Table 2.

Observed dosimetric variations for the bladder, rectum, sigmoid/bowel and HR CTV. Relative differences between dose parameters ($D_{2{\text{cm}}^3}$ or D₉₀) from two images/structure sets were calculated as ΔD = (D_i−D_ref)/D_ref (on reference image and subsequent image number i = 1–4). Mean and SD of the variations are given in % of physical dose. A positive value means that the dose obtained for image set i was higher than on the reference image.

Structure	$\mathrm{\Delta }{D}_{2{\text{cm}}^3}$ between 2 acquisitions [%] (fixed plan, variable anatomy)
	Intra-application only		Inter-application only		Total
	Mean	SD	Mean	SD	Mean	SD
Bladder	1.3	±17.7	−0.1	±21.2	0.6	±19.5
Rectum⁎	3.8	±20.5	4.3	±22.8	4.1	±21.7
Sigmoid	−2.3	±23.5	6.8	±30.2	1.6	±26.8
	ΔD90 between 2 acquisitions [%] (fixed plan, variable anatomy)
	Intra-application only		Inter-application only		Total
	Mean	SD	Mean	SD	Mean	SD
HR CTV	−2.5	±10.8	0.4	±15.1	−1.1	±13.1

^⁎3 Extreme outliers (Δ$D_{2{\text{cm}}^3}$ = 119–240%) were excluded from the overall analysis. Inclusion would result in 11.2 ± 38.3% (mean ± SD) for rectum for intra-application group and 7.7 ± 31.4% for total sample.