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Yang S, Zemzemi C, Escudero DS, Vela DC, Haworth KJ, Holland CK. Histotripsy and Catheter-Directed Lytic: Efficacy in Highly Retracted Porcine Clots In Vitro. ULTRASOUND IN MEDICINE & BIOLOGY 2024; 50:1167-1177. [PMID: 38777639 DOI: 10.1016/j.ultrasmedbio.2024.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 04/02/2024] [Accepted: 04/05/2024] [Indexed: 05/25/2024]
Abstract
OBJECTIVE Standard treatment for deep vein thrombosis (DVT) involves catheter-directed anticoagulants or thrombolytics, but the chronic thrombi present in many DVT cases are often resistant to this therapy. Histotripsy has been found to be a promising adjuvant treatment, using the mechanical action of cavitating bubble clouds to enhance thrombolytic activity. The objective of this study was to determine if histotripsy enhanced recombinant tissue plasminogen activator (rt-PA) thrombolysis in highly retracted porcine clots in vitro in a flow model of occlusive DVT. METHODS Highly retracted porcine whole blood clots were treated for 1 h with either catheter-directed saline (negative control), rt-PA (lytic control), histotripsy, DEFINITY and histotripsy or the combination of rt-PA and histotripsy with or without DEFINITY. Five-cycle, 1.5 MHz histotripsy pulses with a peak negative pressure of 33.2 MPa and pulse repetition frequency of 40 Hz were applied along the clot. B-Mode and passive cavitation images were acquired during histotripsy insonation to monitor bubble activity. RESULTS Clots subjected to histotripsy with and without rt-PA exhibited greater thrombolytic efficacy than controls (7.0% flow recovery or lower), and histotripsy with rt-PA was more efficacious than histotripsy with saline (86.1 ± 10.2% compared with 61.7 ± 19.8% flow recovery). The addition of DEFINITY to histotripsy with or without rt-PA did not enhance either thrombolytic efficacy or cavitation dose. Cavitation dose generally did not correlate with thrombolytic efficacy. CONCLUSION Enhancement of thrombolytic efficacy was achieved using histotripsy, with and without catheter-directed rt-PA, in the presence of physiologic flow. This suggests these treatments may be effective as therapy for DVT.
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Affiliation(s)
- Shumeng Yang
- Department of Biomedical Engineering, University of Cincinnati, Cincinnati, OH, USA.
| | - Chadi Zemzemi
- Department of Internal Medicine, University of Cincinnati, Cincinnati, OH, USA
| | | | - Deborah C Vela
- Cardiovascular Pathology, Texas Heart Institute, Houston, TX, USA
| | - Kevin J Haworth
- Department of Internal Medicine, University of Cincinnati, Cincinnati, OH, USA; Department of Biomedical Engineering, University of Cincinnati, Cincinnati, OH, USA
| | - Christy K Holland
- Department of Internal Medicine, University of Cincinnati, Cincinnati, OH, USA; Department of Biomedical Engineering, University of Cincinnati, Cincinnati, OH, USA
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Edsall C, Huynh L, Mustafa W, Hall TL, Durmaz YY, Vlaisavljevich E. Nanoparticle-Mediated Histotripsy Using Dual-Frequency Pulsing Methods. ULTRASOUND IN MEDICINE & BIOLOGY 2024; 50:1214-1223. [PMID: 38797630 DOI: 10.1016/j.ultrasmedbio.2024.04.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 04/19/2024] [Accepted: 04/21/2024] [Indexed: 05/29/2024]
Abstract
OBJECTIVE Nanoparticle-mediated histotripsy (NMH) is a novel ablation method that combines nanoparticles as artificial cavitation nuclei with focused ultrasound pulsing to achieve targeted, non-invasive, and cell-selective tumor ablation. The study described here examined the effect of dual-frequency histotripsy pulsing on the cavitation threshold, bubble cloud characteristics, and ablative efficiency in NMH. High-speed optical imaging was used to analyze bubble cloud characteristics and to measure ablation efficiency for NMH inside agarose tissue phantoms containing perfluorohexane-filled nanocone clusters, which were previously developed to reduce the histotripsy cavitation threshold for NMH. METHODS Dual-frequency histotripsy pulsing was applied at a 1:1 pressure ratio using a modular 500 kHz and 3 MHz dual-frequency array transducer. Optical imaging results revealed predictable, well-defined bubble clouds generated for all tested cases with similar reductions in the cavitation thresholds observed for single-frequency and dual-frequency pulsing. RESULTS Dual-frequency pulsing was seen to nucleate small, dense clouds in agarose phantoms, intermediate in size of their component frequencies but closer in area to that of the higher component frequency. Red blood cell experiments revealed complete ablations were generated by dual-frequency NMH in all phantoms in <1500 pulses. This result was a significant increase in ablation efficiency compared with the ∼4000 pulses required in prior single-frequency NMH studies. CONCLUSION Overall, this study indicates the potential for using dual-frequency histotripsy methods to increase the ablation efficacy of NMH.
