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Hübner F, Klaus M, Siedow N, Leithäuser C, Vogl TJ. CT-based evaluation of tissue expansion in cryoablation of ex vivo kidney. BIOMED ENG-BIOMED TE 2024; 69:211-217. [PMID: 37924274 DOI: 10.1515/bmt-2023-0174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Accepted: 10/11/2023] [Indexed: 11/06/2023]
Abstract
OBJECTIVES To evaluate tissue expansion during cryoablation, the displacement of markers in ex vivo kidney tissue was determined using computed tomographic (CT) imaging. METHODS CT-guided cryoablation was performed in nine porcine kidneys over a 10 min period. Markers and fiber optic temperature probes were positioned perpendicular to the cryoprobe shaft in an axial orientation. The temperature measurement was performed simultaneously with the acquisitions of the CT images in 5 s intervals. The distance change of the markers to the cryoprobe was determined in each CT image and equated to the measured temperature at the marker. RESULTS The greatest increase in the distance between the markers and the cryoprobe was observed in the initial phase of cryoablation. The maximum displacement of the markers was determined to be 0.31±0.2 mm and 2.8±0.02 %, respectively. CONCLUSIONS The mean expansion of ex vivo kidney tissue during cryoablation with a single cryoprobe is 0.31±0.2 mm. The results can be used for identification of basic parameters for optimization of therapy planning.
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Affiliation(s)
- Frank Hübner
- Institute of Diagnostic and Interventional Radiology, University Hospital, Goethe University Frankfurt, Frankfurt, Germany
| | - Moritz Klaus
- Institute of Diagnostic and Interventional Radiology, University Hospital, Goethe University Frankfurt, Frankfurt, Germany
| | - Norbert Siedow
- Fraunhofer Institute for Industrial Mathematics (ITWM), Kaiserslautern, Germany
| | | | - Thomas Josef Vogl
- Institute of Diagnostic and Interventional Radiology, University Hospital, Goethe University Frankfurt, Frankfurt, Germany
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Moreira P, Tuncali K, Tempany C, Tokuda J. AI-Based Isotherm Prediction for Focal Cryoablation of Prostate Cancer. Acad Radiol 2023; 30 Suppl 1:S14-S20. [PMID: 37236896 PMCID: PMC10524864 DOI: 10.1016/j.acra.2023.04.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 04/04/2023] [Accepted: 04/15/2023] [Indexed: 05/28/2023]
Abstract
RATIONALE AND OBJECTIVES Focal therapies have emerged as minimally invasive alternatives for patients with localized low-risk prostate cancer (PCa) and those with postradiation recurrence. Among the available focal treatment methods for PCa, cryoablation offers several technical advantages, including the visibility of the boundaries of frozen tissue on the intraprocedural images, access to anterior lesions, and the proven ability to treat postradiation recurrence. However, predicting the final volume of the frozen tissue is challenging as it depends on several patient-specific factors, such as proximity to heat sources and thermal properties of the prostatic tissue. MATERIALS AND METHODS This paper presents a convolutional neural network model based on 3D-Unet to predict the frozen isotherm boundaries (iceball) resultant from a given a cryo-needle placement. Intraprocedural magnetic resonance images acquired during 38 cases of focal cryoablation of PCa were retrospectively used to train and validate the model. The model accuracy was assessed and compared against a vendor-provided geometrical model, which is used as a guideline in routine procedures. RESULTS The mean Dice Similarity Coefficient using the proposed model was 0.79±0.08 (mean+SD) vs 0.72±0.06 using the geometrical model (P<.001). CONCLUSION The model provided an accurate iceball boundary prediction in less than 0.4second and has proven its feasibility to be implemented in an intraprocedural planning algorithm.
