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Huang Q, Zhou Y, Li K, Pan L, Liu Y, Bai J, Ji X. Parameter effects on arterial vessel sonicated by high-intensity focused ultrasound: an ex vivo vascular phantom study. Phys Med Biol 2022; 67. [DOI: 10.1088/1361-6560/ac910c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 09/09/2022] [Indexed: 11/11/2022]
Abstract
Abstract
Objective. This study is aimed to explore the effects of vascular and sonication parameters on ex vivo vessel sonicated by high-intensity focused ultrasound. Approach. The vascular phantom embedding the polyolefin tube or ex vivo vessel was sonicated. The vascular phantom with 1.6 and 3.2 mm tubes was sonicated at three acoustic powers (2.0, 3.5, 5.3 W). The occlusion level of post-sonication tubes was evaluated using ultrasound imaging. The vascular phantom with the ex vivo abdominal aorta of rabbit for three flow rates (0, 5, 10 cm s−1) was sonicated at two acoustic powers (3.5 and 5.3 W). Different distances between focus and posterior wall (2, 4, 6 mm) and cooling times (0 and 10 s) were also evaluated. The diameter of the sonicated vessel was measured by B-mode imaging and microscopic photography. Histological examination was performed for the sonicated vessels. Main results. For the 5 cm s−1 flow rate, the contraction index of vascular diameter (Dc) with 5.3 W and 10 s cooling time at 2 mm distance was 39 ± 9% (n = 9). With the same parameters except for 0 cm s−1 flow rate, the Dc was increased to 45 ± 7% (n = 4). At 3.5 W, the Dc with 5 cm s−1 flow rate was 23 ± 15% (n = 4). The distance and cooling time influenced the lesion along the vessel wall. Significance. This study has demonstrated the flow rate and acoustic power have the great impact on the vessel contraction. Besides, the larger lesion covering the vessel wall would promote the vessel contraction. And the in vivo validation is required in the future study.
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Lee TJ, Kim D, Kim T, Pak CJ, Suh HP, Hong JP. Rejuvenation of photoaged aged mouse skin using high intensity focused ultrasound. J Plast Reconstr Aesthet Surg 2022; 75:3859-3868. [DOI: 10.1016/j.bjps.2022.06.073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 06/06/2022] [Indexed: 11/16/2022]
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Development of temperature controller-integrated portable HIFU driver for thermal coagulation. Biomed Eng Online 2019; 18:77. [PMID: 31242902 PMCID: PMC6595699 DOI: 10.1186/s12938-019-0697-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 06/21/2019] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Temperature monitoring during high-intensity focused ultrasound (HIFU) therapy on tissue is essential to regulate the degree of thermal coagulation and to achieve the desired treatment outcomes eventually. The aim of the current study was to design and investigate the feasibility of a proportional-integral-derivative (PID) temperature controller-integrated portable HIFU driver for thermal coagulation. METHODS A portable HIFU driver was designed and operated at a maximum output voltage of 50 V with pulse-width modulation signals at 2 MHz. The temperature of ex vivo bovine liver tissue was monitored using a K-type thermocouple during the 2-MHz HIFU exposure. RESULTS The tissue temperature was maintained at 60 °C using a PID controller-integrated HIFU driver that modulated the output voltage during the 300-s HIFU exposure. The ex vivo testing demonstrated that the tissue temperature at the focal point approached the chosen temperature, i.e., 60 °C, within 70 s. The temperature was maintained with a deviation of less than 4 °C until the HIFU driver voltage was turned off at 300 s. CONCLUSIONS The designed PID controller-integrated HIFU driver can be used as a small portable tool to regulate the tissue temperature in real time and achieve thermal coagulation via HIFU sonication.
