460 / 1578
•
Is 1 respiration correlated 4D-CT representative for the
actual treatment?
Repeated 4D-CTs
during
the treatment course
Second 4D-CT after > 2 fractions (median 6 days):
•
No systematic changes of motion pattern and target volume
•
Target coverage compromised in one patient (atelectasis)
Repeated 4D CBCT scans (median 9) during RT:
•
Stable trajectory with variability (1SD) less than 1mm
•
Significant base-line shifts
Continuous tumor tracking in EPID images:
•
Stable tumor trajectory, both intra-fractional and inter-fractional
Sonke IJROBP 2008
No benefit of replanning because of motion variability
Haasbeck IJROBP 2007
Richter IJROBP 2010
Imaging for target definition: RC-CT
SBRT 2017 - D. Verellen