579 / 1544
ESTRO IMRT course 2015
Adaptive Radiotherapy
Brussels October 8th, 2015
-36-
…this was all portal-image based visualization of implanted fiducial markers.
Improvements by daily
Cone-Beam-CT
-based setup?
CONCLUSIONS:
For protocols with CBCT guidance, RL, AP, and SI margins of 2, 4, and 3 mm
are sufficient to account for translational errors; however, the large variation in
patient-specific margins suggests that adaptive management may be
beneficial.
Note: This is not resulting from geometric considerations (CTV appropriately
covered by PTV), but from dosimetric considerations: coverage by 95% isodose
line.
→
Influence of planning strategy and TPS!
Zero Margins in daily online ART/IGRT?
Intrafraction motion: prostate
J. Adamson et al. 2011: Dosimetric effect of intrafraction motion and residual setup error
for hypofractionated prostate intensity-modulated radiotherapy with online cone beam
computed tomography image guidance. IJROBP 80(2)