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Chang W, Lee JY, Lee JH, Bae JS, Cho YJ, Kang KJ, Son K, Chung YR, Lee KB, Han JK. A portable high-intensity focused ultrasound system for the pancreas with 3D electronic steering: a preclinical study in a swine model. Ultrasonography 2018; 37:298-306. [PMID: 29166762 PMCID: PMC6177688 DOI: 10.14366/usg.17048] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 10/11/2017] [Accepted: 10/13/2017] [Indexed: 12/22/2022] Open
Abstract
PURPOSE The aim of this animal study was to evaluate the safety and feasibility of a portable, ultrasonography-guided, high-intensity focused ultrasound (USg-HIFU) system to treat the pancreas. METHODS Eight swine were included. Using a portable HIFU device (ALPIUS 900, Alpinion Medical Systems), ablations were performed on the pancreas in vivo. Different acoustic intensities were applied (1.7 kW/cm2 or 1.5 kW/cm2 , n=2 [group A for a pilot study]; 1.5 kW/ cm2 , n=3 [group B]; and 1.2 kW/cm2 , n=3 [group C]). Magnetic resonance imaging (MRI) was performed immediately (group A) or 7 days (groups B and C) after HIFU treatment. In groups B and C, serum amylase and lipase levels were measured on days 0 and 7, and performance status was observed every day. Necropsy was performed on days 0 (group A) or 7 (groups B and C) to assess the presence of unintended injuries and to obtain pancreatic and peripancreatic tissue for histological analysis. RESULTS Ablation was noted in the pancreas in all swine on MRI, and all pathologic specimens showed coagulation necrosis in the treated area. The mean ablation areas on MRI were 85.3±38.1 mm2, 90.7±21.2 mm2, and 54.4±30.6 mm2 in groups A, B, and C, respectively (P>0.05). No animals showed evidence of complications, except for one case of a pseudocyst in group B. CONCLUSION This study showed that pancreas ablation using a portable USg-HIFU system may be safe and feasible, and that coagulation necrosis of the pancreas was successfully achieved with a range of acoustic intensities.
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Affiliation(s)
- Won Chang
- Department of Radiology, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Jae Young Lee
- Department of Radiology and the Institute of Radiation Medicine, Seoul National University Hospital, Seoul, Korea
| | - Jae Hwan Lee
- Department of Radiology, National Cancer Center, Goyang, Korea
| | - Jae Seok Bae
- Department of Radiology, Seoul National University Hospital, Seoul, Korea
| | - Yeon Jin Cho
- Department of Radiology, Seoul National University Hospital, Seoul, Korea
| | - Kook Jin Kang
- Therapeutic Ultrasound Division, Alpinion Medical Systems Co., Ltd., Seoul, Korea
| | - Keonho Son
- Therapeutic Ultrasound Division, Alpinion Medical Systems Co., Ltd., Seoul, Korea
| | - Yul Ri Chung
- Department of Pathology, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Kyoung Bun Lee
- Department of Pathology, Seoul National University Hospital, Seoul, Korea
| | - Joon Koo Han
- Department of Radiology and the Institute of Radiation Medicine, Seoul National University Hospital, Seoul, Korea
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Ahn M, Chae YG, Hwang J, Ahn YC, Kang HW. Endoluminal application of glass-capped diffuser for ex vivo endovenous photocoagulation. JOURNAL OF BIOPHOTONICS 2017; 10:997-1007. [PMID: 27507115 DOI: 10.1002/jbio.201500331] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Endovenous laser ablation (EVLA) has frequently been used to treat varicose veins for 20 years. In spite of 90˜95% occlusion rates, clinical complications such as burn and ecchymosis still occur due to excessive thermal injury to perivenous tissue. In the current study, a glass-capped diffusing applicator is designed to validate the feasibility of EVLA as an effective therapeutic device by applying circumferential light distribution. The proposed device is evaluated with a flat fiber as a reference in terms of temperature elevation, fiber degradation, and degree of coagulative necrosis after 532 nm-assisted EVLA at 100 J/cm. The diffusing fiber generates a 40% lower maximum temperature with a 90% lower transient temperature change in blood, compared to the flat fiber. Due to low irradiance (13.5 kW/cm2 ) and wide light distribution, the diffuser tip experiences no significant thermal degradation while severe carbonization occurs at the flat fiber tip. Ex vivo tissue tests verify that the diffusing fiber induces circumferential and consistent tissue denaturation to the vein wall (107.8 ± 7.8 µm) along with 19% vessel shrinkage. The proposed glass-capped diffusing applicator can be a feasible therapeutic device for EVLA with minimal complications by entailing low maximum temperatures and uniform tissue denaturation in the venous tissue.
