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Antoniou A, Damianou C. Feasibility of Ultrasonic Heating through Skull Phantom Using Single-element Transducer. J Med Ultrasound 2024; 32:32-40. [PMID: 38665339 PMCID: PMC11040484 DOI: 10.4103/jmu.jmu_3_23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 03/14/2023] [Accepted: 03/31/2023] [Indexed: 04/28/2024] Open
Abstract
Background Noninvasive neurosurgery has become possible through the use of transcranial focused ultrasound (FUS). This study assessed the heating ability of single element spherically focused transducers operating at 0.4 and 1.1 MHz through three-dimensional (3D) printed thermoplastic skull phantoms. Methods Phantoms with precise skull bone geometry of a male patient were 3D printed using common thermoplastic materials following segmentation on a computed tomography head scan image. The brain tissue was mimicked by an agar-based gel phantom developed in-house. The selection of phantom materials was mainly based on transmission-through attenuation measurements. Phantom sonications were performed through water, and then, with the skull phantoms intervening the beam path. In each case, thermometry was performed at the focal spot using thermocouples. Results The focal temperature change in the presence of the skull phantoms was reduced to less than 20 % of that recorded in free field when using the 0.4 MHz transducer, whereas the 1.1 MHz trans-skull sonication produced minimal or no change in focal temperature. The 0.4 MHz transducer showed better performance in trans-skull transmission but still not efficient. Conclusion The inability of both tested single element transducers to steer the beam through the high attenuating skull phantoms and raise the temperature at the focus was confirmed, underlying the necessity to use a correction technique to compensate for energy losses, such those provided by phased arrays. The proposed phantom could be used as a cost-effective and ergonomic tool for trans-skull FUS preclinical studies.
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Affiliation(s)
- Anastasia Antoniou
- Department of Electrical Engineering, Computer Engineering and Informatics, Cyprus University of Technology, Limassol, Cyprus
| | - Christakis Damianou
- Department of Electrical Engineering, Computer Engineering and Informatics, Cyprus University of Technology, Limassol, Cyprus
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Evripidou N, Antoniou A, Georgiou L, Ioannides C, Spanoudes K, Damianou C. MRI compatibility testing of commercial high intensity focused ultrasound transducers. Phys Med 2024; 117:103194. [PMID: 38048730 DOI: 10.1016/j.ejmp.2023.103194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 11/20/2023] [Accepted: 11/28/2023] [Indexed: 12/06/2023] Open
Abstract
PURPOSE The study aimed to compare the performance of eight commercially available single-element High Intensity Focused Ultrasound (HIFU) transducers in terms of Magnetic Resonance Imaging (MRI) compatibility. METHODS Imaging of an agar-based MRI phantom was performed in a 3 T MRI scanner utilizing T2-Weighted Fast Spin Echo (FSE) and Fast low angle shot (FLASH) sequences, which are typically employed for high resolution anatomical imaging and thermometry, respectively. Reference magnitude and phase images of the phantom were compared with images acquired in the presence of each transducer in terms of the signal to noise ratio (SNR), introduced artifacts, and overall image quality. RESULTS The degree of observed artifacts highly differed among the various transducers. The transducer whose backing material included magnetic impurities showed poor performance in the MRI, introducing significant susceptibility artifacts such as geometric distortions and signal void bands. Additionally, it caused the most significant SNR drop. Other transducers were shown to exhibit high level of MRI compatibility as the resulting images closely resembled the reference images with minimal to no apparent artifacts and comparable SNR values. CONCLUSIONS The study findings may facilitate researchers to select the most suitable transducer for their research, simultaneously avoiding unnecessary testing. The study further provides useful design considerations for MRI compatible transducers.
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Affiliation(s)
- Nikolas Evripidou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
| | - Anastasia Antoniou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
| | - Leonidas Georgiou
- Department of Interventional Radiology, German Oncology Center, Limassol, Cyprus
| | - Cleanthis Ioannides
- Department of Interventional Radiology, German Oncology Center, Limassol, Cyprus
| | | | - Christakis Damianou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus.
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Antoniou A, Evripidou N, Georgiou L, Chrysanthou A, Ioannides C, Damianou C. Tumor phantom model for MRI-guided focused ultrasound ablation studies. Med Phys 2023; 50:5956-5968. [PMID: 37226334 DOI: 10.1002/mp.16480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 03/24/2023] [Accepted: 05/02/2023] [Indexed: 05/26/2023] Open
Abstract
BACKGROUND The persistent development of focused ultrasound (FUS) thermal therapy in the context of oncology creates the need for tissue-mimicking tumor phantom models for early-stage experimentation and evaluation of relevant systems and protocols. PURPOSE This study presents the development and evaluation of a tumor-bearing tissue phantom model for testing magnetic resonance imaging (MRI)-guided FUS (MRgFUS) ablation protocols and equipment based on MR thermometry. METHODS Normal tissue was mimicked by a pure agar gel, while the tumor simulator was differentiated from the surrounding material by including silicon dioxide. The phantom was characterized in terms of acoustic, thermal, and MRI properties. US, MRI, and computed tomography (CT) images of the phantom were acquired to assess the contrast between the two compartments. The phantom's response to thermal heating was investigated by performing high power sonications with a 2.4 MHz single element spherically focused ultrasonic transducer in a 3T MRI scanner. RESULTS The estimated phantom properties fall within the range of literature-reported values of soft tissues. The inclusion of silicon dioxide in the tumor material offered excellent tumor visualization in US, MRI, and CT. MR thermometry revealed temperature elevations in the phantom to ablation levels and clear evidence of larger heat accumulation within the tumor owing to the inclusion of silicon dioxide. CONCLUSION Overall, the study findings suggest that the proposed tumor phantom model constitutes a simple and inexpensive tool for preclinical MRgFUS ablation studies, and potentially other image-guided thermal ablation applications upon minimal modifications.
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Affiliation(s)
- Anastasia Antoniou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
| | - Nikolas Evripidou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
| | - Leonidas Georgiou
- Department of Interventional Radiology, German Oncology Center, Limassol, Cyprus
| | - Antreas Chrysanthou
- Department of Interventional Radiology, German Oncology Center, Limassol, Cyprus
| | - Cleanthis Ioannides
- Department of Interventional Radiology, German Oncology Center, Limassol, Cyprus
| | - Christakis Damianou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
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Antoniou A, Nikolaou A, Evripidou N, Georgiou A, Filippou A, Zinonos V, Giannakou M, Chrysanthou A, Ioannides C, Damianou C. Phantom-based assessment of motion and needle targeting accuracy of robotic devices for magnetic resonance imaging-guided needle biopsy. Int J Med Robot 2023; 19:e2526. [PMID: 37165718 DOI: 10.1002/rcs.2526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 04/18/2023] [Accepted: 04/24/2023] [Indexed: 05/12/2023]
Abstract
BACKGROUND The current study proposes simple methods for assessing the performance of robotic devices intended for Magnetic Resonance Imaging (MRI)-guided needle biopsy. METHODS In-house made agar-based breast phantoms containing biopsy targets served as the main tool in the evaluation process of an MRI compatible positioning device comprising a needle navigator. The motion accuracy of mechanical stages was assessed by calliper measurements. Laboratory evaluation of needle targeting included a repeatability phantom test and a laser-based method. The accuracy and repeatability of needle targeting was also assessed by MRI. RESULTS The maximum error of linear motion for steps up to 10 mm was 0.1 mm. Needle navigation relative to the phantom and alignment with the various biopsy targets were performed successfully in both the laboratory and MRI settings. The proposed biopsy phantoms offered tissue-like signal in MRI and good haptic feedback during needle insertion. CONCLUSIONS The proposed methods could be valuable in the process of validating the accuracy of MRI-guided biopsy robotic devices in both laboratory and real environments.
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Affiliation(s)
- Anastasia Antoniou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
| | - Anastasia Nikolaou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
| | - Nikolas Evripidou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
| | - Andreas Georgiou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
| | - Antria Filippou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
| | - Vasiliki Zinonos
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
| | | | - Antreas Chrysanthou
- Department of Interventional Radiology, German Oncology Center, Limassol, Cyprus
| | - Cleanthis Ioannides
- Department of Interventional Radiology, German Oncology Center, Limassol, Cyprus
| | - Christakis Damianou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
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Filippou A, Georgiou A, Nikolaou A, Evripidou N, Damianou C. Advanced software for MRgFUS treatment planning. Comput Methods Programs Biomed 2023; 240:107726. [PMID: 37480647 DOI: 10.1016/j.cmpb.2023.107726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Revised: 07/18/2023] [Accepted: 07/18/2023] [Indexed: 07/24/2023]
Abstract
BACKGROUND AND OBJECTIVES Herein, a user-friendly software platform for 3-dimensional Focused Ultrasound treatment planning based on Magnetic Resonance Imaging (MRI) images is presented. METHODS The software directly retrieves and loads MRI images. Various design tools can be used on the MRI images to define the treatment area and the sonication parameters. Based on the treatment plan, the software controls the robotic motion and motion pattern of Magnetic Resonance guided Focused Ultrasound (MRgFUS) robotic systems to execute the treatment procedure. Real-time treatment monitoring is achieved through MRI images and thermometry. The software's functionality and performance were evaluated in both laboratory and MRI environments. Different treatment plans were designed on MRI images and sonications were executed on agar-based phantoms and polymer films. RESULTS Magnetic Resonance (MR) thermometry maps were acquired in the agar-based phantoms. An exceptional agreement was observed between the software-planned treatment area and the lesions produced on the polymer films. CONCLUSIONS The developed software was successfully integrated with the MRI and robotic system controls for performing accurate treatment planning and real-time monitoring during sonications. The software provides an extremely user-friendly interface, while in the future it could be enhanced by providing dynamic modulation of the ultrasonic parameters during the treatment process.
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Affiliation(s)
- Antria Filippou
- Cyprus University of Technology, Department of Electrical Engineering, Computer Engineering, and Informatics, 30 Archbishop Kyprianou Str., Limassol 3036, Cyprus.
| | - Andreas Georgiou
- Cyprus University of Technology, Department of Electrical Engineering, Computer Engineering, and Informatics, 30 Archbishop Kyprianou Str., Limassol 3036, Cyprus
| | - Anastasia Nikolaou
- Cyprus University of Technology, Department of Electrical Engineering, Computer Engineering, and Informatics, 30 Archbishop Kyprianou Str., Limassol 3036, Cyprus.
| | - Nikolas Evripidou
- Cyprus University of Technology, Department of Electrical Engineering, Computer Engineering, and Informatics, 30 Archbishop Kyprianou Str., Limassol 3036, Cyprus.
| | - Christakis Damianou
- Cyprus University of Technology, Department of Electrical Engineering, Computer Engineering, and Informatics, 30 Archbishop Kyprianou Str., Limassol 3036, Cyprus.
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Filippou A, Evripidou N, Damianou C. Robotic system for magnetic resonance imaging-guided focused ultrasound treatment of thyroid nodules. Int J Med Robot 2023; 19:e2525. [PMID: 37149886 DOI: 10.1002/rcs.2525] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 04/23/2023] [Accepted: 04/24/2023] [Indexed: 05/09/2023]
Abstract
BACKGROUND Herein, a robotic system offering Magnetic Resonance-guided Focused Ultrasound (MRgFUS) therapy of thyroid nodules was developed. METHODS The robotic system offers linear motion in 2 PC-controlled axes that navigate a 3 MHz single-element focused transducer. The system, through a C-arm structure attaches to the table of Magnetic Resonance Imaging (MRI) scanners and couples to the neck of patients lying in the supine position. The MRI compatibility of the developed system was assessed inside a 3 T scanner. Benchtop and MRI feasibility studies evaluating the heating performance of the system were executed on excised pork tissue and on homogeneous and thyroid model agar-based phantoms. RESULTS The MRI compatibility of the system was successfully established. Grid sonications executed using robotic motion inflicted discrete and overlapping lesions on the excised tissue, while magnetic resonance (MR) thermometry successfully monitored thermal heating in agar-based phantoms. CONCLUSIONS The developed system was found to be efficient with ex-vivo evaluation. The system can perform clinical MRgFUS therapy of thyroid nodules and other shallow targets after further in-vivo evaluation.
