Table 2.

Width, Height and Thickness details for defining and delineating four categories of CTV-T_HR-CT based on CT at diagnosis and CT at BT (CT_DG – CT_BT Environment).

Category of BT	Width	Height		Thickness
	Lateral	Superior	Inferior	Anterior	Posterior
IBT	Lateral boundaries of cervix	Lower two thirds of utero-cervical dimensions	Lower extent of cervical lip with vaginal applicator as surrogate	Outer surface of the cervix &/or uterus	Outer surface of the cervix &/or uterus
IIBT	Proximal parametrium defined by clinical and TRUS (if available) based NMD’s		Include appropriate length of vaginal wall defined by clinical examination and with/without guidance of markers implanted, maybe with safety margins, few mm longitudinal and up to 2 cm circumferential	To utilize TRUS based distances (if available)	To utilize TRUS based distances (if available)
	Additional 3–5 mm margins especially if the corresponding region of parametrium was involved at diagnosis
IIIBT	Distal parametrium/upto lateral pelvic wall defined by clinical and TRUS based NMD’s
	Additional 3–5 mm margins especially if the corresponding region of parametrium was involved at diagnosis
IVBT	Proximal /distal parametrium/upto lateral pelvic wall defined by clinical and TRUS based (if available)			In addition to outer surface of the cervix &/or uterus to include the bladder wall/mucosae involved with 2 cm margins at least.	In addition to outer surface of the cervix &/or uterus to include the rectal wall/mucosae involved with 2 cm margins at least.
	NMD’s Additional 3–5 mm margins especially if the corresponding region of parametrium was involved at diagnosis
				To utilize TRUS based distances (if available)	To utilize TRUS based distances (if available)