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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 2024; 27:263-274. [PMID: 37517052 PMCID: PMC11178743 DOI: 10.1007/s40477-023-00810-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 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, Evripidou N, Chrysanthou A, Georgiou L, Ioannides C, Spanoudes K, Damianou C. Effect of Magnetic Resonance Imaging on the Motion Accuracy of Magnetic Resonance Imaging-compatible Focused Ultrasound Robotic System. J Med Phys 2024; 49:203-212. [PMID: 39131431 PMCID: PMC11309133 DOI: 10.4103/jmp.jmp_7_24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 02/23/2024] [Accepted: 03/29/2024] [Indexed: 08/13/2024] Open
Abstract
Purpose The current study provides insights into the challenges of safely operating a magnetic resonance imaging (MRI)-guided focused ultrasound (MRgFUS) robotic system in a high-field MRI scanner in terms of robotic motion accuracy. Materials and Methods Grid sonications were carried out in phantoms and excised porcine tissue in a 3T MRI scanner using an existing MRgFUS robotic system. Fast low-angle shot-based magnetic resonance thermometry was employed for the intraprocedural monitoring of thermal distribution. Results Strong shifting of the heated spots from the intended points was observed owing to electromagnetic interference (EMI)-induced malfunctions in system's operation. Increasing the slice thickness of the thermometry sequence to at least 8 mm was proven an efficient method for preserving the robotic motion accuracy. Conclusions These findings raise awareness about EMI effects on the motion accuracy of MRgFUS robotic devices and how they can be mitigated by employing suitable thermometry parameters.
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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
| | - Antreas Chrysanthou
- Department of Interventional Radiology, German Oncology Center, 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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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] [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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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: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [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, 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] [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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Gunderman A, Montayre R, Ranjan A, Chen Y. Review of Robot-Assisted HIFU Therapy. SENSORS (BASEL, SWITZERLAND) 2023; 23:3707. [PMID: 37050766 PMCID: PMC10098661 DOI: 10.3390/s23073707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 03/07/2023] [Accepted: 03/14/2023] [Indexed: 06/19/2023]
Abstract
This paper provides an overview of current robot-assisted high-intensity focused ultrasound (HIFU) systems for image-guided therapies. HIFU is a minimally invasive technique that relies on the thermo-mechanical effects of focused ultrasound waves to perform clinical treatments, such as tumor ablation, mild hyperthermia adjuvant to radiation or chemotherapy, vein occlusion, and many others. HIFU is typically performed under ultrasound (USgHIFU) or magnetic resonance imaging guidance (MRgHIFU), which provide intra-operative monitoring of treatment outcomes. Robot-assisted HIFU probe manipulation provides precise HIFU focal control to avoid damage to surrounding sensitive anatomy, such as blood vessels, nerve bundles, or adjacent organs. These clinical and technical benefits have promoted the rapid adoption of robot-assisted HIFU in the past several decades. This paper aims to present the recent developments of robot-assisted HIFU by summarizing the key features and clinical applications of each system. The paper concludes with a comparison and discussion of future perspectives on robot-assisted HIFU.
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Affiliation(s)
- Anthony Gunderman
- Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Rudy Montayre
- Department of Physiological Sciences, College of Veterinary Medicine, Oklahoma State University, Stillwater, OK 74078, USA
| | - Ashish Ranjan
- Department of Physiological Sciences, College of Veterinary Medicine, Oklahoma State University, Stillwater, OK 74078, USA
| | - Yue Chen
- Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
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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] [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] [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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Antoniou A, Georgiou L, Evripidou N, Ioannides C, Damianou C. Challenges regarding MR compatibility of an MRgFUS robotic system. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 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] [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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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] [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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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] [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, Giannakou M, Menikou G, Damianou C. Magnetic Resonance Imaging-Guided Focused Ultrasound Positioning System for Preclinical Studies in Small Animals. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 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] [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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Dai J, He Z, Fang G, Wang X, Li Y, Cheung CL, Liang L, Iordachita I, Chang HC, Kwok KW. A Robotic Platform to Navigate MRI-guided Focused Ultrasound System. IEEE Robot Autom Lett 2021. [DOI: 10.1109/lra.2021.3068953] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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14
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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] [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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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] [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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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] [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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Chen Y, Pais-Roldan P, Chen X, Frosz MH, Yu X. MRI-guided robotic arm drives optogenetic fMRI with concurrent Ca 2+ recording. Nat Commun 2019; 10:2536. [PMID: 31182714 PMCID: PMC6557837 DOI: 10.1038/s41467-019-10450-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Accepted: 05/11/2019] [Indexed: 12/16/2022] Open
Abstract
Optical fiber-mediated optogenetic activation and neuronal Ca2+ recording in combination with fMRI provide a multi-modal fMRI platform. Here, we developed an MRI-guided robotic arm (MgRA) as a flexible positioning system with high precision to real-time assist optical fiber brain intervention for multi-modal animal fMRI. Besides the ex vivo precision evaluation, we present the highly reliable brain activity patterns in the projected basal forebrain regions upon MgRA-driven optogenetic stimulation in the lateral hypothalamus. Also, we show the step-wise optical fiber targeting thalamic nuclei and map the region-specific functional connectivity with whole-brain fMRI accompanied by simultaneous calcium recordings to specify its circuit-specificity. The MgRA also guides the real-time microinjection to specific deep brain nuclei, which is demonstrated by an Mn-enhanced MRI method. The MgRA represents a clear advantage over the standard stereotaxic-based fiber implantation and opens a broad avenue to investigate the circuit-specific functional brain mapping with the multi-modal fMRI platform.
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Affiliation(s)
- Yi Chen
- Research Group of Translational Neuroimaging and Neural Control, High-Field Magnetic Resonance, Max Planck Institute for Biological Cybernetics, 72076, Tuebingen, Germany
- Graduate Training Centre of Neuroscience, University of Tuebingen, 72076, Tuebingen, Germany
| | - Patricia Pais-Roldan
- Research Group of Translational Neuroimaging and Neural Control, High-Field Magnetic Resonance, Max Planck Institute for Biological Cybernetics, 72076, Tuebingen, Germany
- Graduate Training Centre of Neuroscience, University of Tuebingen, 72076, Tuebingen, Germany
| | - Xuming Chen
- Research Group of Translational Neuroimaging and Neural Control, High-Field Magnetic Resonance, Max Planck Institute for Biological Cybernetics, 72076, Tuebingen, Germany
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan University, 430060 Wuhan, China
| | - Michael H Frosz
- Max Planck Institute for the Science of Light, 91058, Erlangen, Germany
| | - Xin Yu
- Research Group of Translational Neuroimaging and Neural Control, High-Field Magnetic Resonance, Max Planck Institute for Biological Cybernetics, 72076, Tuebingen, Germany.
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, 02129, USA.
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