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Xu R, Treeby BE, Martin E. Safety Review of Therapeutic Ultrasound for Spinal Cord Neuromodulation and Blood-Spinal Cord Barrier Opening. ULTRASOUND IN MEDICINE & BIOLOGY 2024; 50:317-331. [PMID: 38182491 DOI: 10.1016/j.ultrasmedbio.2023.11.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Revised: 11/07/2023] [Accepted: 11/10/2023] [Indexed: 01/07/2024]
Abstract
New focused ultrasound spinal cord applications have emerged, particularly those improving therapeutic agent delivery to the spinal cord via blood-spinal cord barrier opening and the neuromodulation of spinal cord tracts. One hurdle in the development of these applications is safety. It may be possible to use safety trends from seminal and subsequent works in focused ultrasound to guide the development of safety guidelines for spinal cord applications. We collated data from decades of pre-clinical studies and illustrate a clear relationship between damage, time-averaged spatial peak intensity and exposure duration. This relationship suggests a thermal mechanism underlies ultrasound-induced spinal cord damage. We developed minimum and mean thresholds for damage from these pre-clinical studies. When these thresholds were plotted against the parameters used in recent pre-clinical ultrasonic spinal cord neuromodulation studies, the majority of the neuromodulation studies were near or above the minimum threshold. This suggests that a thermal neuromodulatory effect may exist for ultrasonic spinal cord neuromodulation, and that the thermal dose must be carefully controlled to avoid damage to the spinal cord. By contrast, the intensity-exposure duration threshold had no predictive value when applied to blood-spinal cord barrier opening studies that employed injected contrast agents. Most blood-spinal cord barrier opening studies observed slight to severe damage, except for small animal studies that employed an active feedback control method to limit pressures based on measured bubble oscillation behavior. The development of new focused ultrasound spinal cord applications perhaps reflects the recent success in the development of focused ultrasound brain applications, and recent work has begun on the translation of these technologies from brain to spinal cord. However, a great deal of work remains to be done, particularly with respect to developing and accepting safety standards for these applications.
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Affiliation(s)
- Rui Xu
- Department of Medical Physics and Biomedical Engineering, University College London, London, UK.
| | - Bradley E Treeby
- Department of Medical Physics and Biomedical Engineering, University College London, London, UK
| | - Eleanor Martin
- Department of Medical Physics and Biomedical Engineering, University College London, London, UK
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2
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Pfannenstiel A, Iannuccilli J, Cornelis FH, Dupuy DE, Beard WL, Prakash P. Shaping the future of microwave tumor ablation: a new direction in precision and control of device performance. Int J Hyperthermia 2022; 39:664-674. [DOI: 10.1080/02656736.2021.1991012] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Affiliation(s)
- Austin Pfannenstiel
- Precision Microwave Inc, Manhattan, KS, USA
- Department of Electrical and Computer Engineering, Kansas State University, Manhattan, KS, USA
| | - Jason Iannuccilli
- Department of Diagnostic Imaging, Division of Interventional Oncology, Rhode Island Hospital, Providence, RI, USA
| | - Francois H. Cornelis
- Interventional Radiology Service, Memorial Sloan Kettering Cancer Center, NY, USA
| | - Damian E. Dupuy
- Diagnostic Imaging, Brown University, Radiology, Cape Cod Hospital, MA, USA
| | - Warren L. Beard
- Department of Clinical Sciences, Kansas State University, Manhattan, KS, USA
| | - Punit Prakash
- Department of Electrical and Computer Engineering, Kansas State University, Manhattan, KS, USA
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3
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Sebek J, Cappiello G, Rahmani G, Zeinali N, Keating M, Fayemiwo M, Harkin J, McDaid L, Gardiner B, Sheppard D, Senanayake R, Gurnell M, O’Halloran M, Dennedy MC, Prakash P. Image-based computer modeling assessment of microwave ablation for treatment of adrenal tumors. Int J Hyperthermia 2022; 39:1264-1275. [PMID: 36137605 PMCID: PMC9820798 DOI: 10.1080/02656736.2022.2125590] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
PURPOSE To assess the feasibility of delivering microwave ablation for targeted treatment of aldosterone producing adenomas using image-based computational models. METHODS We curated an anonymized dataset of diagnostic 11C-metomidate PET/CT images of 14 patients with aldosterone producing adenomas (APA). A semi-automated approach was developed to segment the APA, adrenal gland, and adjacent organs within 2 cm of the APA boundary. The segmented volumes were used to implement patient-specific 3D electromagnetic-bioheat transfer models of microwave ablation with a 2.45 GHz directional microwave ablation applicator. Ablation profiles were quantitatively assessed based on the extent of the APA target encompassed by an ablative thermal dose, while limiting thermal damage to the adjacent normal adrenal tissue and sensitive critical structures. RESULTS Across the 14 patients, adrenal tumor volumes ranged between 393 mm3 and 2,395 mm3. On average, 70% of the adrenal tumor volumes received an ablative thermal dose of 240CEM43, while limiting thermal damage to non-target structures, and thermally sparing 83.5-96.4% of normal adrenal gland. Average ablation duration was 293 s (range: 60-600 s). Simulations indicated coverage of the APA with an ablative dose was limited when the axis of the ablation applicator was not well aligned with the major axis of the targeted APA. CONCLUSIONS Image-based computational models demonstrate the potential for delivering microwave ablation to APA targets within the adrenal gland, while limiting thermal damage to surrounding non-target structures.