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Affiliation(s)
- Pedro Moreira
- Brigham and Women's Hospital, 75 Francis St, Boston, MA 22115 (P.M., K.T., C.T., J.T.); Harvard Medical School, 25 Shattuck St, Boston, MA 02115 (P.M., K.T., C.T., J.T.).
| | - Kemal Tuncali
- Brigham and Women's Hospital, 75 Francis St, Boston, MA 22115 (P.M., K.T., C.T., J.T.); Harvard Medical School, 25 Shattuck St, Boston, MA 02115 (P.M., K.T., C.T., J.T.)
| | - Clare Tempany
- Brigham and Women's Hospital, 75 Francis St, Boston, MA 22115 (P.M., K.T., C.T., J.T.); Harvard Medical School, 25 Shattuck St, Boston, MA 02115 (P.M., K.T., C.T., J.T.)
| | - Junichi Tokuda
- Brigham and Women's Hospital, 75 Francis St, Boston, MA 22115 (P.M., K.T., C.T., J.T.); Harvard Medical School, 25 Shattuck St, Boston, MA 02115 (P.M., K.T., C.T., J.T.)
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Campagnoli E, Giaretto V. Experimental Investigation on Thermal Conductivity and Thermal Diffusivity of Ex-Vivo Bovine Liver from Room Temperature down to -60 °C. Materials (Basel) 2021; 14:3750. [PMID: 34279321 PMCID: PMC8269850 DOI: 10.3390/ma14133750] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 06/23/2021] [Accepted: 07/02/2021] [Indexed: 11/25/2022]
Abstract
Ex vivo animal tissues (e.g., bovine liver) as well as water-agar gel are commonly used to simulate both experimentally and numerically the response of human tissues to cryoablation treatments. Data on the low temperature thermal properties of bovine liver are difficult to find in the literature and very often are not provided for the whole temperature range of interest. This article presents the thermal conductivity and thermal diffusivity measurements performed on ex-vivo bovine liver samples using the transient plane source method. Regression coefficients are provided to determine these properties in different temperature ranges except for the phase transition during which no results were obtained, which suggests an ad hoc calorimetric analysis. A quick procedure is also suggested to determine the water mass fraction in the tissue. Moreover, an attempt to estimate the liver density in the frozen state using measurements performed solely at room temperature is also presented. The measured thermal conductivity and thermal diffusivity values are compared with data reported in literature highlighting a spread up to 40%. Moreover, it emerges that water-agar gel usually made with 2% by weight of agar does not show the same thermal properties as the bovine liver.
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Affiliation(s)
- Elena Campagnoli
- Department of Energy, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Turin, Italy
| | - Valter Giaretto
- Department of Energy, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Turin, Italy
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Daunizeau L, Nguyen A, Le Garrec M, Chapelon JY, N'Djin WA. Robot-assisted ultrasound navigation platform for 3D HIFU treatment planning: Initial evaluation for conformal interstitial ablation. Comput Biol Med 2020; 124:103941. [PMID: 32818742 DOI: 10.1016/j.compbiomed.2020.103941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 07/19/2020] [Accepted: 07/27/2020] [Indexed: 10/23/2022]
Abstract
Interstitial Ultrasound-guided High Intensity Focused Ultrasound (USgHIFU) therapy has the potential to deliver ablative treatments which conform to the target tumor. In this study, a robot-assisted US-navigation platform has been developed for 3D US guidance and planning of conformal HIFU ablations. The platform was used to evaluate a conformal therapeutic strategy associated with an interstitial dual-mode USgHIFU catheter prototype (64 elements linear-array, measured central frequency f = 6.5 MHz), developed for the treatment of HepatoCellular Carcinoma (HCC). The platform included a 3D navigation environment communicating in real-time with an open research dual-mode US scanner/HIFU generator and a robotic arm, on which the USgHIFU catheter was mounted. 3D US-navigation was evaluated in vitro for guiding and planning conformal HIFU ablations using a tumor-mimic model in porcine liver. Tumor-mimic volumes were then used as targets for evaluating conformal HIFU treatment planning in simulation. Height tumor-mimics (ovoid- or disc-shaped, sizes: 3-29 cm3) were created and visualized in liver using interstitial 2D US imaging. Robot-assisted spatial manipulation of these images and real-time 3D navigation allowed reconstructions of 3D B-mode US images for accurate tumor-mimic volume estimation (relative error: 4 ± 5%). Sectorial and full-revolution HIFU scanning (angular sectors: 88-360°) could both result in conformal ablations of the tumor volumes, as soon as their radii remained ≤ 24 mm. The presented US navigation-guided HIFU procedure demonstrated advantages for developing conformal interstitial therapies in standard operative rooms. Moreover, the modularity of the developed platform makes it potentially useful for developing other HIFU approaches.
