's properties independently via control over polymer concentration, microstructure, and crosslinking. This simple approach facilitated us to fabricate multi-layered vascular grafts which were remodelled into high-density vascular tissue after 21-days. The fabrication approach could be translated to a myriad of other tissues while the engineered vascular graft could also be used as a test platform for drugs/medical devices or as a tissue engineering scaffold for vascular grafting for different indications.
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Faridi P, Keselman P, Fallahi H, Prakash P. Experimental assessment of microwave ablation computational modeling with MR thermometry. Med Phys 2020; 47:3777-3788. [PMID: 32506550 DOI: 10.1002/mp.14318] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 05/22/2020] [Accepted: 05/24/2020] [Indexed: 12/23/2022] Open
Abstract
PURPOSE Computational models are widely used during the design and characterization of microwave ablation (MWA) devices, and have been proposed for pretreatment planning. Our objective was to assess three-dimensional (3D) transient temperature and ablation profiles predicted by MWA computational models with temperature profiles measured experimentally using magnetic resonance (MR) thermometry in ex vivo bovine liver. MATERIALS AND METHODS We performed MWA in ex vivo tissue under MR guidance using a custom, 2.45 GHz water-cooled applicator. MR thermometry data were acquired for 2 min prior to heating, during 5-10 min microwave exposures, and for 3 min following heating. Fiber-optic temperature sensors were used to validate the accuracy of MR temperature measurements. A total of 13 ablation experiments were conducted using 30-50 W applied power at the applicator input. MWA computational models were implemented using the finite element method, and incorporated temperature-dependent changes in tissue physical properties. Model-predicted ablation zone extents were compared against MRI-derived Arrhenius thermal damage maps using the Dice similarity coefficient (DSC). RESULTS Prior to heating, the observed standard deviation of MR temperature data was in the range of 0.3-0.7°C. Mean absolute error between MR temperature measurements and fiber-optic temperature probes during heating was in the range of 0.5-2.8°C. The mean DSC between model-predicted ablation zones and MRI-derived Arrhenius thermal damage maps for 13 experimental set-ups was 0.95. When comparing simulated and experimentally (i.e. using MRI) measured temperatures, the mean absolute error (MAE %) relative to maximum temperature change was in the range 5%-8.5%. CONCLUSION We developed a system for characterizing 3D transient temperature and ablation profiles with MR thermometry during MWA in ex vivo liver tissue, and applied the system for experimental validation of MWA computational models.
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Affiliation(s)
- Pegah Faridi
- Mike Wiegers Department of Electrical and Computer Engineering, Kansas State University, Manhattan, KS, 66506, USA
| | - Paul Keselman
- Hoglund Brain Imaging Center, University of Kansas Medical Center, Kansas City, KS, 66160, USA
| | - Hojjatollah Fallahi
- Mike Wiegers Department of Electrical and Computer Engineering, Kansas State University, Manhattan, KS, 66506, USA
| | - Punit Prakash
- Mike Wiegers Department of Electrical and Computer Engineering, Kansas State University, Manhattan, KS, 66506, USA
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30
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Silva NP, Bottiglieri A, Conceição RC, O’Halloran M, Farina L. Characterisation of Ex Vivo Liver Thermal Properties for Electromagnetic-Based Hyperthermic Therapies. SENSORS (BASEL, SWITZERLAND) 2020; 20:E3004. [PMID: 32466323 PMCID: PMC7285484 DOI: 10.3390/s20103004] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 05/21/2020] [Accepted: 05/22/2020] [Indexed: 12/18/2022]
Abstract
Electromagnetic-based hyperthermic therapies induce a controlled increase of temperature in a specific tissue target in order to increase the tissue perfusion or metabolism, or even to induce cell necrosis. These therapies require accurate knowledge of dielectric and thermal properties to optimise treatment plans. While dielectric properties have been well investigated, only a few studies have been conducted with the aim of understanding the changes of thermal properties as a function of temperature; i.e., thermal conductivity, volumetric heat capacity and thermal diffusivity. In this study, we experimentally investigate the thermal properties of ex vivo ovine liver in the hyperthermic temperature range, from 25 °C to 97 °C. A significant increase in thermal properties is observed only above 90 °C. An analytical model is developed to model the thermal properties as a function of temperature. Thermal properties are also investigated during the natural cooling of the heated tissue. A reversible phenomenon of the thermal properties is observed; during the cooling, thermal properties followed the same behaviour observed in the heating process. Additionally, tissue density and water content are evaluated at different temperatures. Density does not change with temperature; mass and volume losses change proportionally due to water vaporisation. A 30% water loss was observed above 90 °C.