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Affiliation(s)
- Connor Edsall
- Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA.
| | - Laura Huynh
- Department of Materials Science and Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Waleed Mustafa
- Department of Biomedical Engineering, Istanbul Medipol University, İstanbul, Turkey
| | - Timothy L Hall
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Yasemin Yuksel Durmaz
- Department of Biomedical Engineering, Istanbul Medipol University, İstanbul, Turkey; Research Institute of Health Science and Technologies (SABITA), Istanbul Medipol University, Istanbul, Turkey
| | - Eli Vlaisavljevich
- Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA; ICTAS Center for Engineered Health, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
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Landry TG, Brown JA. Ultrasound imaging guided precision histotripsy: Effects of pulse settings on ablation properties in rat brain. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2024; 155:2860-2874. [PMID: 38682916 PMCID: PMC11175660 DOI: 10.1121/10.0025832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 03/27/2024] [Accepted: 04/10/2024] [Indexed: 05/01/2024]
Abstract
A high-frequency 6 MHz miniature handheld histotripsy device with an endoscopic form factor and co-registered high-resolution ultrasound imaging was developed. This device could allow precision histotripsy ablation during minimally invasive brain tumor surgeries with real-time image guidance. This study characterized the outcome of acute histotripsy in the normal in vivo rat brain using the device with a range of histotripsy pulse settings, including number of cycles, pulse repetition frequency, and pressure, as well as other experimental factors. The stability and shape of the bubble cloud were measured during ablations, as well as the post-histotripsy ablation shape in ultrasound B-mode and histology. The results were compared between histological images and the ultrasound imaging data to determine how well ultrasound data reflected observable damage in histology. The results indicated that while pulse settings can have some influence on ablation shape, sample-to-sample variation had a larger influence on ablation shape. This suggests that real-time ablation monitoring is essential for accurate knowledge of outcomes. Ultrasound imaging provided an accurate real-time indication of ablation shape both during ablation and post-ablation.
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Affiliation(s)
- Thomas G Landry
- School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada
- Division of Surgery, Nova Scotia Health, Halifax, Nova Scotia, Canada
| | - Jeremy A Brown
- School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada
- Division of Surgery, Nova Scotia Health, Halifax, Nova Scotia, Canada
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Simon A, Edsall C, Maxwell A, Vlaisavljevich E. Effects of pulse repetition frequency on bubble cloud characteristics and ablation in single-cycle histotripsy. Phys Med Biol 2024; 69:025018. [PMID: 38041873 DOI: 10.1088/1361-6560/ad11a1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 12/01/2023] [Indexed: 12/04/2023]
Abstract
Objective. Histotripsy is a cavitation-based ultrasound ablation method in development for multiple clinical applications. This work investigates the effects of pulse repetition frequency (PRF) on bubble cloud characteristics and ablative capabilities for histotripsy using single-cycle pulsing methods.Approach.Bubble clouds produced by a 500 kHz histotripsy system at PRFs from 0.1 to 1000 Hz were visualized using high-speed optical imaging in 1% agarose tissue phantoms at peak negative pressures,p-, of 2-36 MPa.Main results.Results showed a decrease in the cavitation cloud threshold with increasing PRF, ranging from 26.7 ± 0.5 MPa at 0.1 Hz to 15.0 ± 1.9 MPa at 1000 Hz. Bubble cloud analysis showed cavitation clouds generated at low PRFs (0.1-1 Hz) were characterized by consistently dense bubble clouds (41.7 ± 2.8 bubbles mm-2at 0.1 Hz), that closely matched regions of the focus above the histotripsy intrinsic threshold. Bubble clouds formed at higher PRFs measured lower cloud densities (23.1 ± 4.0 bubbles mm-2at 1000 Hz), with the lowest density measured for 10 Hz (8.8 ± 4.1 bubbles mm-2). Furthermore, higher PRFs showed increased pulse-to-pulse correlation, characteristic of cavitation memory effects; however, bubble clouds still filled the entire volume of the focus due to their initial density and enhanced bubble expansion from the restimulation of residual nuclei at the higher PRFs. Histotripsy ablation assessed through lesion analysis in red blood cell (RBC) phantoms showed higher PRFs generated lesions with lower adherence to the initial focal region compared to low PRF ablations; however, no trend of decreasing ablation efficiency with PRF was observed, with similar efficiencies observed for all the PRFs tested in this study.Significance.Notably, this result is different than what has previously been shown for shock-scattering histotripsy, which has shown decreased ablation efficiencies at higher PRFs. Overall, this study demonstrates the essential effects of PRF on single-cycle histotripsy procedures that should be considered to help guide future histotripsy pulsing strategies.
