IMRT Course 2016

Zero Margins in daily online ART/IGRT? Intrafraction motion: prostate

…this was all portal-image based visualization of implanted fiducial markers. Improvements by daily Cone-Beam-CT -based setup? 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) 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!

ESTRO IMRT course 2016 Adaptive Radiotherapy London April 7th, 2016

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