*3.5.1 For definitive radiation therapy*

GTV or gross tumour volume is defined as the visible tumour along with the nodes which are abnormal. HRCTV [High Risk Clinical Target Volume] includes the margin around the GTV and also the first echelon group of nodes which will be level IB to level II. For LRCTV [Low Risk Clinical Target Volume] one would include level III, IV, supraclavicular and IA. Usually bilateral neck is to be treated, based on institutional protocol. PTV [Planning Target Volume] would be 5 mm around the CTV trimmed from skin, but based on institutional protocol, it could range from 3 mm to 10 mm (**Figures 5** and **6**).