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Affiliation(s)
- Alex Simon
- Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA, United States of America
| | - Connor Edsall
- Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA, United States of America
| | - Adam Maxwell
- Department of Urology, University of Washington, Seattle, WA, United States of America
| | - Eli Vlaisavljevich
- Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA, United States of America
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Edsall C, Fergusson A, Davis RM, Meyer CH, Allen SP, Vlaisavljevich E. Probability of Cavitation in a Custom Iron-Based Coupling Medium for Transcranial Magnetic Resonance-Guided Focused Ultrasound Procedures. ULTRASOUND IN MEDICINE & BIOLOGY 2023; 49:2519-2526. [PMID: 37730478 PMCID: PMC10591864 DOI: 10.1016/j.ultrasmedbio.2023.08.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 06/13/2023] [Accepted: 08/16/2023] [Indexed: 09/22/2023]
Abstract
OBJECTIVE A coupling bath of circulating, chilled, degassed water is essential to safe and precise acoustic transmittance during transcranial magnetic resonance-guided focused ultrasound (tMRgFUS) procedures, but the circulating water impairs the critical real-time magnetic resonance imaging (MRI). An iron-based coupling medium (IBCM) using iron oxide nanoparticles previously developed by our group increased the relaxivity of the coupling bath such that it appears to be invisible on MRI compared with degassed water. However, the nanoparticles also reduced the pressure threshold for cavitation. To address this concern for prefocal cavitation, our group recently developed an IBCM of electrosterically stabilized and aggregation-resistant poly(methacrylic acid)-coated iron oxide nanoparticles (PMAA-FeOX) with a similar capability to reduce the MR signal of degassed water. This study examines the effect of the PMAA-FeOX IBCM on the cavitation threshold. METHODS Increasing concentrations of PMAA-FeOX nanoparticles in degassed, deionized water were placed at the focus of two different transducers to assess low and high duty-cycle pulsing parameters which are representative of two modes of focused ultrasound being investigated for tMRgFUS. Passive cavitation detection and high-speed optical imaging were used to measure cavitation threshold pressures. RESULTS The mean cavitation threshold was determined in both cases to be indistinguishable from the degassed water control, between 6-8 MPa for high duty-cycle pulsing (CW) and between 25.5-26.5 MPa for very low duty-cycle pulsing. CONCLUSION The findings of this study indicate that an IBCM of PMAA-FeOX nanoparticles is a possible solution to reducing MRI interference from the coupling bath without increasing the risk of prefocal cavitation.
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Affiliation(s)
- Connor Edsall
- Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Austin Fergusson
- Translational Biology, Medicine, and Health Graduate Program, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Richey M Davis
- Department of Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Craig H Meyer
- Biomedical Engineering, University of Virginia, Charlottesville, VA, USA
| | - Steven P Allen
- Department of Electrical and Computer Engineering, Brigham Young University, Provo, UT, USA
| | - Eli Vlaisavljevich
- Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA; ICTAS Center for Engineered Health, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA.
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Lyons B, Balkaran JPR, Dunn-Lawless D, Lucian V, Keller SB, O’Reilly CS, Hu L, Rubasingham J, Nair M, Carlisle R, Stride E, Gray M, Coussios C. Sonosensitive Cavitation Nuclei-A Customisable Platform Technology for Enhanced Therapeutic Delivery. Molecules 2023; 28:7733. [PMID: 38067464 PMCID: PMC10708135 DOI: 10.3390/molecules28237733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 11/14/2023] [Accepted: 11/16/2023] [Indexed: 12/18/2023] Open
Abstract
Ultrasound-mediated cavitation shows great promise for improving targeted drug delivery across a range of clinical applications. Cavitation nuclei-sound-sensitive constructs that enhance cavitation activity at lower pressures-have become a powerful adjuvant to ultrasound-based treatments, and more recently emerged as a drug delivery vehicle in their own right. The unique combination of physical, biological, and chemical effects that occur around these structures, as well as their varied compositions and morphologies, make cavitation nuclei an attractive platform for creating delivery systems tuned to particular therapeutics. In this review, we describe the structure and function of cavitation nuclei, approaches to their functionalization and customization, various clinical applications, progress toward real-world translation, and future directions for the field.
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Affiliation(s)
- Brian Lyons
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, UK; (J.P.R.B.); (D.D.-L.); (V.L.); (S.B.K.); (L.H.); (J.R.); (M.N.); (R.C.); (E.S.); (M.G.)
| | - Joel P. R. Balkaran
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, UK; (J.P.R.B.); (D.D.-L.); (V.L.); (S.B.K.); (L.H.); (J.R.); (M.N.); (R.C.); (E.S.); (M.G.)
| | - Darcy Dunn-Lawless
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, UK; (J.P.R.B.); (D.D.-L.); (V.L.); (S.B.K.); (L.H.); (J.R.); (M.N.); (R.C.); (E.S.); (M.G.)
| | - Veronica Lucian
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, UK; (J.P.R.B.); (D.D.-L.); (V.L.); (S.B.K.); (L.H.); (J.R.); (M.N.); (R.C.); (E.S.); (M.G.)
| | - Sara B. Keller
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, UK; (J.P.R.B.); (D.D.-L.); (V.L.); (S.B.K.); (L.H.); (J.R.); (M.N.); (R.C.); (E.S.); (M.G.)
| | - Colm S. O’Reilly
- Botnar Research Centre, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences (NDORMS), University of Oxford, Oxford OX1 3PJ, UK;
| | - Luna Hu
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, UK; (J.P.R.B.); (D.D.-L.); (V.L.); (S.B.K.); (L.H.); (J.R.); (M.N.); (R.C.); (E.S.); (M.G.)
| | - Jeffrey Rubasingham
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, UK; (J.P.R.B.); (D.D.-L.); (V.L.); (S.B.K.); (L.H.); (J.R.); (M.N.); (R.C.); (E.S.); (M.G.)
| | - Malavika Nair
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, UK; (J.P.R.B.); (D.D.-L.); (V.L.); (S.B.K.); (L.H.); (J.R.); (M.N.); (R.C.); (E.S.); (M.G.)