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Affiliation(s)
- Jan Sebek
- Mike Wiegers Department of Electrical and Computer Engineering, Kansas State University, Manhattan, KS 66506, USA
| | - Grazia Cappiello
- Translational Medical Devices Lab, National University of Ireland, Galway, Republic of Ireland
| | - George Rahmani
- Department of Radiology, Galway University Hospitals, Galway, Republic Ireland
| | - Nooshin Zeinali
- Mike Wiegers Department of Electrical and Computer Engineering, Kansas State University, Manhattan, KS 66506, USA
| | - Muireann Keating
- School of Medicine, National University of Ireland, Galway, Republic Ireland
| | - Michael Fayemiwo
- School of Computing, Engineering, and Intelligent Systems, Ulster University, Londonderry, Northern Ireland
| | - Jim Harkin
- School of Computing, Engineering, and Intelligent Systems, Ulster University, Londonderry, Northern Ireland
| | - Liam McDaid
- School of Computing, Engineering, and Intelligent Systems, Ulster University, Londonderry, Northern Ireland
| | - Bryan Gardiner
- School of Computing, Engineering, and Intelligent Systems, Ulster University, Londonderry, Northern Ireland
| | - Declan Sheppard
- Department of Radiology, Galway University Hospitals, Galway, Republic Ireland
| | | | - Mark Gurnell
- Institute of Metabolic Science, University of Cambridge, United Kingdom
| | - Martin O’Halloran
- Translational Medical Devices Lab, National University of Ireland, Galway, Republic of Ireland
| | - M. Conall Dennedy
- School of Medicine, National University of Ireland, Galway, Republic Ireland
| | - Punit Prakash
- Mike Wiegers Department of Electrical and Computer Engineering, Kansas State University, Manhattan, KS 66506, USA.,Author to whom correspondence should be addressed: Punit Prakash, 3078 Engineering Hall, 1701D Platt St, Kansas State University, Manhattan, KS 66506, USA.
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Gandomi KY, Carvalho PAWG, Tarasek M, Fiveland EW, Bhushan C, Williams E, Neubauer P, Zhao Z, Pilitsis J, Yeo D, Nycz CJ, Burdette E, Fischer GS. Modeling of Interstitial Ultrasound Ablation for Continuous Applicator Rotation With MR Validation. IEEE Trans Biomed Eng 2021; 68:1838-1846. [PMID: 32924937 PMCID: PMC8189669 DOI: 10.1109/tbme.2020.3023849] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The primary objective of cancer intervention is the selective removal of malignant cells while conserving surrounding healthy tissues. However, the accessibility, size and shape of the cancer can make achieving appropriate margins a challenge. One minimally invasive treatment option for these clinical cases is interstitial needle based therapeutic ultrasound (NBTU). In this work, we develop a finite element model (FEM) capable of simulating continuous rotation of a directional NBTU applicator. The developed model was used to simulate the thermal deposition for different rotation trajectories. The actual thermal deposition patterns for the simulated trajectories were then evaluated using magnetic resonance thermal imaging (MRTI) in a porcine skin gelatin phantom. An MRI-compatible robot was used to control the rotation motion profile of the physical NBTU applicator to match the simulated trajectory. The model showed agreement when compared to experimental measurements with Pearson correlation coefficients greater than 0.839 when comparing temperature fields within an area of 12.6 mm radius from the ultrasound applicator. The average temperature error along a 6.3 mm radius profile from the applicator was 1.27 °C. The model was able to compute 1 s of thermal deposition by the applicator in 0.2 s on average with a 0.1 mm spatial resolution and 0.5 s time steps. The developed simulation demonstrates performance suitable for real-time control which may enable robotically-actuated closed-loop conformal tumor ablation.
