Table 6.

Random tumour bed (TB) setup errors for laser setup (σ_laser) and for bone verification (σ_bone) for groups determined using patient- and treatment-related factors

Laser	Factor	Group 1	σlaser (mm)	Group 2	σlaser (mm)	p-value	Direction
	TB PTV volume	<39.5 cm3	2.6	≥39.5 cm3	2.8	0.041	LR
	TB PTV volume	<39.5 cm3	2.6	≥39.5 cm3	3.1	0.023	AP
	Breast volume	<855 cm	2.4	≥855 cm3	3.1	0.006	LR
	Breast volume	<855 cm	2.4	≥855 cm3	2.8	0.02	SI
	Seroma visibility	Not visible/subtle	2.6	Easily visible	3.1	0.034	AP
Bones	Factor	Group 1	σbone (mm)	Group 2	σbone (mm)	p-value	Direction
	TB axial position	1	2.0	2, 3and 4	1.6	0.025	LR
	TB axial position	1	1.5	2, 3 and 4	2.1	0.004	AP
	TB SI position	1	1.8	3	1.1	0.006	LR
	Breast volume	<855 cm	2.2	≥855 cm3	2.6	0.007	LR
	Breast volume	<855 cm	1.7	≥855 cm3	2.3	0.002	SI
	Trial arm	Synchronous	2.1	Sequential	1.8	0.01	AP
	Surgical technique	Closed	1.4	Open	1.9	<0.001	LR
	Surgical technique	Closed	2.3	Open	2.6	0.009	SI

AP, anteroposterior; LR, left–right; PTV, planning target volume; SI, superior–inferior, TB, tumour bed.

P-values for univariate Kruskal–Wallis test are given.

Data given only for factors that gave a significant difference in systematic bony anatomy verification error between patient groups (p < 0.05).