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Affiliation(s)
- Nuno P. Silva
- Translational Medical Device Lab, National University of Ireland Galway, H91 TK33 Galway, Ireland; (N.P.S.); (A.B.); (M.O.)
- Faculdade de Ciências da Universidade de Lisboa, 1749-016 Lisbon, Portugal
| | - Anna Bottiglieri
- Translational Medical Device Lab, National University of Ireland Galway, H91 TK33 Galway, Ireland; (N.P.S.); (A.B.); (M.O.)
| | - Raquel C. Conceição
- Instituto de Biofísica e Engenharia Biomédica, Faculdade de Ciências Universidade de Lisboa, 1749-016 Lisbon, Portugal;
| | - Martin O’Halloran
- Translational Medical Device Lab, National University of Ireland Galway, H91 TK33 Galway, Ireland; (N.P.S.); (A.B.); (M.O.)
| | - Laura Farina
- Translational Medical Device Lab, National University of Ireland Galway, H91 TK33 Galway, Ireland; (N.P.S.); (A.B.); (M.O.)
- CÚRAM, SFI Research Centre for Medical Devices, National University of Ireland Galway, H91 W2TY Galway, Ireland
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31
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Zang L, Zhou Y, Kang J, Song C. Effect of the Combination of Different Electrode Spacings and Power on Bipolar Radiofrequency Fat Dissolution: A Computational and Experimental Study. Lasers Surg Med 2020; 52:1020-1031. [DOI: 10.1002/lsm.23256] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 03/15/2020] [Accepted: 04/16/2020] [Indexed: 11/10/2022]
Affiliation(s)
- Lianru Zang
- Shanghai Institute for Minimally Invasive Therapy University of Shanghai for Science and Technology 516 Jungong Road 200082 Shanghai China
| | - Yu Zhou
- Shanghai Institute for Minimally Invasive Therapy University of Shanghai for Science and Technology 516 Jungong Road 200082 Shanghai China
| | - Jia Kang
- Shanghai Institute for Minimally Invasive Therapy University of Shanghai for Science and Technology 516 Jungong Road 200082 Shanghai China
| | - ChengLi Song
- Shanghai Institute for Minimally Invasive Therapy University of Shanghai for Science and Technology 516 Jungong Road 200082 Shanghai China
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32
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Thermal Analysis of Infrared Irradiation-Assisted Nanosecond-Pulsed Tumor Ablation. Sci Rep 2020; 10:5122. [PMID: 32198424 PMCID: PMC7083914 DOI: 10.1038/s41598-020-62017-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 03/06/2020] [Indexed: 01/04/2023] Open
Abstract
Nanosecond Pulsed Electric Fields (nsPEF) have the potential to treat a variety of cancer types including melanoma, pancreatic and lung squamous cancers. Recent studies show that nsPEF-based cancer therapy may be improved further with the assistance of moderate heating of the target. A feedback-looped heating system, utilizing a 980-nm fiber optic laser, was integrated into nsPEF electrodes for tumor ablation. The laser beam profile was determined to be Gaussian using a knife-edge technique. Thermal properties of the biological target were evaluated based on the treatment area, penetration depth and thermal distribution due to laser irradiation with or without nsPEF. Synergistic effects between nsPEF and the moderately elevated temperature at the target was observed, resulting in enhanced overall survival tumor regression up to 50% in the treatment of lung squamous cell cancer in mice.