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Adams MS, Lotz JC, Diederich CJ. In silico feasibility assessment of extracorporeal delivery of low-intensity pulsed ultrasound to intervertebral discs within the lumbar spine. Phys Med Biol 2020; 65:215011. [PMID: 32620003 DOI: 10.1088/1361-6560/aba28d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Low intensity pulsed ultrasound (LIPUS) may have utility for non-invasive treatment of discogenic lower back pain through stimulating, remodeling and accelerating healing of injured or degenerated intervertebral disc (IVD) tissues. This study investigates the feasibility of delivering LIPUS to lumbar IVDs between L2 and S1 spine vertebra using a planar extracorporeal phased array (8 × 8 cm, 1024 elements, 500 kHz). Three 3D anatomical models with heterogenous tissues were generated from patient CT image sets and used in the simulation-based analysis. Time-reversal acoustic modeling techniques were applied to optimize posterior-lateral placement of the array with respect to the body to facilitate energy deposition in discrete target regions spanning the annulus fibrosus and central nucleus of each IVD. Forward acoustic and biothermal simulations were performed with time-reversal optimized array placements and driving amplitude/phase settings to predict LIPUS intensity distributions at target sites and to investigate off-target energy deposition and heating potential. Simulation results demonstrate focal intensity gain of 5-168 across all IVD targets and anatomical models, with greater average intensity gain (>50) and energy localization in posterior, posterolateral, and lateral target sites of IVDs. Localized LIPUS delivery was enhanced in thinner patient anatomies and in the high lumbar levels (L2-L3 and L3-L4). Multiple amplitude/phasing illumination patterns could be sequenced at a fixed array position for larger regional energy coverage in the IVD. Biothermal simulations demonstrated that LIPUS-appropriate exposures of 100 mW cm-2 ISPTA to the target disc region would result in <1 °C global peak temperature elevation for all cases. Hence, simulations suggest that spatially-precise extracorporeal delivery of therapeutically relevant LIPUS doses to discrete regions of lumbar IVDs is feasible and may be useful in clinical management of discogenic back pain.
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Affiliation(s)
- Matthew S Adams
- Thermal Therapy Research Group, Department of Radiation Oncology, University of California San Francisco, 2340 Sutter Street, S341, San Francisco, CA 94115, United States of America
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6
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Chen J, LeBlang S, Hananel A, Aginsky R, Perez J, Gofeld M, Shir Y, Aubry JF. An incoherent HIFU transducer for treatment of the medial branch nerve: Numerical study and in vivo validation. Int J Hyperthermia 2020; 37:1219-1228. [PMID: 33106054 DOI: 10.1080/02656736.2020.1828628] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Chronic back pain due to facet related degenerative changes affects 4-6 million patients a year in the United States. Patients refractory to conservative therapy may warrant targeted injections of steroids into the joint or percutaneous medial branch nerve denervation with radiofrequency ablation. We numerically tested a novel noninvasive high intensity focused ultrasound transducer to optimize nerve ablation near a bone-soft tissue interface. METHODS A transducer with 4 elements operating in an incoherent mode was modeled numerically and tested pre-clinically under fluoroscopic guidance. After 6 lumbar medial branch nerve ablations were performed in 2 pigs, they were followed clinically for 1 week and then sacrificed for pathological evaluation. RESULTS Simulations show that the acoustic spot size in water at 6 dB was 14mm axial x 1.6mm lateral and 52mm axial x 1.6mm lateral for coherent and incoherent modes, respectively. We measured the size of N = 6 lesions induced in vivo in a pig model and compared them to the size of the simulated thermal dose. The best match between the simulated and measured lesion size was found with a maximum absorption coefficient in the cortical bone adjusted to 30 dB/cm/MHz. This absorption was used to simulate clinical scenarios in humans to generate lesions with no potential side effects at 1000 and 1500 J. CONCLUSION The elongated spot obtained with the incoherent mode facilitates the targeting during fluoroscopic-guided medial branch nerve ablation.