| | - Robert Carlisle
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, UK; (J.P.R.B.); (D.D.-L.); (V.L.); (S.B.K.); (L.H.); (J.R.); (M.N.); (R.C.); (E.S.); (M.G.)
| | - Eleanor Stride
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, UK; (J.P.R.B.); (D.D.-L.); (V.L.); (S.B.K.); (L.H.); (J.R.); (M.N.); (R.C.); (E.S.); (M.G.)
| | - Michael Gray
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, UK; (J.P.R.B.); (D.D.-L.); (V.L.); (S.B.K.); (L.H.); (J.R.); (M.N.); (R.C.); (E.S.); (M.G.)
| | - Constantin Coussios
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, UK; (J.P.R.B.); (D.D.-L.); (V.L.); (S.B.K.); (L.H.); (J.R.); (M.N.); (R.C.); (E.S.); (M.G.)
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7
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Hay AN, Ruger L, Hsueh A, Vickers E, Klahn S, Vlaisavljevich E, Tuohy J. A review of the development of histotripsy for extremity tumor ablation with a canine comparative oncology model to inform human treatments. Int J Hyperthermia 2023; 40:2274802. [PMID: 37994796 PMCID: PMC10669778 DOI: 10.1080/02656736.2023.2274802] [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: 07/31/2023] [Accepted: 10/19/2023] [Indexed: 11/24/2023] Open
Abstract
Cancer is a devasting disease resulting in millions of deaths worldwide in both humans and companion animals, including dogs. Treatment of cancer is complex and challenging and therefore often multifaceted, as in the case of osteosarcoma (OS) and soft tissue sarcoma (STS). OS predominantly involves the appendicular skeleton and STS commonly develops in the extremities, resulting in treatment challenges due to the need to balance wide-margin resections to achieve local oncological control against the functional outcomes for the patient. To achieve wide tumor resection, invasive limb salvage surgery is often required, and the patient is at risk for numerous complications which can ultimately lead to impaired limb function and mobility. The advent of tumor ablation techniques offers the exciting potential of developing noninvasive or minimally invasive treatment options for extremity tumors. One promising innovative tumor ablation technique with strong potential to serve as a noninvasive limb salvage treatment for extremity tumor patients is histotripsy. Histotripsy is a novel, noninvasive, non-thermal, and non-ionizing focused ultrasound technique which uses controlled acoustic cavitation to mechanically disintegrate tissue with high precision. In this review, we present the ongoing development of histotripsy as a non-surgical alternative for extremity tumors and highlight the value of spontaneously occurring OS and STS in the pet dog as a comparative oncology research model to advance this field of histotripsy research.
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Affiliation(s)
- Alayna N. Hay
- Department of Small Animal Clinical Sciences, Virginia-Maryland College of Veterinary Medicine, Blacksburg, VA
- Virginia Tech Animal Cancer Care and Research Center, Virginia-Maryland College of Veterinary Medicine, Roanoke, VA
| | - Lauren Ruger
- Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, VA
| | - Andy Hsueh
- Department of Small Animal Clinical Sciences, Virginia-Maryland College of Veterinary Medicine, Blacksburg, VA
- Virginia Tech Animal Cancer Care and Research Center, Virginia-Maryland College of Veterinary Medicine, Roanoke, VA
| | - Elliana Vickers
- Department of Small Animal Clinical Sciences, Virginia-Maryland College of Veterinary Medicine, Blacksburg, VA
- Virginia Tech Animal Cancer Care and Research Center, Virginia-Maryland College of Veterinary Medicine, Roanoke, VA
- Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, VA
- Graduate program in Translation Biology, Medicine and Health, Virginia Polytechnic Institute and State University, Roanoke, VA
| | - Shawna Klahn
- Department of Small Animal Clinical Sciences, Virginia-Maryland College of Veterinary Medicine, Blacksburg, VA
- Virginia Tech Animal Cancer Care and Research Center, Virginia-Maryland College of Veterinary Medicine, Roanoke, VA
| | - Eli Vlaisavljevich
- Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, VA
| | - Joanne Tuohy
- Department of Small Animal Clinical Sciences, Virginia-Maryland College of Veterinary Medicine, Blacksburg, VA
- Virginia Tech Animal Cancer Care and Research Center, Virginia-Maryland College of Veterinary Medicine, Roanoke, VA
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Edsall C, Huynh L, Hall TL, Vlaisavljevich E. Bubble cloud characteristics and ablation efficiency in dual-frequency intrinsic threshold histotripsy. Phys Med Biol 2023; 68:225006. [PMID: 37797649 PMCID: PMC10627095 DOI: 10.1088/1361-6560/ad00a5] [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: 06/24/2023] [Revised: 09/20/2023] [Accepted: 10/05/2023] [Indexed: 10/07/2023]
Abstract
Histotripsy is a non-thermal focused ultrasound ablation method that destroys tissue through the generation and activity of acoustic cavitation bubble clouds. Intrinsic threshold histotripsy uses single-cycle pulses to generate bubble clouds when the dominant negative pressure phase exceeds an intrinsic threshold of ∼25-30 MPa. The ablation efficiency is dependent upon the size and density of bubbles within the bubble cloud. This work investigates the effects of dual-frequency pulsing schemes on the bubble cloud behavior and ablation efficiency in intrinsic threshold histotripsy. A modular 500 kHz:3 MHz histotripsy transducer treated agarose phantoms using dual-frequency histotripsy pulses with a 1:1 pressure ratio from 500 kHz and 3 MHz frequency elements and varying arrival times for the 3 MHz pulse relative to the arrival of the 500 kHz pulse (-100 ns, 0 ns, and +100 ns). High-speed optical imaging captured cavitation effects to characterize bubble cloud and individual bubble dynamics. The effects of dual-frequency pulsing on lesion formation and ablation efficiency were also investigated in red blood cell (RBC) phantoms. Results showed that the single bubble and bubble cloud size for dual-frequency cases were intermediate to published results for the component single-frequencies of 500 kHz and 3 MHz. Additionally, bubble cloud size and dynamics were shown to be altered by the arrival time of the 3 MHz pulse with respect to the 500 kHz pulse, with more uniform cloud expansion and collapse observed for early (-100 ns) arrival. Finally, RBC phantom experiments showed that dual-frequency exposures were capable of generating precise lesions with smaller areas and higher ablation efficiencies than previously published results for 500 kHz or 3 MHz. Overall, results demonstrate dual-frequency histotripsy's ability to modulate bubble cloud size and dynamics can be leveraged to produce precise lesions at higher ablation efficiencies than previously observed for single-frequency pulsing.
