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Kumar YN, Singh Z, Wang YN, Kanabolo D, Chen L, Bruce M, Vlaisavljevich E, True L, Maxwell AD, Schade GR. A comparative study of histotripsy parameters for the treatment of fibrotic ex-vivo human benign prostatic hyperplasia tissue. Sci Rep 2024; 14:20365. [PMID: 39223181 PMCID: PMC11369199 DOI: 10.1038/s41598-024-71163-2] [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: 06/08/2024] [Accepted: 08/26/2024] [Indexed: 09/04/2024] Open
Abstract
Histotripsy is a noninvasive focused ultrasound therapy that mechanically fractionates tissue to create well-defined lesions. In a previous clinical pilot trial to treat benign prostatic hyperplasia (BPH), histotripsy did not result in consistent objective improvements in symptoms, potentially because of the fibrotic and mechanically tough nature of this tissue. In this study, we aimed to identify the dosage required to homogenize BPH tissue by different histotripsy modalities, including boiling histotripsy (BH) and cavitation histotripsy (CH). A method for histotripsy lesion quantification via entropy (HLQE) analysis was developed and utilized to quantify lesion area of the respective treatments. These data were correlated to changes in mechanical stiffness measured by ultrasound shear-wave elastography before and after treatment with each parameter set and dose. Time points corresponding to histologically observed complete lesions were qualitatively evaluated and quantitatively measured. For the BH treatment, complete lesions occurred with > = 30 s treatment time, with a corresponding maximum reduction in stiffness of -90.9 ± 7.2(s.d.)%. High pulse repetition frequency (PRF) CH achieved a similar reduction to that of BH at 288 s (-91.6 ± 6.0(s.d.)%), and low-PRF CH achieved a (-82.1 ± 5.1(s.d.)%) reduction in stiffness at dose > = 144 s. Receiver operating characteristic curve analysis showed that a > ~ 75% reduction in stiffness positively correlated with complete lesions observed histologically, and can provide an alternative metric to track treatment progression.
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Affiliation(s)
- Yashwanth Nanda Kumar
- Center for Industrial and Medical Ultrasound, University of Washington, Seattle, 98105, USA.
| | - Zorawar Singh
- Department of Urology, University of Washington, Seattle, 98195, USA
| | - Yak-Nam Wang
- Center for Industrial and Medical Ultrasound, University of Washington, Seattle, 98105, USA
| | - Diboro Kanabolo
- Department of Urology, University of Washington, Seattle, 98195, USA
| | - Lucas Chen
- Department of Urology, University of Washington, Seattle, 98195, USA
| | - Matthew Bruce
- Center for Industrial and Medical Ultrasound, University of Washington, Seattle, 98105, USA
| | - Eli Vlaisavljevich
- Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, 24061, USA
| | - Lawrence True
- Department of Pathology, University of Washington, Seattle, 98195, USA
| | - Adam D Maxwell
- Center for Industrial and Medical Ultrasound, University of Washington, Seattle, 98105, USA
- Department of Urology, University of Washington, Seattle, 98195, USA
| | - George R Schade
- Department of Urology, University of Washington, Seattle, 98195, USA
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Kumar YN, Singh Z, Wang YN, Kanabolo D, Chen L, Bruce M, Vlaisavljevich E, True L, Maxwell AD, Schade GR. A Comparative Study of Histotripsy Parameters for the Treatment of Fibrotic ex-vivo Human Benign Prostatic Hyperplasia Tissue. RESEARCH SQUARE 2024:rs.3.rs-4549536. [PMID: 39011101 PMCID: PMC11247946 DOI: 10.21203/rs.3.rs-4549536/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/17/2024]
Abstract
Histotripsy is a noninvasive focused ultrasound therapy that mechanically fractionates tissue to create well-defined lesions. In a previous clinical pilot trial to treat benign prostatic hyperplasia (BPH), histotripsy did not result in consistent objective improvements in symptoms, potentially because of the fibrotic and mechanically tough nature of this tissue. In this study, we aimed to identify the dosage required to homogenize BPH tissue by different histotripsy modalities, including boiling histotripsy (BH) and cavitation histotripsy (CH). A method for histotripsy lesion quantification via entropy (HLQE) analysis was developed and utilized to quantify lesion area of the respective treatments. These data were correlated to changes in mechanical stiffness measured by ultrasound shear-wave elastography before and after treatment with each parameter set and dose. Time points corresponding to histologically observed complete lesions were qualitatively evaluated and quantitatively measured. For the BH treatment, complete lesions occurred with >=30s treatment time, with a corresponding maximum reduction in stiffness of -90.9±7.2(s.d.)%. High pulse repetition frequency (PRF) CH achieved a similar reduction to that of BH at 288s (-91.6±6.0(s.d.)%), and low-PRF CH achieved a (-82.1±5.1(s.d.)%) reduction in stiffness at dose >=144s. Receiver operating characteristic curve analysis showed that a >~75% reduction in stiffness positively correlated with complete lesions observed histologically, and can provide an alternative metric to track treatment progression.
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Iqbal MF, Shafique MA, Abdur Raqib M, Fadlalla Ahmad TK, Haseeb A, M. A. Mhjoob A, Raja A. Histotripsy: an innovative approach for minimally invasive tumour and disease treatment. Ann Med Surg (Lond) 2024; 86:2081-2087. [PMID: 38576932 PMCID: PMC10990312 DOI: 10.1097/ms9.0000000000001897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Accepted: 02/26/2024] [Indexed: 04/06/2024] Open
Abstract
Histotripsy is a noninvasive medical technique that uses high-intensity focused ultrasound (HIFU) to treat liver tumours. The two main histotripsy methods are boiling histotripsy and cavitation cloud histotripsy. Boiling histotripsy uses prolonged ultrasound pulses to create small boiling bubbles in the tissue, which leads to the breakdown of the tissue into smaller subcellular fragments. Cavitation cloud histotripsy uses the ultrasonic cavitation effect to disintegrate target tissue into precisely defined liquefied lesions. Both methods show similar treatment effectiveness; however, boiling histotripsy ensures treatment stability by producing a stable boiling bubble with each pulse. The therapeutic effect is ascribed to mechanical damage at the subcellular level rather than thermal damage. This article discusses the mechanisms, treatment parameters, and potential of histotripsy as a minimally invasive procedure that provides precise and controlled subcellular damage.
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Affiliation(s)
| | | | | | | | - Abdul Haseeb
- Department of Medicine, Jinnah Sindh Medical University
| | | | - Adarsh Raja
- Department of Medicine, Shaheed Mohtarma Benazir Bhutto Medical College, Karachi, Pakistan
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Worlikar T, Hall T, Zhang M, Mendiratta-Lala M, Green M, Cho CS, Xu Z. Insights from in vivo preclinical cancer studies with histotripsy. Int J Hyperthermia 2024; 41:2297650. [PMID: 38214171 PMCID: PMC11102041 DOI: 10.1080/02656736.2023.2297650] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 12/16/2023] [Indexed: 01/13/2024] Open
Abstract
Histotripsy is the first noninvasive, non-ionizing, and non-thermal ablation technique that mechanically fractionates target tissue into acellular homogenate via controlled acoustic cavitation. Histotripsy has been evaluated for various preclinical applications requiring noninvasive tissue removal including cancer, brain surgery, blood clot and hematoma liquefaction, and correction of neonatal congenital heart defects. Promising preclinical results including local tumor suppression, improved survival outcomes, local and systemic anti-tumor immune responses, and histotripsy-induced abscopal effects have been reported in various animal tumor models. Histotripsy is also being investigated in veterinary patients with spontaneously arising tumors. Research is underway to combine histotripsy with immunotherapy and chemotherapy to improve therapeutic outcomes. In addition to preclinical cancer research, human clinical trials are ongoing for the treatment of liver tumors and renal tumors. Histotripsy has been recently approved by the FDA for noninvasive treatment of liver tumors. This review highlights key learnings from in vivo shock-scattering histotripsy, intrinsic threshold histotripsy, and boiling histotripsy cancer studies treating cancers of different anatomic locations and discusses the major considerations in planning in vivo histotripsy studies regarding instrumentation, tumor model, study design, treatment dose, and post-treatment tumor monitoring.
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Affiliation(s)
- Tejaswi Worlikar
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Timothy Hall
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Man Zhang
- Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA
| | | | - Michael Green
- Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan, USA
- Radiation Oncology, Ann Arbor VA Healthcare, Ann Arbor, Michigan, USA
| | - Clifford S. Cho
- Department of Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Research Service, Ann Arbor VA Healthcare, Ann Arbor, Michigan, USA
| | - Zhen Xu
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA
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Li H, He H, Tang J, Luo T, Yang G, Huang L, Dong X, Liu Z. A new sonoablation using acoustic droplet vaporization and focused ultrasound: A feasibility study. Med Phys 2023; 50:6663-6672. [PMID: 37731063 DOI: 10.1002/mp.16742] [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: 03/08/2023] [Revised: 08/31/2023] [Accepted: 08/31/2023] [Indexed: 09/22/2023] Open
Abstract
BACKGROUND Histotripsy and boiling histotripsy are two methods of mechanical ablation that use high-pressure focused ultrasound (FUS). PURPOSE Here, a new bubble sonoablation technique was investigated using low-pressure FUS in combination with local injection of perfluoropentane (PFP) in rabbit liver. METHODS Fifteen healthy New Zealand white rabbits were treated with FUS alone, FUS + PFP or PFP alone. FUS was performed using a single-element focused transducer (frequency 596 kHz, 0.27 ms pulses, 0.54% duty cycle, and peak negative pressure 2.0 MPa). Ten minutes before FUS treatment, the PFP droplet was locally injected into the rabbit liver, where the ultrasound was focused. Contrast-enhanced ultrasound (CEUS) of the liver was performed, and the temperature at the liver surface in the targeted liver region was recorded during treatment. The livers were collected for pathological examination. Statistical significance was set at p < 0.05. Paired t-tests were used to compare the pre- and post-treatment values. One-way analysis of variance was performed to compare multiple groups, and the least significant difference method was used for further comparisons between the two groups. RESULTS Analysis of CEUS data showed that the values of area under the curve (AUC) were significantly different in the PFP + FUS group pre- (10453.644 ± 1182.93) and post-treatment (4058.098 ± 2720.41), and the AUC values of PFP + FUS post-treatment (4058.098 ± 2720.41) were also significantly lower than those of the FUS (9946.694 ± 1071.54) and the PFP (10364.794 ± 2181.53) groups. The peak intensity values also showed the same results, the value of peak intensity of PFP+FUS post-treatment was 82.958 ± 13.99, whereas there was no difference between FUS (106.61 ± 7.61) and PFP (104.136 ± 10.55). Hematoxylin and eosin (H&E) staining revealed that the pathological damage ratings of the PFP + FUS, PFP, and FUS groups were grade 3, grade 1, and grade 0, respectively. Specifically, the area of liver necrosis in the PFP + FUS group (0.99 ± 0.29 cm2 ) was 198 times higher than that in the PFP group (0.005 ± 0.008 cm2 ), whereas no necrosis was observed in the livers treated with FUS alone. Simultaneously, the number of vacuoles in the liver of the PFP + FUS group (35.50 ± 23.31) was approximately five times that of the PFP group (7.00 ± 12.88), whereas no vacuoles were found in the liver treated with FUS alone. CONCLUSION PFP droplets combined with FUS can destroy liver tissue and cause tissue necrosis in the droplet injection area, without affecting the structure of surrounding tissue.
