TY  - JOUR
A1  - Hardcastle, Nicholas
A1  - Tomé, Wolfgang A.
A1  - Cannon, Donald M.
A1  - Brouwer, Charlotte L.
A1  - Wittendorp, Paul W. H.
A1  - Dogan, Nesrin
A1  - Guckenberger, Matthias
A1  - Allaire, Stéphane
A1  - Mallya, Yogish
A1  - Kumar, Prashant
A1  - Oechsner, Markus
A1  - Richter, Anne
A1  - Song, Shiyu
A1  - Myers, Michael
A1  - Polat, Bülent
A1  - Bzdusek, Karl
T1  - A multi-institution evaluation of deformable image registration algorithms for automatic organ delineation in adaptive head and neck radiotherapy
JF  - Radiation Oncology
N2  - Background: Adaptive Radiotherapy aims to identify anatomical deviations during a radiotherapy course and modify the treatment plan to maintain treatment objectives. This requires regions of interest (ROIs) to be defined using the most recent imaging data. This study investigates the clinical utility of using deformable image registration (DIR) to automatically propagate ROIs. 
Methods: Target (GTV) and organ-at-risk (OAR) ROIs were non-rigidly propagated from a planning CT scan to a per-treatment CT scan for 22 patients. Propagated ROIs were quantitatively compared with expert physician-drawn ROIs on the per-treatment scan using Dice scores and mean slicewise Hausdorff distances, and center of mass distances for GTVs. The propagated ROIs were qualitatively examined by experts and scored based on their clinical utility. 
Results: Good agreement between the DIR-propagated ROIs and expert-drawn ROIs was observed based on the metrics used. 94% of all ROIs generated using DIR were scored as being clinically useful, requiring minimal or no edits. However, 27% (12/44) of the GTVs required major edits. 
Conclusion: DIR was successfully used on 22 patients to propagate target and OAR structures for ART with good anatomical agreement for OARs. It is recommended that propagated target structures be thoroughly reviewed by the treating physician.
KW  - intensity-modulated radiotherapy
KW  - megavoltage computed-tomography
KW  - cancer
KW  - variability
KW  - strategies
KW  - risk
Y1  - 2012
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-134756
VL  - 7
IS  - 90
ER  - 
TY  - JOUR
A1  - Samimi, C.
A1  - Fink, A. H.
A1  - Paeth, H.
T1  - The 2007 flood in the Sahel: causes, characteristics and its presentation in the media and FEWS NET
JF  - Natural Hazards and Earth System Sciences
N2  - During the rainy season in 2007, reports about exceptional rains and floodings in the Sahel were published in the media, especially in August and September. Institutions and organizations like the World Food Programme (WFP) and FEWS NET put the events on the agenda and released alerts and requested help. The partly controversial picture was that most of the Sahel faced a crisis caused by widespread floodings. Our study shows that the rainy season in 2007 was exceptional with regard to rainfall amount and return periods. In many areas the event had a return period between 1 and 50 yr with high spatial heterogeneity, with the exception of the Upper Volta basin, which yielded return periods of up to 1200 yr. Despite the strong rainfall, the interpretation of satellite images show that the floods were mainly confined to lakes and river beds. However, the study also proves the difficulties in assessing the meteorological processes and the demarcation of flooded areas in satellite images without ground truthing. These facts and the somewhat vague and controversial reports in the media and FEWS NET demonstrate that it is crucial to thoroughly analyze such events at a regional and local scale involving the local population.
KW  - prediction
KW  - satellite rainfall products
KW  - tropical North-Africa
KW  - West-Africa
KW  - climate change
KW  - summer rainfall
KW  - variability
KW  - SST
KW  - teleconnection
KW  - validation
Y1  - 2012
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-131790
VL  - 12
IS  - 2
SP  - 313
EP  - 325
ER  -