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33
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Yang CH, Li W, Chen RK. Determination of Tissue Thermal Conductivity as a Function of Thermal Dose and Its Application in Finite Element Modeling of Electrosurgical Vessel Sealing. IEEE Trans Biomed Eng 2020; 67:2862-2869. [PMID: 32054566 DOI: 10.1109/tbme.2020.2972465] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVE Electrosurgical vessel sealing is a process commonly used to control bleeding during surgical procedures. Finite element (FE) modeling is often performed to obtain a better understanding of thermal spread during this process. The accuracy of the FE model depends on the implemented material properties. Thermal conductivity is one of the most important properties that affect temperature distribution. The goal of this study is to determine the tissue thermal conductivity as a function of thermal dose. Methods: We developed an iterative approach to correlating tissue thermal conductivity to more accurately calculated thermal dose, which cannot be experimentally measured. The resulting regression model was then implemented into an electrosurgical vessel sealing FE model to examine the accuracy of this FE model. Results: The results show that with the regression model, more reasonable temperature and thermal dose prediction can be achieved at the center of the sealed vessel tissue. The resulting electrical current and impedance from the FE model match with the experimental results. Conclusion: The developed approach can be used to determine the correlation between thermal dose and thermal conductivity. Describing the thermal conductivity as a function of thermal dose allows modeling of irreversible changes in tissue properties. Significance: By having a more accurate temperature estimation at the center of the sealed vessel, more insight is provided into how the tissue reacts during the vessel sealing process.
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34
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Petras A, Leoni M, Guerra JM, Jansson J, Gerardo-Giorda L. A computational model of open-irrigated radiofrequency catheter ablation accounting for mechanical properties of the cardiac tissue. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2019; 35:e3232. [PMID: 31256443 DOI: 10.1002/cnm.3232] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 05/27/2019] [Accepted: 06/20/2019] [Indexed: 06/09/2023]
Abstract
Radiofrequency catheter ablation (RFCA) is an effective treatment for cardiac arrhythmias. Although generally safe, it is not completely exempt from the risk of complications. The great flexibility of computational models can be a major asset in optimizing interventional strategies if they can produce sufficiently precise estimations of the generated lesion for a given ablation protocol. This requires an accurate description of the catheter tip and the cardiac tissue. In particular, the deformation of the tissue under the catheter pressure during the ablation is an important aspect that is overlooked in the existing literature, which resorts to a sharp insertion of the catheter into an undeformed geometry. As the lesion size depends on the power dissipated in the tissue and the latter depends on the percentage of the electrode surface in contact with the tissue itself, the sharp insertion geometry has the tendency to overestimate the lesion obtained, which is a consequence of the tissue temperature rise overestimation. In this paper, we introduce a full 3D computational model that takes into account the tissue elasticity and is able to capture tissue deformation and realistic power dissipation in the tissue. Numerical results in FEniCS-HPC are provided to validate the model against experimental data and to compare the lesions obtained with the new model and with the classical ones featuring a sharp electrode insertion in the tissue.