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Affiliation(s)
- L Daunizeau
- LabTAU, INSERM, Centre Léon Bérard, Université Lyon 1, Univ Lyon, F-69003, Lyon, France.
| | - A Nguyen
- LabTAU, INSERM, Centre Léon Bérard, Université Lyon 1, Univ Lyon, F-69003, Lyon, France
| | - M Le Garrec
- LabTAU, INSERM, Centre Léon Bérard, Université Lyon 1, Univ Lyon, F-69003, Lyon, France
| | - J Y Chapelon
- LabTAU, INSERM, Centre Léon Bérard, Université Lyon 1, Univ Lyon, F-69003, Lyon, France
| | - W A N'Djin
- LabTAU, INSERM, Centre Léon Bérard, Université Lyon 1, Univ Lyon, F-69003, Lyon, France
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Ratanaprasatporn L, Sainani N, Duda JB, Aghayev A, Tatli S, Silverman SG, Shyn PB. Imaging findings during and after percutaneous cryoablation of hepatic tumors. Abdom Radiol (NY) 2019; 44:2602-26. [PMID: 31004203 DOI: 10.1007/s00261-019-01999-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
OBJECTIVE Imaging plays a key role in the assessment of patients before, during, and after percutaneous cryoablation of hepatic tumors. Intra-procedural and early post-procedure imaging with CT and MRI is vital to the assessment of technical success including adequacy of ablation zone coverage. Recognition of the normal expected post-procedure findings of hepatic cryoablation such as ice ball formation, hydrodissection, and the normal appearance of the ablation zone is crucial to be able to differentiate from complications including vascular, biliary, or non-target organ injury. Delayed imaging is essential for determination of clinical effectiveness and detection of unexpected findings such as residual unablated tumor and local tumor progression. The purpose of this article is to review the spectrum of expected and unexpected imaging findings that may occur during or after percutaneous cryoablation of hepatic tumors. CONCLUSION Differentiating expected from unexpected findings during and after hepatic cryoablation helps radiologists identify residual or recurrent tumor and detect procedure-related complications.
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Abstract
Renal cell carcinoma is a relatively common tumor, with an estimated 63,000 new cases being diagnosed in the United States in 2016. Surgery, be it with partial or total nephrectomy, is considered the mainstay of treatment for many patients. However, those patients with small renal masses, typically less than 3 to 4 cm in size who are deemed unsuitable for surgery, may be suitable for percutaneous thermal ablation. We review the various treatment modalities, including radiofrequency ablation, microwave ablation, and cryoablation; discuss the advantages and disadvantages of each method; and review the latest data concerning the performance of the various ablative modalities compared with each other, and compared with surgery.
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Affiliation(s)
- Colin J McCarthy
- Division of Abdominal Imaging, Massachusetts General Hospital, Boston, Massachusetts
| | - Debra A Gervais
- Division of Abdominal Imaging, Massachusetts General Hospital, Boston, Massachusetts
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Boas FE, Srimathveeravalli G, Durack JC, Kaye EA, Erinjeri JP, Ziv E, Maybody M, Yarmohammadi H, Solomon SB. Development of a Searchable Database of Cryoablation Simulations for Use in Treatment Planning. Cardiovasc Intervent Radiol 2017; 40:761-768. [PMID: 28050658 DOI: 10.1007/s00270-016-1562-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 12/26/2016] [Indexed: 01/20/2023]
Abstract
PURPOSE To create and validate a planning tool for multiple-probe cryoablation, using simulations of ice ball size and shape for various ablation probe configurations, ablation times, and types of tissue ablated. MATERIALS AND METHODS Ice ball size and shape was simulated using the Pennes bioheat equation. Five thousand six hundred and seventy different cryoablation procedures were simulated, using 1-6 cryoablation probes and 1-2 cm spacing between probes. The resulting ice ball was measured along three perpendicular axes and recorded in a database. Simulated ice ball sizes were compared to gel experiments (26 measurements) and clinical cryoablation cases (42 measurements). The clinical cryoablation measurements were obtained from a HIPAA-compliant retrospective review of kidney and liver cryoablation procedures between January 2015 and February 2016. Finally, we created a web-based cryoablation planning tool, which uses the cryoablation simulation database to look up the probe spacing and ablation time that produces the desired ice ball shape and dimensions. RESULTS Average absolute error between the simulated and experimentally measured ice balls was 1 mm in gel experiments and 4 mm in clinical cryoablation cases. The simulations accurately predicted the degree of synergy in multiple-probe ablations. The cryoablation simulation database covers a wide range of ice ball sizes and shapes up to 9.8 cm. CONCLUSION Cryoablation simulations accurately predict the ice ball size in multiple-probe ablations. The cryoablation database can be used to plan ablation procedures: given the desired ice ball size and shape, it will find the number and type of probes, probe configuration and spacing, and ablation time required.