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Affiliation(s)
- Connor Edsall
- Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, 325 Stanger St., Blacksburg, VA, 24061, United States of America
| | - Laura Huynh
- Department of Materials Science and Engineering, Virginia Polytechnic Institute and State University, 445 Old Turner St., Blacksburg, VA 24061, United States of America
| | - Timothy L Hall
- Biomedical Engineering, University of Michigan, Carl A. Gerstacker Building, 2200 Bonisteel Blvd, Ann Arbor, MI 48109-2133, United States of America
| | - Eli Vlaisavljevich
- Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, 325 Stanger St., Blacksburg, VA, 24061, United States of America
- ICTAS Center for Engineered Health, Virginia Polytechnic Institute and State University, 325 Stanger St., Blacksburg, VA, 24061, United States of America
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9
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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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Stettinius A, Holmes H, Zhang Q, Mehochko I, Winters M, Hutchison R, Maxwell A, Holliday J, Vlaisavljevich E. DNA release from plant tissue using focused ultrasound extraction (FUSE). APPLICATIONS IN PLANT SCIENCES 2023; 11:e11510. [PMID: 36818781 PMCID: PMC9934592 DOI: 10.1002/aps3.11510] [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: 07/12/2022] [Revised: 10/31/2022] [Accepted: 11/02/2022] [Indexed: 06/18/2023]
Abstract
PREMISE Sample preparation in genomics is a critical step that is often overlooked in molecular workflows and impacts the success of downstream genetic applications. This study explores the use of a recently developed focused ultrasound extraction (FUSE) technique to enable the rapid release of DNA from plant tissues for genetic analysis. METHODS FUSE generates a dense acoustic cavitation bubble cloud that pulverizes targeted tissue into acellular debris. This technique was applied to leaf samples of American chestnut (Castanea dentata), tulip poplar (Liriodendron tulipifera), red maple (Acer rubrum), and chestnut oak (Quercus montana). RESULTS We observed that FUSE can extract high quantities of DNA in 9-15 min, compared to the 30 min required for control DNA extraction methods. FUSE extracted DNA quantities of 24.33 ± 6.51 ng/mg and 35.32 ± 9.21 ng/mg from American chestnut and red maple, respectively, while control methods yielded 6.22 ± 0.87 ng/mg and 11.51 ± 1.95 ng/mg, respectively. The quality of the DNA released by FUSE allowed for successful amplification and next-generation sequencing. DISCUSSION These results indicate that FUSE can improve DNA extraction efficiency for leaf tissues. Continued development of this technology aims to adapt to field-deployable systems to increase the cataloging of genetic biodiversity, particularly in low-resource biodiversity hotspots.
