% IMPORTANT: The following is UTF-8 encoded. This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.
@ARTICLE{Fiedler:132711,
author = {T. Fiedler$^*$ and M. Ladd$^*$ and A. Bitz$^*$},
title = {{SAR} {S}imulations $\&$ {S}afety.},
journal = {NeuroImage},
volume = {168},
issn = {1053-8119},
address = {Orlando, Fla.},
publisher = {Academic Press},
reportid = {DKFZ-2018-00365},
pages = {33 - 58},
year = {2018},
abstract = {At ultra-high fields, the assessment of radiofrequency (RF)
safety presents several new challenges compared to low-field
systems. Multi-channel RF transmit coils in combination with
parallel transmit techniques produce time-dependent and
spatially varying power loss densities in the tissue.
Further, in ultra-high-field systems, localized field
effects can be more pronounced due to a transition from the
quasi stationary to the electromagnetic field regime.
Consequently, local information on the RF field is required
for reliable RF safety assessment as well as for monitoring
of RF exposure during MR examinations. Numerical RF and
thermal simulations for realistic exposure scenarios with
anatomical body models are currently the only practical way
to obtain the requisite local information on magnetic and
electric field distributions as well as tissue temperature.
In this article, safety regulations and the fundamental
characteristics of RF field distributions in
ultra-high-field systems are reviewed. Numerical methods for
computation of RF fields as well as typical requirements for
the analysis of realistic multi-channel RF exposure
scenarios including anatomical body models are highlighted.
In recent years, computation of the local tissue temperature
has become of increasing interest, since a more accurate
safety assessment is expected because temperature is
directly related to tissue damage. Regarding thermal
simulation, bio-heat transfer models and approaches for
taking into account the physiological response of the human
body to RF exposure are discussed. In addition, suitable
methods are presented to validate calculated RF and thermal
results with measurements. Finally, the concept of
generalized simulation-based specific absorption rate (SAR)
matrix models is discussed. These models can be incorporated
into local SAR monitoring in multi-channel MR systems and
allow the design of RF pulses under constraints for local
SAR.},
subtyp = {Review Article},
cin = {E020},
ddc = {610},
cid = {I:(DE-He78)E020-20160331},
pnm = {315 - Imaging and radiooncology (POF3-315)},
pid = {G:(DE-HGF)POF3-315},
typ = {PUB:(DE-HGF)16},
pubmed = {pmid:28336426},
doi = {10.1016/j.neuroimage.2017.03.035},
url = {https://inrepo02.dkfz.de/record/132711},
}