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Affiliation(s)
- J Chen
- FUSMobile, Alpharetta, GA, USA
| | - S LeBlang
- Focused Ultrasound Foundation, Charlottesville, VA, USA
| | | | | | - J Perez
- McGill University, Montreal, Canada
| | - M Gofeld
- Silver Medical Group, North York, Canada
| | - Y Shir
- McGill University, Montreal, Canada
| | - J F Aubry
- Physics for Medicine Paris, Inserm, ESPCI Paris, CNRS, PSL Research University, Paris, France
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7
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Singh S, Melnik R. Thermal ablation of biological tissues in disease treatment: A review of computational models and future directions. Electromagn Biol Med 2020; 39:49-88. [PMID: 32233691 DOI: 10.1080/15368378.2020.1741383] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Percutaneous thermal ablation has proven to be an effective modality for treating both benign and malignant tumours in various tissues. Among these modalities, radiofrequency ablation (RFA) is the most promising and widely adopted approach that has been extensively studied in the past decades. Microwave ablation (MWA) is a newly emerging modality that is gaining rapid momentum due to its capability of inducing rapid heating and attaining larger ablation volumes, and its lesser susceptibility to the heat sink effects as compared to RFA. Although the goal of both these therapies is to attain cell death in the target tissue by virtue of heating above 50°C, their underlying mechanism of action and principles greatly differs. Computational modelling is a powerful tool for studying the effect of electromagnetic interactions within the biological tissues and predicting the treatment outcomes during thermal ablative therapies. Such a priori estimation can assist the clinical practitioners during treatment planning with the goal of attaining successful tumour destruction and preservation of the surrounding healthy tissue and critical structures. This review provides current state-of-the-art developments and associated challenges in the computational modelling of thermal ablative techniques, viz., RFA and MWA, as well as touch upon several promising avenues in the modelling of laser ablation, nanoparticles assisted magnetic hyperthermia and non-invasive RFA. The application of RFA in pain relief has been extensively reviewed from modelling point of view. Additionally, future directions have also been provided to improve these models for their successful translation and integration into the hospital work flow.
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Affiliation(s)
- Sundeep Singh
- MS2Discovery Interdisciplinary Research Institute, Wilfrid Laurier University, Waterloo, Ontario, Canada
| | - Roderick Melnik
- MS2Discovery Interdisciplinary Research Institute, Wilfrid Laurier University, Waterloo, Ontario, Canada.,BCAM - Basque Center for Applied Mathematics, Bilbao, Spain
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8
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Qiao S, Elbes D, Boubriak O, Urban JPG, Coussios CC, Cleveland RO. Delivering Focused Ultrasound to Intervertebral Discs Using Time-Reversal. ULTRASOUND IN MEDICINE & BIOLOGY 2019; 45:2405-2416. [PMID: 31155405 DOI: 10.1016/j.ultrasmedbio.2019.04.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 04/18/2019] [Accepted: 04/25/2019] [Indexed: 06/09/2023]
Abstract
Chronic low back pain causes more disability worldwide than any other condition and is thought to arise in part through loss of biomechanical function of degenerate intervertebral discs (IVDs). Current treatments can involve replacing part or all of the degenerate IVDs by invasive surgery. Our vision is to develop a minimally invasive approach in which high intensity focused ultrasound (HIFU) is used to mechanically fractionate degenerate tissue in an IVD; a fine needle is then used to first remove the fractionated tissue and then inject a biomaterial able to restore normal physiologic function. The goal of this manuscript is to demonstrate the feasibility of trans-spinal HIFU delivery using simulations of 3-D ultrasound propagation in models derived from patient computed tomography (CT) scans. The CT data were segmented into bone, fat and other soft tissue for three patients. Ultrasound arrays were placed around the waist of each patient model, and time-reversal was used to determine the source signals necessary to create a focus in the center of the disc. The simulations showed that for 0.5 MHz ultrasound, a focus could be created in most of the lumbar IVDs, with the pressure focal gain ranging from 3.2-13.7. In conclusion, it is shown that with patient-specific planning, focusing ultrasound into an IVD is possible in the majority of patients despite the complex acoustic path introduced by the bony structures of the spine.
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Affiliation(s)
- S Qiao
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, UK
| | - D Elbes
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, UK
| | - O Boubriak
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, UK
| | - J P G Urban
- Department of Physiology, Anatomy & Genetics, University of Oxford, UK
| | - C-C Coussios
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, UK
| | - R O Cleveland
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, UK.
