IGRT 2016 Madrid

Head and Neck

IGRT for Head and Neck

Coen Rasch

3-D median surface with local SD

Delineation of GTV in H&N 10 patients with NPC (cT2b – cT4, Nx) 10 Observers from 6 institutes in NL, D

0.0 – 0.5 0.5 – 1.0 1.0 – 1.5 1.5 – 2.0 2.0 – 2.5 2.5 – 3.0 3.0 – 3.5 3.5 – 4.0 4.0 – 4.5 4.5 – 5.0 5.0 – 5.5 5.5 – 6.0 6.0 – 6.5 6.5 – 7.0 7.0 – 7.5 > 7.5 LOCAL SD (mm)

and US Phase I – Delineation of GTV on CT n of GTV on CT – Diagnostic MRI copy available

Phase II, after > 1 year – Improved delineation protocol

– Delineation on co-registered CT/MRI – Computer aided delineation tool (Snake

Overall observer variation (SD)

Delineation effect on dose in conformal and IMRT plans Paranasal sinus cancer, nine patients Two observers – Elective CTV (described in anatomical terms) Mean ratio 0.9 – Boost CTV (the tumor plus margin) Mean ratio 2.6 Two treatment planners – IMRT – 3D conformal

Phase 1

Phase 2

Anatomical regions

SD CT (mm) Agreement (%) All regions 4.4 36 3.3 64 Anterior – Air 3.4 62 2.7 79 Dorsal – Bone 3.6 49 2.7 84 Contra lateral 4.2 16 3.5 66 Pterygoid M. 4.3 35 3.1 61 Parapharyngeal 4.4 31 3.3 59 Soft Palate 4.7 37 3.0 67 Sphenoid 5.0 28 4.2 48 Caudal side 7.7 5 3.3 56 Agreement (%) SD CT/MRI (mm)

•Rasch et al IJROBP 2002