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Affiliation(s)
- F Edward Boas
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Ave., New York, NY, 10065, USA.
| | | | - Jeremy C Durack
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Ave., New York, NY, 10065, USA
| | - Elena A Kaye
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, 1275 York Ave., New York, NY, 10065, USA
| | - Joseph P Erinjeri
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Ave., New York, NY, 10065, USA
| | - Etay Ziv
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Ave., New York, NY, 10065, USA
| | - Majid Maybody
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Ave., New York, NY, 10065, USA
| | - Hooman Yarmohammadi
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Ave., New York, NY, 10065, USA
| | - Stephen B Solomon
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Ave., New York, NY, 10065, USA
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Chan JY, Ooi EH. Sensitivity of thermophysiological models of cryoablation to the thermal and biophysical properties of tissues. Cryobiology 2016; 73:304-315. [DOI: 10.1016/j.cryobiol.2016.10.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2016] [Revised: 10/18/2016] [Accepted: 10/20/2016] [Indexed: 10/20/2022]
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9
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He ZZ, Liu J. An efficient thermal evolution model for cryoablation with arbitrary multi-cryoprobe configuration. Cryobiology 2015; 71:318-28. [PMID: 26256654 DOI: 10.1016/j.cryobiol.2015.08.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 08/04/2015] [Accepted: 08/04/2015] [Indexed: 11/29/2022]
Abstract
Cryoablation has been demonstrated powerful in treating of a variety of diseases, especially for the tumor ablation, which destroys the target tissue through the controlled freezing of cryoprobe. The prediction of temperature evolution during cryoablation is of great importance for developing and improving clinical procedure. This paper presented an efficient thermal model to characterize the freezing effect of cryoprobe with arbitrary layout including its size, orientation and number. The key step of the presented model is to establish a boundary heat source method to implicitly characterize the heat transfer from cryoprobe with fixed temperature or convective heat transfer boundary condition, which is furthermore incorporated to a fast parallel alternating direction explicit (PADE) finite difference method for computation acceleration. A novel dynamical and conformal computational region is designed through the shortest distance definition to balance the thermal effect of tissue and computational efficiency. The detailed test cases including a real head tissue demonstrated that the current model can accurately predict the temperature field evolution induced by arbitrary multi-cryoprobe configuration, and achieve significant computational ability due to allowable large time step (100-fold compared with the explicit finite difference method), compact computational region (at least reducing 40% number of voxels) and high parallel efficiency (speedup ratio about 8 for 12 threads) for complex tissue structure.
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Affiliation(s)
- Zhi-Zhu He
- Key Laboratory of Cryogenics, and Beijing Key Laboratory of Cryo-Biomedical Engineering, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
| | - Jing Liu
- Key Laboratory of Cryogenics, and Beijing Key Laboratory of Cryo-Biomedical Engineering, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China; Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing 100084, China
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Handler M, Fischer G, Seger M, Kienast R, Hanser F, Baumgartner C. Simulation and evaluation of freeze-thaw cryoablation scenarios for the treatment of cardiac arrhythmias. Biomed Eng Online 2015; 14:12. [PMID: 25886498 PMCID: PMC4369072 DOI: 10.1186/s12938-015-0005-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 01/26/2015] [Indexed: 11/23/2022] Open
Abstract
Background Cardiac cryoablation is a minimally invasive procedure to treat cardiac arrhythmias by cooling cardiac tissues responsible for the cardiac arrhythmia to freezing temperatures. Although cardiac cryoablation offers a gentler treatment than radiofrequency ablation, longer interventions and higher recurrence rates reduce the clinical acceptance of this technique. Computer models of ablation scenarios allow for a closer examination of temperature distributions in the myocardium and evaluation of specific effects of applied freeze-thaw protocols in a controlled environment. Methods In this work multiple intervention scenarios with two freeze-thaw cycles were simulated with varying durations and starting times of the interim thawing phase using a finite element model verified by in-vivo measurements and data from literature. To evaluate the effects of different protocols, transmural temperature distributions and iceball dimensions were compared over time. Cryoadhesion durations of the applicator were estimated in the interim thawing phase with varying thawing phase starting times. In addition, the increase of cooling rates was compared between the freezing phases, and the thawing rates of interim thawing phases were analyzed over transmural depth. Results It could be shown that the increase of cooling rate, the regions undergoing additional phase changes and depths of selected temperatures depend on the chosen ablation protocol. Only small differences of the estimated cryoadhesion duration were found for ablation scenarios with interim thawing phase start after 90 s freezing. Conclusions By the presented model a quantification of effects responsible for cell death is possible, allowing for the analysis and optimization of cryoablation scenarios which contribute to a higher clinical acceptance of cardiac cryoablation.