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Affiliation(s)
- Hui Li
- Department of Ultrasound, The Second Affiliated Hospital of Army Medical University, Chongqing, China
| | - Huan He
- Department of Ultrasound, The Second Affiliated Hospital of Army Medical University, Chongqing, China
| | - Jiawei Tang
- Department of Ultrasound, The Second Affiliated Hospital of Army Medical University, Chongqing, China
| | - Tingting Luo
- Department of Ultrasound, The Second Affiliated Hospital of Army Medical University, Chongqing, China
| | - Guoliang Yang
- Department of Ultrasound, The Second Affiliated Hospital of Army Medical University, Chongqing, China
| | - Leidan Huang
- Department of Ultrasound, Shenzhen Second People's Hospital, The First Affiliated Hospital of Shenzhen University, Shenzhen, China
| | - Xiaoxiao Dong
- Department of Ultrasound, The Second Affiliated Hospital of Army Medical University, Chongqing, China
| | - Zheng Liu
- Department of Ultrasound, The Second Affiliated Hospital of Army Medical University, Chongqing, China
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Thomas GPL, Khokhlova TD, Sapozhnikov OA, Khokhlova VA. Enhancement of Boiling Histotripsy by Steering the Focus Axially During the Pulse Delivery. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2023; 70:865-875. [PMID: 37318967 PMCID: PMC10671942 DOI: 10.1109/tuffc.2023.3286759] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Boiling histotripsy (BH) is a pulsed high-intensity focused ultrasound (HIFU) method relying on the generation of high-amplitude shocks at the focus, localized enhanced shock-wave heating, and bubble activity driven by shocks to induce tissue liquefaction. BH uses sequences of 1-20 ms long pulses with shock fronts of over 60 MPa amplitude, initiates boiling at the focus of the HIFU transducer within each pulse, and the remainder shocks of the pulse then interact with the boiling vapor cavities. One effect of this interaction is the creation of a prefocal bubble cloud due to reflection of shocks from the initially generated mm-sized cavities: the shocks are inverted when reflected from a pressure-release cavity wall resulting in sufficient negative pressure to reach intrinsic cavitation threshold in front of the cavity. Secondary clouds then form due to shock-wave scattering from the first one. Formation of such prefocal bubble clouds has been known as one of the mechanisms of tissue liquefaction in BH. Here, a methodology is proposed to enlarge the axial dimension of this bubble cloud by steering the HIFU focus toward the transducer after the initiation of boiling until the end of each BH pulse and thus to accelerate treatment. A BH system comprising a 1.5 MHz 256-element phased array connected to a Verasonics V1 system was used. High-speed photography of BH sonications in transparent gels was performed to observe the extension of the bubble cloud resulting from shock reflections and scattering. Volumetric BH lesions were then generated in ex vivo tissue using the proposed approach. Results showed up to almost threefold increase of the tissue ablation rate with axial focus steering during the BH pulse delivery compared to standard BH.
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Pahk KJ, Heo J, Joung C, Pahk K. Noninvasive mechanical destruction of liver tissue and tissue decellularisation by pressure-modulated shockwave histotripsy. Front Immunol 2023; 14:1150416. [PMID: 37261363 PMCID: PMC10227506 DOI: 10.3389/fimmu.2023.1150416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 05/04/2023] [Indexed: 06/02/2023] Open
Abstract
Introduction Boiling histotripsy (BH) is a promising High Intensity Focused Ultrasound (HIFU) technique that can be used to mechanically fractionate solid tumours at the HIFU focus noninvasively, promoting tumour immunity. Because of the occurrence of shock scattering phenomenon during BH process, the treatment accuracy of BH is, however, somewhat limited. To induce more localised and selective tissue destruction, the concept of pressure modulation has recently been proposed in our previous in vitro tissue phantom study. The aim of the present study was therefore to investigate whether this newly developed histotripsy approach termed pressure-modulated shockwave histotripsy (PSH) can be used to induce localised mechanical tissue fractionation in in vivo animal model. Methods In the present study, 8 Sprague Dawley rats underwent the PSH treatment and were sacrificed immediately after the exposure for morphological and histological analyses (paraffin embedded liver tissue sections were stained with H&E and MT). Partially exteriorised rat's left lateral liver lobe in vivo was exposed to a 2.0 MHz HIFU transducer with peak positive (P +) and negative (P -) pressures of 89.1 MPa and -14.6 MPa, a pulse length of 5 to 34 ms, a pressure modulation time at 4 ms where P + and P - decreased to 29.9 MPa and - 9.6 MPa, a pulse repetition frequency of 1 Hz, a duty cycle of 1% and number of pulses of 1 to 20. Three lesions were produced on each animal. For comparison, the same exposure condition but no pressure modulation was also employed to create a number of lesions in the liver. Results and Discussion Experimental results showed that a partial mechanical destruction of liver tissue in the form of an oval in the absence of thermal damage was clearly observed at the HIFU focus after the PSH exposure. With a single pulse length of 7 ms, a PSH lesion created in the liver was measured to be a length of 1.04 ± 0.04 mm and a width of 0.87 ± 0.21 mm which was 2.37 times in length (p = 0.027) and 1.35 times in width (p = 0.1295) smaller than a lesion produced by no pressure modulation approach (e.g., BH). It was also observed that the length of a PSH lesion gradually grew towards the opposite direction to the HIFU source along the axial direction with the PSH pulse length, eventually leading to the generation of an elongated lesion in the liver. In addition, our experimental results demonstrated the feasibility of inducing partial decellularisation effect where liver tissue was partially destructed with intact extracellular matrix (i.e., intact fibrillar collagen) with the shortest PSH pulse length. Taken together, these results suggest that PSH could be used to induce a highly localised tissue fractionation with a desired degree of mechanical damage from complete tissue fractionation to tissue decellularisation through controlling the dynamics of boiling bubbles without inducing the shock scattering effect.
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Affiliation(s)
- Ki Joo Pahk
- Department of Biomedical Engineering, Kyung Hee University, Yongin, Republic of Korea
| | - Jeongmin Heo
- Center for Bionics, Biomedical Research Institute, Korea Institute of Science and Technology, Seoul, Republic of Korea
| | - Chanmin Joung
- Graduate School of Biomedical Sciences, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Kisoo Pahk
- Department of Nuclear Medicine, Korea University College of Medicine, Seoul, Republic of Korea
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Heo J, Park JH, Kim HJ, Pahk K, Pahk KJ. Sonothrombolysis with an acoustic net-assisted boiling histotripsy: A proof-of-concept study. ULTRASONICS SONOCHEMISTRY 2023; 96:106435. [PMID: 37178667 DOI: 10.1016/j.ultsonch.2023.106435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 05/03/2023] [Accepted: 05/04/2023] [Indexed: 05/15/2023]
Abstract
Whilst sonothrombolysis is a promising and noninvasive ultrasound technique for treating blood clots, bleeding caused by thrombolytic agents used for dissolving clots and potential obstruction of blood flow by detached clots (i.e., embolus) are the major limitations of the current approach. In the present study, a new sonothrombolysis method is proposed for treating embolus without the use of thrombolytic drugs. Our proposed method involves (a) generating a spatially localised acoustic radiation force in a blood vessel against the blood flow to trap moving blood clots (i.e., generation of an acoustic net), (b) producing acoustic cavitation to mechanically destroy the trapped embolus, and (c) acoustically monitoring the trapping and mechanical fractionation processes. Three different ultrasound transducers with different purposes were employed in the proposed method: (1) 1-MHz dual focused ultrasound (dFUS) transducers for capturing moving blood clots, (2) a 2-MHz High Intensity Focused Ultrasound (HIFU) source for fractionating blood clots and (3) a passive acoustic emission detector with broad bandwidth (10 kHz to 20 MHz) for receiving and analysing acoustic waves scattered from a trapped embolus and acoustic cavitation. To demonstrate the feasibility of the proposed method, in vitro experiments with an optically transparent blood vessel-mimicking phantom filled with a blood mimicking fluid and a blood clot (1.2 to 5 mm in diameter) were performed with varying the dFUS and HIFU exposure conditions under various flow conditions (from 1.77 to 6.19 cm/s). A high-speed camera was used to observe the production of acoustic fields, acoustic cavitation formation and blood clot fragmentation within a blood vessel by the proposed method. Numerical simulations of acoustic and temperature fields generated under a given exposure condition were also conducted to further interpret experimental results on the proposed sonothrombolysis. Our results clearly showed that fringe pattern-like acoustic pressure fields (fringe width of 1 mm) produced in a blood vessel by the dFUS captured an embolus (1.2 to 5 mm in diameter) at the flow velocity up to 6.19 cm/s. This was likely to be due to the greater magnitude of the dFUS-induced acoustic radiation force exerted on an embolus in the opposite direction to the flow in a blood vessel than that of the drag force produced by the flow. The acoustically trapped embolus was then mechanically destructed into small pieces of debris (18 to 60 μm sized residual fragments) by the HIFU-induced strong cavitation without damaging the blood vessel walls. We also observed that acoustic emissions emitted from a blood clot captured by the dFUS and cavitation produced by the HIFU were clearly distinguished in the frequency domain. Taken together, these results can suggest that our proposed sonothrombolysis method could be used as a promising tool for treating thrombosis and embolism through capturing and destroying blood clots effectively.
