PMID- 28033416
OWN - NLM
STAT- MEDLINE
DCOM- 20170710
LR  - 20190111
IS  - 1932-6203 (Electronic)
IS  - 1932-6203 (Linking)
VI  - 11
IP  - 12
DP  - 2016
TI  - Comparison of Safety Margin Generation Concepts in Image Guided Radiotherapy to 
      Account for Daily Head and Neck Pose Variations.
PG  - e0168916
LID - 10.1371/journal.pone.0168916 [doi]
LID - e0168916
AB  - PURPOSE: Intensity modulated radiation therapy (IMRT) of head and neck tumors 
      allows a precise conformation of the high-dose region to clinical target volumes 
      (CTVs) while respecting dose limits to organs a risk (OARs). Accurate patient 
      setup reduces translational and rotational deviations between therapy planning 
      and therapy delivery days. However, uncertainties in the shape of the CTV and 
      OARs due to e.g. small pose variations in the highly deformable anatomy of the 
      head and neck region can still compromise the dose conformation. Routinely 
      applied safety margins around the CTV cause higher dose deposition in adjacent 
      healthy tissue and should be kept as small as possible. MATERIALS AND METHODS: In 
      this work we evaluate and compare three approaches for margin generation 1) a 
      clinically used approach with a constant isotropic 3 mm margin, 2) a previously 
      proposed approach adopting a spatial model of the patient and 3) a newly 
      developed approach adopting a biomechanical model of the patient. All approaches 
      are retrospectively evaluated using a large patient cohort of over 500 fraction 
      control CT images with heterogeneous pose changes. Automatic methods for finding 
      landmark positions in the control CT images are combined with a patient specific 
      biomechanical finite element model to evaluate the CTV deformation. RESULTS: The 
      applied methods for deformation modeling show that the pose changes cause 
      deformations in the target region with a mean motion magnitude of 1.80 mm. We 
      found that the CTV size can be reduced by both variable margin approaches by 
      15.6% and 13.3% respectively, while maintaining the CTV coverage. With approach 3 
      an increase of target coverage was obtained. CONCLUSION: Variable margins 
      increase target coverage, reduce risk to OARs and improve healthy tissue sparing 
      at the same time.
FAU - Stoll, Markus
AU  - Stoll M
AUID- ORCID: 0000-0002-9546-6713
AD  - Department of Medical Physics in Radiation Oncology, German Cancer Research 
      Center (DKFZ), Heidelberg, Germany.
AD  - Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation 
      Research in Oncology, Heidelberg, Germany.
FAU - Stoiber, Eva Maria
AU  - Stoiber EM
AD  - Department of Medical Physics in Radiation Oncology, German Cancer Research 
      Center (DKFZ), Heidelberg, Germany.
FAU - Grimm, Sarah
AU  - Grimm S
AD  - Department of Medical Physics in Radiation Oncology, German Cancer Research 
      Center (DKFZ), Heidelberg, Germany.
AD  - Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation 
      Research in Oncology, Heidelberg, Germany.
AD  - Faculty of Computer Science, Heilbronn University, Heilbronn, Germany.
FAU - Debus, Jurgen
AU  - Debus J
AD  - Department of Medical Physics in Radiation Oncology, German Cancer Research 
      Center (DKFZ), Heidelberg, Germany.
AD  - Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation 
      Research in Oncology, Heidelberg, Germany.
AD  - Department of Radiation Oncology, University Hospital, Heidelberg, Germany.
FAU - Bendl, Rolf
AU  - Bendl R
AD  - Department of Medical Physics in Radiation Oncology, German Cancer Research 
      Center (DKFZ), Heidelberg, Germany.
AD  - Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation 
      Research in Oncology, Heidelberg, Germany.
AD  - Faculty of Computer Science, Heilbronn University, Heilbronn, Germany.
FAU - Giske, Kristina
AU  - Giske K
AD  - Department of Medical Physics in Radiation Oncology, German Cancer Research 
      Center (DKFZ), Heidelberg, Germany.
AD  - Heidelberg Institute for Radiation Oncology (HIRO), National Center for Radiation 
      Research in Oncology, Heidelberg, Germany.
LA  - eng
PT  - Comparative Study
PT  - Journal Article
DEP - 20161229
PL  - United States
TA  - PLoS One
JT  - PloS one
JID - 101285081
SB  - IM
MH  - Biomechanical Phenomena
MH  - Cohort Studies
MH  - Head and Neck Neoplasms/*diagnostic imaging/*radiotherapy
MH  - Humans
MH  - Models, Biological
MH  - Organs at Risk/radiation effects
MH  - *Patient Positioning
MH  - Radiotherapy, Image-Guided/*adverse effects
MH  - Radiotherapy, Intensity-Modulated/adverse effects
MH  - Retrospective Studies
MH  - *Safety
MH  - Tomography, X-Ray Computed
MH  - Uncertainty
PMC - PMC5199113
COIS- The authors have declared that no competing interests exist.
EDAT- 2016/12/30 06:00
MHDA- 2017/07/14 06:00
PMCR- 2016/12/29
CRDT- 2016/12/30 06:00
PHST- 2016/05/19 00:00 [received]
PHST- 2016/12/08 00:00 [accepted]
PHST- 2016/12/30 06:00 [entrez]
PHST- 2016/12/30 06:00 [pubmed]
PHST- 2017/07/14 06:00 [medline]
PHST- 2016/12/29 00:00 [pmc-release]
AID - PONE-D-16-20229 [pii]
AID - 10.1371/journal.pone.0168916 [doi]
PST - epublish
SO  - PLoS One. 2016 Dec 29;11(12):e0168916. doi: 10.1371/journal.pone.0168916. 
      eCollection 2016.