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Affiliation(s)
- Michael Handler
- Institute of Electrical and Biomedical Engineering, University for Health Sciences, Medical Informatics and Technology, Eduard Wallnöfer-Zentrum 1, Hall in Tirol, 6060, Austria.
| | - Gerald Fischer
- AFreeze GmbH, Eduard Bodem Gasse 8, Innsbruck, 6020, Austria.
| | - Michael Seger
- Institute of Electrical and Biomedical Engineering, University for Health Sciences, Medical Informatics and Technology, Eduard Wallnöfer-Zentrum 1, Hall in Tirol, 6060, Austria. .,Medical Engineering and Healthcare IT, Carinthia University of Applied Sciences, Primoschgasse 10, Klagenfurt, 9020, Austria.
| | - Roland Kienast
- Institute of Electrical and Biomedical Engineering, University for Health Sciences, Medical Informatics and Technology, Eduard Wallnöfer-Zentrum 1, Hall in Tirol, 6060, Austria.
| | - Friedrich Hanser
- Institute of Electrical and Biomedical Engineering, University for Health Sciences, Medical Informatics and Technology, Eduard Wallnöfer-Zentrum 1, Hall in Tirol, 6060, Austria.
| | - Christian Baumgartner
- Institute of Electrical and Biomedical Engineering, University for Health Sciences, Medical Informatics and Technology, Eduard Wallnöfer-Zentrum 1, Hall in Tirol, 6060, Austria. .,Institute of Health Care Engineering with European Notified Body of Medical Devices, Graz University of Technology, Kopernikusgasse 24, Graz, 8010, Austria.
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Abstract
Tumor ablation is a minimally invasive technique that is commonly used in the treatment of tumors of the liver, kidney, bone, and lung. During tumor ablation, thermal energy is used to heat or cool tissue to cytotoxic levels (less than -40°C or more than 60°C). An additional technique is being developed that targets the permeability of the cell membrane and is ostensibly nonthermal. Within the classification of tumor ablation, there are several modalities used worldwide: radiofrequency, microwave, laser, high-intensity focused ultrasound, cryoablation, and irreversible electroporation. Each technique, although similar in purpose, has specific and optimal indications. This review serves to discuss general principles and technique, reviews each modality, and discusses modality selection.
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Affiliation(s)
- Erica M Knavel
- Department of Radiology, University of Wisconsin Madison, Clinical Sciences Center, Madison, WI.
