Table 2.

Image-Guided Radiotherapy Techniques

Frequency	Daily	Weekly	Day 1–3 or 1–5 daily, then weekly	Other		N/R
	18	12	7	3		70
No-action-level used	Yes	No				N/R
	8	14				88
IGRT technique	3D	2D	Surface scanner	Other		N/R
	21	14	1	6		72
Matching structures	Bone	Soft Tissue	Fiducials	Surface	Other	N/R
	13	3	0	0	0	96
Immobilization mask	Head	Head & neck	Head, neck & shoulder	Unspecified type	None	N/R
	2	8	39	29	4	28
Immobilization support	Bite block	Other	Stereotactic head frame (invasive and non-invasive)		None	N/R
	7	13	4		15	71
Setup correction	3DoF	4DoF	6DoF			N/R
	9	0	1			100

DoF: Degrees of freedom; IGRT: Image-guided radiotherapy; N/R: Not reported;