Table 4.

The comparison of plan robustness using the width of dose‐volume‐histogram (DVH) index bands.

DVH index	VMAT	IMPT	P‐value
CTVhigh D95% (normalized)	0.7%	1.8%	<0.0001
CTVhigh ${\text{D}}_{2{\text{cm}}^3}$ (normalized)	0.73%	1.9%	0.0002
CTVhigh D5%–D95% (normalized)	0.41%	1.4%	<0.0001
CTVlow D95% (normalized)	1.3%	2.4%	0.0005
Liver V30Gy[RBE] (%)	2.19%	2.76%	0.29
Liver Dmean (Gy[RBE])	1.03	1.22	0.31
Lung Dmean (Gy[RBE])	0.80	0.58	0.12
Lung V5Gy[RBE] (%)	4.73%	2.99%	0.0057
Lung V20Gy[RBE] (%)	1.58%	1.31%	0.43
Heart Dmean (Gy[RBE])	2.65	4.13	0.002
Heart V20Gy[RBE] (%)	8.28%	8.91%	0.23
Heart V30Gy[RBE] (%)	6.31%	8.24%	0.014
Heart V40Gy[RBE] (%)	4.28%	6.69%	0.0027
Cord Dmax (Gy[RBE])	2.17	2.35	0.58
Cord ${\text{D}}_{0.03{\text{cm}}^3}$ (Gy[RBE])	2.21	2.12	0.80
Kidney V18Gy[RBE] (%)	2.42%	1.16%	0.21
Stomach V45Gy[RBE] (cm3)	11.34	16.99	0.25

CTV, clinical target volume; IMPT, intensity‐modulated proton therapy; VMAT, volumetric‐modulated arc therapy.

Bold values represent significant difference between IMPT and VMAT DVH indices.