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Affiliation(s)
- Antria Filippou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
| | - Nikolas Evripidou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
| | - Christakis Damianou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
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Antoniou A, Evripidou N, Damianou C. Focused ultrasound heating in brain tissue/skull phantoms with 1 MHz single-element transducer. J Ultrasound 2023:10.1007/s40477-023-00810-7. [PMID: 37517052 DOI: 10.1007/s40477-023-00810-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Accepted: 07/09/2023] [Indexed: 08/01/2023] Open
Abstract
PURPOSE The study aims to provide insights on the practicality of using single-element transducers for transcranial Focused Ultrasound (tFUS) thermal applications. METHODS FUS sonications were performed through skull phantoms embedding agar-based tissue mimicking gels using a 1 MHz single-element spherically focused transducer. The skull phantoms were 3D printed with Acrylonitrile Butadiene Styrene (ABS) and Resin thermoplastics having the exact skull bone geometry of a healthy volunteer. The temperature field distribution during and after heating was monitored in a 3 T Magnetic Resonance Imaging (MRI) scanner using MR thermometry. The effect of the skull's thickness on intracranial heating was investigated. RESULTS A single FUS sonication at focal acoustic intensities close to 1580 W/cm2 for 60 s in free field heated up the agar phantom to ablative temperatures reaching about 90 °C (baseline of 37 °C). The ABS skull strongly blocked the ultrasonic waves, resulting in zero temperature increase within the phantom. Considerable heating was achieved through the Resin skull, but it remained at hyperthermia levels. Conversely, tFUS through a 1 mm Resin skull showed enhanced ultrasonic penetration and heating, with the focal temperature reaching 70 °C. CONCLUSIONS The ABS skull demonstrated poorer performance in terms of tFUS compared to the Resin skull owing to its higher ultrasonic attenuation and porosity. The thin Resin phantom of 1 mm thickness provided an efficient acoustic window for delivering tFUS and heating up deep phantom areas. The results of such studies could be particularly useful for accelerating the establishment of a wider range of tFUS applications.
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Affiliation(s)
- Anastasia Antoniou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, 30 Archbishop Kyprianou Street, 3036, Limassol, Cyprus
| | - Nikolas Evripidou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, 30 Archbishop Kyprianou Street, 3036, Limassol, Cyprus
| | - Christakis Damianou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, 30 Archbishop Kyprianou Street, 3036, Limassol, Cyprus.
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Antoniou A, Stavrou M, Evripidou N, Georgiou E, Kousiappa I, Koupparis A, Papacostas SS, Kleopa KA, Damianou C. FUS-mediated blood-brain barrier disruption for delivering anti-Aβ antibodies in 5XFAD Alzheimer's disease mice. J Ultrasound 2023:10.1007/s40477-023-00805-4. [PMID: 37516718 DOI: 10.1007/s40477-023-00805-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Accepted: 06/28/2023] [Indexed: 07/31/2023] Open
Abstract
PURPOSE Amyloid-β (Aβ) peptides, the main component of amyloid plaques found in the Alzheimer's disease (AD) brain, are implicated in its pathogenesis, and are considered a key target in AD therapeutics. We herein propose a reliable strategy for non-invasively delivering a specific anti-Aβ antibody in a mouse model of AD by microbubbles-enhanced Focused Ultrasound (FUS)-mediated Blood-brain barrier disruption (BBBD), using a simple single stage MR-compatible positioning device. METHODS The initial experimental work involved wild-type mice and was devoted to selecting the sonication protocol for efficient and safe BBBD. Pulsed FUS was applied using a single-element FUS transducer of 1 MHz (80 mm radius of curvature and 50 mm diameter). The success and extent of BBBD were assessed by Evans Blue extravasation and brain damage by hematoxylin and eosin staining. 5XFAD mice were divided into different subgroups; control (n = 1), FUS + MBs alone (n = 5), antibody alone (n = 5), and FUS + antibody combined (n = 10). The changes in antibody deposition among groups were determined by immunohistochemistry. RESULTS It was confirmed that the antibody could not normally enter the brain parenchyma. A single treatment with MBs-enhanced pulsed FUS using the optimized protocol (1 MHz, 0.5 MPa in-situ pressure, 10 ms bursts, 1% duty factor, 100 s duration) transiently disrupted the BBB allowing for non-invasive antibody delivery to amyloid plaques within the sonicated brain regions. This was consistently reproduced in ten mice. CONCLUSION These preliminary findings should be confirmed by longer-term studies examining the antibody effects on plaque clearance and cognitive benefit to hold promise for developing disease-modifying anti-Aβ therapeutics for clinical use.
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Affiliation(s)
- Anastasia Antoniou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
| | - Marios Stavrou
- Department of Neurobiology, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Nikolas Evripidou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
| | - Elena Georgiou
- Department of Neuroscience, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Ioanna Kousiappa
- Department of Neurobiology, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Andreas Koupparis
- Department of Neurobiology, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Savvas S Papacostas
- Department of Neurobiology, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Kleopas A Kleopa
- Department of Neuroscience, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Christakis Damianou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus.
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Antoniou A, Spanoudes K, Damianou C. Treatment of mammary cancer with focused ultrasound: A pilot study in canine and feline patients. Ultrasonics 2023; 132:106974. [PMID: 36917874 DOI: 10.1016/j.ultras.2023.106974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 01/30/2023] [Accepted: 02/27/2023] [Indexed: 05/29/2023]
Abstract
In recent years, veterinary medicine has expanded its practices beyond conventional methods, gradually integrating the Focused Ultrasound (FUS) technology in the care of companion animals like dogs and cats. The current study aimed to examine the feasibility and provide insights into the application of thermal FUS in canine and feline mammary cancer therapy. FUS was delivered by a 2-MHz single-element spherically focused ultrasonic transducer as integrated with an existing robotic positioning device. The functionality of the FUS system and sonication protocol in efficiently and safely ablating live tissue was initially validated in a rabbit thigh model in a laboratory environment. Nine (9) dogs and cats with superficial mammary cancer were recruited through a dedicated campaign according to specific safety criteria. The veterinary patients underwent FUS ablation followed by immediate surgical resection of the entire malignancy. Histopathology examination demonstrated well-defined regions of coagulative necrosis in all treated tumors with no off-target damage. Further study with a larger patient population is needed to confirm the current findings and demonstrate the safety and feasibility of complete FUS ablation of deep-seated tumors.
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Affiliation(s)
- Anastasia Antoniou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus.
| | - Kyriakos Spanoudes
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus.
| | - Christakis Damianou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus.
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Drakos T, Evripidou G, Damianou C. An in vitro Model for Experimental Evaluation of Sonothrombolysis under Tissue-mimicking Material Conditions. J Med Ultrasound 2023; 31:211-217. [PMID: 38025011 PMCID: PMC10668898 DOI: 10.4103/jmu.jmu_52_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Revised: 07/12/2022] [Accepted: 08/10/2022] [Indexed: 12/01/2023] Open
Abstract
Background The mechanical properties of therapeutic ultrasound (US) have attracted scientific interest for thrombolysis enhancement in combination with thrombolytic agents and microbubbles (MBs). The aim of the study was to develop an in vitro model to observe how the effects of sonothrombolysis change in the case where a tissue-mimicking material (TMM) is placed in the path of the US beam before the clot. Methods Fully retracted blood clots were prepared and pulse sonicated for 1 h under various conditions. The system was in a state of real circulating flow with a branch of an open bypass and an occluded tube containing a blood clot, thus mimicking the case of ischemic stroke. The effectiveness of thrombolysis was quantified in milligrams of clots removed. An agar-based TMM was developed around the occluded tube. Results The clot breakdown in a TMM was found to be more pronounced than in water, presumably due to the retention of the acoustic field. A higher level of acoustic power was required to initiate clot lysis (>76 W acoustic power) using only focused US (FUS). The greatest thrombolysis enhancement was observed with the largest chosen pulse duration (PD) and the use of MBs (150 mg clot mass lysis). The synergistic effect of FUS in combination with MBs on the enzymatic fibrinolysis enhanced thrombolysis efficacy by 260% compared to thrombolysis induced using only FUS. A reduction in the degree of clot lysis was detected due to the attenuation factor of the intervening material (30 mg at 1 and 4 ms PD). Conclusion In vitro thrombolytic models including a TMM can provide a more realistic evaluation of new thrombolytic protocols. However, higher acoustic power should be considered to compensate for the attenuation factor. The rate of clot lysis is slow and the clinical use of this method will be challenging.
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Affiliation(s)
| | - Georgios Evripidou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
| | - Christakis Damianou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
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Antoniou A, Nikolaou A, Georgiou A, Evripidou N, Damianou C. Development of an US, MRI, and CT imaging compatible realistic mouse phantom for thermal ablation and focused ultrasound evaluation. Ultrasonics 2023; 131:106955. [PMID: 36854247 DOI: 10.1016/j.ultras.2023.106955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 11/09/2022] [Accepted: 02/10/2023] [Indexed: 06/18/2023]
Abstract
Tissue mimicking phantoms (TMPs) play an essential role in modern biomedical research as cost-effective quality assurance and training tools, simultaneously contributing to the reduction of animal use. Herein, we present the development and evaluation of an anatomically accurate mouse phantom intended for image-guided thermal ablation and Focused Ultrasound (FUS) applications. The proposed mouse model consists of skeletal and soft tissue mimics, whose design was based on the Computed tomography (CT) scans data of a live mouse. Advantageously, it is compatible with US, CT, and Magnetic Resonance Imaging (MRI). The compatibility assessment was focused on the radiological behavior of the phantom due to the lack of relevant literature. The X-ray linear attenuation coefficient of candidate materials was estimated to assess the one that matches best the radiological behavior of living tissues. The bone part was manufactured by Fused Deposition Modeling (FDM) printing using Acrylonitrile styrene acrylate (ASA) material. For the soft-tissue mimic, a special mold was 3D printed having a cavity with the unique shape of the mouse body and filled with an agar-based silica-doped gel. The mouse phantom accurately matched the size and reproduced the body surface of the imaged mouse. Tissue-equivalency in terms of X-ray attenuation was demonstrated for the agar-based soft-tissue mimic. The phantom demonstrated excellent MRI visibility of the skeletal and soft-tissue mimics. Good radiological contrast between the skeletal and soft-tissue models was also observed in the CT scans. The model was also able to reproduce realistic behavior during trans-skull sonication as proved by thermocouple measurements. Overall, the proposed phantom is inexpensive, ergonomic, and realistic. It could constitute a powerful tool for image-guided thermal ablation and FUS studies in terms of testing and optimizing the performance of relevant equipment and protocols. It also possess great potential for use in transcranial FUS applications, including the emerging topic of FUS-mediated blood brain barrier (BBB) disruption.
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Affiliation(s)
- Anastasia Antoniou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus.
| | - Anastasia Nikolaou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus.
| | - Andreas Georgiou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus.
| | - Nikolas Evripidou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus.
| | - Christakis Damianou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus.
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Sotiriou M, Damianou C. Evaluating acoustic and thermal properties of a plaque phantom. J Ultrasound 2023:10.1007/s40477-023-00778-4. [PMID: 37031317 DOI: 10.1007/s40477-023-00778-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Accepted: 02/07/2023] [Indexed: 04/10/2023] Open
Abstract
PURPOSE The aim of this study is to evaluate the acoustic and thermal properties of a plaque phantom. This is very important for the effective implementation of ultrasound not only in diagnosis but especially in treatment for the future. MATERIAL AND METHODS An evaluation of acoustic and thermal properties of plaque phantoms to test their suitability mainly for ultrasound imaging and therapy was presented. The evaluation included measurements of the acoustic propagation speed using pulse-echo technique, ultrasonic attenuation coefficient using through transmission immersion technique, and absorption coefficient. Moreover, thermal properties (thermal conductivity, volumetric specific heat capacity and thermal diffusivity) were measured with the transient method using a needle probe. RESULTS It was shown that acoustic and thermal properties of atherosclerotic plaque phantoms fall well within the range of reported values for atherosclerotic plaque and slightly different for thermal diffusivity and volumetric specific heat capacity for soft tissues. The mean value of acoustic and thermal properties and their standard deviation of plaque phantoms were 1523 ± 23 m/s for acoustic speed, 0.50 ± 0.02 W/mK for thermal conductivity, 0.30 ± 0.21 db/cm-MHz for ultrasonic absorption coefficient and 1.63 ± 0.46 db/cm-MHz for ultrasonic attenuation coefficient. CONCLUSIONS This study demonstrated that acoustic and thermal properties of atherosclerotic plaque phantoms were within the range of reported values. Future studies should be focused on the optimum recipe of the atherosclerotic plaque phantoms that mimics the human atherosclerotic plaque (agar 4% w/v, gypsum 10% w/v and butter 10% w/v) and can be used for HIFU therapy.