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Affiliation(s)
- Minwoo Ahn
- Department of Biomedical Engineering, Pukyong National University, Busan, 608-737, Korea
| | - Yu-Gyeong Chae
- Interdisciplinary Program of Marine-Bio, Electrical & Mechanical Engineering, Pukyong National University, Busan, 608-737, Korea
- Center for Marine-Integrated Biomedical Technology (BK21 Plus), Pukyong National University, Busan, 608-737, Korea
| | - Jieun Hwang
- Department of Biomedical Engineering, Pukyong National University, Busan, 608-737, Korea
| | - Yeh-Chan Ahn
- Department of Biomedical Engineering, Pukyong National University, Busan, 608-737, Korea
- Interdisciplinary Program of Marine-Bio, Electrical & Mechanical Engineering, Pukyong National University, Busan, 608-737, Korea
- Center for Marine-Integrated Biomedical Technology (BK21 Plus), Pukyong National University, Busan, 608-737, Korea
| | - Hyun Wook Kang
- Department of Biomedical Engineering, Pukyong National University, Busan, 608-737, Korea
- Interdisciplinary Program of Marine-Bio, Electrical & Mechanical Engineering, Pukyong National University, Busan, 608-737, Korea
- Center for Marine-Integrated Biomedical Technology (BK21 Plus), Pukyong National University, Busan, 608-737, Korea
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Kim MS, Kim JY, Noh SC, Choi HH. Thermal characteristics of non-biological vessel phantoms for treatment of varicose veins using high-intensity focused ultrasound. PLoS One 2017; 12:e0174922. [PMID: 28384210 PMCID: PMC5383065 DOI: 10.1371/journal.pone.0174922] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 03/18/2017] [Indexed: 11/18/2022] Open
Abstract
The ultrasonic treatment of varicose veins uses high-intensity focused ultrasound, in which a blood vessel is contracted by converting acoustic energy into thermal energy. In this study, we propose a phantom of varicose veins that can be applied for the efficient evaluation of ultrasonic treatment in varicose veins. The proposed phantom consisted of glycerol base tissue equivalent material, vessel mimic tube, and blood mimic substances. The vessel mimic tube was placed inner glycerol phantom and it was filled with blood mimic substances. Blood-mimicked substances are prepared by adjusting the concentration of the glycerol solution to be similar to the acoustic properties of the blood, and vessel-mimicking materials are selected by measuring acoustic properties and thermal shrinkage of various materials in a heat-shrinkable tube. The blood vessels surrounding the tissue are replaced with the phantom similar to glycerol-based organization, and venous blood flow is implemented using a DC motor. The heating characteristics according to the ultrasonic wave using the manufactured varicose veins phantom were evaluated. As the sound wave irradiation time and power increased, the contractility of the vessel mimicking materials and the temperature of the surrounding tissues were increased. When the blood-mimicking material was circulated, the highest temperature in the focused region and the contractility of vessel mimicking materials were reduced under the same conditions as used for sonication. The manufactured phantom may contribute to the treatment of varicose veins and can be used to predict the ultrasonic therapeutic efficiency of varicose veins.
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Affiliation(s)
- Mi-sun Kim
- Medical Device Evaluation Department, National Institute of Food and Drug Safety Evaluation, Cheongju, Chungcheongbuk-do, Korea
| | - Ju-Young Kim
- Department of Biomedical Engineering, Inje University, Gimhae, Kyoungsangnam-do, Korea
| | - Si-Cheol Noh
- Department of Radiological Science, International University of Korea, Jinju, Kyoungsangnam-do, Korea
| | - Heung-Ho Choi
- Department of Biomedical Engineering, Inje University, Gimhae, Kyoungsangnam-do, Korea
- * E-mail:
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Bazzocchi A, Napoli A, Sacconi B, Battista G, Guglielmi G, Catalano C, Albisinni U. MRI-guided focused ultrasound surgery in musculoskeletal diseases: the hot topics. Br J Radiol 2015; 89:20150358. [PMID: 26607640 DOI: 10.1259/bjr.20150358] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
MRI-guided focused ultrasound surgery (MRgFUS) is a minimally invasive treatment guided by the most sophisticated imaging tool available in today's clinical practice. Both the imaging and therapeutic sides of the equipment are based on non-ionizing energy. This technique is a very promising option as potential treatment for several pathologies, including musculoskeletal (MSK) disorders. Apart from clinical applications, MRgFUS technology is the result of long, heavy and cumulative efforts exploring the effects of ultrasound on biological tissues and function, the generation of focused ultrasound and treatment monitoring by MRI. The aim of this article is to give an updated overview on a "new" interventional technique and on its applications for MSK and allied sciences.