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Affiliation(s)
| | - Massimiliano Leoni
- Basque Center for Applied Mathematics, Bilbao, Spain
- Department of Computational Science and Technology, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Jose M Guerra
- Department of Cardiology, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Johan Jansson
- Basque Center for Applied Mathematics, Bilbao, Spain
- Department of Computational Science and Technology, KTH Royal Institute of Technology, Stockholm, Sweden
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35
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Lopresto V, Argentieri A, Pinto R, Cavagnaro M. Temperature dependence of thermal properties of ex vivo liver tissue up to ablative temperatures. ACTA ACUST UNITED AC 2019; 64:105016. [DOI: 10.1088/1361-6560/ab1663] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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36
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Thermal Conductivity of Protein-Based Materials: A Review. Polymers (Basel) 2019; 11:polym11030456. [PMID: 30960440 PMCID: PMC6473335 DOI: 10.3390/polym11030456] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 03/06/2019] [Accepted: 03/07/2019] [Indexed: 01/15/2023] Open
Abstract
Fibrous proteins such as silks have been used as textile and biomedical materials for decades due to their natural abundance, high flexibility, biocompatibility, and excellent mechanical properties. In addition, they also can avoid many problems related to traditional materials such as toxic chemical residues or brittleness. With the fast development of cutting-edge flexible materials and bioelectronics processing technologies, the market for biocompatible materials with extremely high or low thermal conductivity is growing rapidly. The thermal conductivity of protein films, which is usually on the order of 0.1 W/m·K, can be rather tunable as the value for stretched protein fibers can be substantially larger, outperforming that of many synthetic polymer materials. These findings indicate that the thermal conductivity and the heat transfer direction of protein-based materials can be finely controlled by manipulating their nano-scale structures. This review will focus on the structure of different fibrous proteins, such as silks, collagen and keratin, summarizing factors that can influence the thermal conductivity of protein-based materials and the different experimental methods used to measure their heat transfer properties.
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37
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Kumar R, Vashishth AK, Ghangas S. Variable thermal conductivity approach for bioheat transfer during thermal ablation. ARAB JOURNAL OF BASIC AND APPLIED SCIENCES 2019. [DOI: 10.1080/25765299.2019.1566982] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Affiliation(s)
- Rajneesh Kumar
- Department of Mathematics, Kurukshetra University, Haryana, India
| | | | - Suniti Ghangas
- Department of Mathematics, Kurukshetra University, Haryana, India
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38
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Mickle AD, Won SM, Noh KN, Yoon J, Meacham KW, Xue Y, McIlvried LA, Copits BA, Samineni VK, Crawford KE, Kim DH, Srivastava P, Kim BH, Min S, Shiuan Y, Yun Y, Payne MA, Zhang J, Jang H, Li Y, Lai HH, Huang Y, Park SI, Gereau RW, Rogers JA. A wireless closed-loop system for optogenetic peripheral neuromodulation. Nature 2019; 565:361-365. [PMID: 30602791 PMCID: PMC6336505 DOI: 10.1038/s41586-018-0823-6] [Citation(s) in RCA: 236] [Impact Index Per Article: 47.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 11/14/2018] [Indexed: 11/18/2022]
Abstract
The fast-growing field of bioelectronic medicine aims to develop engineered systems that relieve clinical conditions through stimulation of the peripheral nervous system (PNS)1–5. Technologies of this type rely largely on electrical stimulation to provide neuromodulation of organ function or pain. One example is sacral nerve stimulation to treat overactive bladder, urinary incontinence and interstitial cystitis/bladder pain syndrome4,6,7. Conventional, continuous stimulation protocols, however, cause discomfort and pain, particularly when treating symptoms that can be intermittent in nature (e.g. sudden urinary urgency)8. Direct physical coupling of electrodes to the nerve can lead to injury and inflammation9–11. Furthermore, typical therapeutic stimulators target large nerve bundles that innervate multiple structures, resulting in a lack of organ specificity. This paper introduces a miniaturized bio-optoelectronic implant that avoids these limitations, via the use of (1) an optical stimulation interface that exploits microscale inorganic light emitting diodes (μ-ILEDs) to activate opsins, (2) a soft, precision biophysical sensor system that allows continuous measurements of organ function, and (3) a control module and data analytics approach that allows coordinated, closed-loop operation of the system to eliminate pathological behaviors as they occur in real-time. In an example reported here, a soft strain gauge yields real-time information on bladder function. Data analytics algorithms identify pathological behavior, and automated, closed-loop optogenetic neuromodulation of bladder sensory afferents normalize bladder function in the context of acute cystitis. This all-optical scheme for neuromodulation offers chronic stability and the potential for cell-type-specific stimulation.