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Affiliation(s)
- Michalis Sotiriou
- Electrical Engineering Department, Cyprus University of Technology, 30 Archbishop Kyprianos Street, 3036, Limassol, Cyprus
| | - Christakis Damianou
- Electrical Engineering Department, Cyprus University of Technology, 30 Archbishop Kyprianos Street, 3036, Limassol, Cyprus.
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Giannakou M, Antoniou A, Damianou C. Preclinical robotic device for magnetic resonance imaging guided focussed ultrasound. Int J Med Robot 2023; 19:e2466. [PMID: 36169287 PMCID: PMC10078206 DOI: 10.1002/rcs.2466] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 09/12/2022] [Accepted: 09/27/2022] [Indexed: 01/05/2023]
Abstract
BACKGROUND A robotic device featuring three motion axes was manufactured for preclinical research on focussed ultrasound (FUS). The device comprises a 2.75 MHz single element ultrasonic transducer and is guided by Magnetic Resonance Imaging (MRI). METHODS The compatibility of the device with the MRI was evaluated by estimating the influence on the signal-to-noise ratio (SNR). The efficacy of the transducer in generating ablative temperatures was evaluated in phantoms and excised porcine tissue. RESULTS System's activation in the MRI scanner reduced the SNR to an acceptable level without compromising the image quality. The transducer demonstrated efficient heating ability as proved by MR thermometry. Discrete and overlapping thermal lesions were inflicted in excised tissue. CONCLUSIONS The FUS system was proven effective for FUS thermal applications in the MRI setting. It can thus be used for multiple preclinical applications of the emerging MRI-guided FUS technology. The device can be scaled-up for human use with minor modifications.
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Affiliation(s)
| | - Anastasia Antoniou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
| | - Christakis Damianou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
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Filippou A, Damianou C. Experimental evaluation of high intensity focused ultrasound for fat reduction of ex vivo porcine adipose tissue. J Ultrasound 2022; 25:815-825. [PMID: 35106735 PMCID: PMC9705658 DOI: 10.1007/s40477-022-00663-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 01/12/2022] [Indexed: 10/19/2022] Open
Abstract
PURPOSE The present study was stimulated by the continuous growth of commercially available high intensity focused ultrasound (HIFU) systems for fat reduction. Herein, HIFU was utilised for fat ablation using a single-element ultrasonic transducer operating in thermal mode. METHODS The custom-made concave transducer that operates at 1.1 MHz was assessed on excised porcine adipose tissue for its ability to reduce fat. Ultrasonic sonications were executed on the adipose tissue utilising acoustical power between 14 and 75 W and sonication time in the range of 1-10 min. The mass of the adipose tissue sample was weighed afore and after ultrasonic sonications and the effect of the sonication on the mass change was recorded. RESULTS Mass change was linearly dependent with either increasing acoustical power or sonication time and was in the range of 0.46-1.9 g. High acoustical power of 62.5 W for a sonication time of 1 min and a power of 75 W for a sonication time of 5 min, respectively resulted in the formation of a lesion or possible cavitation on the piece of excised adipose tissue. CONCLUSION The study demonstrated the efficacy of the proposed transducer in achieving a reduction of excised fat tissue. The present findings indicate the potential use of the transducer in a HIFU system indicated for the reduction of subcutaneous adipose tissue where increased values of acoustical power can result in increased amounts of fat reduction.
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Affiliation(s)
- Antria Filippou
- Department of Electrical Engineering, Computer Engineering and Informatics, Cyprus University of Technology, 30 Archbishop Kyprianou Street, 3036, Limassol, Cyprus
| | - Christakis Damianou
- Department of Electrical Engineering, Computer Engineering and Informatics, Cyprus University of Technology, 30 Archbishop Kyprianou Street, 3036, Limassol, Cyprus.
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Antoniou A, Giannakou M, Georgiou E, Kleopa KA, Damianou C. Robotic device for transcranial focussed ultrasound applications in small animal models. Int J Med Robot 2022; 18:e2447. [PMID: 35924335 PMCID: PMC9786580 DOI: 10.1002/rcs.2447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 07/22/2022] [Accepted: 07/23/2022] [Indexed: 12/30/2022]
Abstract
BACKGROUND Focussed Ultrasound (FUS) combined with microbubbles (MBs) was proven a promising modality for non-invasive blood brain barrier disruption (BBBD). Herein, two devices for FUS-mediated BBBD in rodents are presented. METHODS A two-axes robotic device was manufactured for navigating a single element FUS transducer of 1 MHz relative to the brain of rodents. A second more compact device featuring a single motorized vertical axis was also developed. Their performance was assessed in terms of motion accuracy, MRI compatibility and trans-skull BBBD in wild type mice using MBs in synergy with pulsed FUS. RESULTS Successful BBBD was evidenced by the Evans Blue dye method, as well as by Fibronectin and Fibrinogen immunostaining. BBB permeability was enhanced when the applied acoustic intensity was increased. CONCLUSIONS The proposed devices constitute a cost-effective and ergonomic solution for FUS-mediated BBBD in small animal models. Further experimentation is needed to examine the repeatability of results and optimise the therapeutic protocol.
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Affiliation(s)
- Anastasia Antoniou
- Department of Electrical Engineering, Computer Engineering, and InformaticsCyprus University of TechnologyLimassolCyprus
| | | | - Elena Georgiou
- Department of NeuroscienceThe Cyprus Institute of Neurology and GeneticsNicosiaCyprus
| | - Kleopas A. Kleopa
- Department of NeuroscienceThe Cyprus Institute of Neurology and GeneticsNicosiaCyprus
| | - Christakis Damianou
- Department of Electrical Engineering, Computer Engineering, and InformaticsCyprus University of TechnologyLimassolCyprus
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Antoniou A, Evripidou N, Panayiotou S, Spanoudes K, Damianou C. Treatment of canine and feline sarcoma using MR-guided focused ultrasound system. J Ultrasound 2022; 25:895-904. [PMID: 35277843 PMCID: PMC9705640 DOI: 10.1007/s40477-022-00672-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 02/27/2022] [Indexed: 11/30/2022] Open
Abstract
PURPOSE In recent years, veterinary medicine has enhanced its applications beyond traditional approaches, progressively incorporating the Focused Ultrasound (FUS) technology. This study investigated the ability of FUS to precisely ablate naturally occurring canine and feline soft tissue sarcomas (STS). METHODS Six dogs and four cats with superficial tumours were enrolled in the study. The tumours were treated with a Magnetic Resonance guided FUS (MRgFUS) robotic system featuring a single element spherically focused transducer of 2.6 MHz. The tumours were then removed by surgery and sent for hematoxylin and eosin (H&E) staining. RESULTS The MRgFUS system was capable of inflicting well-defined overlapping lesions in the tumours. The anatomical sites of the treated tumours were the neck, leg, face, back and belly. Coagulative necrosis was evidenced by histopathology assessment in 80% of cases. CONCLUSION Therefore, this technology can be a therapeutic solution for veterinary cancer and a model for advancing the knowledge on human STS.
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Affiliation(s)
- Anastasia Antoniou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, 30 Archbishop Kyprianou Street, 3036, Limassol, Cyprus
| | - Nikolas Evripidou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, 30 Archbishop Kyprianou Street, 3036, Limassol, Cyprus
| | - Stelios Panayiotou
- SGS Diagnostic Centre of Histopathology and Cytology Limited, 21 Thessalonikis, 3025, Limassol, Cyprus
| | - Kyriakos Spanoudes
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, 30 Archbishop Kyprianou Street, 3036, Limassol, Cyprus
| | - Christakis Damianou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, 30 Archbishop Kyprianou Street, 3036, Limassol, Cyprus.
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Filippou A, Louca I, Damianou C. Characterization of a fat tissue mimicking material for high intensity focused ultrasound applications. J Ultrasound 2022:10.1007/s40477-022-00746-4. [DOI: 10.1007/s40477-022-00746-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 10/11/2022] [Indexed: 11/23/2022] Open
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Antoniou A, Georgiou L, Evripidou N, Ioannides C, Damianou C. Challenges regarding MR compatibility of an MRgFUS robotic system. J Magn Reson 2022; 344:107317. [PMID: 36279604 DOI: 10.1016/j.jmr.2022.107317] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 10/11/2022] [Accepted: 10/13/2022] [Indexed: 06/16/2023]
Abstract
Numerous challenges are faced when employing Magnetic Resonance guided Focused Ultrasound (MRgFUS) hardware in the Magnetic Resonance Imaging (MRI) setting. The current study aimed to provide insights on this topic through a series of experiments performed in the framework of evaluating the MRI compatibility of an MRgFUS robotic device. All experiments were performed in a 1.5 T MRI scanner. The main metric for MRI compatibility assessment was the signal to noise ratio (SNR). Measurements were carried out in a tissue mimicking phantom and freshly excised pork tissue under various activation states of the system. In the effort to minimize magnetic interference and image distortion, various set-up parameters were examined. Significant SNR degradation and image distortion occurred when the FUS transducer was activated mainly owing to FUS-induced target and coil vibrations and was getting worse as the output power was increased. Proper design and stable positioning of the imaged phantom play a critical role in reducing these vibrations. Moreover, isolation of the phantom from the imaging coil was proven essential for avoiding FUS-induced vibrations from being transferred to the coil during sonication and resulted in a more than 3-fold increase in SNR. The use of a multi-channel coil increased the SNR by up to 50 % compared to a single-channel coil. Placement of the electronics outside the coil detection area increased the SNR by about 65 %. A similar SNR improvement was observed when the encoders' counting pulses were deactivated. Overall, this study raises awareness about major challenges regarding operation of an MRgFUS system in the MRI environment and proposes simple measures that could mitigate the impact of noise sources so that the monitoring value of MR imaging in FUS applications is not compromised.
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Affiliation(s)
- Anastasia Antoniou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus.
| | - Leonidas Georgiou
- German Oncology Center, Department of Interventional Radiology, Limassol, Cyprus.
| | - Nikolas Evripidou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus.
| | - Cleanthis Ioannides
- German Oncology Center, Department of Interventional Radiology, Limassol, Cyprus.
| | - Christakis Damianou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus.
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Filippou A, Damianou C. Evaluation of ultrasonic scattering in agar-based phantoms using 3D printed scattering molds. J Ultrasound 2022; 25:597-609. [PMID: 34997563 PMCID: PMC9402872 DOI: 10.1007/s40477-021-00630-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 09/30/2021] [Indexed: 10/19/2022] Open
Abstract
PURPOSE Acoustic characterization of tissue mimicking materials in terms of attenuation, absorption, scattering and propagation velocity is essential for their utilisation in experiments, thus sparing the need for living tissues or cadavers. Although there is a vast literature regarding the acoustic characterization of such materials in terms of attenuation or propagation velocity, there is limited data regarding the quantification of the scattering coefficient. Herein stimulated the utilisation of four agar-based phantoms featuring different sizes of scattering agar-structures on one of their surfaces so as to provide experimental evaluation of the magnitude of scattering. METHODS The agar-based phantoms were developed with 6% w/v agar and 4% w/v silica and featured scatterers of sizes of 0-1 mm. The acoustic properties of propagation speed, impedance, insertion loss and attenuation were evaluated utilising the pulse-echo and through-transmission techniques. Scattering was deduced from the data. RESULTS The propagation speed measured at 2.7 MHz was in the range of 1531.23-1542.97 m/s. Respectively the attenuation as measured at 1.1 MHz was in the range of 1.216-1.546 dB/cm increasing with increased scatterer size. Respectively the scattering coefficient was in the range of 0.078-0.324 dB/cm. Moreover, the scattering coefficient was linearly dependent on frequency in the range of 0.8-2.1 MHz indicating a 6-23% effect of the total attenuation. CONCLUSIONS The experimental results demonstrate the utilisation of the procedure for quantification of the scattering coefficient of tissue mimicking materials thus improving the diagnostic and therapeutic uses of ultrasound.
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Affiliation(s)
- Antria Filippou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, 30 Archbishop Kyprianou Street, 3036, Limassol, Cyprus
| | - Christakis Damianou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, 30 Archbishop Kyprianou Street, 3036, Limassol, Cyprus.