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Affiliation(s)
- Alberto Bazzocchi
- 1 Diagnostic and Interventional Radiology, The "Rizzoli" Orthopaedic Institute, Bologna, Italy
| | - Alessandro Napoli
- 2 Department of Radiology, Sapienza University of Rome, Umberto I Hospital, Rome, Italy
| | - Beatrice Sacconi
- 2 Department of Radiology, Sapienza University of Rome, Umberto I Hospital, Rome, Italy
| | - Giuseppe Battista
- 3 Department of Specialized, Diagnostic, and Experimental Medicine, University of Bologna, Sant'Orsola-Malpighi Hospital, Bologna, Italy
| | - Giuseppe Guglielmi
- 4 Department of Radiology, University of Foggia, Foggia, Italy.,5 Department of Radiology, Scientific Institute "Casa Sollievo della Sofferenza" Hospital, Foggia, Italy
| | - Carlo Catalano
- 2 Department of Radiology, Sapienza University of Rome, Umberto I Hospital, Rome, Italy
| | - Ugo Albisinni
- 1 Diagnostic and Interventional Radiology, The "Rizzoli" Orthopaedic Institute, Bologna, Italy
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Shaw CJ, ter Haar GR, Rivens IH, Giussani DA, Lees CC. Pathophysiological mechanisms of high-intensity focused ultrasound-mediated vascular occlusion and relevance to non-invasive fetal surgery. J R Soc Interface 2014; 11:20140029. [PMID: 24671935 PMCID: PMC4006242 DOI: 10.1098/rsif.2014.0029] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 03/06/2014] [Indexed: 12/27/2022] Open
Abstract
High-intensity focused ultrasound (HIFU) is a non-invasive technology, which can be used occlude blood vessels in the body. Both the theory underlying and practical process of blood vessel occlusion are still under development and relatively sparse in vivo experimental and therapeutic data exist. HIFU would however provide an alternative to surgery, particularly in circumstances where serious complications inherent to surgery outweigh the potential benefits. Accordingly, the HIFU technique would be of particular utility for fetal and placental interventions, where open or endoscopic surgery is fraught with difficulty and likelihood of complications including premature delivery. This assumes that HIFU could be shown to safely and effectively occlude blood vessels in utero. To understand these mechanisms more fully, we present a review of relevant cross-specialty literature on the topic of vascular HIFU and suggest an integrative mechanism taking into account clinical, physical and engineering considerations through which HIFU may produce vascular occlusion. This model may aid in the design of HIFU protocols to further develop this area, and might be adapted to provide a non-invasive therapy for conditions in fetal medicine where vascular occlusion is beneficial.
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Affiliation(s)
- C. J. Shaw
- Imperial College London, Hammersmith Campus, Du Cane Road, London W12 0HS, UK
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK
| | - G. R. ter Haar
- Joint Department of Physics, Institute of Cancer Research: Royal Marsden NHSF Trust, Downs Road, Sutton, Surrey SM2 5PT, UK
| | - I. H. Rivens
- Joint Department of Physics, Institute of Cancer Research: Royal Marsden NHSF Trust, Downs Road, Sutton, Surrey SM2 5PT, UK
| | - D. A. Giussani
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK
| | - C. C. Lees
- Imperial College London, Hammersmith Campus, Du Cane Road, London W12 0HS, UK
- Department of Obstetrics and Gynaecology, University Hospitals Leuven, Campus Gasthuisberg, KU Leuven, Belgium
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Chen BT, Shieh J, Huang CW, Chen WS, Chen SR, Chen CS. Ultrasound thermal mapping based on a hybrid method combining physical and statistical models. ULTRASOUND IN MEDICINE & BIOLOGY 2014; 40:115-129. [PMID: 24210856 DOI: 10.1016/j.ultrasmedbio.2013.09.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2012] [Revised: 09/09/2013] [Accepted: 09/10/2013] [Indexed: 06/02/2023]
Abstract
Non-invasive temperature measurement of tissues deep inside the body has great potential for clinical applications, such as temperature monitoring during thermal therapy and early diagnosis of diseases. We developed a novel method for both temperature estimation and thermal mapping that uses ultrasound B-mode radiofrequency data. The proposed method is a hybrid that combines elements of physical and statistical models to achieve higher precision and resolution of temperature variations and distribution. We propose a dimensionless combined index (CI) that combines the echo shift differential and signal intensity difference with a weighting factor relative to the distance from the heat source. In vitro experiments verified that the combined index has a strong linear relationship with temperature variation and can be used to effectively estimate temperature with an average relative error <5%. This algorithm provides an alternative for imaging guidance-based techniques during thermal therapy and could easily be integrated into existing ultrasound systems.