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Affiliation(s)
- Aaron D Mickle
- Washington University Pain Center and Department of Anesthesiology, Washington University, St Louis, MO, USA.,Washington University School of Medicine, St Louis, MO, USA
| | - Sang Min Won
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Kyung Nim Noh
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Jangyeol Yoon
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Kathleen W Meacham
- Washington University Pain Center and Department of Anesthesiology, Washington University, St Louis, MO, USA.,Washington University School of Medicine, St Louis, MO, USA
| | - Yeguang Xue
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, IL, USA.,Mechanical Engineering, Northwestern University, Evanston, IL, USA.,Materials Science and Engineering, Northwestern University, Evanston, IL, USA
| | - Lisa A McIlvried
- Washington University Pain Center and Department of Anesthesiology, Washington University, St Louis, MO, USA.,Washington University School of Medicine, St Louis, MO, USA
| | - Bryan A Copits
- Washington University Pain Center and Department of Anesthesiology, Washington University, St Louis, MO, USA.,Washington University School of Medicine, St Louis, MO, USA
| | - Vijay K Samineni
- Washington University Pain Center and Department of Anesthesiology, Washington University, St Louis, MO, USA.,Washington University School of Medicine, St Louis, MO, USA
| | - Kaitlyn E Crawford
- Department of Materials Science and Engineering, University of Central Florida, Orlando, FL, USA
| | - Do Hoon Kim
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Paulome Srivastava
- Washington University Pain Center and Department of Anesthesiology, Washington University, St Louis, MO, USA.,Washington University School of Medicine, St Louis, MO, USA
| | - Bong Hoon Kim
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA.,Materials Science and Engineering, Northwestern University, Evanston, IL, USA.,Simpson Querrey Institute, Northwestern University, Chicago, IL, USA.,Center for Bio-integrated Electronics, Northwestern University, Evanston, IL, USA
| | - Seunghwan Min
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Young Shiuan
- Washington University Pain Center and Department of Anesthesiology, Washington University, St Louis, MO, USA.,Washington University School of Medicine, St Louis, MO, USA
| | - Yeojeong Yun
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Maria A Payne
- Washington University School of Medicine, St Louis, MO, USA.,Washington University Department of Surgery - Division of Urologic Surgery, St Louis, MO, USA
| | - Jianpeng Zhang
- Institute of Solid Mechanics, Beihang University (BUAA), Beijing, China
| | - Hokyung Jang
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Yuhang Li
- Institute of Solid Mechanics, Beihang University (BUAA), Beijing, China
| | - H Henry Lai
- Washington University Pain Center and Department of Anesthesiology, Washington University, St Louis, MO, USA.,Washington University School of Medicine, St Louis, MO, USA.,Washington University Department of Surgery - Division of Urologic Surgery, St Louis, MO, USA
| | - Yonggang Huang
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, IL, USA.,Mechanical Engineering, Northwestern University, Evanston, IL, USA.,Materials Science and Engineering, Northwestern University, Evanston, IL, USA
| | - Sung-Il Park
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX, USA
| | - Robert W Gereau
- Washington University Pain Center and Department of Anesthesiology, Washington University, St Louis, MO, USA. .,Washington University School of Medicine, St Louis, MO, USA.
