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@ARTICLE{Piroth:810995,
author = {Piroth, Marc D. and Galldiks, Norbert and Pinkawa, Michael
and Holy, Richard and Stoffels, Gabriele and Ermert,
Johannes and Mottaghy, Felix M. and Shah, N. J. and Langen,
Karl-Josef and Eble, Michael J.},
title = {{R}elapse patterns after radiochemotherapy of glioblastoma
with {FET} {PET}-guided boost irradiation and simulation to
optimize radiation target volume},
journal = {Radiation oncology},
volume = {11},
number = {1},
issn = {1748-717X},
address = {London},
publisher = {BioMed Central},
reportid = {FZJ-2016-03533},
pages = {87},
year = {2016},
abstract = {BackgroundO-(2-18 F-fluoroethyl)-L-tyrosine-(FET)-PET may
be helpful to improve the definition of radiation target
volumes in glioblastomas compared with MRI. We analyzed the
relapse patterns in FET-PET after a FET- and MRI-based
integrated-boost intensity-modulated radiotherapy (IMRT) of
glioblastomas to perform an optimized target volume
definition.MethodsA relapse pattern analysis was performed
in 13 glioblastoma patients treated with radiochemotherapy
within a prospective phase-II-study between 2008 and 2009.
Radiotherapy was performed as an integrated-boost
intensity-modulated radiotherapy (IB-IMRT). The prescribed
dose was 72 Gy for the boost target volume, based on
baseline FET-PET (FET-1) and 60 Gy for the MRI-based (MRI-1)
standard target volume. The single doses were 2.4 and 2.0
Gy, respectively. Location and volume of recurrent tumors in
FET-2 and MRI-2 were analyzed related to initial tumor,
detected in baseline FET-1. Variable target volumes were
created theoretically based on FET-1 to optimally cover
recurrent tumor.ResultsThe tumor volume overlap in FET and
MRI was poor both at baseline (median 12 $\%;$ range 0–32)
and at time of recurrence (13 $\%;$ 0–100). Recurrent
tumor volume in FET-2 was localized to 39 $\%$ (12–91) in
the initial tumor volume (FET-1). Over the time a shrinking
(mean 12 (5–26) ml) and shifting (mean 6 (1–10 mm) of
the resection cavity was seen. A simulated target volume
based on active tumor in FET-1 with an additional safety
margin of 7 mm around the FET-1 volume covered recurrent FET
tumor volume (FET-2) significantly better than a
corresponding target volume based on contrast enhancement in
MRI-1 with a same safety margin of 7 mm (100 $\%$ (54–100)
versus 85 $\%$ (0–100); p < 0.01). A simulated
planning target volume (PTV), based on FET-1 and additional
7 mm margin plus 5 mm margin for setup-uncertainties was
significantly smaller than the conventional, MR-based PTV
applied in this study (median 160 (112–297) ml versus 231
(117–386) ml, p < 0.001).ConclusionsIn this small
study recurrent tumor volume in FET-PET (FET-2) overlapped
only to one third with the boost target volume, based on
FET-1. The shrinking and shifting of the resection cavity
may have an influence considering the limited overlap of
initial and relapse tumor volume. A simulated target volume,
based on FET-1 with 7 mm margin covered 100 $\%$ of relapse
volume in median and led to a significantly reduced PTV,
compared to MRI-based PTVs. This approach may achieve
similar therapeutic efficacy but lower side effects offering
a broader window to intensify concomitant systemic treatment
focusing distant failures.},
cin = {INM-3 / INM-4 / INM-5 / JARA-BRAIN},
ddc = {610},
cid = {I:(DE-Juel1)INM-3-20090406 / I:(DE-Juel1)INM-4-20090406 /
I:(DE-Juel1)INM-5-20090406 / $I:(DE-82)080010_20140620$},
pnm = {573 - Neuroimaging (POF3-573)},
pid = {G:(DE-HGF)POF3-573},
typ = {PUB:(DE-HGF)16},
UT = {WOS:000378576700001},
pubmed = {pmid:27342976},
doi = {10.1186/s13014-016-0665-z},
url = {https://juser.fz-juelich.de/record/810995},
}