Table 2.

Dosimetric comparisons between the PTV-based and robust optimizations for the nominal plan.

	PTV-based optimized plans	Robust optimized plans	p-Value
CTV: D98% (cGy)	4913.7 ± 78.8 (4717.0–4992.0)	4900.0 ± 0.0 (4900–4900)	0.375
CTV: D50% (cGy)	5037.3 ± 63.4 (4891.0–5092.0)	5044.8 ± 26.3 (4982.0–5071.0)	0.922
CTV: D2% (cGy)	5113.8 ± 65.9 (4986.0–5211.0)	5169.5 ± 38.6 (5105.0–5219.0)	0.193
Liver-CTV: mean dose (cGy)	491.7 ± 179.4 (205.0–756.0)	505.6 ± 181.4 (213.0–786.0)	0.023*
Liver-CTV: D2% (cGy)	3407.6 ± 637.1 (2118.0–4464.0)	3611.8 ± 699.7 (2228.0–4669.0)	0.002*
Liver-CTV: V20Gy (%)	5.6 ± 2.2 (2.2–9.3)	5.8 ± 2.3 (2.4–9.8)	0.004*
MU	1702.2 ± 176.2 (1385.4–1944.0)	1688.1 ± 162.7 (1438.6–1917.7)	0.160

Data are presented as group averages with ranges in parentheses (n = 10).

CTV, clinical target volume; MU, monitor unit.

^*Wilcoxon signed-rank test resulted in a statistically significant difference (p < 0.05).