Table 2.

Dosimetric comparison between the clinical IMRT plans (of both supine and prone setups) and their knowledge-based re-optimization using the DVH estimation model trained on supine VMAT plans

		Mean	SD	95 % Confidence intervals		△(%)	P
				Lower	Upper
HI_PGTV	Original	0.04	0.01	0.04	0.05	0.01	0.04
	RP-IMRT	0.05	0.01	0.04	0.05
HI_PTV	Original	0.25	0.01	0.24	0.25	0.01	0.01*
	RP-IMRT	0.26	0.01	0.25	0.26
CI_PGTV	Original	1.03	0.05	1.01	1.05	0.01	0.61
	RP-IMRT	1.02	0.05	1.00	1.04
CI_PTV	Original	1.01	0.02	1.00	1.02	0.17	<0.01*
	RP-IMRT	1.18	0.05	1.16	1.20
Dmax	Original	52.95	0.44	52.78	53.11	1.51 (2.85 %)	<0.01
	RP-IMRT	54.46	1.52	53.89	55.02
D2 %	Original	52.61	0.43	52.44	52.77	0.15 (0.29 %)	0.09
	RP-IMRT	52.76	0.51	52.57	52.95
D50 %_UB	Original	33.85	2.96	32.74	34.95	8.76 (25.88 %)	<0.01*
	RP-IMRT	25.09	1.32	24.59	25.58
D50 %_FH	Original	15.65	3.33	14.41	16.90	1.92 (12.27 %)	<0.01*
	RP-IMRT	13.73	1.43	13.19	14.26
Dmean_UB	Original	33.99	2.77	32.95	35.02	7.74 (22.77 %)	<0.01
	RP-IMRT	26.25	1.22	25.79	26.70
Dmean_FH	Original	16.26	2.74	15.24	17.28	1.64 (10.09)	<0.01
	RP-IMRT	14.62	1.10	14.21	15.04
MUs	Original	805	82	774	836	394 (48.94 %)	<0.01*
	RP-IMRT	1199	80	1169	1229

Abbreviations: HI homogeneity index, CI conformity index, D _max global maximum dose, D _{2 %} near maximum dose, SD standard deviation, △(%) difference between the original and RP-VMAT plans (% relative to the original value), D _{50 %} dose to the 50 % volume of the structure, D _mean mean dose, FH femoral head, UB urinary bladder, MU monitor unit, RP-IMRT intensity modulated radiotherapy plans optimized by RapidPlan. Dose unit (Gy)

*Paired sample T test, otherwise Wilcoxon signed ranks test was used