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Affiliation(s)
- Alexia Stettinius
- Department of Biomedical Engineering and MechanicsVirginia Polytechnic Institute and State UniversityBlacksburgVirginiaUSA
| | - Hal Holmes
- Department of Biomedical Engineering and MechanicsVirginia Polytechnic Institute and State UniversityBlacksburgVirginiaUSA
- Conservation X LabsSeattleWashingtonUSA
| | - Qian Zhang
- Department of Forest Resources and Environmental ConservationVirginia Polytechnic Institute and State UniversityBlacksburgVirginiaUSA
| | - Isabelle Mehochko
- Department of Biomedical Engineering and MechanicsVirginia Polytechnic Institute and State UniversityBlacksburgVirginiaUSA
| | | | - Ruby Hutchison
- Department of Biomedical Engineering and MechanicsVirginia Polytechnic Institute and State UniversityBlacksburgVirginiaUSA
| | - Adam Maxwell
- Department of UrologyUniversity of WashingtonSeattleWashingtonUSA
| | - Jason Holliday
- Department of Forest Resources and Environmental ConservationVirginia Polytechnic Institute and State UniversityBlacksburgVirginiaUSA
| | - Eli Vlaisavljevich
- Department of Biomedical Engineering and MechanicsVirginia Polytechnic Institute and State UniversityBlacksburgVirginiaUSA
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11
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Ruger L, Yang E, Coutermarsh-Ott S, Vickers E, Gannon J, Nightengale M, Hsueh A, Ciepluch B, Dervisis N, Vlaisavljevich E, Klahn S. Histotripsy ablation for the treatment of feline injection site sarcomas: a first-in-cat in vivo feasibility study. Int J Hyperthermia 2023; 40:2210272. [PMID: 37196996 DOI: 10.1080/02656736.2023.2210272] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 04/28/2023] [Accepted: 04/28/2023] [Indexed: 05/19/2023] Open
Abstract
PURPOSE Feline soft tissue sarcoma (STS) and injection site sarcoma (fISS) are rapidly growing tumors with low metastatic potential, but locally aggressive behavior. Histotripsy is a non-invasive focused ultrasound therapy using controlled acoustic cavitation to mechanically disintegrate tissue. In this study, we investigated the in vivo safety and feasibility of histotripsy to treat fISS using a custom 1 MHz transducer. MATERIALS AND METHODS Three cats with naturally-occurring STS were treated with histotripsy before surgical removal of the tumor 3 to 6 days later. Gross and histological analyses were used to characterize the ablation efficacy of the treatment, and routine immunohistochemistry and batched cytokine analysis were used to investigate the acute immunological effects of histotripsy. RESULTS Results showed that histotripsy ablation was achievable and well-tolerated in all three cats. Precise cavitation bubble clouds were generated in all patients, and hematoxylin & eosin stained tissues revealed ablative damage in targeted regions. Immunohistochemical results identified an increase in IBA-1 positive cells in treated tissues, and no significant changes in cytokine concentrations were identified post-treatment. CONCLUSIONS Overall, the results of this study demonstrate the safety and feasibility of histotripsy to target and ablate superficial feline STS and fISS tumors and guide the clinical development of histotripsy devices for this application.
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Affiliation(s)
- Lauren Ruger
- Department of Biomedical Engineering and Mechanics, VA Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Ester Yang
- Department of Small Animal Clinical Sciences, Virginia-MD College of Veterinary Medicine, Blacksburg, VA, USA
- Virginia Tech Animal Cancer Care and Research Center, Virginia-Maryland College of Veterinary Medicine, Roanoke, VA, USA
| | - Sheryl Coutermarsh-Ott
- Biomedical Sciences and Pathobiology, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Elliana Vickers
- Department of Biomedical Engineering and Mechanics, VA Polytechnic Institute and State University, Blacksburg, VA, USA
- Virginia Tech Animal Cancer Care and Research Center, Virginia-Maryland College of Veterinary Medicine, Roanoke, VA, USA
- Graduate Program in Translational Biology, Medicine and Health, Virginia Polytechnic Institute and State University, Roanoke, VA, USA
| | - Jessica Gannon
- Department of Biomedical Engineering and Mechanics, VA Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Marlie Nightengale
- Department of Small Animal Clinical Sciences, Virginia-MD College of Veterinary Medicine, Blacksburg, VA, USA
- Virginia Tech Animal Cancer Care and Research Center, Virginia-Maryland College of Veterinary Medicine, Roanoke, VA, USA
| | - Andy Hsueh
- Department of Small Animal Clinical Sciences, Virginia-MD College of Veterinary Medicine, Blacksburg, VA, USA
- Virginia Tech Animal Cancer Care and Research Center, Virginia-Maryland College of Veterinary Medicine, Roanoke, VA, USA
| | - Brittany Ciepluch
- Department of Small Animal Clinical Sciences, Virginia-MD College of Veterinary Medicine, Blacksburg, VA, USA
- Virginia Tech Animal Cancer Care and Research Center, Virginia-Maryland College of Veterinary Medicine, Roanoke, VA, USA
| | - Nikolaos Dervisis
- Department of Small Animal Clinical Sciences, Virginia-MD College of Veterinary Medicine, Blacksburg, VA, USA
- Virginia Tech Animal Cancer Care and Research Center, Virginia-Maryland College of Veterinary Medicine, Roanoke, VA, USA
- Department of Internal Medicine, Virginia Tech Carilion School of Medicine, Roanoke, VA, USA
| | - Eli Vlaisavljevich
- Department of Biomedical Engineering and Mechanics, VA Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Shawna Klahn
- Department of Small Animal Clinical Sciences, Virginia-MD College of Veterinary Medicine, Blacksburg, VA, USA
- Virginia Tech Animal Cancer Care and Research Center, Virginia-Maryland College of Veterinary Medicine, Roanoke, VA, USA
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12
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Stocker GE, Lundt JE, Sukovich JR, Miller RM, Duryea AP, Hall TL, Xu Z. A Modular, Kerf-Minimizing Approach for Therapeutic Ultrasound Phased Array Construction. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2022; 69:2766-2775. [PMID: 35617178 PMCID: PMC9594968 DOI: 10.1109/tuffc.2022.3178291] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
A novel method for fabricating a modular, kerf-minimizing histotripsy phased array was developed and tested. The method utilizes arbitrarily shaped elements, 3-D printing, water jet cutting, and a thin, 125- [Formula: see text] electrically insulating epoxy coating to maximize aperture utilization while allowing for replacement of individual transducer modules. The method was used to fabricate a 750-kHz truncated circular aperture array (165 mm ×234 mm) transducer with a focal length of 142 mm. The aperture was segmented into 260 arc-shaped modular elements, each approximately 11.5 mm ×11.5 mm, arranged in concentric rings. The resulting aperture utilization was 92%. The full-width-half-maximum (FWHM) focal zone of the array was measured to be 1.6 mm ×1.1 mm ×4.5 mm, and the FWHM electrical steering range was measured to be 38.5 mm ×33 mm 40 mm. The array was estimated to be capable of generating approximately 120-MPa peak negative pressure at the geometric focus. In addition, the array was used to ablate a 5-cm3 volume of tissue with electric focal steering.