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Sotiriou M, Yiannakou M, Damianou C. Investigating atherosclerotic plaque phantoms for ultrasound therapy. J Ultrasound 2022; 25:709-720. [PMID: 35098435 PMCID: PMC9402861 DOI: 10.1007/s40477-022-00658-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 01/12/2022] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The aim of the proposed study was to conduct a feasibility study using a flat rectangular (2 × 10 mm2) transducer operating at 4.0 MHz for creating thermal lesions in an arterial atherosclerotic plaque phantom. The proposed method can be used in the future for treating atherosclerotic plaques in human arteries. MATERIALS AND METHODS The flat rectangular transducer was firstly assessed in agar/silica evaporated milk phantom, polyacrylamide phantom and freshly excised turkeytissue phantom. Then, the same transducer was assessed in an arterial atherosclerotic plaque phantom which was created in the laboratory with a very low cost. The recipe of the atherosclerotic plaque phantom was 4% w/v agar, 1% w/v gypsum, 2% w/v butter and 93% water. The amount of plaque removal was evaluated visually and using an X-Ray system. RESULTS It was shown that the flat rectangular transducer can create thermal lesions on the agar/silica evaporated milk phantom, polyacrylamide phantom and in excised tissue. The size of the lesions matches the geometry of the transducer. Moreover, this transducer destroyed 27.1% of the atherosclerotic plaque phantom with 8 W acoustical power and 30 s duration. CONCLUSIONS This feasibility study demonstrated that atherosclerotic plaque can be destroyed using a very small flat rectangular (2 × 10 mm2) transducer in a very small time interval of 30 s. In future clinical trials the transducer will be incorporated in a catheter which will be inserted intravascular (1-3 mm) wide and can be used to treat atherosclerotic plaques in the coronary arteries.
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Affiliation(s)
- Michalis Sotiriou
- Electrical Engineering Department, Cyprus University of Technology, 30 Archbishop Kyprianos Street, 3036 Limassol, Cyprus
| | - Marinos Yiannakou
- Electrical Engineering Department, Cyprus University of Technology, 30 Archbishop Kyprianos Street, 3036 Limassol, Cyprus
| | - Christakis Damianou
- Electrical Engineering Department, Cyprus University of Technology, 30 Archbishop Kyprianos Street, 3036 Limassol, Cyprus
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21
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Filippou A, Damianou C. Ultrasonic attenuation of canine mammary tumours. Ultrasonics 2022; 125:106798. [PMID: 35785631 DOI: 10.1016/j.ultras.2022.106798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 05/10/2022] [Accepted: 06/23/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Canine mammary tumours (CMTs) are the most common neoplasm appearing in female dogs and are considered the equivalent animal model of human breast cancer. However, in the literature, there is a gap for ultrasonic characterisation of these tumours. In this study, experimental measurements for acoustic attenuation and propagation speed of three surgically excised malignant CMTs were implemented. METHODS The three tumours were fixed in formaldehyde for up to 72 h and a total of five sample pieces were sectioned from the three tumours to account for the varied morphology observed along the tumours. The through-transmission and pulse-echo techniques were employed for experimental measurements of the acoustic attenuation and propagation speed. RESULTS Acoustic propagation speed of the five samples as measured at 2.7 MHz was in the range of 1568-1636 m/s. Correspondingly, acoustic attenuation was in the range of 1.95-3.45 dB/cm.MHz. Variations in both speed and attenuation were observed between samples acquired from the same tumour. CONCLUSIONS Present findings suggest that both acoustic attenuation and propagation speed of CMTs are higher than normal canine tissues due to increased heterogeneity and varied morphology visually observed between the tumour specimens and evidenced by histological examination. Nevertheless, experimental results could aid in enhancing the use of ultrasound in the diagnosis and treatment of CMTs as well as provide essential data for comparative oncology.
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Affiliation(s)
- Antria Filippou
- Cyprus University of Technology, Department of Electrical Engineering, Computer Engineering, and Informatics, Limassol, Cyprus.
| | - Christakis Damianou
- Cyprus University of Technology, Department of Electrical Engineering, Computer Engineering, and Informatics, Limassol, Cyprus.
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22
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Antoniou A, Georgiou A, Evripidou N, Damianou C. Full coverage path planning algorithm for MRgFUS therapy. Int J Med Robot 2022; 18:e2389. [PMID: 35257476 PMCID: PMC9286630 DOI: 10.1002/rcs.2389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 03/04/2022] [Accepted: 03/06/2022] [Indexed: 11/17/2022]
Abstract
Background High‐quality methods for Magnetic Resonance guided Focussed Ultrasound (MRgFUS) therapy planning are needed for safe and efficient clinical practices. Herein, an algorithm for full coverage path planning based on preoperative MR images is presented. Methods The software functionalities of an MRgFUS robotic system were enhanced by implementing the developed algorithm. The algorithm's performance in accurate path planning following a Zig‐Zag pathway was assessed on MR images. The planned sonication paths were performed on acrylic films using the robotic system carrying a 2.75 MHz single element transducer. Results Ablation patterns were successfully planned on MR images and produced on acrylic films by overlapping lesions with excellent match between the planned and experimental lesion shapes. Conclusions The advanced software was proven efficient in planning and executing full ablation of any segmented target. The reliability of the algorithm could be enhanced through the development of a fully automated segmentation procedure.
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Affiliation(s)
- Anastasia Antoniou
- Department of Electrical Engineering Computer Engineering, and Informatics Cyprus University of Technology Limassol Cyprus
| | - Andreas Georgiou
- Department of Electrical Engineering Computer Engineering, and Informatics Cyprus University of Technology Limassol Cyprus
| | - Nikolas Evripidou
- Department of Electrical Engineering Computer Engineering, and Informatics Cyprus University of Technology Limassol Cyprus
| | - Christakis Damianou
- Department of Electrical Engineering Computer Engineering, and Informatics Cyprus University of Technology Limassol Cyprus
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Roussakis Y, Antorkas G, Antoniou A, Cloconi C, Karagiannis E, Ferentinos K, Damianou C, Strouthos I. MO-0302 Implementation of high-dose-rate brachytherapy as monotherapy for over-sized prostatic gland. Radiother Oncol 2022. [DOI: 10.1016/s0167-8140(22)02334-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Antoniou A, Georgiou L, Christodoulou T, Panayiotou N, Ioannides C, Zamboglou N, Damianou C. MR relaxation times of agar-based tissue-mimicking phantoms. J Appl Clin Med Phys 2022; 23:e13533. [PMID: 35415875 PMCID: PMC9121050 DOI: 10.1002/acm2.13533] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 12/29/2021] [Indexed: 12/31/2022] Open
Abstract
Agar gels were previously proven capable of accurately replicating the acoustical and thermal properties of real tissue and widely used for the construction of tissue-mimicking phantoms (TMPs) for focused ultrasound (FUS) applications. Given the current popularity of magnetic resonance-guided FUS (MRgFUS), we have investigated the MR relaxation times T1 and T2 of different mixtures of agar-based phantoms. Nine TMPs were constructed containing agar as the gelling agent and various concentrations of silicon dioxide and evaporated milk. An agar-based phantom doped with wood powder was also evaluated. A series of MR images were acquired in a 1.5 T scanner for T1 and T2 mapping. T2 was predominantly affected by varying agar concentrations. A trend toward decreasing T1 with an increasing concentration of evaporated milk was observed. The addition of silicon dioxide decreased both relaxation times of pure agar gels. The proposed phantoms have great potential for use with the continuously emerging MRgFUS technology. The MR relaxation times of several body tissues can be mimicked by adjusting the concentration of ingredients, thus enabling more accurate and realistic MRgFUS studies.
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Affiliation(s)
- Anastasia Antoniou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
| | - Leonidas Georgiou
- Department of Interventional Radiology, German Oncology Center, Limassol, Cyprus
| | | | - Natalie Panayiotou
- Department of Interventional Radiology, German Oncology Center, Limassol, Cyprus
| | - Cleanthis Ioannides
- Department of Interventional Radiology, German Oncology Center, Limassol, Cyprus
| | - Nikolaos Zamboglou
- Department of Interventional Radiology, German Oncology Center, Limassol, Cyprus
| | - Christakis Damianou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
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Antoniou A, Giannakou M, Evripidou N, Stratis S, Pichardo S, Damianou C. Robotic system for top to bottom MRgFUS therapy of multiple cancer types. Int J Med Robot 2022; 18:e2364. [DOI: 10.1002/rcs.2364] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 01/05/2022] [Accepted: 01/05/2022] [Indexed: 12/18/2022]
Affiliation(s)
- Anastasia Antoniou
- Department of Electrical Engineering, Computer Engineering, and Informatics Cyprus University of Technology Limassol Cyprus
| | | | - Nikolas Evripidou
- Department of Electrical Engineering, Computer Engineering, and Informatics Cyprus University of Technology Limassol Cyprus
| | - Stylianos Stratis
- Department of Electrical Engineering, Computer Engineering, and Informatics Cyprus University of Technology Limassol Cyprus
| | - Samuel Pichardo
- Hotchkiss Brain Institute Cumming School of Medicine University of Calgary Calgary Alberta Canada
| | - Christakis Damianou
- Department of Electrical Engineering, Computer Engineering, and Informatics Cyprus University of Technology Limassol Cyprus
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Antoniou A, Damianou C. MR relaxation properties of tissue-mimicking phantoms. Ultrasonics 2022; 119:106600. [PMID: 34627028 DOI: 10.1016/j.ultras.2021.106600] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/20/2021] [Accepted: 09/21/2021] [Indexed: 06/13/2023]
Abstract
High quality tissue-mimicking phantoms (TMPs) have a critical role in the preclinical testing of emerging modalities for diagnosis and therapy. TMPs capable of accurately mimicking real tissue in Magnetic Resonance guided Focused Ultrasound (MRgFUS) applications should be fabricated with precise T1 and T2 relaxation times. Given the current popularity of the MRgFUS technology, we herein performed a systematic review on the MR relaxation properties of different phantoms types. Polyacrylamide (PAA) and agar based phantoms were proven capable of accurately replicating critical thermal, acoustical, and MR relaxation properties of various body tissues. Although gelatin phantoms were also proven factional in this regard, they lack the capacity to withstand ablation temperatures, and thus, are only recommended for hyperthermia applications. Other gelling agents identified in the literature are Poly-vinyl alcohol (PVA), Polyvinyl Chloride (PVC), silicone, and TX-150/ TX-151; however, their efficacy in thermal studies is yet to be established. PAA gels are favorable in that they offer optical transparency enabling direct visualization of coagulative lesions. On the other hand, agar phantoms have lower preparation costs and were proven very promising for use with the MRgFUS technology, without the toxicity issues related to the preparation and storage of PAA materials. Remarkably, agar turned out to be the prominent modifier of the T2 relaxation time even for phantoms containing other types of gelling agents instead of agar. This review could be useful in manufacturing realistic MRgFUS phantoms while simultaneously indicating an opportunity for further research in the field with a particular focus on the MR behavior of agar-based TMPs.
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Affiliation(s)
- Anastasia Antoniou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
| | - Christakis Damianou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus.
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Karanicola P, Patsalou M, Stergiou PY, Kavallieratou A, Evripidou N, Christou P, Panagiotou G, Damianou C, Papamichael EM, Koutinas M. Ultrasound-assisted dilute acid hydrolysis for production of essential oils, pectin and bacterial cellulose via a citrus processing waste biorefinery. Bioresour Technol 2021; 342:126010. [PMID: 34852446 DOI: 10.1016/j.biortech.2021.126010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/15/2021] [Accepted: 09/19/2021] [Indexed: 06/13/2023]
Abstract
An orange peel waste biorefinery was developed employing a design of experiments approach to optimize the ultrasound-assisted dilute acid hydrolysis process applied for production of useful commodities. Central composite design-based response surface methodology was used to approximate the combined effects of process parameters in simultaneous production of essential oils, pectin and a sugar-rich hydrolyzate. Application of a desirability function determined the optimal conditions required for maximal production efficiency of essential oils, pectin and sugars as 5.75% solid loading, 1.21% acid concentration and 34.2 min duration. Maximum production yields of 0.12% w/w essential oils, 45% w/w pectin and 40% w/w sugars were achieved under optimized conditions in lab- and pilot-scale facilities. The hydrolyzate formed was applied in bacterial cellulose fermentations producing 5.82 g biopolymer per 100 g waste. Design of experiments was efficient for process analysis and optimization providing a systems platform for the study of biomass-based biorefineries.
