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IGRT for rectal cancer: boost
- IGRT focused on the boost volume
(simpler assessment of margins ?)
- Rectal motion as a surrogate of
GTV/CTVboost
- Reported trend for rectal volume
reduction and for shape variation
(Njikamp 2012, Maggiulli 2012,
Raso 2015)
Maggiulli 2012
- Residual deformation error after
rigid correction: anisotropic, higher
in the first few fractions
- Relatively small «optimal» margins
reported (especially if excluding the
first fractions)….mainly 5-15 mm
- Larger motion in female pts
….to be better discussed later (IGRT & adaptive)
Raso 2015