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9
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Singh S, Melnik R. Radiofrequency Ablation for Treating Chronic Pain of Bones: Effects of Nerve Locations. BIOINFORMATICS AND BIOMEDICAL ENGINEERING 2019. [DOI: 10.1007/978-3-030-17935-9_38] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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10
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Hudson TJ, Looi T, Pichardo S, Amaral J, Temple M, Drake JM, Waspe AC. Simulating thermal effects of MR-guided focused ultrasound in cortical bone and its surrounding tissue. Med Phys 2017; 45:506-519. [DOI: 10.1002/mp.12704] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 11/03/2017] [Accepted: 11/09/2017] [Indexed: 12/23/2022] Open
Affiliation(s)
- Thomas J. Hudson
- Centre for Image Guided Innovation and Therapeutic Intervention; Hospital for Sick Children; Toronto Ontario M5G 1X8 Canada
- Institute of Biomaterials and Biomedical Engineering; University of Toronto; Toronto Ontario M5S 3G9 Canada
| | - Thomas Looi
- Centre for Image Guided Innovation and Therapeutic Intervention; Hospital for Sick Children; Toronto Ontario M5G 1X8 Canada
- Institute of Biomaterials and Biomedical Engineering; University of Toronto; Toronto Ontario M5S 3G9 Canada
| | - Samuel Pichardo
- Thunder Bay Regional Health Research Institute; Thunder Bay Ontario P7B 6V4 Canada
- Electrical Engineering and Physics; Lakehead University; Thunder Bay Ontario P7B 5E1 Canada
| | - Joao Amaral
- Centre for Image Guided Innovation and Therapeutic Intervention; Hospital for Sick Children; Toronto Ontario M5G 1X8 Canada
- Department of Medical Imaging; University of Toronto; Toronto Ontario M5T 1W7 Canada
| | - Michael Temple
- Centre for Image Guided Innovation and Therapeutic Intervention; Hospital for Sick Children; Toronto Ontario M5G 1X8 Canada
- Department of Medical Imaging; University of Toronto; Toronto Ontario M5T 1W7 Canada
| | - James M. Drake
- Centre for Image Guided Innovation and Therapeutic Intervention; Hospital for Sick Children; Toronto Ontario M5G 1X8 Canada
- Institute of Biomaterials and Biomedical Engineering; University of Toronto; Toronto Ontario M5S 3G9 Canada
| | - Adam C. Waspe
- Centre for Image Guided Innovation and Therapeutic Intervention; Hospital for Sick Children; Toronto Ontario M5G 1X8 Canada
- Department of Medical Imaging; University of Toronto; Toronto Ontario M5T 1W7 Canada
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11
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Schwenke M, Georgii J, Preusser T. Fast Numerical Simulation of Focused Ultrasound Treatments During Respiratory Motion With Discontinuous Motion Boundaries. IEEE Trans Biomed Eng 2017; 64:1455-1468. [DOI: 10.1109/tbme.2016.2619741] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Michael Schwenke
- Fraunhofer Institute for Medical Image Computing MEVIS, Bremen, Germany
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12
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Scott SJ, Adams MS, Salgaonkar V, Sommer FG, Diederich CJ. Theoretical investigation of transgastric and intraductal approaches for ultrasound-based thermal therapy of the pancreas. J Ther Ultrasound 2017; 5:10. [PMID: 28469915 PMCID: PMC5414307 DOI: 10.1186/s40349-017-0090-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 02/07/2017] [Indexed: 02/07/2023] Open
Abstract
Background The goal of this study was to theoretically investigate the feasibility of intraductal and transgastric approaches to ultrasound-based thermal therapy of pancreatic tumors, and to evaluate possible treatment strategies. Methods This study considered ultrasound applicators with 1.2 mm outer diameter tubular transducers, which are inserted into the tissue to be treated by an endoscopic approach, either via insertion through the gastric wall (transgastric) or within the pancreatic duct lumen (intraductal). 8 patient-specific, 3D, transient, biothermal and acoustic finite element models were generated to model hyperthermia (n = 2) and ablation (n = 6), using sectored (210°–270°, n = 4) and 360° (n = 4) transducers for treatment of 3.3–17.0 cm3 tumors in the head (n = 5), body (n = 2), and tail (n = 1) of the pancreas. A parametric study was performed to determine appropriate treatment parameters as a function of tissue attenuation, blood perfusion rates, and distance to sensitive anatomy. Results Parametric studies indicated that pancreatic tumors up to 2.5 or 2.7 cm diameter can be ablated within 10 min with the transgastric and intraductal approaches, respectively. Patient-specific simulations demonstrated that 67.1–83.3% of the volumes of four sample 3.3–11.4 cm3 tumors could be ablated within 3–10 min using transgastric or intraductal approaches. 55.3–60.0% of the volume of a large 17.0 cm3 tumor could be ablated using multiple applicator positions within 20–30 min with either transgastric or intraductal approaches. 89.9–94.7% of the volume of two 4.4–11.4 cm3 tumors could be treated with intraductal hyperthermia. Sectored applicators are effective in directing acoustic output away from and preserving sensitive structures. When acoustic energy is directed towards sensitive structures, applicators should be placed at least 13.9–14.8 mm from major vessels like the aorta, 9.4–12.0 mm from other vessels, depending on the vessel size and flow rate, and 14 mm from the duodenum. Conclusions This study demonstrated the feasibility of generating shaped or conformal ablative or hyperthermic temperature distributions within pancreatic tumors using transgastric or intraductal ultrasound.
