Table 3.

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

Category of BT	Width	Height		Thickness
	Lateral	Superior	Inferior	Anterior	Posterior
IBT	Lateral boundaries of cervix		Lower extent of cervical lip with vaginal applicator as surrogate
IIBT	Proximal parametrium defined by clinical and TRUS based (if available) NMD’s	Maximum height of disease extent seen on MR at diagnosis.	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 circumferential	Outer surface of the cervix &/or uterus.	Outer surface of the cervix &/or uterus.
	Width should not exceed the parametrial disease on MR at diagnosis	Guided by the upper extent of disease seen on MR at diagnosis. Distances from the outer surface of fundus to upper extent of disease to be utilized* * may not be applicable in enlarged uterine cavity due to fluid collection		To utilize TRUS based distances (if available)	To utilize TRUS based distances (if available)
IIIBT	Distal parametrium/ upto lateral pelvic wall defined by clinical and TRUS based (if available) NMD’s		Length and circumference of vagina should not exceed vaginal disease on MR at diagnosis
	Width should not exceed the parametrial disease on MR at diagnosis
IVBT	Proximal /distal parametrium/Up to lateral pelvic wall defined by clinical and TRUS based (if available) NMD’s			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.
	Width should not exceed the parametrial disease on MR at diagnosis			To utilize TRUS based distances (if available)	To utilize TRUS based distances (if available)