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Affiliation(s)
- Panayiota Karanicola
- Department of Chemical Engineering, Cyprus University of Technology, 30 Archbishop Kyprianou Str., 3036 Limassol, Cyprus; KEAN Soft Drinks Ltd, 35 Promachon Eleftherias, 4103, Agios Athanasios, Limassol, Cyprus
| | - Maria Patsalou
- Department of Chemical Engineering, Cyprus University of Technology, 30 Archbishop Kyprianou Str., 3036 Limassol, Cyprus
| | | | - Alexandra Kavallieratou
- Department of Chemical Engineering, Cyprus University of Technology, 30 Archbishop Kyprianou Str., 3036 Limassol, Cyprus
| | - Nikolas Evripidou
- Department of Electrical Engineering, Computer Engineering and Informatics, Cyprus University of Technology, 30 Archbishop Kyprianou Str., 3036 Limassol, Cyprus
| | - Panagiotis Christou
- KEAN Soft Drinks Ltd, 35 Promachon Eleftherias, 4103, Agios Athanasios, Limassol, Cyprus
| | - George Panagiotou
- KEAN Soft Drinks Ltd, 35 Promachon Eleftherias, 4103, Agios Athanasios, Limassol, Cyprus
| | - Christakis Damianou
- Department of Electrical Engineering, Computer Engineering and Informatics, Cyprus University of Technology, 30 Archbishop Kyprianou Str., 3036 Limassol, Cyprus
| | | | - Michalis Koutinas
- Department of Chemical Engineering, Cyprus University of Technology, 30 Archbishop Kyprianou Str., 3036 Limassol, Cyprus.
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Spanoudes K, Evripidou N, Giannakou M, Drakos T, Menikou G, Damianou C. A High Intensity Focused Ultrasound System for Veterinary Oncology Applications. J Med Ultrasound 2021; 29:195-202. [PMID: 34729329 PMCID: PMC8515634 DOI: 10.4103/jmu.jmu_130_20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 10/05/2020] [Accepted: 11/18/2020] [Indexed: 11/04/2022] Open
Abstract
Background Magnetic resonance-guided focused ultrasound surgery is an incisionless energy-based thermal method that is used for ablating tumors in the veterinary clinic. Aims and Objectives In this article we describe a prototype of a veterinary system compatible with magnetic resonance imaging intended for small-to-medium-sized companion animals that was developed and tested in vivo in adult rabbits. Methods Real-time monitoring of the ablation during the experiment was possible with MR thermometry. Experiments involved thermal monitoring of sonications applied in the thigh of the rabbits. A 38-mm diameter transducer operating at 2.6 MHz was used with a 60-mm-focal length. The robotic system employed 3 linear axes and one angular axis. For this study, only X and Y axis were enabled. Due to the target size limitations, motion in Z and Θ was not needed. The functionality of the positioning device was evaluated by means of MR thermometry, demonstrating sufficient heating and accurate motion in both axes of operation. Results The postmortem findings confirm the ability of the system to induce thermal ablations in vivo in the absence of adverse effects. Conclusions The device is a reliable and affordable solution for companion animal hospitals, offering and additional tool for the veterinary oncology society.
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Affiliation(s)
- Kyriakos Spanoudes
- Department of Electrical Engineering, Cyprus University of Technology, Limassol, Cyprus.,Vet Ex Machina Ltd., Nicosia, Cyprus
| | - Nikolas Evripidou
- Department of Electrical Engineering, Cyprus University of Technology, Limassol, Cyprus
| | | | - Theocharis Drakos
- Department of Electrical Engineering, Cyprus University of Technology, Limassol, Cyprus.,Medsonic Ltd., Limassol, Cyprus
| | - George Menikou
- Medical Physics Sector, General Hospital of Nicosia, Nicosia, Cyprus
| | - Christakis Damianou
- Department of Electrical Engineering, Cyprus University of Technology, Limassol, Cyprus
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Drakos T, Antoniou A, Evripidou N, Alecou T, Giannakou M, Menikou G, Constantinides G, Damianou C. Ultrasonic Attenuation of an Agar, Silicon Dioxide, and Evaporated Milk Gel Phantom. J Med Ultrasound 2021; 29:239-249. [PMID: 35127403 PMCID: PMC8772477 DOI: 10.4103/jmu.jmu_145_20] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 12/26/2020] [Accepted: 01/07/2021] [Indexed: 11/11/2022] Open
Abstract
Background: It has been demonstrated that agar-based gel phantoms can emulate the acoustic parameters of real tissues and are the most commonly used tissue-mimicking materials for high-intensity focused ultrasound applications. The following study presents ultrasonic attenuation measurements of agar-based phantoms with different concentrations of additives (percent of agar, silicon dioxide and evaporated milk) in an effort of matching the material's acoustic property as close as possible to human tissues. Methods: Nine different agar-based phantoms with various amounts of agar, silicon dioxide, and evaporated milk were prepared. Attenuation measurements of the samples were conducted using the through-transmission immersion techniques. Results: The ultrasonic attenuation coefficient of the agar-based phantoms varied in the range of 0.30–1.49 dB/cm-MHz. The attenuation was found to increase in proportion to the concentration of agar and evaporated milk. Silicon dioxide was found to significantly contribute to the attenuation coefficient up to 4% weight to volume (w/v) concentration. Conclusion: The acoustic attenuation coefficient of agar-based phantoms can be adjusted according to the tissue of interest in the range of animal and human tissues by the proper selection of agar, silicon dioxide, and evaporated milk.
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Affiliation(s)
| | - Anastasia Antoniou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
| | - Nikolas Evripidou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
| | - Tereza Alecou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
| | | | - Georgios Menikou
- Medical Physics Sector, State Health Services Organization, Nicosia General Hospital, Nicosia, Cyprus
| | - Georgios Constantinides
- Department of Mechanical Engineering and Materials Science and Engineering, Cyprus University of Technology, Limassol, Cyprus
| | - Christakis Damianou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
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Filippou A, Drakos T, Giannakou M, Evripidou N, Damianou C. Experimental evaluation of the near-field and far-field heating of focused ultrasound using the thermal dose concept. Ultrasonics 2021; 116:106513. [PMID: 34293620 DOI: 10.1016/j.ultras.2021.106513] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 06/28/2021] [Accepted: 06/30/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Conventional motion algorithms utilized during High Intensity Focused Ultrasound (HIFU) procedures usually sonicate successive tissue cells, thereby inducing excess deposition of thermal dose in the pre-focal region. Long delays (~60 s) are used to reduce the heating around the focal region. In the present study the experimental evaluation of six motion algorithms so as to examine the required delay and algorithm for which the pre-focal (near-field) and post-focal (far-field) heating can be reduced using thermal dose estimations is presented. MATERIALS AND METHODS A single element spherically focused transducer operating at 1.1 MHz and focusing beam at 9 cm, was utilized for sonication on a 400 mm2 area of an agar-based phantom. Movement of the transducer was performed with each algorithm, using 0-60 s (10 s step) delays between sonications. Temperatures were recorded at both near and far-field regions and thermal dose calculations were implemented. RESULTS With the algorithms used in the present study, a delay of 50-60 s was required to reduce heating in the near-field region. A 30 s delay induced a safe thermal dose in the far-field region using all algorithms except sequential which still required 60 s delay. CONCLUSIONS The study verified the conservative need for 60 s delay for the sequential plan treatment. Nevertheless, present findings suggest that prolonged treatment times can be significantly reduced in homogeneous tissues by selection of the optimized nonlinear algorithm and delay.
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Affiliation(s)
- Antria Filippou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus.
| | | | | | - Nikolas Evripidou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus.
| | - Christakis Damianou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus.
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31
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Drakos T, Giannakou M, Menikou G, Damianou C. Magnetic Resonance Imaging-Guided Focused Ultrasound Positioning System for Preclinical Studies in Small Animals. J Ultrasound Med 2021; 40:1343-1352. [PMID: 33031567 PMCID: PMC8246715 DOI: 10.1002/jum.15514] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 08/06/2020] [Accepted: 09/07/2020] [Indexed: 06/01/2023]
Abstract
OBJECTIVES A positioning device compatible with magnetic resonance imaging (MRI) used for preclinical studies in small animals was developed that fits in MRI scanners up to 7 T. The positioning device was designed with two computer-controlled linear stages. METHODS The positioning device was evaluated in an agar-based phantom, which mimics soft tissues, and in a rabbit. Experiments with this positioning device were performed in an MRI system using the agar-based phantom. The transducer used had a diameter of 50 mm, operated at 0.5 MHz, and focused energy at 60 mm. RESULTS Magnetic resonance thermometry was used to assess the functionality of the device, which showed adequate deposition of thermal energy and sufficient positional accuracy in all axes. CONCLUSIONS The proposed system fits in MRI scanners up to 7 T. Because of the size of the positioning device, at the moment, it can be used to perform preclinical studies on small animals such as mice, rats, and rabbits.
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Affiliation(s)
| | | | - Georgios Menikou
- Department of Electrical EngineeringCyprus University of TechnologyLimassolCyprus
| | - Christakis Damianou
- Department of Electrical EngineeringCyprus University of TechnologyLimassolCyprus
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32
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Antoniou A, Giannakou M, Evripidou N, Evripidou G, Spanoudes K, Menikou G, Damianou C. Robotic system for magnetic resonance guided focused ultrasound ablation of abdominal cancer. Int J Med Robot 2021; 17:e2299. [PMID: 34105234 DOI: 10.1002/rcs.2299] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 06/07/2021] [Accepted: 06/08/2021] [Indexed: 12/19/2022]
Abstract
BACKGROUND A prototype robotic system that uses magnetic resonance guided focused ultrasound (MRgFUS) technology is presented. It features three degrees of freedom (DOF) and is intended for thermal ablation of abdominal cancer. METHODS The device is equipped with three identical transducers being offset between them, thus focussing at different depths in tissue. The efficacy and safety of the system in ablating rabbit liver and kidney was assessed, both in laboratory and magnetic resonance imaging (MRI) conditions. RESULTS Despite these organs' challenging location, in situ coagulative necrosis of a tissue area was achieved. Heating of abdominal organs in rabbit was successfully monitored with MR thermometry. CONCLUSIONS The MRgFUS system was proven successful in creating lesions in the abdominal area of rabbits. The outcomes of the study are promising for future translation of the technology to the clinic.
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Affiliation(s)
- Anastasia Antoniou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
| | | | - Nikolas Evripidou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
| | - Georgios Evripidou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
| | - Kyriakos Spanoudes
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
| | - Georgios Menikou
- Medical Physics Sector, State Health Services Organization, Nicosia General Hospital, Nicosia, Cyprus
| | - Christakis Damianou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
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33
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Antoniou A, Drakos T, Giannakou M, Evripidou N, Georgiou L, Christodoulou T, Panayiotou N, Ioannides C, Zamboglou N, Damianou C. Simple methods to test the accuracy of MRgFUS robotic systems. Int J Med Robot 2021; 17:e2287. [PMID: 34021694 PMCID: PMC8365756 DOI: 10.1002/rcs.2287] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 05/21/2021] [Accepted: 05/21/2021] [Indexed: 01/09/2023]
Abstract
Background Robotic‐assisted diagnostic and therapeutic modalities require a highly accurate performance to be certified for clinical application. In this paper, three simple methods for assessing the accuracy of motion of magnetic resonance‐guided focused ultrasound (MRgFUS) robotic systems are presented. Methods The accuracy of motion of a 4 degrees of freedom robotic system intended for preclinical use of MRgFUS was evaluated by calliper‐based and magnetic resonance imaging (MRI) methods, as well as visually by performing multiple ablations on a plastic film. Results The benchtop results confirmed a highly accurate motion in all axes of operation. The spatial positioning errors estimated by MRI evaluation were defined by the size of the imaging pixels. Lesions arrangement in discrete and overlapping patterns confirmed satisfactory alignment of motion trajectories. Conclusions We believe the methods presented here should serve as a standard for evaluating the accuracy of motion of MRgFUS robotic systems.