| | - John A Rogers
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA. .,Mechanical Engineering, Northwestern University, Evanston, IL, USA. .,Materials Science and Engineering, Northwestern University, Evanston, IL, USA. .,Simpson Querrey Institute, Northwestern University, Chicago, IL, USA. .,Center for Bio-integrated Electronics, Northwestern University, Evanston, IL, USA. .,Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA. .,Department of Chemistry, Northwestern University, Evanston, IL, USA. .,Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
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39
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Effect of tumor properties on energy absorption, temperature mapping, and thermal dose in 13.56-MHz radiofrequency hyperthermia. J Therm Biol 2018; 74:281-289. [DOI: 10.1016/j.jtherbio.2018.04.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 04/20/2018] [Accepted: 04/20/2018] [Indexed: 10/17/2022]
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40
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Awojoyogbe BO, Dada MO. Computational Design of an RF Controlled Theranostic Model for Evaluation of Tissue Biothermal Response. J Med Biol Eng 2018. [DOI: 10.1007/s40846-018-0386-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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41
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Kaboli M, Yao K, Feng D, Cheng G. Tactile-based active object discrimination and target object search in an unknown workspace. Auton Robots 2018. [DOI: 10.1007/s10514-018-9707-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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42
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Yang CH, Li W, Chen RK. Characterization and Modeling of Tissue Thermal Conductivity During an Electrosurgical Joining Process. IEEE Trans Biomed Eng 2018; 65:365-370. [DOI: 10.1109/tbme.2017.2770095] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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43
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Dillon CR, Rieke V, Ghanouni P, Payne A. Thermal diffusivity and perfusion constants from in vivo MR-guided focussed ultrasound treatments: a feasibility study. Int J Hyperthermia 2017; 34:352-362. [DOI: 10.1080/02656736.2017.1340677] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Affiliation(s)
- Christopher R. Dillon
- Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, USA
| | - Viola Rieke
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA
| | - Pejman Ghanouni
- Department of Radiology, Stanford University, Stanford, CA, USA
| | - Allison Payne
- Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, USA
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44
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Lopresto V, Pinto R, Farina L, Cavagnaro M. Microwave thermal ablation: Effects of tissue properties variations on predictive models for treatment planning. Med Eng Phys 2017. [PMID: 28647287 DOI: 10.1016/j.medengphy.2017.06.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Microwave thermal ablation (MTA) therapy for cancer treatments relies on the absorption of electromagnetic energy at microwave frequencies to induce a very high and localized temperature increase, which causes an irreversible thermal damage in the target zone. Treatment planning in MTA is based on experimental observations of ablation zones in ex vivo tissue, while predicting the treatment outcomes could be greatly improved by reliable numerical models. In this work, a fully dynamical simulation model is exploited to look at effects of temperature-dependent variations in the dielectric and thermal properties of the targeted tissue on the prediction of the temperature increase and the extension of the thermally coagulated zone. In particular, the influence of measurement uncertainty of tissue parameters on the numerical results is investigated. Numerical data were compared with data from MTA experiments performed on ex vivo bovine liver tissue at 2.45GHz, with a power of 60W applied for 10min. By including in the simulation model an uncertainty budget (CI=95%) of ±25% in the properties of the tissue due to inaccuracy of measurements, numerical results were achieved in the range of experimental data. Obtained results also showed that the specific heat especially influences the extension of the thermally coagulated zone, with an increase of 27% in length and 7% in diameter when a variation of -25% is considered with respect to the value of the reference simulation model.
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Affiliation(s)
- Vanni Lopresto
- ENEA, Division of Health Protection Technologies, Casaccia Research Centre, Rome, Italy.
| | - Rosanna Pinto
- ENEA, Division of Health Protection Technologies, Casaccia Research Centre, Rome, Italy
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Natesan H, Bischof JC. Multiscale Thermal Property Measurements for Biomedical Applications. ACS Biomater Sci Eng 2017; 3:2669-2691. [PMID: 33418696 DOI: 10.1021/acsbiomaterials.6b00565] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Bioheat transfer-based innovations in health care include applications such as focal treatments for cancer and cardiovascular disease and the preservation of tissues and organs for transplantation. In these applications, the ability to preserve or destroy a biomaterial is directly dependent on its temperature history. Thus, thermal measurement and modeling are necessary to either avoid or induce the injury required. In this review paper, we will first define and discuss thermal conductivity and calorimetric measurements of biomaterials in the cryogenic (<-40 °C), subzero (<0 °C), hypothermic (<37 °C), and hyperthermic (>37 °C) regimes. For thermal conductivity measurements, we review the use of 3ω and laser flash techniques for measurement of thermal conductivity in thin (1 μm-2 mm thick), anisotropic, and/or multilayered tissues. At the nanoscale, we review the use of pump-probe and scanning probe methods to measure thermal conductivity at short temporal scales (10 ps-100 ns) and spatial scales (1 nm-1 μm), particularly in the coating and surrounding medium around metallic nanoparticles (1 nm-20 nm). For calorimetric techniques, we review differential scanning calorimetry (DSC), which is intrinsically at the microscale (e.g., tissue pieces or millions of cells in media). DSC is used with large sample mass (∼3-100 mg) over wide temperature ranges (-180 to 750 °C) with low-temperature scanning rates (<750 °C/min). The need to assess smaller samples at higher rates has led to the development of nanocalorimetry on a silicon based membrane. Here the sample weight is as low as 10 ng, thereby allowing ultra-rapid heating rates (∼1 × 107 C/min). Finally, we discuss various opportunities that are driving the need for new micro- and nanoscale thermal measurements.