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Affiliation(s)
- Jeongmin Heo
- Bionics Research Center, Biomedical Research Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Jun Hong Park
- Department of Radiology, Stanford University, Stanford, CA 94305, USA
| | - Hyo Jun Kim
- LAAS-CNRS, University of Toulouse, CNRS, Toulouse, France
| | - Kisoo Pahk
- Department of Nuclear Medicine, Korea University College of Medicine, Seoul 02841, Republic of Korea
| | - Ki Joo Pahk
- Department of Biomedical Engineering, Kyung Hee University, Yongin 17104, Republic of Korea.
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Froghi S, Hall A, Hanafi Bin Jalal A, de Andrade MO, Mohammad Hadi L, Rashidi H, Gélat P, Saffari N, Davidson B, Quaglia A. Ultrasound Histotripsy on a Viable Perfused Whole Porcine Liver: Histological Aspects, Including 3D Reconstruction of the Histotripsy Site. Bioengineering (Basel) 2023; 10:bioengineering10030278. [PMID: 36978669 PMCID: PMC10044833 DOI: 10.3390/bioengineering10030278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/26/2023] [Accepted: 02/11/2023] [Indexed: 02/24/2023] Open
Abstract
Non-invasive therapeutic-focused ultrasound (US) can be used for the mechanical dissociation of tissue and is described as histotripsy. We have performed US histotripsy in viable perfused ex vivo porcine livers as a step in the development of a novel approach to hepatocyte cell transplantation. The histotripsy nidus was created with a 2 MHz single-element focused US transducer, producing 50 pulses of 10 ms duration, with peak positive and negative pressure values of P+ = 77.7 MPa and P− = –13.7 MPaat focus, respectively, and a duty cycle of 1%. Here, we present the histological analysis, including 3D reconstruction of histotripsy sites. Five whole porcine livers were retrieved fresh from the abattoir using human transplant retrieval and cold static preservation techniques and were then perfused using an organ preservation circuit. Whilst under perfusion, histotripsy was performed to randomly selected sites on the live. Fifteen lesional sites were formalin-fixed and paraffin-embedded. Sections were stained with Haematoxylin and Eosin and picro-Sirius red, and they were also stained for reticulin. Additionally, two lesion sites were used for 3D reconstruction. The core of the typical lesion consisted of eosinophilic material associated with reticulin loss, collagen damage including loss of birefringence to fibrous septa, and perilesional portal tracts, including large portal vein branches, but intact peri-lesional hepatic plates. The 3D reconstruction of two histotripsy sites was successful and confirmed the feasibility of this approach to investigate the effects of histotripsy on tissue in detail.
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Affiliation(s)
- Saied Froghi
- Department of HPB & Liver Transplantation Surgery, Royal Free London NHS Foundation Trust, Pond Street, Hampstead, London NW3 2QG, UK
- Centre for Surgical Innovation, Organ Regeneration and Transplantation, UCL Division of Surgery & Interventional Sciences, Royal Free Hospital Campus, Pond Street, Hampstead, London NW3 2QG, UK
| | - Andrew Hall
- Department of Cellular Pathology, UCL Cancer Institute Royal Free London NHS Foundation Trust, Pond Street, Hampstead, London NW3 2QG, UK
| | - Arif Hanafi Bin Jalal
- UCL Medical School, University College London, 74 Huntley Street, London WC1E 6BT, UK
| | - Matheus Oliveira de Andrade
- Ultrasonics Group, Department of Mechanical Engineering, Roberts Engineering Building, University College London, Torrington Place, London WC1E 7JE, UK
| | - Layla Mohammad Hadi
- Centre for Surgical Innovation, Organ Regeneration and Transplantation, UCL Division of Surgery & Interventional Sciences, Royal Free Hospital Campus, Pond Street, Hampstead, London NW3 2QG, UK
| | - Hassan Rashidi
- Developmental Biology and Cancer Program, UCL Great Ormond Street, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK
| | - Pierre Gélat
- Department of Surgical Biotechnology, Division of Surgery and Interventional Science, UCL, Royal Free Hospital Campus, Pond Street, Hampstead, London NW3 2QG, UK
| | - Nader Saffari
- Ultrasonics Group, Department of Mechanical Engineering, Roberts Engineering Building, University College London, Torrington Place, London WC1E 7JE, UK
| | - Brian Davidson
- Department of HPB & Liver Transplantation Surgery, Royal Free London NHS Foundation Trust, Pond Street, Hampstead, London NW3 2QG, UK
- Centre for Surgical Innovation, Organ Regeneration and Transplantation, UCL Division of Surgery & Interventional Sciences, Royal Free Hospital Campus, Pond Street, Hampstead, London NW3 2QG, UK
| | - Alberto Quaglia
- Department of Cellular Pathology, UCL Cancer Institute Royal Free London NHS Foundation Trust, Pond Street, Hampstead, London NW3 2QG, UK
- Correspondence:
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Froghi S, de Andrade MO, Hadi LM, Gelat P, Rashidi H, Quaglia A, Fuller B, Saffari N, Davidson B. Liver Ultrasound Histotripsy: Novel Analysis of the Histotripsy Site Cell Constituents with Implications for Histotripsy Application in Cell Transplantation and Cancer Therapy. Bioengineering (Basel) 2023; 10:bioengineering10020276. [PMID: 36829770 PMCID: PMC9952788 DOI: 10.3390/bioengineering10020276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/14/2023] [Accepted: 02/09/2023] [Indexed: 02/25/2023] Open
Abstract
Introduction: Allogenic hepatocyte transplantation is an attractive alternative to whole-organ transplantation, particularly for the treatment of metabolic disorders and acute liver failure. However, the shortage of human donor organs for cell isolation, the low cell yield from decellularisation regimes, and low engraftment rates from portal administration of donor cells have restricted its clinical application. Using ultrasound histotripsy to provide a nidus in the liver for direct cell transplantation offers a new approach to overcoming key limitations in current cell therapy. We have analysed the liver cavity constituents to assess their potential as a site for cell delivery and implantation. Methods: Using human organ retrieval techniques, pig livers were collected from the abattoir and transported in ice-cold storage to the laboratory. Following 2 h of cold storage, the livers were flushed with organ preservation solution and placed on an organ perfusion circuit to maintain viability. Organs were perfused with Soltran™ organ preservation solution via the portal vein at a temperature of 24-30 °C. The perfusion circuit was oxygenated through equilibration with room air. Perfused livers (n=5) were subjected to ultrasound histotripsy, producing a total of 130 lesions. Lesions were generated by applying 50 pulses at 1 Hz pulse repetition frequency and 1% duty cycle using a single element 2 MHz bowl-shaped transducer (Sonic Concepts, H-148). Following histotripsy, a focal liver lesion was produced, which had a liquid centre. The fluid from each lesion was aspirated and cultured in medium (RPMI) at 37 °C in an incubator. Cell cultures were analysed at 1 and 7 days for cell viability and a live-dead assay was performed. The histotripsy sites were excised following aspiration and H&E staining was used to characterise the liver lesions. Cell morphology was determined by histology. Results: Histotripsy created a subcapsular lesion (~5 mm below the liver capsule; size ranging from 3 to 5 mm), which contained a suspension of cells. On average, 61×104 cells per mL were isolated. Hepatocytes were present in the aspirate, were viable at 24 h post isolation and remained viable in culture for up to 1 week, as determined by phalloidin/DAPI cell viability stains. Cultures up to 21 days revealed metabolically active live hepatocyte. Live-dead assays confirmed hepatocyte viability at 1 week (Day 1: 12% to Day 7: 45% live cells; p < 0.0001), which retained metabolic activity and morphology, confirmed on assay and microscopy. Cell Titre-GloTM showed a peak metabolic activity at 1 week (average luminescence 24.6 RLU; p < 0.0001) post-culture compared with the control (culture medium alone), reduced to 1/3 of peak level (7.85 RLU) by day 21. Conclusions: Histotripsy of the liver allows isolation and culture of hepatocytes with a high rate of viability after 1 week in culture. Reproducing these findings using human livers may lead to wide clinical applications in cell therapy.