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Etheridge ML, Choi J, Ramadhyani S, Bischof JC. Methods for characterizing convective cryoprobe heat transfer in ultrasound gel phantoms. J Biomech Eng 2013; 135:021002. [PMID: 23445047 DOI: 10.1115/1.4023237] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
While cryosurgery has proven capable in treating of a variety of conditions, it has met with some resistance among physicians, in part due to shortcomings in the ability to predict treatment outcomes. Here we attempt to address several key issues related to predictive modeling by demonstrating methods for accurately characterizing heat transfer from cryoprobes, report temperature dependent thermal properties for ultrasound gel (a convenient tissue phantom) down to cryogenic temperatures, and demonstrate the ability of convective exchange heat transfer boundary conditions to accurately describe freezing in the case of single and multiple interacting cryoprobe(s). Temperature dependent changes in the specific heat and thermal conductivity for ultrasound gel are reported down to -150 °C for the first time here and these data were used to accurately describe freezing in ultrasound gel in subsequent modeling. Freezing around a single and two interacting cryoprobe(s) was characterized in the ultrasound gel phantom by mapping the temperature in and around the "iceball" with carefully placed thermocouple arrays. These experimental data were fit with finite-element modeling in COMSOL Multiphysics, which was used to investigate the sensitivity and effectiveness of convective boundary conditions in describing heat transfer from the cryoprobes. Heat transfer at the probe tip was described in terms of a convective coefficient and the cryogen temperature. While model accuracy depended strongly on spatial (i.e., along the exchange surface) variation in the convective coefficient, it was much less sensitive to spatial and transient variations in the cryogen temperature parameter. The optimized fit, convective exchange conditions for the single-probe case also provided close agreement with the experimental data for the case of two interacting cryoprobes, suggesting that this basic characterization and modeling approach can be extended to accurately describe more complicated, multiprobe freezing geometries. Accurately characterizing cryoprobe behavior in phantoms requires detailed knowledge of the freezing medium's properties throughout the range of expected temperatures and an appropriate description of the heat transfer across the probe's exchange surfaces. Here we demonstrate that convective exchange boundary conditions provide an accurate and versatile description of heat transfer from cryoprobes, offering potential advantages over the traditional constant surface heat flux and constant surface temperature descriptions. In addition, although this study was conducted on Joule-Thomson type cryoprobes, the general methodologies should extend to any probe that is based on convective exchange with a cryogenic fluid.
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Affiliation(s)
- Michael L Etheridge
- Department of Mechanical Engineering, Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455, USA
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Handler M, Fischer G, Seger M, Kienast R, Nowak CN, Pehböck D, Hintringer F, Baumgartner C. Computer simulation of cardiac cryoablation: comparison with in vivo data. Med Eng Phys 2013; 35:1754-61. [PMID: 23972331 DOI: 10.1016/j.medengphy.2013.07.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2012] [Revised: 05/09/2013] [Accepted: 07/23/2013] [Indexed: 11/24/2022]
Abstract
Simulation of cardiac cryoablation by the finite element method can contribute to optimizing ablation results and understanding the effects of modifications prior to time-consuming and expensive experiments. In this work an intervention scenario using a 9 Fr 8 mm tip applicator applied to ventricular tissue was simulated using the effective heat capacity model based on Pennes' bioheat equation. Using experimentally obtained refrigerant flow rates and temperature profiles recorded by a thermocouple located at the tip of the applicator the cooling performance of the refrigerant was estimated and integrated by time and temperature dependent boundary conditions based on distinct phases of a freeze-thaw cycle. Our simulations exhibited a mean difference of approximately 6°C at the applicator tip compared to temperature profiles obtained during in vivo experiments. The presented model is a useful tool for simulation and validation of new developments in clinical cardiac cryoablation.
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Affiliation(s)
- Michael Handler
- Institute of Electrical and Biomedical Engineering, University for Health Sciences, Medical Informatics and Technology, Eduard Wallnöfer-Zentrum 1, 6060 Hall in Tirol, Austria.
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14
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Abstract
CLINICAL ISSUE Primary and secondary liver tumors often limit patient outcome and only a minority of patients are eligible for potential curative surgery. Minimally invasive treatments, such as radiofrequency ablation (RFA), microwave ablation (MWA) and cryoablation are alternative treatment options in a curative and palliative setting. One major limitation of RFA and MWA is the limited size of tumor ablation. Furthermore during the procedure the ablation size can only be roughly estimated using RFA and MWA. STANDARD TREATMENT RFA is the standard modality of minimally invasive tumor therapy. In comparison cryoablation is rarely used despite its advantages. TREATMENT INNOVATIONS Argon-helium-based cryoablation systems of the newest generation combine the advantage of small diameter applicators comparable with those of RFA and MWA systems with intrinsic advantages. ACHIEVEMENTS Cryoablation is a minimally invasive treatment option with advantages, such as virtually unlimited ablation size, real-time visualization using computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound and intrinsic analgesic effects. On the other hand it is not very time-efficient in comparison to MWA. Especially in liver metastases RFA is the preferred treatment option. PRACTICAL RECOMMENDATIONS Cryoablation is a fascinating treatment option in minimally invasive tumor treatment. It demonstrates good results in hepatocellular carcinoma within the Milan criteria and T1a renal cell carcinoma. Furthermore it is a well-established treatment modality for palliative pain management in bone tumors.