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Affiliation(s)
- Anastasia Antoniou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
| | | | | | - Nikolas Evripidou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
| | | | | | | | | | | | - Christakis Damianou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus
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Drakos T, Giannakou M, Menikou G, Constantinides G, Damianou C. Characterization of a soft tissue-mimicking agar/wood powder material for MRgFUS applications. Ultrasonics 2021; 113:106357. [PMID: 33548756 DOI: 10.1016/j.ultras.2021.106357] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 12/29/2020] [Accepted: 01/06/2021] [Indexed: 06/12/2023]
Abstract
This study describes the development and characterization of an agar-based soft tissue-mimicking material (TMM) doped with wood powder destined for fabricating MRgFUS applications. The main objective of the following work was to investigate the suitability of wood powder as an inexpensive alternative in replacing other added materials that have been suggested in previous studies for controlling the ultrasonic properties of TMMs. The characterization procedure involved a series of experiments designed to estimate the acoustic (attenuation coefficient, absorption coefficient, propagation speed, and impedance), thermal (conductivity, diffusivity, specific heat capacity), and MR properties (T1 and T2 relaxation times) of the wood-powder doped material. The developed TMM (2% w/v agar and 4% w/v wood powder) as expected demonstrated compatibility with MRI scanner following images artifacts evaluation. The acoustic attenuation coefficient of the proposed material was measured over the frequency range of 1.1-3 MHz and found to be nearly proportional to frequency. The measured attenuation coefficient was 0.48 dB/cm at 1 MHz which was well within the range of soft tissue. Temperatures over 37 °C proved to increase marginally the attenuation coefficient. Following the transient thermoelectric method, the acoustic absorption coefficient was estimated at 0.34 dB/cm-MHz. The estimated propagation speed (1487 m/s) was within the range of soft tissue at room temperature, while it significantly increased with higher temperature. The material possessed an acoustic impedance of 1.58 MRayl which was found to be comparable to the corresponding value of muscle tissue. The thermal conductivity of the material was estimated at 0.51 W/m K. The measured relaxation times T1 (844 ms) and T2 (66 ms) were within the range of values found in the literature for soft tissue. The phantom was tested for its suitability for evaluating MRgFUS thermal protocols. High acoustic energy was applied, and temperature change was recorded using thermocouples and MR thermometry. MR thermal maps were acquired using single-shot Echo Planar Imaging (EPI) gradient echo sequence. The TMM matched adequately the acoustic and thermal properties of human tissues and through a series of experiments, it was proven that wood concentration enhances acoustic absorption. Experiments using MR thermometry demonstrated the usefulness of this phantom to evaluate ultrasonic thermal protocols by monitoring peak temperatures in real-time. Thermal lesions formed above a thermal dose were observed in high-resolution MR images and visually in dissections of the proposed TMM.
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Affiliation(s)
| | | | - Georgios Menikou
- Medical Physics Sector, State Health Services Organization, Nicosia General Hospital, Nicosia, Cyprus.
| | - Georgios Constantinides
- Department of Mechanical Engineering and Materials Science and Engineering, Cyprus University of Technology, Limassol, Cyprus.
| | - Christakis Damianou
- Department of Electrical Engineering, Computer Engineering and Informatics, Cyprus University of Technology, Limassol, Cyprus.
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Antoniou A, Evripidou N, Giannakou M, Constantinides G, Damianou C. Acoustical properties of 3D printed thermoplastics. J Acoust Soc Am 2021; 149:2854. [PMID: 33940906 DOI: 10.1121/10.0004772] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 04/03/2021] [Indexed: 06/12/2023]
Abstract
With focused ultrasound (FUS) gaining popularity as a therapeutic modality for brain diseases, the need for skull phantoms that are suitable for evaluating FUS protocols is increasing. In the current study, the acoustical properties of several three-dimensional (3D) printed thermoplastic samples were evaluated to assess their suitability to mimic human skull and bone accurately. Samples were 3D printed using eight commercially available thermoplastic materials. The acoustic properties of the printed samples, including attenuation coefficient, speed of sound, and acoustic impedance, were investigated using transmission-through and pulse-echo techniques. The ultrasonic attenuation, estimated at a frequency of 1.1 MHz, varied from approximately 7 to 32 dB/cm. The frequency dependence of attenuation was described by a power law in the frequency range of 0.2-3.5 MHz, and the exponential index of frequency was found to vary from 1.30 to 2.24. The longitudinal velocity of 2.7 MHz sound waves was in the range of 1700-3050 m/s. The results demonstrate that thermoplastics could potentially be used for the 3D construction of high-quality skull phantoms.
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Affiliation(s)
- Anastasia Antoniou
- Department of Electrical Engineering and Computer Engineering and Informatics, Cyprus University of Technology, 30 Archiepiskopou Kyprianou Street, Limassol, 3036, Cyprus
| | - Nikolas Evripidou
- Department of Electrical Engineering and Computer Engineering and Informatics, Cyprus University of Technology, 30 Archiepiskopou Kyprianou Street, Limassol, 3036, Cyprus
| | - Marinos Giannakou
- MEDSONIC LTD, 35 Christaki Kranou Street, Germasogia, Limassol, 4041, Cyprus
| | - Georgios Constantinides
- Department of Mechanical Engineering and Materials Science and Engineering, Cyprus University of Technology, 30 Archiepiskopou Kyprianou Street, Limassol, 3036, Cyprus
| | - Christakis Damianou
- Department of Electrical Engineering and Computer Engineering and Informatics, Cyprus University of Technology, 30 Archiepiskopou Kyprianou Street, Limassol, 3036, Cyprus
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36
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Giannakou M, Drakos T, Menikou G, Evripidou N, Filippou A, Spanoudes K, Ioannou L, Damianou C. Magnetic resonance image-guided focused ultrasound robotic system for transrectal prostate cancer therapy. Int J Med Robot 2021; 17:e2237. [PMID: 33533112 PMCID: PMC8244034 DOI: 10.1002/rcs.2237] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 01/02/2021] [Accepted: 01/17/2021] [Indexed: 12/24/2022]
Abstract
Background A magnetic resonance image (MRI) guided robotic device for focussed ultrasound therapy of prostate cancer (PC) was developed. The device offers movement in 5 degrees of freedom (DOF) and uses a single‐element transducer that operates at 3.2 MHz, has a diameter of 25 mm and focuses at 45 mm. Methods The MRI compatibility of the system was evaluated in a 1.5 T scanner. The ability of the transducer to create lesions was evaluated in laboratory and MRI settings, on ex vivo pork tissue and in vivo rabbit thigh tissue. Results Cavitational and thermal lesions were created on the excised pork tissue. In vivo experiments proved the efficacy of the system in ablating muscle tissue without damaging intervening areas. Conclusions The MRI compatible robotic system can be placed on the table of any commercial MRI scanner up to 7 T. The device has the ability of future use for transrectal focal therapy of PC with the patient in supine position.
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Affiliation(s)
| | | | - Georgios Menikou
- Electrical Engineering Department, Cyprus University of Technology, Limassol, Cyprus
| | - Nikolas Evripidou
- Electrical Engineering Department, Cyprus University of Technology, Limassol, Cyprus
| | - Antria Filippou
- Electrical Engineering Department, Cyprus University of Technology, Limassol, Cyprus
| | - Kyriakos Spanoudes
- Electrical Engineering Department, Cyprus University of Technology, Limassol, Cyprus
| | | | - Christakis Damianou
- Electrical Engineering Department, Cyprus University of Technology, Limassol, Cyprus
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Alekou T, Giannakou M, Damianou C. Focused ultrasound phantom model for blood brain barrier disruption. Ultrasonics 2021; 110:106244. [PMID: 32942090 DOI: 10.1016/j.ultras.2020.106244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 08/11/2020] [Accepted: 08/31/2020] [Indexed: 06/11/2023]
Abstract
In this paper a high intensity focused ultrasound (FUS) phantom model was developed, in order to be used in experiments for Blood Brain Barrier (BBB) disruption. The target was to create a phantom model that represents the disruption of the BBB during ultrasound application. An appropriate experimental setup was created bearing a single element transducer with diameter 50 mm and geometric focus 100 mm operating at 0.5 MHz. It included a set of tubes and a connector with multiple 0.4 mm openings, through which a suitable liquid is being circulated with a pump. The lesions were sealed with a thin homogenous layer of wax, preventing a liquid leakage. The system was tested successfully with FUS and a liquid leakage was achieved after FUS application. This set up is the first phantom model that has the potential to be utilized as a cost-effective solution for performing experiments for BBB disruption, without the need of using animal models.
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Affiliation(s)
- Tereza Alekou
- Department of Electrical Engineering and Computer Engineering and Informatics, Cyprus University of Technology, Cyprus
| | - Marinos Giannakou
- Department of Electrical Engineering and Computer Engineering and Informatics, Cyprus University of Technology, Cyprus
| | - Christakis Damianou
- Department of Electrical Engineering and Computer Engineering and Informatics, Cyprus University of Technology, Cyprus.
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Damianou C, Giannakou M, Evripidou N, Kegel S, Huber P, Jenne J. Focused ultrasound robotic system for very small bore magnetic resonance imaging. Int J Med Robot 2020; 16:1-9. [PMID: 32927501 PMCID: PMC7816236 DOI: 10.1002/rcs.2165] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 09/01/2020] [Accepted: 09/05/2020] [Indexed: 11/06/2022]
Abstract
Background A magnetic resonance imaging (MRI) compatible robotic system for focused ultrasound was developed for small animal like mice or rats that fits into a 9.4 T MRI scanner (Bruker Biospec 9420, Bruker Biospin, Ettlingen, Germany). The robotic system includes two computer‐controlled linear stages. Materials and Methods The robotic system was evaluated in a mouse‐shaped, real‐size agar‐based mimicking material, which has similar acoustical properties as soft tissues. The agar content was 6% weight per volume (w/v), 4% w/v silica while the rest was degassed water. The transducer used has a diameter of 4 cm, operates with 2.6 MHz and focuses energy at 5 cm. Results The MRI compatibility of the robotic system was evaluated in a 9.4 T small animal scanner. The efficacy of the ultrasonic transducer was evaluated in the mimicking material using temperature measurements. Conclusions The proposed robotic system can be utilized in a 9.4 T small animal MRI scanner. The proposed system is functional, compact and simple thus providing a useful tool for preclinical research in mice and rats.
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Affiliation(s)
- Christakis Damianou
- Electrical Engineering and Computer Engineering and Informatics Department, Cyprus University of Technology, Limassol, Cyprus
| | - Marinos Giannakou
- Electrical Engineering and Computer Engineering and Informatics Department, Cyprus University of Technology, Limassol, Cyprus.,MEDSONIC LTD, Limassol, Cyprus
| | - Nikolas Evripidou
- Electrical Engineering and Computer Engineering and Informatics Department, Cyprus University of Technology, Limassol, Cyprus
| | - Stefan Kegel
- German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Peter Huber
- German Cancer Research Center (DKFZ), Heidelberg, Germany
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39
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Drakos T, Giannakou M, Menikou G, Ioannides C, Damianou C. An improved method to estimate ultrasonic absorption in agar-based gel phantom using thermocouples and MR thermometry. Ultrasonics 2020; 103:106089. [PMID: 32045747 DOI: 10.1016/j.ultras.2020.106089] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 12/30/2019] [Accepted: 01/05/2020] [Indexed: 06/10/2023]
Abstract
In this paper, a novel experimental set-up was developed that measures the absorption coefficient. The proposed system was evaluated in an agar-based gel phantom. The new experimental system provides accurate and fast measurement of the rate of temperature change within the phantom. The rate of temperature change was measured using thermocouple and was confirmed using MR thermometry. An ultrasonic transducer with a broad beam was used in order to reduce the conduction effect. The absorption coefficient of the agar-based phantom was 0.26 dB/cm-MHz using 4% agar, 30% evaporated milk and 4% silica. The absorption coefficient increased by increasing the volume of the evaporated milk, and agar. The absorption coefficient increased at low silica concentration (<4%) and then decreased at higher concentration of silica (>4%). By proper selection of evaporated milk, agar and silica concentration, it is possible to achieve similar coefficient like in soft tissues. Acoustic absorption measurement is considered as a difficult measurement in ultrasonics because obtaining the precise temperature change in the focus is challenging. Due to the quick and accurate placement of the thermocouple at the ultrasonic beam, it is possible with the proposed system to perform absorption measurement is less than one minute.
