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@ARTICLE{Niebuhr:130243,
author = {N. I. Niebuhr$^*$ and W. Johnen$^*$ and T. Güldaglar$^*$
and A. Runz$^*$ and G. Echner$^*$ and P. Mann$^*$ and C.
Möhler$^*$ and A. Pfaffenberger$^*$ and O. Jäkel$^*$ and
S. Greilich$^*$},
title = {{T}echnical {N}ote: {R}adiological properties of tissue
surrogates used in a multimodality deformable pelvic phantom
for {MR}-guided radiotherapy.},
journal = {Medical physics},
volume = {43},
number = {2},
issn = {0094-2405},
address = {New York, NY},
reportid = {DKFZ-2017-05323},
pages = {908 - 916},
year = {2016},
abstract = {Phantom surrogates were developed to allow multimodal
[computed tomography (CT), magnetic resonance imaging (MRI),
and teletherapy] and anthropomorphic tissue simulation as
well as materials and methods to construct deformable organ
shapes and anthropomorphic bone models.Agarose gels of
variable concentrations and loadings were investigated to
simulate various soft tissue types. Oils, fats, and Vaseline
were investigated as surrogates for adipose tissue and bone
marrow. Anthropomorphic shapes of bone and organs were
realized using 3D-printing techniques based on segmentations
of patient CT-scans. All materials were characterized in
dual energy CT and MRI to adapt CT numbers, electron
density, effective atomic number, as well as T1- and
T2-relaxation times to patient and literature values.Soft
tissue simulation could be achieved with agarose gels in
combination with a gadolinium-based contrast agent and NaF
to simulate muscle, prostate, and tumor tissues. Vegetable
oils were shown to be a good representation for adipose
tissue in all modalities. Inner bone was realized using a
mixture of Vaseline and K2HPO4, resulting in both a fatty
bone marrow signal in MRI and inhomogeneous areas of low and
high attenuation in CT. The high attenuation of outer bone
was additionally adapted by applying gypsum bandages to the
3D-printed hollow bone case with values up to 1200 HU.
Deformable hollow organs were manufactured using silicone.
Signal loss in the MR images based on the conductivity of
the gels needs to be further investigated.The presented
surrogates and techniques allow the customized construction
of multimodality, anthropomorphic, and deformable phantoms
as exemplarily shown for a pelvic phantom, which is intended
to study adaptive treatment scenarios in MR-guided radiation
therapy.},
cin = {E040},
ddc = {610},
cid = {I:(DE-He78)E040-20160331},
pnm = {315 - Imaging and radiooncology (POF3-315)},
pid = {G:(DE-HGF)POF3-315},
typ = {PUB:(DE-HGF)16},
pubmed = {pmid:26843251},
doi = {10.1118/1.4939874},
url = {https://inrepo02.dkfz.de/record/130243},
}