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Affiliation(s)
- Saied Froghi
- Department of HPB & Liver Transplantation Surgery, Royal Free London NHS Foundation Trust, Pond Street, Hampstead, London NW3 2QG, UK
- Centre for Surgical Innovation, Organ Regeneration and Transplantation, UCL Division of Surgery & Interventional Sciences, Royal Free Hospital Campus, Pond Street, Hampstead, London NW3 2QG, UK
- Correspondence: or
| | - Matheus Oliveira de Andrade
- Ultrasonics Group, Department of Mechanical Engineering, Roberts Engineering Building, University College London, Torrington Place, London WC1E 7JE, UK
| | - Layla Mohammad Hadi
- Centre for Surgical Innovation, Organ Regeneration and Transplantation, UCL Division of Surgery & Interventional Sciences, Royal Free Hospital Campus, Pond Street, Hampstead, London NW3 2QG, UK
| | - Pierre Gelat
- Centre for Surgical Innovation, Organ Regeneration and Transplantation, UCL Division of Surgery & Interventional Sciences, Royal Free Hospital Campus, Pond Street, Hampstead, London NW3 2QG, UK
| | - Hassan Rashidi
- Stem Cell & Regenerative Medicine Section, UCL Great Ormond Street Institute of Child Health, London WC1N 1EH, UK
| | - Alberto Quaglia
- Department of Cellular Pathology, Royal Free London NHS Foundation Trust, Pond Street, Hampstead, London NW3 2QG, UK
| | - Barry Fuller
- Centre for Surgical Innovation, Organ Regeneration and Transplantation, UCL Division of Surgery & Interventional Sciences, Royal Free Hospital Campus, Pond Street, Hampstead, London NW3 2QG, UK
| | - Nader Saffari
- Ultrasonics Group, Department of Mechanical Engineering, Roberts Engineering Building, University College London, Torrington Place, London WC1E 7JE, UK
| | - Brian Davidson
- Department of HPB & Liver Transplantation Surgery, Royal Free London NHS Foundation Trust, Pond Street, Hampstead, London NW3 2QG, UK
- Centre for Surgical Innovation, Organ Regeneration and Transplantation, UCL Division of Surgery & Interventional Sciences, Royal Free Hospital Campus, Pond Street, Hampstead, London NW3 2QG, UK
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Khokhlova VA, Rosnitskiy PB, Tsysar SA, Buravkov SV, Ponomarchuk EM, Sapozhnikov OA, Karzova MM, Khokhlova TD, Maxwell AD, Wang YN, Kadrev AV, Chernyaev AL, Chernikov VP, Okhobotov DA, Kamalov AA, Schade GR. Initial Assessment of Boiling Histotripsy for Mechanical Ablation of Ex Vivo Human Prostate Tissue. ULTRASOUND IN MEDICINE & BIOLOGY 2023; 49:62-71. [PMID: 36207225 PMCID: PMC9712256 DOI: 10.1016/j.ultrasmedbio.2022.07.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Revised: 07/27/2022] [Accepted: 07/31/2022] [Indexed: 05/16/2023]
Abstract
Boiling histotripsy (BH) is a focused ultrasound technology that uses millisecond-long pulses with shock fronts to induce mechanical tissue ablation. The pulsing scheme and mechanisms of BH differ from those of cavitation cloud histotripsy, which was previously developed for benign prostatic hyperplasia. The goal of the work described here was to evaluate the feasibility of using BH to ablate fresh ex vivo human prostate tissue as a proof of principle for developing BH for prostate applications. Fresh human prostate samples (N = 24) were obtained via rapid autopsy (<24 h after death, institutional review board exempt). Samples were analyzed using shear wave elastography to ensure that mechanical properties of autopsy tissue were clinically representative. Samples were exposed to BH using 10- or 1-ms pulses with 1% duty cycle under real-time B-mode and Doppler imaging. Volumetric lesions were created by sonicating 1-4 rectangular planes spaced 1 mm apart, containing a grid of foci spaced 1-2 mm apart. Tissue then was evaluated grossly and histologically, and the lesion content was analyzed using transmission electron microscopy and scanning electron microscopy. Observed shear wave elastography characterization of ex vivo prostate tissue (37.9 ± 22.2 kPa) was within the typical range observed clinically. During BH, hyperechoic regions were visualized at the focus on B-mode, and BH-induced bubbles were also detected using power Doppler. As treatment progressed, hypoechoic regions of tissue appeared, suggesting successful tissue fractionation. BH treatment was twofold faster using shorter pulses (1 ms vs. 10 ms). Histological analysis revealed lesions containing completely homogenized cell debris, consistent with histotripsy-induced mechanical ablation. It was therefore determined that BH is feasible in fresh ex vivo human prostate tissue producing desired mechanical ablation. The study supports further work aimed at translating BH technology as a clinical option for prostate ablation.
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Affiliation(s)
- Vera A. Khokhlova
- University of Washington, Applied Physics Laboratory, Center for Industrial and Medical Ultrasound, Seattle, WA
- Lomonosov Moscow State University, Physics Faculty, Moscow, Russia
| | | | - Sergey A. Tsysar
- Lomonosov Moscow State University, Physics Faculty, Moscow, Russia
| | - Sergey V. Buravkov
- Lomonosov Moscow State University, Faculty of Fundamental Medicine, Laboratory of Cell Image Analysis, Moscow, Russia
- Research Institute of Human Morphology, Moscow, Russia
| | | | - Oleg A. Sapozhnikov
- University of Washington, Applied Physics Laboratory, Center for Industrial and Medical Ultrasound, Seattle, WA
- Lomonosov Moscow State University, Physics Faculty, Moscow, Russia
| | - Maria M. Karzova
- Lomonosov Moscow State University, Physics Faculty, Moscow, Russia
| | - Tatiana D. Khokhlova
- University of Washington School of Medicine, Department of Medicine Division of Gastroenterology, Seattle, WA
| | - Adam D. Maxwell
- University of Washington School of Medicine, Department of Urology, Seattle, WA
| | - Yak-Nam Wang
- University of Washington, Applied Physics Laboratory, Center for Industrial and Medical Ultrasound, Seattle, WA
| | - Alexey V. Kadrev
- Lomonosov Moscow State University, Medical Research and Educational Center, Department of Urology and Andrology, Moscow, Russia
- Russian Medical Academy of Continuous Professional Education, Diagnostic Ultrasound Division, Moscow, Russia
| | - Andrey L. Chernyaev
- Research Institute of Human Morphology, Moscow, Russia
- Pulmonology Scientific Research Institute, Moscow, Russia
| | | | - Dmitriy A. Okhobotov
- Lomonosov Moscow State University, Medical Research and Educational Center, Department of Urology and Andrology, Moscow, Russia
| | - Armais A. Kamalov
- Lomonosov Moscow State University, Medical Research and Educational Center, Department of Urology and Andrology, Moscow, Russia
| | - George R. Schade
- University of Washington School of Medicine, Department of Urology, Seattle, WA
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12
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Williams RP, Simon JC, Khokhlova VA, Sapozhnikov OA, Khokhlova TD. The histotripsy spectrum: differences and similarities in techniques and instrumentation. Int J Hyperthermia 2023; 40:2233720. [PMID: 37460101 PMCID: PMC10479943 DOI: 10.1080/02656736.2023.2233720] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 06/15/2023] [Accepted: 07/02/2023] [Indexed: 07/20/2023] Open
Abstract
Since its inception about two decades ago, histotripsy - a non-thermal mechanical tissue ablation technique - has evolved into a spectrum of methods, each with distinct potentiating physical mechanisms: intrinsic threshold histotripsy, shock-scattering histotripsy, hybrid histotripsy, and boiling histotripsy. All methods utilize short, high-amplitude pulses of focused ultrasound delivered at a low duty cycle, and all involve excitation of violent bubble activity and acoustic streaming at the focus to fractionate tissue down to the subcellular level. The main differences are in pulse duration, which spans microseconds to milliseconds, and ultrasound waveform shape and corresponding peak acoustic pressures required to achieve the desired type of bubble activity. In addition, most types of histotripsy rely on the presence of high-amplitude shocks that develop in the pressure profile at the focus due to nonlinear propagation effects. Those requirements, in turn, dictate aspects of the instrument design, both in terms of driving electronics, transducer dimensions and intensity limitations at surface, shape (primarily, the F-number) and frequency. The combination of the optimized instrumentation and the bio-effects from bubble activity and streaming on different tissues, lead to target clinical applications for each histotripsy method. Here, the differences and similarities in the physical mechanisms and resulting bioeffects of each method are reviewed and tied to optimal instrumentation and clinical applications.
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Affiliation(s)
- Randall P Williams
- Division of Gastroenterology, Department of Medicine, University of Washington, Seattle, WA, USA
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, WA, USA
| | - Julianna C Simon
- Graduate Program in Acoustics, The Pennsylvania State University, University Park, PA, USA
| | - Vera A Khokhlova
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, WA, USA
- Department of Acoustics, Physics Faculty, Moscow State University, Moscow, Russia
| | - Oleg A Sapozhnikov
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, WA, USA
- Department of Acoustics, Physics Faculty, Moscow State University, Moscow, Russia
| | - Tatiana D Khokhlova
- Division of Gastroenterology, Department of Medicine, University of Washington, Seattle, WA, USA
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, WA, USA
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13
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Zhao Y, Qin D, Chen J, Hou J, Ilovitsh T, Wan M, Wu L, Feng Y. On-demand regulation and enhancement of the nucleation in acoustic droplet vaporization using dual-frequency focused ultrasound. ULTRASONICS SONOCHEMISTRY 2022; 90:106224. [PMID: 36368292 PMCID: PMC9649937 DOI: 10.1016/j.ultsonch.2022.106224] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 10/29/2022] [Accepted: 11/03/2022] [Indexed: 06/16/2023]
Abstract
Acoustic droplet vaporization (ADV) plays an important role in focused ultrasound theranostics. Better understanding of the relationship between the ultrasound parameters and the ADV nucleation could provide an on-demand regulation and enhancement of ADV for improved treatment outcome. In this work, ADV nucleation was performed in a dual-frequency focused ultrasound configuration that consisted of a continuous low-frequency ultrasound and a short high-frequency pulse. The combination was modelled to investigate the effects of the driving frequency and acoustic power on the nucleation rate, efficiency, onset time, and dimensions of the nucleation region. The results showed that the inclusion of short pulsed high-frequency ultrasound significantly increased the nucleation rate with less energy, reduced the nucleation onset time, and changed the length-width ratio of the nucleation region, indicating the dual-frequency ultrasound mode yields an efficient enhancement of the ADV nucleation, compared to a single-frequency ultrasound mode. Furthermore, the acoustic and temperature fields varied independently with the dual-frequency ultrasound parameters. This facilitated the spatial and temporal control over the ADV nucleation, and opens the door to the possibility to realize on-demand regulation of the ADV occurrence in ultrasound theranostics. In addition, the improved energy efficacy that is obtained with the dual-frequency configuration lowered the requirements on hardware system, increasing its flexibility and could facilitate its implementation in practical applications.
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Affiliation(s)
- Yubo Zhao
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, People's Republic of China
| | - Dui Qin
- School of Bioinformatics, Chongqing University of Posts and Telecommunications, Chongqing, People's Republic of China
| | - Junjie Chen
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, People's Republic of China
| | - Jin Hou
- Department of Otorhinolaryngology Head & Neck Surgery, Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, People's Republic of China
| | - Tali Ilovitsh
- Department of Biomedical Engineering, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Mingxi Wan
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, People's Republic of China
| | - Liang Wu
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, People's Republic of China.
| | - Yi Feng
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, People's Republic of China.
