A multi-institution evaluation of deformable image registration algorithms for automatic organ delineation in adaptive head and neck radiotherapy.
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.


CONCLUSIONS
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.
Department of Human Oncology, University of Wisconsin-Madison, Madison, WI, USA. nicholas.hardcastle@petermac.org
Nicholas
N
Hardcastle
Wolfgang A
WA
Tomé
Donald M
DM
Cannon
Charlotte L
CL
Brouwer
Paul W H
PW
Wittendorp
Nesrin
N
Dogan
Matthias
M
Guckenberger
Stéphane
S
Allaire
Yogish
Y
Mallya
Prashant
P
Kumar
Markus
M
Oechsner
Anne
A
Richter
Shiyu
S
Song
Michael
M
Myers
Bülent
B
Polat
Karl
K
Bzdusek
D000465:Algorithms; D006258:Head and Neck Neoplasms / Q000532:radiotherapy*; D006801:Humans; D018787:Radiation Oncology / Q000379:methods*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*