Table 4.

CTV–PTV margin for oesophageal cancer according to image modality used for the three orthogonal directions.

Direction	∑setup (cm)	σsetup (mm)	Msetup (cm)	Author
Planar image
Vertical	0.12	0.24	0.5	Hawkins et al.a
0.32	0.19	0.94	This study
Longitudinal	0.27	0.33	0.9	Hawkins et al.a
0.36	0.22	1.05	This study
Lateral	0.19	0.29	0.7	Hawkins et al.a
0.26	0.17	0.76	This study
CBCT
Vertical	0.4	0.1	0.8	Yamashita et al.
0.14	0.20	0.5	Hawkins et al.
0.2	0.16	0.61	Yang et al.
0.20	0.18	0.61	This study
Longitudinal	0.38	0.41	1.23	Yamashita et al.
0.17	0.39	0.7	Hawkins et al.
0.4	0.1	0.8	Yang et al.
0.21	0.22	0.67	This study
Lateral	0.2	0	5	Yamashita et al.
0.13	0.26	0.5	Hawkins et al.
0.23	0.24	0.75	Yang et al.
0.31	0.18	0.89	This study

^aCTV–PTV margins calculated based on MV portal images.