Basic Treatment Planning

Target Volume Definition

Phase I GTV

Primary tumour + involved LN GTV +2.5-3cm margin + (at risk LN) ext/int/pre-sacral/mesorectal (up to mid SIJ)

CTV

PTV

CTV +8-10mm

Dose: 30.6Gy/17#/3.5 weeks. 6-15MV photons