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14
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Heo J, Joung C, Pahk K, Pahk KJ. Investigation of the long-term healing response of the liver to boiling histotripsy treatment in vivo. Sci Rep 2022; 12:14462. [PMID: 36002564 PMCID: PMC9402918 DOI: 10.1038/s41598-022-18544-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 08/16/2022] [Indexed: 11/09/2022] Open
Abstract
Boiling histotripsy (BH) is a promising High-Intensity Focused Ultrasound technique that can be employed to mechanically fractionate solid tumours. Whilst studies have shown the feasibility of BH to destroy liver cancer, no study has reported on the healing process of BH-treated liver tissue. We therefore extensively investigated the evolution of the healing response of liver to BH in order to provide an insight into the healing mechanisms. In the present study, 14 Sprague Dawley rats underwent the BH treatment and were sacrificed on days 0, 3, 7, 14, and 28 for morphological, histological, serological and qPCR analyses. The area of the treated region was 1.44 cm2 (1.2 cm × 1.2 cm). A well-defined BH lesion filled with coagulated blood formed on day 0. A week after the treatment, fibroblast activation was induced at the treatment site, leading to the formation of extracellular matrix structure (ECM). The ECM was then disrupted for 7 to 28 days. Regenerated normal hepatocytes and newly formed blood vessels were found within the BH region with the absence of hepatic fibrosis. No significant morphological, histological and genetic changes around the BH lesion occurred. These results suggest that BH could be a safe and promising therapeutic tool for treating solid tumours without inducing any significant adverse effect such as the formation of liver fibrosis.
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Affiliation(s)
- Jeongmin Heo
- Center for Bionics, Biomedical Research Institute, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea
| | - Chanmin Joung
- Institute for Inflammation Control, Korea University, Seoul, Republic of Korea
| | - Kisoo Pahk
- Department of Nuclear Medicine, Korea University College of Medicine, Anam-dong 5-ga, Seongbuk-gu, Seoul, 02841, Republic of Korea.
| | - Ki Joo Pahk
- Department of Biomedical Engineering, Kyung Hee University, 1732 Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do, 17104, Republic of Korea.
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15
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de Andrade MO, Haqshenas R, Pahk KJ, Saffari N. Mechanisms of nuclei growth in ultrasound bubble nucleation. ULTRASONICS SONOCHEMISTRY 2022; 88:106091. [PMID: 35839705 PMCID: PMC9287806 DOI: 10.1016/j.ultsonch.2022.106091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/20/2022] [Accepted: 07/04/2022] [Indexed: 06/15/2023]
Abstract
This paper interrogates the intersections between bubble dynamics and classical nucleation theory (CNT) towards constructing a model that describes intermediary nucleation events between the extrema of cavitation and boiling. We employ Zeldovich's hydrodynamic approach to obtain a description of bubble nuclei that grow simultaneously via hydrodynamic excitation by the acoustic field and vapour transport. By quantifying the relative dominance of both mechanisms, it is then possible to discern the extent to which viscosity, inertia, surface tension and vapour transport shape the growth of bubble nuclei through non-dimensional numbers that naturally arise within the theory. The first non-dimensional number Φ12/Φ2 is analogous to the Laplace number, representing the balance between surface tension and inertial constraints to viscous effects. The second non-dimensional number δ represents how enthalpy transport into the bubble can reduce nucleation rates by cooling the surrounding liquid. This formulation adds to the current understanding of ultrasound bubble nucleation by accounting for bubble dynamics during nucleation, quantifying the physical distinctions between "boiling" and "cavitation" bubbles through non-dimensional parameters, and outlining the characteristic timescales of nucleation according to the growth mechanism of bubbles throughout the histotripsy temperature range. We observed in our simulations that viscous effects control the process of ultrasound nucleation in water-like media throughout the 0-120 °C temperature range, although this dominance decreases with increasing temperatures. Enthalpy transport was found to reduce nucleation rates for increasing temperatures. This effect becomes significant at temperatures above 30 °C and favours the creation of fewer nuclei that are larger in size. Conversely, negligible enthalpy transport at lower temperatures can enable the nucleation of dense clusters of small nuclei, such as cavitation clouds. We find that nuclei growth as modelled by the Rayleigh-Plesset equation occurs over shorter timescales than as modelled by vapour-dominated growth. This suggests that the first stage of bubble nuclei growth is hydrodynamic, and vapour transport effects can only be observed over longer timescales. Finally, we propose that this framework can be used for comparison between different experiments in bubble nucleation, towards standardisation and dosimetry of protocols.
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Affiliation(s)
| | - Reza Haqshenas
- UCL Mechanical Engineering, University College London, London, United Kingdom
| | - Ki Joo Pahk
- Department of Biomedical Engineering, Kyung Hee University, Yongin, Republic of Korea
| | - Nader Saffari
- UCL Mechanical Engineering, University College London, London, United Kingdom
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16
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Habibi M, Foroughi S, Karamzadeh V, Packirisamy M. Direct sound printing. Nat Commun 2022; 13:1800. [PMID: 35387993 PMCID: PMC8986813 DOI: 10.1038/s41467-022-29395-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Accepted: 03/09/2022] [Indexed: 11/30/2022] Open
Abstract
Photo- and thermo-activated reactions are dominant in Additive Manufacturing (AM) processes for polymerization or melting/deposition of polymers. However, ultrasound activated sonochemical reactions present a unique way to generate hotspots in cavitation bubbles with extraordinary high temperature and pressure along with high heating and cooling rates which are out of reach for the current AM technologies. Here, we demonstrate 3D printing of structures using acoustic cavitation produced directly by focused ultrasound which creates sonochemical reactions in highly localized cavitation regions. Complex geometries with zero to varying porosities and 280 μm feature size are printed by our method, Direct Sound Printing (DSP), in a heat curing thermoset, Poly(dimethylsiloxane) that cannot be printed directly so far by any method. Sonochemiluminescnce, high speed imaging and process characterization experiments of DSP and potential applications such as remote distance printing are presented. Our method establishes an alternative route in AM using ultrasound as the energy source. Photo- and thermo-activated polymerization and melting processes are dominant in Additive Manufacturing (AM) while ultrasound activated sonochemical reactions have not been explored for AM so far. Here, the authors demonstrate 3D printing of structures using acoustic cavitation produced directly by focused ultrasound which creates sonochemical reactions in highly localized cavitation regions.
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Affiliation(s)
- Mohsen Habibi
- Optical Bio Microsystems Laboratory, Micro-Nano-Bio Integration Center, Department of Mechanical, Industrial and Aerospace Engineering, Concordia University, Montreal, QC, Canada
| | - Shervin Foroughi
- Optical Bio Microsystems Laboratory, Micro-Nano-Bio Integration Center, Department of Mechanical, Industrial and Aerospace Engineering, Concordia University, Montreal, QC, Canada
| | - Vahid Karamzadeh
- Optical Bio Microsystems Laboratory, Micro-Nano-Bio Integration Center, Department of Mechanical, Industrial and Aerospace Engineering, Concordia University, Montreal, QC, Canada
| | - Muthukumaran Packirisamy
- Optical Bio Microsystems Laboratory, Micro-Nano-Bio Integration Center, Department of Mechanical, Industrial and Aerospace Engineering, Concordia University, Montreal, QC, Canada.
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17
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Sang PG, Biswas D, Lee SJ, Won SM, Son D, Ok JG, Park HJ, Baac HW. Experimental Demonstration of a Stacked Hybrid Optoacoustic-Piezoelectric Transducer for Localized Heating and Enhanced Cavitation. MICROMACHINES 2021; 12:mi12101268. [PMID: 34683319 PMCID: PMC8540735 DOI: 10.3390/mi12101268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Revised: 10/08/2021] [Accepted: 10/13/2021] [Indexed: 11/16/2022]
Abstract
Laser-generated focused ultrasound (LGFU) is an emerging modality for cavitation-based therapy. However, focal pressure amplitudes by LGFU alone to achieve pulsed cavitation are often lacking as a treatment depth increases. This requires a higher pressure from a transmitter surface and more laser energies that even approach to a damage threshold of transmitter. To mitigate the requirement for LGFU-induced cavitation, we propose LGFU configurations with a locally heated focal zone using an additional high-intensity focused ultrasound (HIFU) transmitter. After confirming heat-induced cavitation enhancement using two separate transmitters, we then developed a stacked hybrid optoacoustic-piezoelectric transmitter, which is a unique configuration made by coating an optoacoustic layer directly onto a piezoelectric substrate. This shared curvature design has great practical advantage without requiring the complex alignment of two focal zones. Moreover, this enabled the amplification of cavitation bubble density by 18.5-fold compared to the LGFU operation alone. Finally, the feasibility of tissue fragmentation was confirmed through a tissue-mimicking gel, using the combination of LGFU and HIFU (not via a stacked structure). We expect that the stacked transmitter can be effectively used for stronger and faster tissue fragmentation than the LGFU transmitter alone.
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Affiliation(s)
- Pil Gyu Sang
- Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon 16419, Korea; (P.G.S.); (D.B.); (S.J.L.); (S.M.W.); (D.S.)
| | - Deblina Biswas
- Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon 16419, Korea; (P.G.S.); (D.B.); (S.J.L.); (S.M.W.); (D.S.)
| | - Seung Jin Lee
- Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon 16419, Korea; (P.G.S.); (D.B.); (S.J.L.); (S.M.W.); (D.S.)
| | - Sang Min Won
- Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon 16419, Korea; (P.G.S.); (D.B.); (S.J.L.); (S.M.W.); (D.S.)
| | - Donghee Son
- Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon 16419, Korea; (P.G.S.); (D.B.); (S.J.L.); (S.M.W.); (D.S.)
| | - Jong G. Ok
- Department of Mechanical and Automotive Engineering, Seoul National University of Science and Technology, Seoul 01811, Korea;
| | - Hui Joon Park
- Department of Organic and Nano Engineering, Hanyang University, Seoul 04763, Korea;
| | - Hyoung Won Baac
- Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon 16419, Korea; (P.G.S.); (D.B.); (S.J.L.); (S.M.W.); (D.S.)