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Affiliation(s)
- Ben-Ting Chen
- Department of Civil Engineering, Chung Yuan Christian University, Chung Li, Taiwan
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Tokarczyk A, Rivens I, van Bavel E, Symonds-Tayler R, ter Haar G. An experimental system for the study of ultrasound exposure of isolated blood vessels. Phys Med Biol 2013; 58:2281-304. [PMID: 23478592 DOI: 10.1088/0031-9155/58/7/2281] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
An experimental system designed for the study of the effects of diagnostic or therapeutic ultrasound exposure on isolated blood vessels in the presence or absence of intraluminal contrast agent is described. The system comprised several components. A microscope was used to monitor vessel size (and thus vessel functionality), and potential leakage of intraluminal 70 kDa FITC-dextran fluorescence marker. A vessel chamber allowed the mounting of an isolated vessel whilst maintaining its viability, with pressure regulation for the control of intraluminal pressure and induction of flow for the infusion of contrast microbubbles. A fibre-optic hydrophone sensor mounted on the vessel chamber using a micromanipulator allowed pre-exposure targeting of the vessel to within 150 µm, and monitoring of acoustic cavitation emissions during exposures. Acoustic cavitation was also detected using changes in the ultrasound drive voltage and by detection of audible emissions using a submerged microphone. The suitability of this system for studying effects in the isolated vessel model has been demonstrated using a pilot study of 6 sham exposed and 18 high intensity focused ultrasound exposed vessels, with or without intraluminal contrast agent (SonoVue) within the vessels.
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Affiliation(s)
- Anna Tokarczyk
- Therapeutic Ultrasound, Joint Department of Physics, Royal Marsden NHS Foundation Trust: Institute of Cancer Research, Downs Road, Sutton, Surrey, SM2 5PT, UK
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Lewis GK, Schulz ZR, Pannullo SC, Southard TL, Olbricht WL. Ultrasound-assisted convection-enhanced delivery to the brain in vivo with a novel transducer cannula assembly: laboratory investigation. J Neurosurg 2012; 117:1128-40. [PMID: 22998056 DOI: 10.3171/2012.7.jns11144] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT In convection-enhanced delivery (CED), drugs are infused locally into tissue through a cannula inserted into the brain parenchyma to enhance drug penetration over diffusion strategies. The purpose of this study was to demonstrate the feasibility of ultrasound-assisted CED (UCED) in the rodent brain in vivo using a novel, low-profile transducer cannula assembly (TCA) and portable, pocket-sized ultrasound system. METHODS Forty Sprague-Dawley rats (350-450 g) were divided into 2 equal groups (Groups 1 and 2). Each group was divided again into 4 subgroups (n = 5 in each). The caudate of each rodent brain was infused with 0.25 wt% Evans blue dye (EBD) in phosphate-buffered saline at 2 different infusion rates of 0.25 μl/minute (Group 1), and 0.5 μl/minute (Group 2). The infusion rates were increased slowly over 10 minutes from 0.05 to 0.25 μl/minute (Group 1) and from 0.1 to 0.5 μl/minute (Group 2). The final flow rate was maintained for 20 minutes. Rodents in the 4 control subgroups were infused using the TCA without ultrasound and without and with microbubbles added to the infusate (CED and CED + MB, respectively). Rodents in the 4 UCED subgroups were infused without and with microbubbles added to the infusate (UCED and UCED + MB) using the TCA with continuous-wave 1.34-MHz low-intensity ultrasound at a total acoustic power of 0.11 ± 0.005 W and peak spatial intensity at the cannula tip of 49.7 mW/cm(2). An additional 4 Sprague-Dawley rats (350-450 g) received UCED at 4 different and higher ultrasound intensities at the cannula tip ranging from 62.0 to 155.0 mW/cm(2) for 30 minutes. The 3D infusion distribution was reconstructed using MATLAB analysis. Tissue damage and morphological changes to the brain were assessed using H & E. RESULTS The application of ultrasound during infusion (UCED and UCED + MB) improved the volumetric distribution of EBD in the brain by a factor of 2.24 to 3.25 when there were no microbubbles in the infusate and by a factor of 1.16 to 1.70 when microbubbles were added to the infusate (p < 0.001). On gross and histological examination, no damage to the brain tissue was found for any acoustic exposure applied to the brain. CONCLUSIONS The TCA and ultrasound device show promise to improve the distribution of infused compounds during CED. The results suggest further studies are required to optimize infusion and acoustic parameters for small compounds and for larger molecular weight compounds that are representative of promising antitumor agents. In addition, safe levels of ultrasound exposure in chronic experiments must be determined for practical clinical evaluation of UCED. Extension of these experiments to larger animal models is warranted to demonstrate efficacy of this technique.