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Affiliation(s)
- T Drakos
- Electrical Engineering Department, Cyprus University of Technology, Cyprus
| | - M Giannakou
- Electrical Engineering Department, Cyprus University of Technology, Cyprus
| | - G Menikou
- Medical Physics Division, General Hospital of Nicosia, Nicosia, Cyprus
| | - C Ioannides
- Radiology Department, Ygia Polyclinic, Limassol, Cyprus
| | - C Damianou
- Electrical Engineering Department, Cyprus University of Technology, Cyprus
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Damianou C, Giannakou M, Menikou G, Ioannou L. Magnetic resonance imaging-guided focused ultrasound robotic system with the subject placed in the prone position. ACTA ACUST UNITED AC 2020. [DOI: 10.4103/digm.digm_2_20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Papadopoulos N, Damianou C. Comment on “The Enhancing Effect of Focused Ultrasound on TNK-Tissue Plasminogen Activator-Induced Thrombolysis Using an In Vitro circulating Flow Model”. J Stroke Cerebrovasc Dis 2019; 28:2053. [DOI: 10.1016/j.jstrokecerebrovasdis.2019.03.047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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Giannakou M, Yiallouras C, Menikou G, Ioannides C, Damianou C. MRI-guided frameless biopsy robotic system with the inclusion of unfocused ultrasound transducer for brain cancer ablation. Int J Med Robot 2018; 15:e1951. [PMID: 30157310 DOI: 10.1002/rcs.1951] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 08/04/2018] [Accepted: 08/06/2018] [Indexed: 11/10/2022]
Abstract
BACKGROUND A magnetic resonance image (MRI) guided robotic system dedicated for brain biopsy was developed. The robotic system carries a biopsy needle and a small rectangular unfocused, single element, planar ultrasonic transducer which can be potentially utilized to ablate small and localized brain cancer. MATERIALS AND METHODS The robotic device includes six computer-controlled axes. An agar-based phantom was developed which included an olive that mimics brain target. A rectangular ultrasonic transducer operated at 4 MHz was used. RESULTS The functionality of the robotic system was assessed by means of ultrasound imaging, MRI imaging, and MR thermometry, demonstrating effective targeting. The heating capabilities of the ultrasonic transducer were also evaluated. CONCLUSIONS A functional MRI-guided robotic system was produced which can perform frameless brain biopsy. In the future, if a tumour is proven malignant, the needle can be pulled-out and a small ultrasonic transducer can be inserted to ablate the tumour.
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Affiliation(s)
- Marinos Giannakou
- Electrical Engineering Department, Cyprus University of Technology, Cyprus
| | | | - Georgios Menikou
- Department of Bioengineering, City University, London, UK.,R&D, MEDSONIC LTD, Limassol, Cyprus
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Papadopoulos N, Kyriacou PA, Damianou C. Review of Protocols Used in Ultrasound Thrombolysis. J Stroke Cerebrovasc Dis 2017; 26:2447-2469. [DOI: 10.1016/j.jstrokecerebrovasdis.2017.07.032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2016] [Revised: 07/01/2017] [Accepted: 07/30/2017] [Indexed: 01/01/2023] Open
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Alecou T, Giannakou M, Damianou C. Amyloid β Plaque Reduction With Antibodies Crossing the Blood-Brain Barrier, Which Was Opened in 3 Sessions of Focused Ultrasound in a Rabbit Model. J Ultrasound Med 2017; 36:2257-2270. [PMID: 28543446 DOI: 10.1002/jum.14256] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 01/18/2017] [Accepted: 02/08/2017] [Indexed: 05/28/2023]
Abstract
OBJECTIVES The main objective of this study was to remove amyloid β plaques by applying multiple sessions of focused ultrasound (US)-induced blood-brain barrier (BBB) opening using microbubbles with and without delivery of antibodies in a rabbit model. METHODS The animal model was achieved by feeding a high-cholesterol diet to rabbits for 4 months. Fifty-two New Zealand White rabbits were divided into treatment groups: untreated control, high-cholesterol diet only, antibodies only, focused US only, and focused US and antibodies. Three sessions of focused US were administered to the treatment groups. RESULTS It was shown that with this animal model, the plaques were 30 μm in diameter. By increasing the number of sessions, the number of plaques decreased (both for focused US only and focused US and antibodies). Without the application of focused US, the average number of plaques dropped from 200/cm2 (before treatment) to 170/cm2 (after treatment). The effect of treatment with focused US with antibodies was more drastic. With 3 BBB opening sessions, the average number of plaques was reduced from 200 to 78/cm2 . CONCLUSIONS This feasibility study had demonstrated that by opening the BBB, it will be possible to deliver exogenous antibodies to the brain, thus eliminating amyloid β plaques. More importantly with repeated opening of the BBB (3 times in this study), the reduction in the number of plaques was increased.
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Affiliation(s)
- Tereza Alecou
- Department of Electrical Engineering, Cyprus University of Technology, Limassol, Cyprus
| | - Marinos Giannakou
- Department of Electrical Engineering, Cyprus University of Technology, Limassol, Cyprus
| | - Christakis Damianou
- Department of Electrical Engineering, Cyprus University of Technology, Limassol, Cyprus
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Menikou G, Yiannakou M, Yiallouras C, Ioannides C, Damianou C. MRI-compatible breast/rib phantom for evaluating ultrasonic thermal exposures. Int J Med Robot 2017; 14. [DOI: 10.1002/rcs.1849] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 05/24/2017] [Accepted: 05/24/2017] [Indexed: 01/12/2023]
Affiliation(s)
| | | | - Christos Yiallouras
- Cyprus University of Technology; Limassol Cyprus
- MEDSONIC LTD; Limassol Cyprus
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Menikou G, Damianou C. Acoustic and thermal characterization of agar based phantoms used for evaluating focused ultrasound exposures. J Ther Ultrasound 2017; 5:14. [PMID: 28572977 PMCID: PMC5452295 DOI: 10.1186/s40349-017-0093-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 03/01/2017] [Indexed: 11/26/2022] Open
Abstract
Background This study describes a series of experimental work completed towards characterizing candidate materials for fabricating brain and muscle tissue mimicking phantoms. Methods The acoustic speed, attenuation, impedance, thermal diffusivity, specific heat and thermal conductivity were measured. Results The resulting brain (2% w/v agar-1.2% w/v Silica Dioxide-25%v/v evaporated milk) and muscle tissue recipe (2% w/v agar-2% w/v Silica Dioxide-40%v/v evaporated milk) introduced a total attenuation coefficient of 0.59 dB/cm-MHz and 0.99 dB/cm-MHz respectively. Acrylonitrile Butadiene Styrene (ABS) possessed an attenuation coefficient of 16 dB/cm at 1 MHz which was found within the very wide range of attenuation coefficient values of human bones in literature. The thermal conductivity of the brain tissue phantom was estimated at 0.52 W/m°C and at 0.57 W/m.°Cfor the muscle. These values demonstrated that the proposed recipes conducted heat similar to the majority of most soft tissues found from bibliography. The soft tissue phantoms were also evaluated for their thermal repeatability after treating them repeatedly at different locations with the same sonication protocol and configuration. The average coefficient of variation of the maximum temperature at focus between the different locations was 2.6% for the brain phantom and 2.8% for the muscle phantom. Conclusions The proposed phantom closely matched the acoustic and thermal properties of tissues. Experiments using MR thermometry demonstrated the usefulness of this phantom to evaluate ultrasonic exposures.
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Affiliation(s)
- Georgios Menikou
- Research Centre for Biomedical Engineering, City, University of London, London, UK
| | - Christakis Damianou
- Electrical Engineering Department, Cyprus University of Technology, Limassol, Cyprus
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Fowlkes B, Ghanouni P, Sanghvi N, Coussios C, Lyon PC, Gray M, Mannaris C, Victor MDS, Stride E, Cleveland R, Carlisle R, Wu F, Middleton M, Gleeson F, Aubry JF, Pauly KB, Moonen C, Vortman J, Ghanouni P, Sharabi S, Daniels D, Last D, Guez D, Levy Y, Volovick A, Grinfeld J, Rachmilevich I, Amar T, Zibly Z, Mardor Y, Harnof S, Plaksin M, Weissler Y, Shoham S, Kimmel E, Naor O, Farah N, Shoham S, Paeng DG, Xu Z, Snell J, Quigg AH, Eames M, Jin C, Everstine AC, Sheehan JP, Lopes BS, Kassell N, Looi T, Khokhlova V, Mougenot C, Hynynen K, Drake J, Slayton M, Amodei RC, Compton K, McNelly A, Latt D, Slayton M, Amodei RC, Compton K, Kearney J, Melodelima D, Dupre A, Chen Y, Perol D, Vincenot J, Chapelon JY, Rivoire M, Guo W, Ren G, Shen G, Neidrauer M, Zubkov L, Weingarten MS, Margolis DJ, Lewin PA, McDannold N, Sutton J, Vykhodtseva N, Livingstone M, Kobus T, Zhang YZ, Vykhodtseva N, McDannold N, Schwartz M, Huang Y, Lipsman N, Jain J, Chapman M, Sankar T, Lozano A, Hynynen K, Schwartz M, Yeung R, Huang Y, Lipsman N, Jain J, Chapman M, Lozano A, Hynynen K, Damianou C, Papadopoulos N, Volovick A, Grinfeld J, Levy Y, Brokman O, Zadicario E, Brenner O, Castel D, Wu SY, Grondin J, Zheng W, Heidmann M, Karakatsani ME, Sánchez CJS, Ferrera V, Konofagou EE, Damianou C, Yiannakou M, Cho H, Lee H, Han M, Choi JR, Lee T, Ahn S, Chang Y, Park J, Ellens N, Partanen A, Farahani K, Airan R, Carpentier A, Canney M, Vignot A, Lafon C, Chapelon JY, Delattre JY, Idbaih A, Odéen H, Bolster B, Jeong EK, Parker DL, Gaur P, Feng X, Fielden S, Meyer C, Werner B, Grissom W, Marx M, Ghanouni P, Pauly KB, Weber H, Taviani V, Pauly KB, Ghanouni P, Hargreaves B, Tanaka J, Kikuchi K, Ishijima A, Azuma T, Minamihata K, Yamaguchi S, Nagamune T, Sakuma I, Takagi S, Santin MD, Marsac L, Maimbourg G, Monfort M, Larrat B, François C, Lehéricy S, Tanter M, Aubry JF, Karakatsani ME, Samiotaki G, Wang S, Acosta C, Feinberg ER, Konofagou EE, Kovacs ZI, Tu TW, Papadakis GZ, Reid WC, Hammoud DA, Frank JA, Kovacs ZI, Kim S, Jikaria N, Bresler M, Qureshi F, Frank JA, Xia J, Tsui PS, Liu HL, Plata JC, Fielden S, Sveinsson B, Hargreaves B, Meyer C, Pauly KB, Plata JC, Salgaonkar VA, Adams M, Diederich C, Ozhinsky E, Bucknor MD, Rieke V, Partanen A, Mikhail A, Severance L, Negussie AH, Wood B, de Greef M, Schubert G, Moonen C, Ries M, Poorman ME, Dockery M, Chaplin V, Dudzinski SO, Spears R, Caskey C, Giorgio T, Grissom W, Costa MM, Papaevangelou E, Shah A, Rivens I, Box C, Bamber J, ter Haar G, Burks SR, Nagle M, Nguyen B, Bresler M, Frank JA, Burks SR, Nagle M, Nguyen B, Bresler M, Kim S, Milo B, Frank JA, Le NM, Song S, Zhou K, Nabi G, Huang Z, Ben-Ezra S, Rosen S, Mihcin S, Strehlow J, Karakitsios I, Le N, Schwenke M, Demedts D, Prentice P, Haase S, Preusser T, Melzer A, Mestas JL, Chettab K, Gomez GS, Dumontet C, Werle B, Lafon C, Marquet F, Bour P, Vaillant F, Amraoui S, Dubois R, Ritter