- Correspondence:
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18
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Bawiec CR, Rosnitskiy PB, Peek AT, Maxwell AD, Kreider W, Haar GRT, Sapozhnikov OA, Khokhlova VA, Khokhlova TD. Inertial Cavitation Behaviors Induced by Nonlinear Focused Ultrasound Pulses. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2021; 68:2884-2895. [PMID: 33861702 PMCID: PMC8500614 DOI: 10.1109/tuffc.2021.3073347] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Inertial cavitation induced by pulsed high-intensity focused ultrasound (pHIFU) has previously been shown to successfully permeabilize tumor tissue and enhance chemotherapeutic drug uptake. In addition to HIFU frequency, peak rarefactional pressure ( p- ), and pulse duration, the threshold for cavitation-induced bioeffects has recently been correlated with asymmetric distortion caused by nonlinear propagation, diffraction and formation of shocks in the focal waveform, and therefore with the transducer F -number. To connect previously observed bioeffects with bubble dynamics and their attendant physical mechanisms, the dependence of inertial cavitation behavior on shock formation was investigated in transparent agarose gel phantoms using high-speed photography and passive cavitation detection (PCD). Agarose phantoms with concentrations ranging from 1.5% to 5% were exposed to 1-ms pulses using three transducers of the same aperture but different focal distances ( F -numbers of 0.77, 1.02, and 1.52). Pulses had central frequencies of 1, 1.5, or 1.9 MHz and a range of p- at the focus varying within 1-18 MPa. Three distinct categories of bubble behavior were observed as the acoustic power increased: stationary near-spherical oscillation of individual bubbles, proliferation of multiple bubbles along the pHIFU beam axis, and fanned-out proliferation toward the transducer. Proliferating bubbles were only observed under strongly nonlinear or shock-forming conditions regardless of frequency, and only where the bubbles reached a certain threshold size range. In stiffer gels with higher agarose concentrations, the same pattern of cavitation behavior was observed, but the dimensions of proliferating clouds were smaller. These observations suggest mechanisms that may be involved in bubble proliferation: enhanced growth of bubbles under shock-forming conditions, subsequent shock scattering from the gel-bubble interface, causing an increase in the repetitive tension created by the acoustic wave, and the appearance of a new growing bubble in the proximal direction. Different behaviors corresponded to specific spectral characteristics in the PCD signals: broadband noise in all cases, narrow peaks of backscattered harmonics in the case of stationary bubbles, and broadened, shifted harmonic peaks in the case of proliferating bubbles. The shift in harmonic peaks can be interpreted as a Doppler shift from targets moving at speeds of up to 2 m/s, which correspond to the observed bubble proliferation speeds.
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Thomas GPL, Khokhlova TD, Khokhlova VA. Partial Respiratory Motion Compensation for Abdominal Extracorporeal Boiling Histotripsy Treatments With a Robotic Arm. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2021; 68:2861-2870. [PMID: 33905328 PMCID: PMC8513721 DOI: 10.1109/tuffc.2021.3075938] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Extracorporeal boiling histotripsy (BH), a noninvasive method for mechanical tissue disintegration, is getting closer to clinical applications. However, the motion of the targeted organs, mostly resulting from the respiratory motion, reduces the efficiency of the treatment. Here, a practical and affordable unidirectional respiratory motion compensation method for BH is proposed and evaluated in ex vivo tissues. The BH transducer is fixed on a robotic arm following the motion of the skin, which is tracked using an inline ultrasound imaging probe. In order to compensate for system lags and obtain a more accurate compensation, an autoregressive motion prediction model is implemented. BH pulse gating is also implemented to ensure targeting accuracy. The system is then evaluated with ex vivo BH treatments of tissue samples undergoing motion simulating breathing with the movement of amplitudes between 5 and 10 mm, the frequency between 16 and 18 breaths/min, and a maximum speed of 14.2 mm/s. Results show a reduction of at least 89% of the value of the targeting error during treatment while only increasing the treatment time by no more than 1%. The lesions obtained by treating with the motion compensation were close in size and affected area to the no-motion case, whereas lesions obtained without the compensation were often incomplete and had larger affected areas. This approach to motion compensation could benefit extracorporeal BH and other histotripsy methods in clinical translation.
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de Andrade MO, Haqshenas SR, Pahk KJ, Saffari N. Modeling the Physics of Bubble Nucleation in Histotripsy. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2021; 68:2871-2883. [PMID: 34260353 DOI: 10.1109/tuffc.2021.3097118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
This work aims to establish a theoretical framework for the modeling of bubble nucleation in histotripsy. A phenomenological version of the classical nucleation theory was parametrized with histotripsy experimental data, fitting a temperature-dependent activity factor that harmonizes theoretical predictions and experimental data for bubble nucleation at both high and low temperatures. Simulations of histotripsy pressure and temperature fields are then used in order to understand spatial and temporal properties of bubble nucleation at varying sonication conditions. This modeling framework offers a thermodynamic understanding on the role of the ultrasound frequency, waveforms, peak focal pressures, and duty cycle on patterns of ultrasound-induced bubble nucleation. It was found that at temperatures lower than 50 °C, nucleation rates are more appreciable at very large negative pressures such as -30 MPa. For focal peak-negative pressures of -15 MPa, characteristic of boiling histotripsy, nucleation rates grow by 20 orders of magnitude in the temperature interval 60 °C-100 °C.
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Pahk KJ. Control of the dynamics of a boiling vapour bubble using pressure-modulated high intensity focused ultrasound without the shock scattering effect: A first proof-of-concept study. ULTRASONICS SONOCHEMISTRY 2021; 77:105699. [PMID: 34371476 PMCID: PMC8358471 DOI: 10.1016/j.ultsonch.2021.105699] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 07/19/2021] [Accepted: 07/27/2021] [Indexed: 05/27/2023]
Abstract
Boiling histotripsy is a promising High-Intensity Focused Ultrasound (HIFU) technique that can be used to induce mechanical tissue fractionation at the HIFU focus via cavitation. Two different types of cavitation produced during boiling histotripsy exposure can contribute towards mechanical tissue destruction: (1) a boiling vapour bubble at the HIFU focus and (2) cavitation clouds in between the boiling bubble and the HIFU source. Control of the extent and degree of mechanical damage produced by boiling histotripsy is necessary when treating a solid tumour adjacent to normal tissue or major blood vessels. This is, however, difficult to achieve with boiling histotripsy due to the stochastic formation of the shock scattering-induced inertial cavitation clouds. In the present study, a new histotripsy method termed pressure-modulated shockwave histotripsy is proposed as an alternative to or in addition to boiling histotripsy without inducing the shock scattering effect. The proposed concept is (a) to generate a boiling vapour bubble via localised shockwave heating and (b) subsequently control its extent and lifetime through manipulating peak pressure magnitudes and a HIFU pulse length. To demonstrate the feasibility of the proposed method, bubble dynamics induced at the HIFU focus in an optically transparent liver tissue phantom were investigated using a high speed camera and a passive cavitation detection systems under a single 10, 50 or 100 ms-long 2, 3.5 or 5 MHz pressure-modulated HIFU pulse with varying peak positive and negative pressure amplitudes from 5 to 89 MPa and -3.7 to -14.6 MPa at the focus. Furthermore, a numerical simulation of 2D nonlinear wave propagation with the presence of a boiling bubble at the focus of a HIFU field was conducted by numerically solving the generalised Westervelt equation. The high speed camera experimental results showed that, with the proposed pressure-modulated shockwave histotripsy, boiling bubbles generated by shockwave heating merged together, forming a larger bubble (of the order of a few hundred micron) at the HIFU focus. This coalesced boiling bubble then persisted and maintained within the HIFU focal zone until the end of the exposure (10, 50, or 100 ms). Furthermore, and most importantly, no violent cavitation clouds which typically appear in boiling histotripsy occurred during the proposed histotripsy excitation (i.e. no shock scattering effect). This was likely because that the peak negative pressure magnitude of the backscattered acoustic field by the boiling bubble was below the cavitation cloud intrinsic threshold. The size of the coalesced boiling bubble gradually increased with the peak pressure magnitudes. In addition, with the proposed method, an oval shaped lesion with a length of 0.6 mm and a width of 0.1 mm appeared at the HIFU focus in the tissue phantom, whereas a larger lesion in the form of a tadpole (length: 2.7 mm, width: 0.3 mm) was produced by boiling histotripsy. Taken together, these results suggest that the proposed pressure-modulated shockwave histotripsy could potentially be used to induce a more spatially localised tissue destruction with a desired degree of mechanical damage through controlling the size and lifetime of a boiling bubble without the shock scattering effect.
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Affiliation(s)
- Ki Joo Pahk
- Center for Bionics, Biomedical Research Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Division of Bio-Medical Science & Technology, KIST School, University of Science and Technology (UST), Seoul 02792, Republic of Korea.
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Bawiec CR, Khokhlova TD, Sapozhnikov OA, Rosnitskiy PB, Cunitz BW, Ghanem MA, Hunter C, Kreider W, Schade GR, Yuldashev PV, Khokhlova VA. A Prototype Therapy System for Boiling Histotripsy in Abdominal Targets Based on a 256-Element Spiral Array. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2021; 68:1496-1510. [PMID: 33156788 PMCID: PMC8191454 DOI: 10.1109/tuffc.2020.3036580] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Boiling histotripsy (BH) uses millisecond-long ultrasound (US) pulses with high-amplitude shocks to mechanically fractionate tissue with potential for real-time lesion monitoring by US imaging. For BH treatments of abdominal organs, a high-power multielement phased array system capable of electronic focus steering and aberration correction for body wall inhomogeneities is needed. In this work, a preclinical BH system was built comprising a custom 256-element 1.5-MHz phased array (Imasonic, Besançon, France) with a central opening for mounting an imaging probe. The array was electronically matched to a Verasonics research US system with a 1.2-kW external power source. Driving electronics and software of the system were modified to provide a pulse average acoustic power of 2.2 kW sustained for 10 ms with a 1-2-Hz repetition rate for delivering BH exposures. System performance was characterized by hydrophone measurements in water combined with nonlinear wave simulations based on the Westervelt equation. Fully developed shocks of 100-MPa amplitude are formed at the focus at 275-W acoustic power. Electronic steering capabilities of the array were evaluated for shock-producing conditions to determine power compensation strategies that equalize BH exposures at multiple focal locations across the planned treatment volume. The system was used to produce continuous volumetric BH lesions in ex vivo bovine liver with 1-mm focus spacing, 10-ms pulselength, five pulses/focus, and 1% duty cycle.
