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Geometric impact and dose estimation of on-patient placement of a lightweight receiver coil in a clinical magnetic resonance imaging-only radiotherapy workflow for prostate cancer

Scherman, Jonas ; af Wetterstedt, Sacha ; Persson, Emilia LU ; Olsson, Lars E. LU orcid and Jamtheim Gustafsson, Christian LU (2023) In Physics and imaging in radiation oncology 26.
Abstract

Background and Purpose: For pelvic magnetic resonance imaging (MRI)-only radiotherapy the use of receiver coil bridges (CB) is recommended to avoid deformation of the patient. Development in coil technology has enabled lightweight, flexible coils. In this work we evaluate the effects of a lightweight coil in a pelvic MRI-only radiotherapy workflow. Materials and Methods: Twenty-one patients, referred to prostate MRI-only radiotherapy, were included. Images were acquired with and without CB. Anatomical deformation from the on-patient coil placement was measured in the anterior-posterior (AP) and left–right (LR) direction. The change in signal-to-noise ratio (SNR) was measured in phantom and in vivo. The clinical treatment plan, created... (More)

Background and Purpose: For pelvic magnetic resonance imaging (MRI)-only radiotherapy the use of receiver coil bridges (CB) is recommended to avoid deformation of the patient. Development in coil technology has enabled lightweight, flexible coils. In this work we evaluate the effects of a lightweight coil in a pelvic MRI-only radiotherapy workflow. Materials and Methods: Twenty-one patients, referred to prostate MRI-only radiotherapy, were included. Images were acquired with and without CB. Anatomical deformation from the on-patient coil placement was measured in the anterior-posterior (AP) and left–right (LR) direction. The change in signal-to-noise ratio (SNR) was measured in phantom and in vivo. The clinical treatment plan, created on the image with CB, was transferred and recalculated on the image without the CB. Dose metrics for the targets (planning- and clinical target volume) and organs at risks (OAR) were analyzed. Results: There was a statistically significant increase in SNR in-vivo (median 21 %, p = 0.002) when removing the CB. Anatomical differences after removing the CB in patients were −1.5 mm in AP (median change) and + 2.5 mm in LR direction. Dosimetric differences for the target structures were clinically negligible, but statistically significant. The difference in target mean doses were 0.2 % (both p = 0.004) of the prescribed dose. No dosimetric differences were observed for the OAR, except for the penile bulb. Conclusions: We concluded that anatomical change and dosimetric differences, originating from scanning without CB were minor. The CB can thereby be removed from the workflow, enabling easier patient positioning and increased SNR when using lightweight coils.

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author
; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Coil bridge, MRI-only, Prostate cancer, Radiotherapy
in
Physics and imaging in radiation oncology
volume
26
article number
100433
publisher
Elsevier
external identifiers
  • pmid:37063614
  • scopus:85151298372
ISSN
2405-6316
DOI
10.1016/j.phro.2023.100433
language
English
LU publication?
yes
id
c1a52b62-8728-441b-b3ed-ecdd00ddb302
date added to LUP
2023-05-22 13:18:19
date last changed
2024-06-29 04:18:03
@article{c1a52b62-8728-441b-b3ed-ecdd00ddb302,
  abstract     = {{<p>Background and Purpose: For pelvic magnetic resonance imaging (MRI)-only radiotherapy the use of receiver coil bridges (CB) is recommended to avoid deformation of the patient. Development in coil technology has enabled lightweight, flexible coils. In this work we evaluate the effects of a lightweight coil in a pelvic MRI-only radiotherapy workflow. Materials and Methods: Twenty-one patients, referred to prostate MRI-only radiotherapy, were included. Images were acquired with and without CB. Anatomical deformation from the on-patient coil placement was measured in the anterior-posterior (AP) and left–right (LR) direction. The change in signal-to-noise ratio (SNR) was measured in phantom and in vivo. The clinical treatment plan, created on the image with CB, was transferred and recalculated on the image without the CB. Dose metrics for the targets (planning- and clinical target volume) and organs at risks (OAR) were analyzed. Results: There was a statistically significant increase in SNR in-vivo (median 21 %, p = 0.002) when removing the CB. Anatomical differences after removing the CB in patients were −1.5 mm in AP (median change) and + 2.5 mm in LR direction. Dosimetric differences for the target structures were clinically negligible, but statistically significant. The difference in target mean doses were 0.2 % (both p = 0.004) of the prescribed dose. No dosimetric differences were observed for the OAR, except for the penile bulb. Conclusions: We concluded that anatomical change and dosimetric differences, originating from scanning without CB were minor. The CB can thereby be removed from the workflow, enabling easier patient positioning and increased SNR when using lightweight coils.</p>}},
  author       = {{Scherman, Jonas and af Wetterstedt, Sacha and Persson, Emilia and Olsson, Lars E. and Jamtheim Gustafsson, Christian}},
  issn         = {{2405-6316}},
  keywords     = {{Coil bridge; MRI-only; Prostate cancer; Radiotherapy}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{Physics and imaging in radiation oncology}},
  title        = {{Geometric impact and dose estimation of on-patient placement of a lightweight receiver coil in a clinical magnetic resonance imaging-only radiotherapy workflow for prostate cancer}},
  url          = {{http://dx.doi.org/10.1016/j.phro.2023.100433}},
  doi          = {{10.1016/j.phro.2023.100433}},
  volume       = {{26}},
  year         = {{2023}},
}