P, Haïssaguerre M, Hocini M, Bernus O, Quesson B, Livneh A, Kimmel E, Adam D, Robin J, Arnal B, Fink M, Tanter M, Pernot M, Khokhlova TD, Schade GR, Wang YN, Kreider W, Simon J, Starr F, Karzova M, Maxwell A, Bailey MR, Khokhlova V, Lundt JE, Allen SP, Sukovich JR, Hall T, Xu Z, Schade GR, Wang YN, Khokhlova TD, May P, Lin DW, Bailey MR, Khokhlova V, Constans C, Deffieux T, Tanter M, Aubry JF, Park EJ, Ahn YD, Kang SY, Park DH, Lee JY, Vidal-Jove J, Perich E, Ruiz A, Jaen A, Eres N, del Castillo MA, Myers R, Kwan J, Coviello C, Rowe C, Crake C, Finn S, Jackson E, Carlisle R, Coussios C, Pouliopoulos A, Li C, Tinguely M, Tang MX, Garbin V, Choi JJ, Lyon PC, Mannaris C, Gray M, Folkes L, Stratford M, Carlisle R, Wu F, Middleton M, Gleeson F, Coussios C, Nwokeoha S, Carlisle R, Cleveland R, Wang YN, Khokhlova TD, Li T, Farr N, D’Andrea S, Starr F, Gravelle K, Chen H, Partanen A, Lee D, Hwang JH, Tardoski S, Ngo J, Gineyts E, Roux JP, Clézardin P, Melodelima D, Conti A, Magnin R, Gerstenmayer M, Lux F, Tillement O, Mériaux S, Penna SD, Romani GL, Dumont E, Larrat B, Sun T, Power C, Zhang YZ, Sutton J, Miller E, McDannold N, Sapozhnikov O, Tsysar S, Yuldashev PV, Khokhlova V, Svet V, Kreider W, Li D, Pellegrino A, Petrinic N, Siviour C, Jerusalem A, Cleveland R, Yuldashev PV, Karzova M, Cunitz BW, Dunmire B, Kreider W, Sapozhnikov O, Bailey MR, Khokhlova V, Inserra C, Guedra M, Mauger C, Gilles B, Solovchuk M, Sheu TWH, Thiriet M, Zhou Y, Neufeld E, Baumgartner C, Payne D, Kyriakou A, Kuster N, Xiao X, McLeod H, Melzer A, Dillon C, Rieke V, Ghanouni P, Parker DL, Payne A, Khokhova VA, Yuldashev PV, Sinilshchikov I, Andriyakhina Y, Khokhlova TD, Kreider W, Maxwell A, Sapozhnikov O, Partanen A, Rybyanets A, Shvetsova N, Berkovich A, Shvetsov I, Sapozhnikov O, Khokhlova V, Shaw CJ, Rivens I, Civale J, Giussani D, ter Haar G, Lees C, Bour P, Marquet F, Ozenne V, Toupin S, Quesson B, Dumont E, Ozhinsky E, Salgaonkar V, Diederich C, Rieke V, Kaye E, Monette S, Maybody M, Srimathveeravalli G, Solomon S, Gulati A, Preusser T, Haase S, Bezzi M, Jenne JW, Lango T, Levy Y, Müller M, Sat G, Tanner C, Zangos S, Günther M, Melzer A, Lafon C, Dinh AH, Niaf E, Bratan F, Guillen N, Souchon R, Lartizien C, Crouzet S, Rouviere O, Chapelon JY, Han Y, Wang S, Konofagou EE, Payen T, Palermo C, Sastra S, Chen H, Han Y, Olive K, Konofagou EE, van Breugel JM, de Greef M, Mougenot C, van den Bosch MA, Moonen C, Ries M, Gerstenmayer M, Magnin R, Fellah B, Le Bihan D, Larrat B, Gerstenmayer M, Magnin R, Mériaux S, Le Bihan D, Larrat B, Allen SP, Hernandez-Garcia L, Cain CA, Hall T, Lyka E, Elbes D, Coviello C, Cleveland R, Coussios C, Zhou K, Le NM, Li C, Huang Z, Tamano S, Jimbo H, Azuma T, Yoshizawa S, Fujiwara K, Itani K, Umemura SI, Damianou C, Yiannakou M, Ellens N, Partanen A, Stoianovici D, Farahani K, Zaini Z, Takagi R, Yoshizawa S, Umemura SI, Zong S, Shen G, Watkins R, Pascal-Tenorio A, Adams M, Plata JC, Salgaonkar V, Jones P, Butts-Pauly K, Diederich C, Bouley D, Rybyanets A, Ren G, Guo W, Shen G, Chen Y, Lin CY, Hsieh HY, Wei KC, Liu HL, Garnier C, Renault G, Farr N, Partanen A, Negussie AH, Mikhail A, Seifabadi R, Wilson E, Eranki A, Kim P, Wood B, Lübke D, Jenne JW, Huber P, Günther M, Lübke D, Georgii J, Schwenke M, Dresky CV, Haller J, Günther M, Preusser T, Jenne JW, Eranki A, Farr N, Partanen A, Yarmolenko P, Negussie AH, Sharma K, Celik H, Wood B, Kim P, Li G, Qiu W, Zheng H, Tsai MY, Chu PC, Liu HL, Webb T, Vyas U, Pauly KB, Walker M, Zhong J, Looi T, Waspe AC, Drake J, Hodaie M, Yang FY, Huang SL, Zur Y, Volovick A, Assif B, Aurup C, Kamimura H, Wang S, Chen H, Acosta C, Carneiro AA, Konofagou EE, Volovick A, Grinfeld J, Castel D, Rothlübbers S, Schwaab J, Tanner C, Mihcin S, Houston G, Günther M, Jenne JW, Ozhinsky E, Bucknor MD, Rieke V, Azhari H, Weiss N, Sosna J, Goldberg SN, Barrere V, Melodelima D, Jang KW, Burks SR, Kovacs ZI, Tu TW, Lewis B, Kim S, Nagle M, Jikaria N, Frank JA, Zhou Y, Wang X, Ahn YD, Park EJ, Park DH, Kang SY, Lee JY, Suomi V, Konofagou EE, Edwards D, Cleveland R, Larrabee Z, Eames M, Hananel A, Aubry JF, Rafaely B, Volovick A, Grinfeld J, Kimmel E, Debbiny RE, Dekel CZ, Assa M, Kimmel E, Menikou G, Damianou C, Mouratidis P, Rivens I, ter Haar G, Pineda-Pardo JA, de Pedro MDÁ, Martinez R, Hernandez F, Casas S, Oliver C, Pastor P, Vela L, Obeso J, Greillier P, Zorgani A, Souchon R, Melodelima D, Catheline S, Lafon C, Solovov V, Vozdvizhenskiy MO, Orlov AE, Wu CH, Sun MK, Shih TT, Chen WS, Prieur F, Pillon A, Mestas JL, Cartron V, Cebe P, Chansard N, Lafond M, Lafon C, Inserra C, Seya PM, Chen WS, Bera JC, Boissenot T, Larrat B, Fattal E, Bordat A, Chacun H, Guetin C, Tsapis N, Maruyama K, Unga J, Suzuki R, Fant C, Lafond M, Rogez B, Ngo J, Lafon C, Mestas JL, Afadzi M, Myhre OF, Vea S, Bjørkøy A, Yemane PT, van Wamel A, Berg S, Hansen R, Angelsen B, Davies C. International Society for Therapeutic Ultrasound Conference 2016. J Ther Ultrasound 2017. [PMCID: PMC5374646 DOI: 10.1186/s40349-016-0079-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
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Papadopoulos N, Damianou C. Microbubble-Based Sonothrombolysis Using a Planar Rectangular Ultrasonic Transducer. J Stroke Cerebrovasc Dis 2017; 26:1287-1296. [PMID: 28236599 DOI: 10.1016/j.jstrokecerebrovasdis.2017.01.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 12/13/2016] [Accepted: 01/24/2017] [Indexed: 10/20/2022] Open
Abstract
BACKGROUND The aim of the proposed study was to evaluate in an in vitro flow model the ability of small planar rectangular (2 × 10 mm2) ultrasonic transducer to enhance thrombolysis induced by the thrombolytic agent tenecteplase (TNK-tPA). METHODS To provide a more realistic clinical environment of stroke, the study was conducted under realistic flow conditions and TNK-tPA concentrations. Fully retracted porcine blood clots were used to determine the thrombolytic efficacy of ultrasound (US) waves as an adjunct to TNK-tPA or in combination with microbubbles (MBs). Two ultrasonic flat rectangular transducers were used in the experiments, operating at 3.7 and 5.2 MHz respectively. A pulsed US protocol that maintained temperature elevation at the target of 1°C was applied. Thrombolysis efficacy was measured in milligrams of mass clot removed. RESULTS The effect of experimental parameters, such as power, frequency, and MBs administration, on thrombolysis efficacy was explored. CONCLUSIONS The results revealed that thrombolysis efficacy decreases at higher frequency, and therefore, the possibility of using lower frequency to improve efficacy should be further investigated. Additionally, study findings demonstrated that the combination of 3.7 MHz with MBs as an adjunct to TNK-tPA strongly enhanced thrombolysis efficacy, because with 30 minutes of treatment, 700 mg of clot was removed through nonthermal mechanisms. As a final point, this study has shown that MBs dose influences thrombolysis enhancement, because higher thrombolytic efficacy was observed with higher doses of MBs.
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Affiliation(s)
| | - Christakis Damianou
- Electrical Engineering Department, Cyprus University of Technology, Limassol, Cyprus.
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Yiannakou M, Menikou G, Yiallouras C, Ioannides C, Damianou C. MRI guided focused ultrasound robotic system for animal experiments. Int J Med Robot 2017; 13. [PMID: 28211622 DOI: 10.1002/rcs.1804] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 12/12/2016] [Accepted: 12/13/2016] [Indexed: 11/07/2022]
Abstract
BACKGROUND In this paper an MRI-guided focused ultrasound (MRgFUS) robotic system was developed that can be used for conducting experiments in small animals.The target for this robotic system regarding motion was to move a therapeutic ultrasound transducer in two Cartesian axes. METHODS A single element spherically focused transducer of 3 cm diameter, focusing at 7 cm and operating at 0.4 MHz was used. The positioning device incorporates only MRI compatible materials. The propagation of ultrasound is a bottom to top approach. The 2-D positioning device is controlled by custom-made software and a custom-made electronic system which controls the two piezoelectric motors. RESULTS The system was tested successfully in agar/silica/evaporated milk phantom for various tasks (robot motion, MR compatibility, and MR thermometry). The robotic system is capable of moving the focused ultrasound transducer to perform MR-guided focused ultrasound experiments in small animals. CONCLUSIONS This system has the potential to be deployed as a cost effective solution for performing experiments in small animals.
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Affiliation(s)
- Marinos Yiannakou
- Electrical Engineering Department, Cyprus University of Technology, Cyprus
| | | | - Christos Yiallouras
- Electrical Engineering Department, Cyprus University of Technology, Cyprus.,R&D, MEDSONIC LTD, Limassol, Cyprus
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Papadopoulos N, Menikou G, Yiannakou M, Yiallouras C, Ioannides K, Damianou C. Evaluation of a small flat rectangular therapeutic ultrasonic transducer intended for intravascular use. Ultrasonics 2017; 74:196-203. [PMID: 27835808 DOI: 10.1016/j.ultras.2016.10.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 09/26/2016] [Accepted: 10/28/2016] [Indexed: 06/06/2023]
Abstract
BACKGROUND The aim of the proposed study was to evaluate the performance of a flat rectangular (2×10mm2) transducer operating at 4MHz. The intended application of this transducer is intravascular treatment of thrombosis and atherosclerosis. METHODS The transducer's thermal capabilities were tested in two different gel phantoms. MR thermometry was used to demonstrate the thermal capabilities of this type of transducer. RESULTS Temperature measurements demonstrated that this simple and small transducer adequately produced high temperatures, which can be utilized for therapeutic purposes. These high temperatures were confirmed using thermocouple and MR measurements. Pulsed ultrasound in combination with thrombolytic drugs and microbubbles was utilized to eliminate porcine thrombi. CONCLUSIONS The proposed transducer has the potentials to treat atherosclerotic lesions using the thermal properties of ultrasound, since high temperatures can be achieved in less than 5s. The results revealed that the destruction of thrombi using pulsed ultrasound requires long exposure time and high microbubble dosage.
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Affiliation(s)
- N Papadopoulos
- Department of Bioengineering, City University, London, UK
| | - G Menikou
- Department of Bioengineering, City University, London, UK
| | - M Yiannakou
- Electrical Engineering Department, Cyprus University of Technology, Cyprus
| | - C Yiallouras
- Electrical Engineering Department, Cyprus University of Technology, Cyprus; R&D, MEDSONIC LTD, Limassol, Cyprus
| | - K Ioannides
- Radiology, Ygia Polyclinic, Limassol, Cyprus
| | - C Damianou
- Electrical Engineering Department, Cyprus University of Technology, Cyprus.
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