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Affiliation(s)
- Serena J Scott
- Department of Radiation Oncology, Thermal Therapy Research Group, University of California, San Francisco, 1600 Divisadero Street, Suite H1031, San Francisco, CA 94143-1708 USA
| | - Matthew S Adams
- Department of Radiation Oncology, Thermal Therapy Research Group, University of California, San Francisco, 1600 Divisadero Street, Suite H1031, San Francisco, CA 94143-1708 USA.,UC Berkeley - UC San Francisco Graduate Program in Bioengineering, California, USA
| | - Vasant Salgaonkar
- Department of Radiation Oncology, Thermal Therapy Research Group, University of California, San Francisco, 1600 Divisadero Street, Suite H1031, San Francisco, CA 94143-1708 USA
| | - F Graham Sommer
- Department of Radiology, Stanford University School of Medicine, Stanford, CA USA
| | - Chris J Diederich
- Department of Radiation Oncology, Thermal Therapy Research Group, University of California, San Francisco, 1600 Divisadero Street, Suite H1031, San Francisco, CA 94143-1708 USA.,UC Berkeley - UC San Francisco Graduate Program in Bioengineering, California, USA
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13
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A review of radiofrequency ablation: Large target tissue necrosis and mathematical modelling. Phys Med 2016; 32:961-71. [PMID: 27461969 DOI: 10.1016/j.ejmp.2016.07.092] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2015] [Revised: 06/06/2016] [Accepted: 07/18/2016] [Indexed: 12/15/2022] Open
Abstract
Radiofrequency ablation (RFA) is an effective clinical method for tumour ablation with minimum intrusiveness. However, the use of RFA is mostly restricted to small tumours, especially those <3cm in diameter. This paper discusses the state-of-the-art of RFA, drawn from experimental and clinical results, for large tumours (i.e. ⩾3cm in diameter). In particular, the paper analyses clinical results related to target tissue necrosis (TTN) and mathematical modelling of the RFA procedure to understand the mechanism whereby the TTN is limited to under 3cm with RFA. This paper also discusses a strategy of controlling of the temperature of target tissue in the RFA procedure with the state-of-art device, which has the potential to increase the size of TTN. This paper ends with a discussion of some future ideas to solve the so-called 3-cm problem with RFA.
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14
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Kaye EA, Monette S, Srimathveeravalli G, Maybody M, Solomon SB, Gulati A. MRI-guided focused ultrasound ablation of lumbar medial branch nerve: Feasibility and safety study in a swine model. Int J Hyperthermia 2016; 32:786-94. [PMID: 27443328 DOI: 10.1080/02656736.2016.1197972] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
PURPOSE About 10-40% of chronic low back pain cases involve facet joints, which are commonly treated with lumbar medial branch (MB) radiofrequency neurotomy. Magnetic resonance imaging-guided focused ultrasound (MRgFUS), a non-invasive, non-ionising ablation modality used to treat tumours, neuropathic pain and painful bone metastasis can also be used to disrupt nerve conduction. This work's purpose was to study the feasibility and safety of direct MRgFUS ablation of the lumbar MB nerve in acute and subacute swine models. MATERIALS AND METHODS In vivo MRgFUS ablation was performed in six swine (three acute and three subacute) using a clinical MRgFUS system and a 3-T MRI scanner combination. Behavioural assessment was performed, and imaging and histology were used to assess the treatment. RESULTS AND CONCLUSIONS Histological analysis of the in vivo studies confirmed thermal necrosis of the MB nerve could be achieved without damaging the spinal cord or adjacent nerve roots. MRgFUS did not cause changes in the animals' behaviour or ambulation.