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Affiliation(s)
- Greyson E. Stocker
- Department of Biomedical Engineering at the University of Michigan, Ann Arbor, MI 48109
| | | | - Jonathan R. Sukovich
- Department of Biomedical Engineering at the University of Michigan, Ann Arbor, MI 48109
| | | | | | - Timothy L. Hall
- Department of Biomedical Engineering at the University of Michigan, Ann Arbor, MI 48109
| | - Zhen Xu
- Department of Biomedical Engineering at the University of Michigan, Ann Arbor, MI 48109
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13
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Simon A, Robinson F, Anzivino A, Boyer M, Hendricks-Wenger A, Guilliams D, Casey J, Grider D, Valea F, Vlaisavljevich E. Histotripsy for the Treatment of Uterine Leiomyomas: A Feasibility Study in Ex Vivo Uterine Fibroids. ULTRASOUND IN MEDICINE & BIOLOGY 2022; 48:1652-1662. [PMID: 35641394 DOI: 10.1016/j.ultrasmedbio.2022.04.214] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 04/01/2022] [Accepted: 04/22/2022] [Indexed: 06/15/2023]
Abstract
Uterine fibroids (leiomyomas), the most common benign tumors in women of reproductive age, are a frequent cause of abnormal vaginal bleeding and other reproductive complaints among women. This study investigates the feasibility of using histotripsy, a non-invasive, non-thermal focused ultrasound ablation method, to ablate uterine fibroids. Human fibroid samples (n = 16) were harvested after hysterectomy or myomectomy procedures at Carilion Memorial Hospital. Histotripsy was applied to ex vivo fibroids in two sets of experiments using a 700-kHz clinical transducer to apply multicycle histotripsy pulses and a prototype 500-kHz transducer to apply single-cycle histotripsy pulses. Ultrasound imaging was used for real-time treatment monitoring, and post-treatment ablation was quantified histologically using hematoxylin and eosin and Masson trichrome stains. Results revealed that multicycle histotripsy generated diffuse cavitation in targeted fibroids, with minimal cellular ablative changes after treatment with 2000 pulses/point. Single-cycle pulsing generated well-confined bubble clouds with evidence of early coagulative necrosis on histological assessment in samples treated with 2000 pulses/point, near-complete ablation in samples treated with 4000 pulses/point and complete tissue destruction in samples treated with 10,000 pulses/point. This study illustrates that histotripsy is capable of fibroid ablation under certain pulsing parameters and warrants further investigation as an improved non-invasive ablation method for the treatment of leiomyomas.
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Affiliation(s)
- Alex Simon
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, Virginia, USA
| | - Faith Robinson
- Virginia Tech Carilion School of Medicine, Roanoke, Virginia, USA
| | - Anthony Anzivino
- Virginia Tech Carilion School of Medicine, Roanoke, Virginia, USA
| | - Maggie Boyer
- Department of Biological Systems Engineering, Virginia Tech, Blacksburg, Virginia, USA
| | - Alissa Hendricks-Wenger
- Department of Translational Biology, Medicine and Health, Virginia Tech, Blacksburg, VA, USA
| | - Danielle Guilliams
- Department of Research and Development, Carilion Clinic, Roanoke, Virginia, USA
| | - James Casey
- Virginia Tech Carilion School of Medicine, Roanoke, Virginia, USA; Department of Obstetrics and Gynecology, Carilion Clinic Gynecological Oncology, Roanoke, Virginia, USA
| | - Douglas Grider
- Virginia Tech Carilion School of Medicine, Roanoke, Virginia, USA; Dominion Pathology Associates, Roanoke, Virginia, USA
| | - Fidel Valea
- Virginia Tech Carilion School of Medicine, Roanoke, Virginia, USA; Department of Obstetrics and Gynecology, Carilion Clinic Gynecological Oncology, Roanoke, Virginia, USA
| | - Eli Vlaisavljevich
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, Virginia, USA.