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Thomas GPL, Khokhlova TD, Bawiec CR, Peek AT, Sapozhnikov OA, O'Donnell M, Khokhlova VA. Phase-Aberration Correction for HIFU Therapy Using a Multielement Array and Backscattering of Nonlinear Pulses. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2021; 68:1040-1050. [PMID: 33052845 PMCID: PMC8476183 DOI: 10.1109/tuffc.2020.3030890] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Phase aberrations induced by heterogeneities in body wall tissues introduce a shift and broadening of the high-intensity focused ultrasound (HIFU) focus, associated with decreased focal intensity. This effect is particularly detrimental for HIFU therapies that rely on shock front formation at the focus, such as boiling histotripsy (BH). In this article, an aberration correction method based on the backscattering of nonlinear ultrasound pulses from the focus is proposed and evaluated in tissue-mimicking phantoms. A custom BH system comprising a 1.5-MHz 256-element array connected to a Verasonics V1 engine was used as a pulse/echo probe. Pulse inversion imaging was implemented to visualize the second harmonic of the backscattered signal from the focus inside a phantom when propagating through an aberrating layer. Phase correction for each array element was derived from an aberration-correction method for ultrasound imaging that combines both the beamsum and the nearest neighbor correlation method and adapted it to the unique configuration of the array. The results were confirmed by replacing the target tissue with a fiber-optic hydrophone. Comparing the shock amplitude before and after phase-aberration correction showed that the majority of losses due to tissue heterogeneity were compensated, enabling fully developed shocks to be generated while focusing through aberrating layers. The feasibility of using a HIFU phased-array transducer as a pulse-echo probe in harmonic imaging mode to correct for phase aberrations was demonstrated.
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Pahk KJ. Evidence of the formation of the shock scattering induced violent cavitation cluster during boiling histotripsy insonation: A numerical case study. ACTA ACUST UNITED AC 2021. [DOI: 10.1088/1742-6596/1761/1/012006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Pahk KJ, Lee S, Gélat P, de Andrade MO, Saffari N. The interaction of shockwaves with a vapour bubble in boiling histotripsy: The shock scattering effect. ULTRASONICS SONOCHEMISTRY 2021; 70:105312. [PMID: 32866882 PMCID: PMC7786583 DOI: 10.1016/j.ultsonch.2020.105312] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 06/24/2020] [Accepted: 08/17/2020] [Indexed: 05/13/2023]
Abstract
Boiling histotripsy is a High Intensity Focused Ultrasound (HIFU) technique which uses a number of short pulses with high acoustic pressures at the HIFU focus to induce mechanical tissue fractionation. In boiling histotripsy, two different types of acoustic cavitation contribute towards mechanical tissue destruction: a boiling vapour bubble and cavitation clouds. An understanding of the mechanisms underpinning these phenomena and their dynamics is therefore paramount to predicting and controlling the overall size of a lesion produced for a given boiling histotripsy exposure condition. A number of studies have shown the effects of shockwave heating in generating a boiling bubble at the HIFU focus and have studied its dynamics under boiling histotripsy insonation. However, not much is known about the subsequent production of cavitation clouds that form between the HIFU transducer and the boiling bubble. The main objective of the present study is to examine what causes this bubble cluster formation after the generation of a boiling vapour bubble. A numerical simulation of 2D nonlinear wave propagation with the presence of a bubble at the focus of a HIFU field was performed using the k-Wave MATLAB toolbox for time domain ultrasound simulations, which numerically solves the generalised Westervelt equation. The numerical results clearly demonstrate the appearance of the constructive interference of a backscattered shockwave by a bubble with incoming incident shockwaves. This interaction (i.e., the reflected and inverted peak positive phase from the bubble with the incoming incident rarefactional phase) can eventually induce a greater peak negative pressure field compared to that without the bubble at the HIFU focus. In addition, the backscattered peak negative pressure magnitude gradually increased from 17.4 MPa to 31.6 MPa when increasing the bubble size from 0.2 mm to 1.5 mm. The latter value is above the intrinsic cavitation threshold of -28 MPa in soft tissue. Our results suggest that the formation of a cavitation cloud in boiling histotripsy is a threshold effect which primarily depends (a) the size and location of a boiling bubble, and (b) the sum of the incident field and that scattered by a bubble.
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Affiliation(s)
- Ki Joo Pahk
- Center for Bionics, Biomedical Research Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea.
| | - Sunho Lee
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Pierre Gélat
- Department of Mechanical Engineering, University College London, London WC1E 7JE, UK
| | | | - Nader Saffari
- Department of Mechanical Engineering, University College London, London WC1E 7JE, UK
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Nam G, Pahk KJ, Jeon S, Park H, Kim GB, Oh SJ, Kim K, Kim H, Yang Y. Investigation of the Potential Immunological Effects of Boiling Histotripsy for Cancer Treatment. ADVANCED THERAPEUTICS 2020. [DOI: 10.1002/adtp.201900214] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Gi‐Hoon Nam
- Center for TheragnosisBiomedical Research InstituteKorea Institute of Science and Technology (KIST) Seoul 02792 Republic of Korea
| | - Ki Joo Pahk
- Center for BionicsBiomedical Research InstituteKorea Institute of Science and Technology (KIST) Seoul 02792 Republic of Korea
| | - Sangmin Jeon
- Center for TheragnosisBiomedical Research InstituteKorea Institute of Science and Technology (KIST) Seoul 02792 Republic of Korea
| | - Hyun‐Ju Park
- Center for TheragnosisBiomedical Research InstituteKorea Institute of Science and Technology (KIST) Seoul 02792 Republic of Korea
- Division of Bio‐Medical Science and TechnologyKIST SchoolKorea University of Science and Technology Seoul 02792 Republic of Korea
| | - Gi Beom Kim
- Center for TheragnosisBiomedical Research InstituteKorea Institute of Science and Technology (KIST) Seoul 02792 Republic of Korea
- KU‐KIST Graduate School of Converging Science and TechnologyKorea University Seoul 02841 Republic of Korea
| | - Seung Ja Oh
- Center for BiomaterialsBiomedical Research InstituteKorea Institute of Science and Technology (KIST) Seoul 02792 Republic of Korea
| | - Kwangmeyung Kim
- Center for TheragnosisBiomedical Research InstituteKorea Institute of Science and Technology (KIST) Seoul 02792 Republic of Korea
| | - Hyungmin Kim
- Center for BionicsBiomedical Research InstituteKorea Institute of Science and Technology (KIST) Seoul 02792 Republic of Korea
- Division of Bio‐Medical Science and TechnologyKIST SchoolKorea University of Science and Technology Seoul 02792 Republic of Korea
| | - Yoosoo Yang
- Center for TheragnosisBiomedical Research InstituteKorea Institute of Science and Technology (KIST) Seoul 02792 Republic of Korea
- Division of Bio‐Medical Science and TechnologyKIST SchoolKorea University of Science and Technology Seoul 02792 Republic of Korea
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de Andrade MO, Haqshenas SR, Pahk KJ, Saffari N. The effects of ultrasound pressure and temperature fields in millisecond bubble nucleation. ULTRASONICS SONOCHEMISTRY 2019; 55:262-272. [PMID: 30952547 DOI: 10.1016/j.ultsonch.2019.01.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Revised: 01/11/2019] [Accepted: 01/16/2019] [Indexed: 06/09/2023]
Abstract
A phenomenological implementation of Classical Nucleation Theory (CNT) is employed to investigate the connection between high intensity focused ultrasound (HIFU) pressure and temperature fields with the energetic requirements of bubble nucleation. As a case study, boiling histotripsy in tissue-mimicking phantoms is modelled. The physics of key components in the implementation of CNT in HIFU conditions such as the derivation of nucleation pressure thresholds and approximations regarding the surface tension of the liquid are reviewed and discussed. Simulations show that the acoustic pressure is the ultimate trigger for millisecond bubble nucleation in boiling histotripsy, however, HIFU heat deposition facilitates nucleation by lowering nucleation pressure thresholds. Nucleation thus occurs preferentially at the regions of highest heat deposition within the HIFU field. This implies that bubble nucleation subsequent to millisecond HIFU heat deposition can take place at temperatures below 100 °C as long as the focal HIFU peak negative pressure exceeds the temperature-dependent nucleation threshold. It is also found that the magnitude of nucleation pressure thresholds decreases with decreasing frequencies. Overall, results indicate that it is not possible to separate thermal and mechanical effects of HIFU in the nucleation of bubbles for timescales of a few milliseconds. This methodology provides a promising framework for studying time and space dependencies of the energetics of bubble nucleation within a HIFU field.
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Affiliation(s)
| | - Seyyed Reza Haqshenas
- UCL Mechanical Engineering, University College London, London WC1E 7JE, United Kingdom
| | - Ki Joo Pahk
- Center for Bionics, Biomedical Research Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Nader Saffari
- UCL Mechanical Engineering, University College London, London WC1E 7JE, United Kingdom
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Pahk KJ, Shin CH, Bae IY, Yang Y, Kim SH, Pahk K, Kim H, Oh SJ. Boiling Histotripsy-induced Partial Mechanical Ablation Modulates Tumour Microenvironment by Promoting Immunogenic Cell Death of Cancers. Sci Rep 2019; 9:9050. [PMID: 31227775 PMCID: PMC6588624 DOI: 10.1038/s41598-019-45542-z] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 06/06/2019] [Indexed: 01/18/2023] Open
Abstract
Boiling histotripsy is a promising non-invasive High-Intensity Focused Ultrasound (HIFU) technique that employs HIFU mechanical effects to fractionate solid tumours without causing any significant thermal damage. It has been suggested that boiling histotripsy may induce a strong immune response due to the absence of denatured antigenic protein at the HIFU focus. The underlying immunological mechanisms of this technique are, however, poorly understood. In this study, we demonstrated the feasibility of using boiling histotripsy to mechanically fractionate human breast adenocarcinoma cells (MDA-MB-231) and the potential immunological effects induced by boiling histotripsy, for the first time. Our results showed that mechanical stresses produced by boiling histotripsy promote immunogenic cell death of cancer cells via TNF-induced necrosis signaling pathway. This immunogenic cell death significantly increases secretions of damage-associated molecular patterns (CRT, HSP70, HMGB-1), pro-inflammatory cytokines (IFN-γ, IL-1α, IL-1β, IL-18) and chemokines (IL-8) which are related to M1 macrophage activation. Furthermore, the levels of these signaling proteins increase with the degree of mechanical damage induced by boiling histotripsy. Together, the results presented can suggest that boiling histotripsy could be a potential therapeutic approach for not only mechanically destroying solid tumours (e.g., breast cancer) but also promoting immunogenic cell death via TNF-induced necrosis to trigger antitumour immunity.
