From GTV to CTV
The risk of extracapsular extension (ECE) has to be taken into account!
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Consider 3-5 mm around nodal GTV for ECE (and internal position shifts)
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Take into account anatomical barriers (muscle, bone, surrounding organs)
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Node CTV should be included in the elective CTV (45 -50 Gy)
What should be the margin around the nodal GTV?