Table 1.

Population statistics of intrafractional baseline variation

	Craniocaudal (mm)	Anterior‐Posterior (mm)	Left‐Right (mm)	3D (mm)
GM	‐1.2	‐0.7	0.2	1.8
Σ	1.5	0.7	0.5	1.4
σ	1.9	1.0	0.6	2.3

GM = group mean; Σ = systematic error; σ = random error.