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Affiliation(s)
- Harishankar Natesan
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - John C Bischof
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
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Johnson SL, Dillon C, Odéen H, Parker D, Christensen D, Payne A. Development and validation of a MRgHIFU non-invasive tissue acoustic property estimation technique. Int J Hyperthermia 2016; 32:723-34. [PMID: 27441427 PMCID: PMC5054420 DOI: 10.1080/02656736.2016.1216184] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 06/16/2016] [Accepted: 07/18/2016] [Indexed: 10/21/2022] Open
Abstract
MR-guided high-intensity focussed ultrasound (MRgHIFU) non-invasive ablative surgeries have advanced into clinical trials for treating many pathologies and cancers. A remaining challenge of these surgeries is accurately planning and monitoring tissue heating in the face of patient-specific and dynamic acoustic properties of tissues. Currently, non-invasive measurements of acoustic properties have not been implemented in MRgHIFU treatment planning and monitoring procedures. This methods-driven study presents a technique using MR temperature imaging (MRTI) during low-temperature HIFU sonications to non-invasively estimate sample-specific acoustic absorption and speed of sound values in tissue-mimicking phantoms. Using measured thermal properties, specific absorption rate (SAR) patterns are calculated from the MRTI data and compared to simulated SAR patterns iteratively generated via the Hybrid Angular Spectrum (HAS) method. Once the error between the simulated and measured patterns is minimised, the estimated acoustic property values are compared to the true phantom values obtained via an independent technique. The estimated values are then used to simulate temperature profiles in the phantoms, and compared to experimental temperature profiles. This study demonstrates that trends in acoustic absorption and speed of sound can be non-invasively estimated with average errors of 21% and 1%, respectively. Additionally, temperature predictions using the estimated properties on average match within 1.2 °C of the experimental peak temperature rises in the phantoms. The positive results achieved in tissue-mimicking phantoms presented in this study indicate that this technique may be extended to in vivo applications, improving HIFU sonication temperature rise predictions and treatment assessment.
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Affiliation(s)
| | | | - Henrik Odéen
- Department of Radiology and Imaging Sciences, University of Utah
| | - Dennis Parker
- Department of Radiology and Imaging Sciences, University of Utah
| | - Douglas Christensen
- Department of Bioengineering, University of Utah
- Department of Electrical and Computer Engineering, University of Utah
| | - Allison Payne
- Department of Radiology and Imaging Sciences, University of Utah
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Lopresto V, Pinto R, Farina L, Cavagnaro M. Treatment planning in microwave thermal ablation: clinical gaps and recent research advances. Int J Hyperthermia 2016; 33:83-100. [PMID: 27431328 DOI: 10.1080/02656736.2016.1214883] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Microwave thermal ablation (MTA) is a minimally invasive therapeutic technique aimed at destroying pathologic tissues through a very high temperature increase induced by the absorption of an electromagnetic field at microwave (MW) frequencies. Open problems, which are delaying MTA applications in clinical practice, are mainly linked to the extremely high temperatures, up to 120 °C, reached by the tissue close to the antenna applicator, as well as to the ability of foreseeing and controlling the shape and dimension of the thermally ablated area. Recent research was devoted to the characterisation of dielectric, thermal and physical properties of tissue looking at their changes with the increasing temperature, looking for possible developments of reliable, automatic and personalised treatment planning. In this paper, a review of the recently obtained results as well as new unpublished data will be presented and discussed.