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Affiliation(s)
- George K Lewis
- Department of Biomedical Engineering, Cornell University, Ithaca, New York, USA.
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Chen WS, Shen CC, Wang JC, Ko CT, Liu HL, Ho MC, Chen CN, Yeh CK. Single-element ultrasound transducer for combined vessel localization and ablation. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2011; 58:766-775. [PMID: 21507754 DOI: 10.1109/tuffc.2011.1869] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
This report describes a system that utilizes a single high-intensity focused ultrasound (HIFU) transducer for both the localization and ablation of arteries with internal diameters of 0.5 and 1.3 mm. In vitro and in vivo tests were performed to demonstrate both the imaging and ablation functionalities of this system. For imaging mode, pulsed acoustic waves (3 cycles for in vitro and 10 cycles for in vivo tests, 2 MPa peak pressure) were emitted from the 2-MHz HIFU transducer, and the backscattered ultrasonic signal was collected by the same transducer to calculate Doppler shifts in the target region. The maximum signal amplitude of the Doppler shift was used to determine the location of the target vessel. The operation mode was then switched to the therapeutic mode and vessel occlusion was successfully produced by high-intensity continuous HIFU waves (12 MPa) for 60 s. The system was then switched back to imaging mode for residual flow to determine the need for a second ablation treatment. The new system might be used to target and occlude unwanted vessels such as vasculature around tumors, and to help with tumor destruction.
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Affiliation(s)
- Wen-Shiang Chen
- Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital, and National Taiwan University College of Medicine, Taipei, Taiwan
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Driving circuitry for focused ultrasound noninvasive surgery and drug delivery applications. SENSORS 2011; 11:539-56. [PMID: 22346589 PMCID: PMC3274078 DOI: 10.3390/s110100539] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 12/10/2010] [Accepted: 01/04/2011] [Indexed: 11/17/2022]
Abstract
Recent works on focused ultrasound (FUS) have shown great promise for cancer therapy. Researchers are continuously trying to improve system performance, which is resulting in an increased complexity that is more apparent when using multi-element phased array systems. This has led to significant efforts to reduce system size and cost by relying on system integration. Although ideas from other fields such as microwave antenna phased arrays can be adopted in FUS, the application requirements differ significantly since the frequency range used in FUS is much lower. In this paper, we review recent efforts to design efficient power monitoring, phase shifting and output driving techniques used specifically for high intensity focused ultrasound (HIFU).
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Time-reversal Techniques in Ultrasound-assisted Convection-enhanced Drug Delivery to the Brain: Technology Development and In Vivo Evaluation. PROCEEDINGS OF MEETINGS ON ACOUSTICS. ACOUSTICAL SOCIETY OF AMERICA 2011; 11:20005-20031. [PMID: 21881622 DOI: 10.1121/1.3616358] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We describe a drug delivery method that combines Time-Reversal Acoustics (TRA) with Convection-Enhanced Delivery (CED) to improve the delivery of therapeutics to the interstitium of the brain. The Ultrasound-assisted CED approach (UCED) circumvents the blood-brain barrier by infusing compounds through a cannula that is inserted into the brain while simultaneously delivering ultrasound to improve the penetration of pharmaceuticals. CED without ultrasound-assistance has been used to treat a variety of neural disorders, including glioblastoma multiforme, a malignancy that presents a very poor prognosis for patients. We describe a novel system that is used to infuse fluids into the brain parenchyma while simultaneously exposing the tissue to safe levels of 1-MHz, low intensity, ultrasound energy. The system includes a combined infusion needle-hydrophone, a 10-channel ultralow-output impedance amplifier, a broad-band ultrasound resonator, and MatLab®-based TRA control and user-interface. TRA allows easy coupling of ultrasound therapy through the skull without complex phase-correction and array design. The smart targeting UCED system has been tested in vivo and results show it provides 1.5-mm spatial resolution for UCED and improves tracer distribution in the brain over CED alone.
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