Table 2.

Diameter of the computed radiation isocentre for each phantom for TrueBeam with aS1200 EPID.

Series number	Component	PTW Isoball	Aquilab Isocentre Phanton	Varian Isocentre Cube
1	Collimator	0.70	0.73	0.72
	Gantry	0.41	0.33	0.65
	Couch	0.72	0.70	1.92
2	Collimator	0.77	0.72	0.75
	Gantry	0.18	0.24	0.70
	Couch	1.10	0.41	1.47
3	Collimator	0.80	0.72	0.68
	Gantry	0.30	0.29	0.78
	Couch	1.60	1.25	1.14
4	Collimator	0.72	0.69	0.68
	Gantry	0.28	0.31	0.80
	Couch	0.70	0.82	0.69
5	Collimator	0.89	0.74	0.73
	Gantry	0.33	0.29	0.79
	Couch	0.38	0.67	1.14
6	Collimator	0.72	0.70	0.73
	Gantry	0.31	0.39	0.88
	Couch	0.39	1.32	0.81