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@ARTICLE{Fiedler:293575,
author = {T. Fiedler$^*$ and M. E. Ladd$^*$ and S. Orzada$^*$},
title = {{L}ocal and whole-body {SAR} in {UHF} body imaging:
{I}mplications for {SAR} matrix compression.},
journal = {Magnetic resonance in medicine},
volume = {93},
number = {2},
issn = {1522-2594},
address = {New York, NY [u.a.]},
publisher = {Wiley-Liss},
reportid = {DKFZ-2024-01898},
pages = {842-849},
year = {2025},
note = {#EA:E020#LA:E020# / 2025 Feb;93(2):842-849},
abstract = {Transmit arrays for body imaging have characteristics of
both volume and local transmit coils. This study evaluates
two specific absorption rate (SAR) aspects, local and
whole-body SAR, of arrays for body imaging at 7 T and also
for a 3 T birdcage.Simulations were performed for six
antenna arrays at 7 T and one 3 T birdcage. Local SAR
matrices and the whole-body SAR matrix were computed and
evaluated with random shims. A set of reduced local SAR
matrices was determined by removing all matrices dominated
by the whole-body SAR matrix.The results indicate that all
RF transmit coils for body imaging in this study are
constrained by the local SAR limit. The ratio between local
and whole-body SAR is nevertheless smaller for arrays with
large FOV, as these arrays also expose a larger part of the
human body. By using the whole-body SAR matrix, the number
of local SAR matrices can be reduced (e.g., $33.3\%$
matrices remained for an 8-channel local array and $89.7\%$
for a 30-channel remote array; $12.1\%$ for the 3 T
birdcage).For transmit antenna arrays used for body imaging
at 7 T as well as for the 3 T birdcage, all evaluated cases
show that the local SAR limit was reached before reaching
the whole-body SAR limit. Nevertheless, the whole-body SAR
matrix can be used to reduce the number of local SAR
matrices, which is important to reduce memory and computing
time for a virtual observation points (VOP) compression.
This step can be included as a pre-compression prior to a
VOP compression.},
keywords = {UHF body imaging (Other) / VOPs (Other) / local SAR (Other)
/ whole‐body SAR (Other)},
cin = {E020},
ddc = {610},
cid = {I:(DE-He78)E020-20160331},
pnm = {315 - Bildgebung und Radioonkologie (POF4-315)},
pid = {G:(DE-HGF)POF4-315},
typ = {PUB:(DE-HGF)16},
pubmed = {pmid:39301784},
doi = {10.1002/mrm.30306},
url = {https://inrepo02.dkfz.de/record/293575},
}