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Affiliation(s)
- Elena A Kaye
- a Department of Medical Physics , Memorial Sloan Kettering Cancer Center , New York
| | - Sebastien Monette
- b Tri-Institutional Laboratory of Comparative Pathology, Memorial Sloan Kettering Cancer Center , Rockefeller University, Weill Cornell Medical College , New York
| | | | - Majid Maybody
- c Department of Radiology , Memorial Sloan Kettering Cancer Center , New York
| | - Stephen B Solomon
- c Department of Radiology , Memorial Sloan Kettering Cancer Center , New York
| | - Amitabh Gulati
- d Department of Anesthesiology , Memorial Sloan Kettering Cancer Center , New York , USA
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15
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Irastorza RM, Trujillo M, Martel Villagrán J, Berjano E. Computer modelling of RF ablation in cortical osteoid osteoma: Assessment of the insulating effect of the reactive zone. Int J Hyperthermia 2016; 32:221-30. [DOI: 10.3109/02656736.2015.1135998] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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16
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ten Eikelder HMM, Bošnački D, Elevelt A, Donato K, Di Tullio A, Breuer BJT, van Wijk JH, van Dijk EVM, Modena D, Yeo SY, Grüll H. Modelling the temperature evolution of bone under high intensity focused ultrasound. Phys Med Biol 2016; 61:1810-28. [PMID: 26854572 DOI: 10.1088/0031-9155/61/4/1810] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Magnetic resonance-guided high intensity focused ultrasound (MR-HIFU) has been clinically shown to be effective for palliative pain management in patients suffering from skeletal metastasis. The underlying mechanism is supposed to be periosteal denervation caused by ablative temperatures reached through ultrasound heating of the cortex. The challenge is exact temperature control during sonication as MR-based thermometry approaches for bone tissue are currently not available. Thus, in contrast to the MR-HIFU ablation of soft tissue, a thermometry feedback to the HIFU is lacking, and the treatment of bone metastasis is entirely based on temperature information acquired in the soft tissue adjacent to the bone surface. However, heating of the adjacent tissue depends on the exact sonication protocol and requires extensive modelling to estimate the actual temperature of the cortex. Here we develop a computational model to calculate the spatial temperature evolution in bone and the adjacent tissue during sonication. First, a ray-tracing technique is used to compute the heat production in each spatial point serving as a source term for the second part, where the actual temperature is calculated as a function of space and time by solving the Pennes bio-heat equation. Importantly, our model includes shear waves that arise at the bone interface as well as all geometrical considerations of transducer and bone geometry. The model was compared with a theoretical approach based on the far field approximation and an MR-HIFU experiment using a bone phantom. Furthermore, we investigated the contribution of shear waves to the heat production and resulting temperatures in bone. The temperature evolution predicted by our model was in accordance with the far field approximation and agreed well with the experimental data obtained in phantoms. Our model allows the simulation of the HIFU treatments of bone metastasis in patients and can be extended to a planning tool prior to MR-HIFU treatments.
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Adams MS, Scott SJ, Salgaonkar VA, Sommer G, Diederich CJ. Thermal therapy of pancreatic tumours using endoluminal ultrasound: Parametric and patient-specific modelling. Int J Hyperthermia 2016; 32:97-111. [PMID: 27097663 DOI: 10.3109/02656736.2015.1119892] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
PURPOSE The aim of this study is to investigate endoluminal ultrasound applicator configurations for volumetric thermal ablation and hyperthermia of pancreatic tumours using 3D acoustic and biothermal finite element models. MATERIALS AND METHODS Parametric studies compared endoluminal heating performance for varying applicator transducer configurations (planar, curvilinear-focused, or radial-diverging), frequencies (1-5 MHz), and anatomical conditions. Patient-specific pancreatic head and body tumour models were used to evaluate feasibility of generating hyperthermia and thermal ablation using an applicator positioned in the duodenal or stomach lumen. Temperature and thermal dose were calculated to define ablation (> 240 EM(43 °C)) and moderate hyperthermia (40-45 °C) boundaries, and to assess sparing of sensitive tissues. Proportional-integral control was incorporated to regulate maximum temperature to 70-80 °C for ablation and 45 °C for hyperthermia in target regions. RESULTS Parametric studies indicated that 1-3 MHz planar transducers are the most suitable for volumetric ablation, producing 5-8 cm(3) lesion volumes for a stationary 5-min sonication. Curvilinear-focused geometries produce more localised ablation to 20-45 mm depth from the GI tract and enhance thermal sparing (T(max) < 42 °C) of the luminal wall. Patient anatomy simulations show feasibility in ablating 60.1-92.9% of head/body tumour volumes (4.3-37.2 cm(3)) with dose < 15 EM(43 °C) in the luminal wall for 18-48 min treatment durations, using 1-3 applicator placements in GI lumen. For hyperthermia, planar and radial-diverging transducers could maintain up to 8 cm(3) and 15 cm(3) of tissue, respectively, between 40-45 °C for a single applicator placement. CONCLUSIONS Modelling studies indicate the feasibility of endoluminal ultrasound for volumetric thermal ablation or hyperthermia treatment of pancreatic tumour tissue.