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14
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Kaymaz B, Mustafa W, Hall S, Vlaisavljevich E, Sensoy O, Yuksel Durmaz Y. Experimental and Computational Investigation of Clustering Behavior of Cyclodextrin-Perfluorocarbon Inclusion Complexes as Effective Histotripsy Agents. Mol Pharm 2022; 19:2907-2921. [PMID: 35839291 DOI: 10.1021/acs.molpharmaceut.2c00268] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Recently developed nanocones (NCs), which are inclusion complexes that are made up of cyclodextrins (CDs) and perfluorocarbons (PFCs), have shown promising results in nanoparticle-mediated histotripsy (NMH) applications due to stable inclusion complexation, PFC quantification, simple synthesis, and processing. FDA-approved βCD and its modified versions such as low-degree methylated βCD have been previously demonstrated as prime examples of structures capable of accommodating PFC molecules. However, the complex formation potential of different CDs with various cavity sizes in the presence of PFC molecules, and their consequent aggregation, needs to be explored. In the present study, the complexation and aggregation potential of some natural CDs and their respective derivatives either exposed to perfluoropentane (PFP) or perfluorohexane (PFH) were studied in the wet lab. Computational studies were also performed to account for the limitations faced in PFC quantification because of the low optical density of PFCs within the CD complex and to discover the best candidate for NMH applications. All results revealed that only βCD and γCD (except HMγCD) derivatives form an inclusion complex with PFCs and only LMβCD, βCD, and γCD form nanocone clusters (NCCs), which precipitate and can be collected for use. Furthermore, the data collectively show that βCD and PFCs have the best complexation due to stable complex formation, ease of production, and product recovery, especially with PFH as a more suitable candidate due to its high boiling point, which allows workability during synthesis. Although simulations suggest that highly stable inclusion complexes exist, such as HPβCD, the cluster formation resulting in precipitation is hindered due to the high solubility of CDs in water, resulting in intangible yields to work with even after employing general laboratory recovery methods. Conclusively, histotripsy cavitation experiments successfully showed a decreased cavitation threshold among optimal NCC candidates that were identified, supporting their use in NMH.
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Affiliation(s)
- Betül Kaymaz
- Department of Biomedical Engineering, School of Engineering and Natural Sciences, Istanbul Medipol University, 34810 Istanbul, Turkey
| | - Waleed Mustafa
- Department of Biomedical Engineering, School of Engineering and Natural Sciences, Istanbul Medipol University, 34810 Istanbul, Turkey
| | - Sarah Hall
- Department of Biomedical Engineering and Mechanics, Virginia Tech 24061, United States
| | - Eli Vlaisavljevich
- Department of Biomedical Engineering and Mechanics, Virginia Tech 24061, United States
| | - Ozge Sensoy
- Department of Biomedical Engineering, School of Engineering and Natural Sciences, Istanbul Medipol University, 34810 Istanbul, Turkey.,Research Institute of Health Science and Technologies (SABITA), Istanbul Medipol University, 34810 Istanbul, Turkey
| | - Yasemin Yuksel Durmaz
- Department of Biomedical Engineering, School of Engineering and Natural Sciences, Istanbul Medipol University, 34810 Istanbul, Turkey.,Research Institute of Health Science and Technologies (SABITA), Istanbul Medipol University, 34810 Istanbul, Turkey
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15
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Tašič Muc B, Vella D, Lukač N, Kos M, Jezeršek M. Amplification of high-intensity pressure waves and cavitation in water using a multi-pulsed laser excitation and black-TiOx optoacoustic lens. BIOMEDICAL OPTICS EXPRESS 2022; 13:3993-4006. [PMID: 35991925 PMCID: PMC9352300 DOI: 10.1364/boe.460713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 05/28/2022] [Accepted: 06/02/2022] [Indexed: 06/15/2023]
Abstract
A method for amplification of high-intensity pressure waves generated with a multi-pulsed Nd:YAG laser coupled with a black-TiOx optoacoustic lens in the water is presented and characterized. The investigation was focused on determining how the multi-pulsed laser excitation with delays between 50 µs and 400 µs influences the dynamics of the bubbles formed by a laser-induced breakdown on the upper surface of the lens, the acoustic cavitation in the focal region of the lens, and the high-intensity pressure waves generation. A needle hydrophone and a high-speed camera were used to analyze the spatial distribution and time-dependent development of the above-mentioned phenomena. Our results show how different delays (td ) of the laser pulses influence optoacoustic dynamics. When td is equal to or greater than the bubble oscillation time, acoustic cavitation cloud size increases 10-fold after the fourth laser pulse, while the pressure amplitude increases by more than 75%. A quasi-deterministic creation of cavitation due to consecutive transient pressure waves is also discussed. This is relevant for localized ablative laser therapy.
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Affiliation(s)
- Blaž Tašič Muc
- Faculty of Mechanical Engineering, University of Ljubljana, Aškerčeva 6, Ljubljana, Slovenia
- Fotona d.o.o., Stegne 7, Ljubljana, Slovenia
| | - Daniele Vella
- Faculty of Mechanical Engineering, University of Ljubljana, Aškerčeva 6, Ljubljana, Slovenia
| | - Nejc Lukač
- Faculty of Mechanical Engineering, University of Ljubljana, Aškerčeva 6, Ljubljana, Slovenia
- Fotona d.o.o., Stegne 7, Ljubljana, Slovenia
| | - Matjaž Kos
- Faculty of Mechanical Engineering, University of Ljubljana, Aškerčeva 6, Ljubljana, Slovenia
| | - Matija Jezeršek
- Faculty of Mechanical Engineering, University of Ljubljana, Aškerčeva 6, Ljubljana, Slovenia
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