Adams, C, McLaughlan, JR orcid.org/0000-0001-5795-4372, Carpenter, TM orcid.org/0000-0001-5676-1739 et al. (1 more author) (2020) HIFU Power Monitoring Using Combined Instantaneous Current and Voltage Measurement. IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, 67 (2). ISSN 0885-3010
Abstract
During HIFU therapy it is important that the electrical power delivered to the transducer is monitored to avoid under or over exposure, ensure patient safety and to protect the transducer itself. Due to ease of measurement, the transducer’s potential difference may be as an indicator of power delivery. However, even when a transducer’s complex impedance is well characterised at small amplitudes and matching networks are used, voltage-only (VO) monitoring cannot account for the presence of drive waveform distortion, changes to the acoustic path or damage to the transducer. In this study, combined current and voltage (CCV) is proposed as an MRI-compatible, miniature alternative to bi-directional power couplers that is compatible with switched amplifiers. For CCV power measurement, current probe data was multiplied by the voltage waveform and integrated in the frequency domain. Transducer efficiency was taken into account to predict acoustic power. The technique was validated with a radiation force balance (RFB). When using a typical HIFU transducer and amplifier, VO predictions and acoustic power had a maximum difference of 20%. However, under the same conditions, CCV only had a maximum difference of 5%. The technique was applied to several lesioning experiments and it was shown that when VO was used as a control between two amplifiers there was up to a 38% difference in lesion area. This greatly reduced to a maximum of 5% once CCV was used instead. These results demonstrate that CCV can accurately predict real-time electrical power delivery leading to safer HIFU treatments.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2019 IEEE. This is an author produced version of a paper published in IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Transducers; Acoustics; Impedance; Voltage measurement; Acoustic measurements; Frequency control; Current measurement |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Electronic & Electrical Engineering (Leeds) > Robotics, Autonomous Systems & Sensing (Leeds) |
Funding Information: | Funder Grant number EPSRC EP/P023266/1 EPSRC Not Known Royal Society RG170324 EPSRC EP/S001069/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 24 Oct 2019 13:47 |
Last Modified: | 21 Feb 2020 05:55 |
Status: | Published |
Publisher: | Institute of Electrical and Electronics Engineers |
Identification Number: | 10.1109/TUFFC.2019.2941185 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:152553 |