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Affiliation(s)
- V Lopresto
- a Division of Health Protection Technologies , Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA) , Rome , Italy
| | - R Pinto
- a Division of Health Protection Technologies , Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA) , Rome , Italy
| | - L Farina
- b Department of Information Engineering, Electronics and Telecommunications , Sapienza University of Rome , Rome , Italy
| | - M Cavagnaro
- b Department of Information Engineering, Electronics and Telecommunications , Sapienza University of Rome , Rome , Italy
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Karaki W, Akyildiz A, De S, Borca Tasciuc DA. Energy Dissipation in Ex Vivo Porcine Liver During Electrosurgery. IEEE Trans Biomed Eng 2016; 64:1211-1217. [PMID: 27479955 DOI: 10.1109/tbme.2016.2595525] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
This paper explores energy dissipation in ex vivo liver tissue during radiofrequency current excitation with application in electrosurgery. Tissue surface temperature for monopolar electrode configuration is measured using infrared thermometry. The experimental results are fitted to a finite-element model for transient heat transfer taking into account energy storage and conduction in order to extract information about "apparent" specific heat, which encompasses storage and phase change. The average apparent specific heat determined for low temperatures is in agreement with published data. However, at temperatures approaching the boiling point of water, apparent specific heat increases by a factor of five, indicating that vaporization plays an important role in the energy dissipation through latent heat loss.
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Affiliation(s)
- Lawrence Lau
- Department of Mechanical Engineering, Seattle University, Seattle, WA 98122
| | - Yen-Lin Han
- Department of Mechanical Engineering, Seattle University, Seattle, WA 98122
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Huang CW, Sun MK, Chen BT, Shieh J, Chen CS, Chen WS. Simulation of thermal ablation by high-intensity focused ultrasound with temperature-dependent properties. ULTRASONICS SONOCHEMISTRY 2015; 27:456-465. [PMID: 26186867 DOI: 10.1016/j.ultsonch.2015.06.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 06/08/2015] [Accepted: 06/08/2015] [Indexed: 06/04/2023]
Abstract
An integrated computational framework was developed in this study for modeling high-intensity focused ultrasound (HIFU) thermal ablation. The temperature field was obtained by solving the bioheat transfer equation (BHTE) through the finite element method; while, the thermal lesion was considered as a denatured material experiencing phase transformation and modeled with the latent heat. An equivalent attenuation coefficient, which considers the temperature-dependent properties of the target material and the ultrasound diffraction due to bubbles, was proposed in the nonlinear thermal transient analysis. Finally, a modified thermal dose formulation was proposed to predict the lesion size, shape and location. In-vitro thermal ablation experiments on transparent tissue phantoms at different energy levels were carried out to validate this computational framework. The temperature histories and lesion areas from the proposed model show good correlation with those from the in-vitro experiments.
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Affiliation(s)
- C W Huang
- Department of Civil Engineering, Chung Yuan Christian University, Taoyuan, Taiwan.
| | - M K Sun
- Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital & College of Medicine, Taipei, Taiwan; Division of Medical Engineering Research, National Health Research Institutes, Miaoli, Taiwan
| | - B T Chen
- Department of Civil Engineering, Chung Yuan Christian University, Taoyuan, Taiwan
| | - J Shieh
- Department of Materials Science and Engineering, National Taiwan University, Taipei, Taiwan
| | - C S Chen
- Department of Civil Engineering, National Taiwan University, Taipei, Taiwan
| | - W S Chen
- Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital & College of Medicine, Taipei, Taiwan; Division of Medical Engineering Research, National Health Research Institutes, Miaoli, Taiwan.
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