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Affiliation(s)
- P Isfort
- Klinik für Diagnostische und Interventionelle Radiologie, Universitätsklinikum RWTH Aachen, Pauwelsstr. 30, 52074, Aachen, Deutschland
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15
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Abstract
Image-guided tumor ablation with both thermal and nonthermal sources has received substantial attention for the treatment of many focal malignancies. Increasing interest has been accompanied by continual advances in energy delivery, application technique, and therapeutic combinations with the intent to improve the efficacy and/or specificity of ablative therapies. This review outlines clinical percutaneous tumor ablation technology, detailing the science, devices, techniques, technical obstacles, current trends, and future goals in percutaneous tumor ablation. Methods such as chemical ablation, cryoablation, high-temperature ablation (radiofrequency, microwave, laser, and ultrasound), and irreversible electroporation will be discussed. Advances in technique will also be covered, including combination therapies, tissue property modulation, and the role of computer modeling for treatment optimization.
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Affiliation(s)
- Muneeb Ahmed
- Laboratory for Minimally Invasive Tumor Therapy, Section of Interventional Radiology, and Section of Abdominal Imaging, Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, 1 Deaconess Rd, Boston, MA 02215, USA.
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Blezek DJ, Carlson DG, Cheng LT, Christensen JA, Callstrom MR, Erickson BJ. Cell accelerated cryoablation simulation. Comput Methods Programs Biomed 2010; 98:241-252. [PMID: 19854531 DOI: 10.1016/j.cmpb.2009.09.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2009] [Revised: 08/17/2009] [Accepted: 09/03/2009] [Indexed: 05/28/2023]
Abstract
Tumor cryoablation is a clinical procedure where supercooled probes are used to destroy cancerous lesions. Cryoablation is a safe and effective palliative treatment for skeletal metastases, providing immediate and long term pain relief, increasing mobility and improving quality of life. Ideally, lesions are encompassed by an ice ball and frozen to a sufficiently low temperature to ensure cell death. "Lethal ice" is the term used to describe regions within the ice ball where cell death occurs. Failure to achieve lethal ice in all portions of a lesion may explain the high recurrence rate currently observed. Tracking growth of lethal ice is critical to success of percutaneous ablations, however, no practical methods currently exist for non-invasive temperature monitoring. Physicians lack planning tools which provide accurate estimation of the ice formation. Simulation of ice formation, while possible, is computationally demanding and too time consuming to be of clinical utility. We developed the computational framework for the simulation, acceleration strategies for multicore Intel x86 and IBM Cell architectures, and performed preliminary validation of the simulation. Our results demonstrate that the streaming SIMD implementation has better performance and scalability. Both accelerated and non-accelerated algorithms demonstrate good agreement between simulation and manually identified ice ball boundaries in phantom and patient images. Our results show promise for the development of novel cryoablation planning tools with real-time monitoring capability for clinical use.
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Affiliation(s)
- Daniel J Blezek
- Department of Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA.
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Abstract
Cryoablation is a minimally invasive ablation technique for primary and metastatic hepatic tumors. Inadequate freezing around large blood vessels due to the warm blood flow can lead to local recurrence, and thus, necessitates close application of a cryoprobe to the large blood vessels. In this study, we constructed a perfusion model with an ex vivo bovine liver and ablated the tissue around a large blood vessel with one or two cryoprobes applied to the side of the vessel. The finite-element computer model developed in our previous study was modified to include a blood vessel and its convective heat transfer to the vicinity of the blood vessel. We compared the predicted simulation results to those acquired from this ex vivo perfusion model. The results indicate that blood vessels act as a heat source and generate steep temperature profiles in the area next to the large blood vessel. After validation, the maximum allowable distance between the cryoprobe and the large blood vessel for successful cryoablation was presented. The results of this study should be considered when placing cryoprobes in the vicinity of large blood vessels.
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Affiliation(s)
- Cheolkyun Kim
- Department of Biomedical Engineering, University of Wisconsin, Madison, WI 53706, USA.
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