Table 2.

Centre of mass distances between contours for different CT scans

Observer	Difference between CTs (cm)	CTV	Liver	L-kidney	R-kidney
A	1–2	0.51	0.59	0.60	0.66
	1–3	0.28	0.50	0.63	0.50
	2–3	0.40	0.43	0.68	0.60
	Mean	0.40	0.51	0.64	0.59
B	1–2	0.28	0.54	0.62	0.66
	1–3	0.31	0.40	0.57	0.46
	2–3	0.26	0.36	0.71	0.62
	Mean	0.28	0.43	0.63	0.58
C	1–2	0.49	0.69	0.57	0.66
	1–3	0.43	0.75	0.66	0.57
	2–3	0.52	0.68	0.67	0.60
	Mean	0.48	0.71	0.63	0.61
D	1–2	0.46	0.72	0.63	0.72
	1–3	0.42	0.47	0.68	0.63
	2–3	0.43	0.58	0.73	0.64
	Mean	0.44	0.59	0.68	0.66

CTV, clinical tumour volume; L, left; R, right.