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Segmented RF shield design to minimize eddy currents for low-field Halbach MRI systems.

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Title: Segmented RF shield design to minimize eddy currents for low-field Halbach MRI systems.
Authors: de Vos, Bart1,2 (AUTHOR) b.de_vos@lumc.nl, Remis, Rob2 (AUTHOR), Webb, Andrew1,2 (AUTHOR)
Source: Journal of Magnetic Resonance. May2024, Vol. 362, pN.PAG-N.PAG. 1p.
Subjects: Eddies, Magnetic resonance imaging, Noise measurement, Radio frequency, Work design, Time management
Abstract: MRI systems have a thin conducting layer placed between the gradient and RF coils, this acts as a shield at the RF-frequency, minimizing noise coupled into the experiment, and decreasing the coupling between the RF and gradient coils. Ideally, this layer should be transparent to the gradient fields to reduce eddy currents. In this work the design of such a shield, specifically for low-field point-of-care Halbach based MRI devices, is discussed. A segmented double layer shield is designed and constructed based on eddy current simulations. Subsequently, the performance of the improved shield is compared to a reference shield by measuring the eddy current decay times as well as using noise measurements. A maximum reduction factor of 2.9 in the eddy current decay time is observed. The segmented shield couples in an equivalent amount of noise when compared to the unsegmented reference shield. Turbo spin echo images of a phantom and the brain of a healthy volunteer show improvements in terms of blurring using the segmented shield. [Display omitted] • Segmented shield improves eddy current characteristics while keeping shielding properties. • Shield designed for solenoidal radio frequency transmit/receive coils. • Eddy current simulations with and without segmentation. • Noise measurements with and without segmented shield. [ABSTRACT FROM AUTHOR]
Copyright of Journal of Magnetic Resonance is the property of Academic Press Inc. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database: Engineering Source
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Header DbId: egs
DbLabel: Engineering Source
An: 177313501
AccessLevel: 6
PubType: Academic Journal
PubTypeId: academicJournal
PreciseRelevancyScore: 0
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Items – Name: Title
  Label: Title
  Group: Ti
  Data: Segmented RF shield design to minimize eddy currents for low-field Halbach MRI systems.
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  Label: Authors
  Group: Au
  Data: <searchLink fieldCode="AR" term="%22de+Vos%2C+Bart%22">de Vos, Bart</searchLink><relatesTo>1,2</relatesTo> (AUTHOR)<i> b.de_vos@lumc.nl</i><br /><searchLink fieldCode="AR" term="%22Remis%2C+Rob%22">Remis, Rob</searchLink><relatesTo>2</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Webb%2C+Andrew%22">Webb, Andrew</searchLink><relatesTo>1,2</relatesTo> (AUTHOR)
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  Data: <searchLink fieldCode="JN" term="%22Journal+of+Magnetic+Resonance%22">Journal of Magnetic Resonance</searchLink>. May2024, Vol. 362, pN.PAG-N.PAG. 1p.
– Name: Subject
  Label: Subjects
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  Data: <searchLink fieldCode="DE" term="%22Eddies%22">Eddies</searchLink><br /><searchLink fieldCode="DE" term="%22Magnetic+resonance+imaging%22">Magnetic resonance imaging</searchLink><br /><searchLink fieldCode="DE" term="%22Noise+measurement%22">Noise measurement</searchLink><br /><searchLink fieldCode="DE" term="%22Radio+frequency%22">Radio frequency</searchLink><br /><searchLink fieldCode="DE" term="%22Work+design%22">Work design</searchLink><br /><searchLink fieldCode="DE" term="%22Time+management%22">Time management</searchLink>
– Name: Abstract
  Label: Abstract
  Group: Ab
  Data: MRI systems have a thin conducting layer placed between the gradient and RF coils, this acts as a shield at the RF-frequency, minimizing noise coupled into the experiment, and decreasing the coupling between the RF and gradient coils. Ideally, this layer should be transparent to the gradient fields to reduce eddy currents. In this work the design of such a shield, specifically for low-field point-of-care Halbach based MRI devices, is discussed. A segmented double layer shield is designed and constructed based on eddy current simulations. Subsequently, the performance of the improved shield is compared to a reference shield by measuring the eddy current decay times as well as using noise measurements. A maximum reduction factor of 2.9 in the eddy current decay time is observed. The segmented shield couples in an equivalent amount of noise when compared to the unsegmented reference shield. Turbo spin echo images of a phantom and the brain of a healthy volunteer show improvements in terms of blurring using the segmented shield. [Display omitted] • Segmented shield improves eddy current characteristics while keeping shielding properties. • Shield designed for solenoidal radio frequency transmit/receive coils. • Eddy current simulations with and without segmentation. • Noise measurements with and without segmented shield. [ABSTRACT FROM AUTHOR]
– Name: AbstractSuppliedCopyright
  Label:
  Group: Ab
  Data: <i>Copyright of Journal of Magnetic Resonance is the property of Academic Press Inc. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.)
PLink https://search.ebscohost.com/login.aspx?direct=true&site=eds-live&db=egs&AN=177313501
RecordInfo BibRecord:
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    Identifiers:
      – Type: doi
        Value: 10.1016/j.jmr.2024.107669
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      – Code: eng
        Text: English
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      Pagination:
        PageCount: 1
        StartPage: N.PAG
    Subjects:
      – SubjectFull: Eddies
        Type: general
      – SubjectFull: Magnetic resonance imaging
        Type: general
      – SubjectFull: Noise measurement
        Type: general
      – SubjectFull: Radio frequency
        Type: general
      – SubjectFull: Work design
        Type: general
      – SubjectFull: Time management
        Type: general
    Titles:
      – TitleFull: Segmented RF shield design to minimize eddy currents for low-field Halbach MRI systems.
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            NameFull: de Vos, Bart
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            NameFull: Remis, Rob
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            NameFull: Webb, Andrew
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            – D: 01
              M: 05
              Text: May2024
              Type: published
              Y: 2024
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              Value: 362
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