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Repeated 4D-CTs
before
treatment planning
Four 4D-CTs in ten minutes intervals:
•
No systematic changes of motion pattern
•
Increased variability for lower lobe tumors
Two successive 4D-CTs:
•
Volume of the PTV not systematically different
•
Motion range variability <2mm in 81%
•
Coverage not compromised
Guckenberger IJROBP 2007
van der Geld Radiat Oncol. 2006
No benefit of repeated 4D-CT imaging in 1 session
Imaging for target definition: RC-CT
•
Is 1 respiration correlated 4D-CT representative for the
actual treatment?
SBRT 2017 - D. Verellen