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Affiliation(s)
- Ki Joo Pahk
- Center for Bionics, Biomedical Research Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Cheol-Hee Shin
- Center for Biomaterials, Biomedical Research Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - In Yeong Bae
- Center for Biomaterials, Biomedical Research Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Yoosoo Yang
- Center for Theragnosis, Biomedical Research Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Sang-Heon Kim
- Center for Biomaterials, Biomedical Research Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Kisoo Pahk
- Institute for Inflammation Control, Korea University, Seoul, 02841, Republic of Korea
- Department of Nuclear Medicine, Korea University Anam Hospital, Seoul, 02841, Republic of Korea
| | - Hyungmin Kim
- Center for Bionics, Biomedical Research Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea.
| | - Seung Ja Oh
- Center for Biomaterials, Biomedical Research Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea.
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Pahk KJ, de Andrade MO, Gélat P, Kim H, Saffari N. Mechanical damage induced by the appearance of rectified bubble growth in a viscoelastic medium during boiling histotripsy exposure. ULTRASONICS SONOCHEMISTRY 2019; 53:164-177. [PMID: 30686603 DOI: 10.1016/j.ultsonch.2019.01.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 12/23/2018] [Accepted: 01/02/2019] [Indexed: 05/13/2023]
Abstract
In boiling histotripsy, the presence of a boiling vapour bubble and understanding of its dynamic behaviour are crucially important for the initiation of the tissue fractionation process and for the control of the size of a lesion produced. Whilst many in vivo studies have shown the feasibility of using boiling histotripsy in mechanical fractionation of solid tumours, not much is known about the evolution of a boiling vapour bubble in soft tissue induced by boiling histotripsy. The main objective of this present study is therefore to investigate the formation and dynamic behaviour of a boiling vapour bubble which occurs under boiling histotripsy insonation. Numerical and experimental studies on the bubble dynamics induced in optically transparent tissue-mimicking gel phantoms exposed to the field of a 2.0 MHz High Intensity Focused Ultrasound (HIFU) transducer were performed with a high speed camera. The Gilmore-Zener bubble model coupled with the Khokhlov-Zabolotskaya-Kuznetsov and the Bio-heat Transfer equations was used to simulate bubble dynamics driven by boiling histotripsy waveforms (nonlinear-shocked wave excitation) in a viscoelastic medium as functions of surrounding temperature and of tissue elasticity variations. In vivo animal experiments were also conducted to examine cellular structures around a freshly created lesion in the liver resulting from boiling histotripsy. To the best of our knowledge, this is the first study reporting the numerical and experimental evidence of the appearance of rectified bubble growth in a viscoelastic medium. Accounting for tissue phantom elasticity adds a mechanical constraint on vapour bubble growth, which improves the agreement between the simulation and the experimental results. In addition the numerical calculations showed that the asymmetry in a shockwave and water vapour transport can result in rectified bubble growth which could be responsible for HIFU-induced tissue decellularisation. Strain on liver tissue induced by this radial motion can damage liver tissue while preserving blood vessels.
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Affiliation(s)
- Ki Joo Pahk
- Center for Bionics, Biomedical Research Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea.
| | | | - Pierre Gélat
- Department of Mechanical Engineering, University College Londo, London WC1E 7JE, UK.
| | - Hyungmin Kim
- Center for Bionics, Biomedical Research Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea.
| | - Nader Saffari
- Department of Mechanical Engineering, University College Londo, London WC1E 7JE, UK.
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Bader KB, Vlaisavljevich E, Maxwell AD. For Whom the Bubble Grows: Physical Principles of Bubble Nucleation and Dynamics in Histotripsy Ultrasound Therapy. ULTRASOUND IN MEDICINE & BIOLOGY 2019; 45:1056-1080. [PMID: 30922619 PMCID: PMC6524960 DOI: 10.1016/j.ultrasmedbio.2018.10.035] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 09/28/2018] [Accepted: 10/03/2018] [Indexed: 05/04/2023]
Abstract
Histotripsy is a focused ultrasound therapy for non-invasive tissue ablation. Unlike thermally ablative forms of therapeutic ultrasound, histotripsy relies on the mechanical action of bubble clouds for tissue destruction. Although acoustic bubble activity is often characterized as chaotic, the short-duration histotripsy pulses produce a unique and consistent type of cavitation for tissue destruction. In this review, the action of histotripsy-induced bubbles is discussed. Sources of bubble nuclei are reviewed, and bubble activity over the course of single and multiple pulses is outlined. Recent innovations in terms of novel acoustic excitations, exogenous nuclei for targeted ablation and histotripsy-enhanced drug delivery and image guidance metrics are discussed. Finally, gaps in knowledge of the histotripsy process are highlighted, along with suggested means to expedite widespread clinical utilization of histotripsy.
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Affiliation(s)
- Kenneth B Bader
- Department of Radiology and Committee on Medical Physics, University of Chicago, Chicago, Illinois, USA.
| | - Eli Vlaisavljevich
- Department of Biomedical Engineering and Mechanics, Virginia Tech University, Blacksburg, Virginia, USA
| | - Adam D Maxwell
- Department of Urology, University of Washington School of Medicine, Seattle, Washington, USA
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Pahk KJ, de Andrade MO, Kim H, Saffari N. The effects of the size of a boiling bubble on lesion production in boiling histotripsy. ACTA ACUST UNITED AC 2019. [DOI: 10.1088/1742-6596/1184/1/012007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Pahk KJ, Gélat P, Kim H, Saffari N. Bubble dynamics in boiling histotripsy. ULTRASOUND IN MEDICINE & BIOLOGY 2018; 44:2673-2696. [PMID: 30228043 DOI: 10.1016/j.ultrasmedbio.2018.07.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 07/13/2018] [Accepted: 07/24/2018] [Indexed: 05/24/2023]
Abstract
Boiling histotripsy is a non-invasive, cavitation-based ultrasonic technique which uses a number of millisecond pulses to mechanically fractionate tissue. Though a number of studies have demonstrated the efficacy of boiling histotripsy for fractionation of solid tumours, treatment monitoring by cavitation measurement is not well studied because of the limited understanding of the dynamics of bubbles induced by boiling histotripsy. The main objectives of this work are to (a) extract qualitative and quantitative features of bubbles excited by shockwaves and (b) distinguish between the different types of cavitation activity for either a thermally or a mechanically induced lesion in the liver. A numerical bubble model based on the Gilmore equation accounting for heat and mass transfer (gas and water vapour) was developed to investigate the dynamics of a single bubble in tissue exposed to different High Intensity Focused Ultrasound fields as a function of temperature variation in the fluid. Furthermore, ex vivo liver experiments were performed with a passive cavitation detection system to obtain acoustic emissions. The numerical simulations showed that the asymmetry in a shockwave and water vapour transport are the key parameters which lead the bubble to undergo rectified growth at a boiling temperature of 100°C. The onset of rectified radial bubble motion manifested itself as (a) an increase in the radiated pressure and (b) the sudden appearance of higher order multiple harmonics in the corresponding spectrogram. Examining the frequency spectra produced by the thermal ablation and the boiling histotripsy exposures, it was observed that higher order multiple harmonics as well as higher levels of broadband emissions occurred during the boiling histotripsy insonation. These unique features in the emitted acoustic signals were consistent with the experimental measurements. These features can, therefore, be used to monitor (a) the different types of acoustic cavitation activity for either a thermal ablation or a mechanical fractionation process and (b) the onset of the formation of a boiling bubble at the focus in the course of HIFU exposure.
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Affiliation(s)
- Ki Joo Pahk
- Center for Bionics, Biomedical Research Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Pierre Gélat
- Department of Mechanical Engineering, University College London, London, WC1E 7JE, UK
| | - Hyungmin Kim
- Center for Bionics, Biomedical Research Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Nader Saffari
- Department of Mechanical Engineering, University College London, London, WC1E 7JE, UK.
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Li Y, Wang R, Lu M, Zhang L, Liu Y, Han D, Wang X, Geng Y, Wan M. Histotripsy Using Fundamental and Second Harmonic Superposition Combined with Hundred-Microsecond Ultrasound Pulses. ULTRASOUND IN MEDICINE & BIOLOGY 2018; 44:2089-2104. [PMID: 30054023 DOI: 10.1016/j.ultrasmedbio.2018.05.024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 04/23/2018] [Accepted: 05/29/2018] [Indexed: 06/08/2023]
Abstract
A novel histotripsy approach based on fundamental and second harmonic superposition and incorporating hundred-microsecond-long pulses and two-stage pulse protocol is proposed in this study to rapidly generate mechanically homogenized lesions. Two pulse stages were applied: stage 1, pulses with a pulse duration of 500-600 μs and pulse repetition frequency of 100 Hz, and stage 2, multiple periods, each composed of multiple pulses with the same pulse duration and pulse repetition frequency as those in stage 1, but with an off-time of 600 ms between periods. A custom-designed 1.1/2.2-MHz two-element confocal-annular array, with an f-number of 0.69, and lateral and axial full width at half-maximum pressure dimensions of approximately 1.0 and 6.0 mm, was used. The peak positive/negative pressures at the focus were +22/-7 MPa for 1.1 MHz and +56/-14 MPa with shock wave for 2.2 MHz. To investigate the feasibility of this approach, experiments were designed and performed in tissue-mimicking polyacrylamide gel phantoms with bovine serum albumin and in ex vivo porcine tissues. Cavitation and boiling activities were observed through high-speed photography, and the corresponding acoustic emissions were recorded through passive cavitation detection. Ex vivo experimental results revealed that complete tissue homogeneous regions with regular long tear shape and typical dimensions of 5.80 ± 0.19 mm in axial and 2.20 ± 0.26 mm in lateral were successfully generated in porcine kidney samples. The hematoxylin and eosin staining evidenced that the lesions were thoroughly homogenized and sharply demarcated from untreated regions. These results indicated that the histotripsy approach using fundamental and second harmonic superposition combined with hundred-microsecond pulses and two-stage pulse protocol can efficiently obtain a mechanical disruption of soft tissues with spatial precision, and this approach may have the potential to be developed as a useful tool for precise tumor treatment.
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Affiliation(s)
- Yujiao Li
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Rui Wang
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Mingzhu Lu
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China.
| | - Linglu Zhang
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Yanshan Liu
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Dan Han
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Xuan Wang
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Yizhe Geng
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Mingxi Wan
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
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