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Affiliation(s)
- Matthew S Adams
- a Thermal Therapy Research Group, University of California , San Francisco , California .,b University of California, Berkeley - University of California, San Francisco Graduate Program in Bioengineering , California , and
| | - Serena J Scott
- a Thermal Therapy Research Group, University of California , San Francisco , California
| | - Vasant A Salgaonkar
- a Thermal Therapy Research Group, University of California , San Francisco , California
| | - Graham Sommer
- c Stanford Medical Center , Stanford , California , USA
| | - Chris J Diederich
- a Thermal Therapy Research Group, University of California , San Francisco , California .,b University of California, Berkeley - University of California, San Francisco Graduate Program in Bioengineering , California , and
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Rodrigues DB, Stauffer PR, Vrba D, Hurwitz MD. Focused ultrasound for treatment of bone tumours. Int J Hyperthermia 2015; 31:260-71. [DOI: 10.3109/02656736.2015.1006690] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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Salgaonkar VA, Diederich CJ. Catheter-based ultrasound technology for image-guided thermal therapy: current technology and applications. Int J Hyperthermia 2015; 31:203-15. [PMID: 25799287 DOI: 10.3109/02656736.2015.1006269] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Catheter-based ultrasound (CBUS) is applied to deliver minimally invasive thermal therapy to solid cancer tumours, benign tissue growth, vascular disease, and tissue remodelling. Compared to other energy modalities used in catheter-based surgical interventions, unique features of ultrasound result in conformable and precise energy delivery with high selectivity, fast treatment times, and larger treatment volumes. We present a concise review of CBUS technology being currently utilized in animal and clinical studies or being developed for future applications. CBUS devices have been categorised into interstitial, endoluminal and endovascular/cardiac applications. Basic applicator designs, site-specific evaluations and possible treatment applications have been discussed in brief. Particular emphasis has been given to ablation studies that incorporate image guidance for applicator placement, therapy monitoring, feedback control, and post-procedure assessment. Examples of devices included here span the entire spectrum of the development cycle from preliminary simulation-based design studies to implementation in clinical investigations. The use of CBUS under image guidance has the potential for significantly improving precision and applicability of thermal therapy delivery.
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Affiliation(s)
- Vasant A Salgaonkar
- Department of Radiation Oncology, University of California , San Francisco, California , USA
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Schwenke M, Strehlow J, Haase S, Jenne J, Tanner C, Langø T, Loeve AJ, Karakitsios I, Xiao X, Levy Y, Sat G, Bezzi M, Braunewell S, Guenther M, Melzer A, Preusser T. An integrated model-based software for FUS in moving abdominal organs. Int J Hyperthermia 2015; 31:240-50. [DOI: 10.3109/02656736.2014.1002817] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
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Rossmann C, Haemmerich D. Review of temperature dependence of thermal properties, dielectric properties, and perfusion of biological tissues at hyperthermic and ablation temperatures. Crit Rev Biomed Eng 2014; 42:467-92. [PMID: 25955712 PMCID: PMC4859435 DOI: 10.1615/critrevbiomedeng.2015012486] [Citation(s) in RCA: 156] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The application of supraphysiological temperatures (>40°C) to biological tissues causes changes at the molecular, cellular, and structural level, with corresponding changes in tissue function and in thermal, mechanical and dielectric tissue properties. This is particularly relevant for image-guided thermal treatments (e.g. hyperthermia and thermal ablation) delivering heat via focused ultrasound (FUS), radiofrequency (RF), microwave (MW), or laser energy; temperature induced changes in tissue properties are of relevance in relation to predicting tissue temperature profile, monitoring during treatment, and evaluation of treatment results. This paper presents a literature survey of temperature dependence of electrical (electrical conductivity, resistivity, permittivity) and thermal tissue properties (thermal conductivity, specific heat, diffusivity). Data of soft tissues (liver, prostate, muscle, kidney, uterus, collagen, myocardium and spleen) for temperatures between 5 to 90°C, and dielectric properties in the frequency range between 460 kHz and 3 GHz are reported. Furthermore, perfusion changes in tumors including carcinomas, sarcomas, rhabdomyosarcoma, adenocarcinoma and ependymoblastoma in response to hyperthmic temperatures up to 46°C are presented. Where appropriate, mathematical models to describe temperature dependence of properties are presented. The presented data is valuable for mathematical models that predict tissue temperature during thermal therapies (e.g. hyperthermia or thermal ablation), as well as for applications related to prediction and monitoring of temperature induced tissue changes.
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Affiliation(s)
- Christian Rossmann
- Department of Pediatrics, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Dieter Haemmerich
- Department of Pediatrics, Medical University of South Carolina, Charleston, South Carolina, USA; Department of Bioengineering, Clemson University, Clemson, South Carolina, USA
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