Table 3.

Dose‐volumetric comparison of 6 MV, 15 MV, and mixed‐energy IMRT.

Variable	6 MV IMRT	15 MV IMRT	Mixed‐energy IMRT	p‐value (6 vs. 15) a	p‐value (6 vs. mixed) b	p‐value (15 vs. mixed) c
Primary Plan $(\mathit{mean}\pm \mathit{standard}\hspace{0.17em}\mathit{deviation})$
Conformity Index	$1.04\pm 0.04$	$1.05\pm 0.02$	$1.04\pm 0.02$	0.902	0.281	$<\mathit{0.001}$
Homogeneity Index	$1.05\pm 0.01$	$1.06\pm 0.01$	$1.06\pm 0.01$	0.407	$<\mathit{0.001}$	$<\mathit{0.001}$
Gradient Measure (cm)	$2.62\pm 0.29$	$2.29\pm 0.20$	$2.34\pm 0.24$	$<\mathit{0.001}$	$<\mathit{0.001}$	0.006
Max Dose to ${\text{PTV}}_{\mathrm{P}}$ (Gy) d	$51.58\pm 0.77$	$51.39\pm 0.38$	$51.93\pm 0.48$	0.231	0.034	$<\mathit{0.001}$
Mean Dose to ${\text{PTV}}_{\mathrm{P}}$ (Gy)	$49.31\pm 0.47$	$49.33\pm 0.67$	$49.69\pm 0.27$	0.907	$<\mathit{0.001}$	0.037
Mean Dose to Rectum Wall (Gy)	$33.81\pm 2.87$	$32.72\pm 3.88$	$32.13\pm 3.91$	0.039	0.002	0.100
Mean Dose to Bladder (Gy)	$29.21\pm 8.64$	$29.71\pm 8.62$	$29.12\pm 8.85$	0.082	0.685	0.003
Mean Dose to Femoral Heads (Gy)	$22.27\pm 3.89$	$18.61\pm 3.35$	$18.23\pm 3.12$	$<\mathit{0.001}$	$<\mathit{0.001}$	0.414
Boost Plan $(\mathit{mean}\pm \mathit{standard}\hspace{0.17em}\mathit{deviation})$
Conformity Index	$1.08\pm 0.03$	$1.10\pm 0.03$	$1.09\pm 0.03$	$<\mathit{0.001}$	0.075	0.041
Homogeneity Index	$1.04\pm 0.01$	$1.06\pm 0.01$	$1.06\pm 0.01$	$<\mathit{0.001}$	$<\mathit{0.001}$	0.512
Gradient Measure (cm)	$1.79\pm 0.27$	$1.67\pm 0.18$	$1.71\pm 0.18$	$<\mathit{0.001}$	0.013	0.015
Max Dose to ${\text{PTV}}_{\mathrm{B}}$ (Gy) e	$30.81\pm 0.38$	$30.95\pm 0.27$	$31.21\pm 0.33$	0.051	$<\mathit{0.001}$	$<\mathit{0.001}$
Mean Dose to ${\text{PTV}}_{\mathrm{B}}$ (Gy)	$29.83\pm 0.26$	$30.14\pm 0.19$	$30.22\pm 0.22$	$<\mathit{0.001}$	$<\mathit{0.001}$	0.044
Mean Dose to Rectum Wall (Gy)	$12.68\pm 1.88$	$12.33\pm 1.92$	$11.71\pm 2.19$	0.169	0.003	0.011
Mean Dose to Bladder (Gy)	$9.63\pm 4.15$	$9.77\pm 4.52$	$9.53\pm 4.52$	0.198	0.323	$<\mathit{0.001}$
Mean Dose to Femoral Heads (Gy)	$9.38\pm 3.07$	$7.79\pm 2.37$	$7.93\pm 2.24$	$<\mathit{0.001}$	$<\mathit{0.001}$	0.199
Sum Plan $(\mathit{mean}\pm \mathit{standard}\hspace{0.17em}\mathit{deviation})$
Maximum Dose (Gy)	$81.63\pm 0.99$	$82.22\pm 2.28$	$82.27\pm 0.62$	0.332	$<\mathit{0.001}$	0.925
Mean Dose to ${\text{PTV}}_{\mathrm{P}}$ (Gy)	$71.47\pm 2.53$	$72.04\pm 2.62$	$72.01\pm 2.63$	$<\mathit{0.001}$	$<\mathit{0.001}$	0.413
Mean Dose to ${\text{PTV}}_{\mathrm{B}}$ (Gy)	$79.18\pm 0.70$	$79.78\pm 0.38$	$80.05\pm 0.46$	$<\mathit{0.001}$	$<\mathit{0.001}$	$<\mathit{0.001}$
Mean Dose to Rectum Wall (Gy)	$46.50\pm 3.44$	$45.06\pm 4.88$	$43.84\pm 4.83$	0.050	$<\mathit{0.001}$	0.015
${\mathrm{V}}_{70\text{Gy}}$ f of Rectum Wall (%)	$16.7\pm 5.4$	$17.9\pm 6.3$	$16.3\pm 6.1$	0.002	0.222	$<\mathit{0.001}$
${\mathrm{V}}_{66.6\text{Gy}}$ of Rectum Wall (%)	$19.2\pm 5.5$	$20.6\pm 6.7$	$18.7\pm 6.5$	0.003	0.332	$<\mathit{0.001}$
${\mathrm{V}}_{50\text{Gy}}$ of Rectum Wall (%)	$38.6\pm 7.7$	$39.5\pm 8.7$	$37.0\pm 8.3$	0.151	0.012	$<\mathit{0.001}$
${\mathrm{V}}_{40\text{Gy}}$ of Rectum Wall (%)	$55.6\pm 9.4$	$53.2\pm 9.9$	$50.0\pm 10.3$	0.240	0.012	0.002
${\mathrm{V}}_{20\text{Gy}}$ of Rectum Wall (%)	$95.6\pm 4.4$	$89.4\pm 8.4$	$89.0\pm 8.2$	0.001	$<\mathit{0.001}$	0.675
${\mathrm{D}}_{50\%}$ g of Rectum Wall (Gy)	$42.69\pm 5.56$	$42.31\pm 6.76$	$39.90\pm 6.80$	0.708	0.006	$<\mathit{0.001}$
Mean Dose to Bladder (Gy)	$38.30\pm 13.45$	$39.45\pm 12.76$	$38.65\pm 12.96$	0.043	0.532	$<\mathit{0.001}$
${\mathrm{V}}_{70\text{Gy}}$ of Bladder (%)	$19.9\pm 10.3$	$21.1\pm 11.6$	$20.5\pm 11.5$	0.003	0.068	0.001
${\mathrm{V}}_{66.6\text{Gy}}$ of Bladder (%)	$23.4\pm 11.8$	$24.4\pm 12.9$	$23.7\pm 12.8$	0.015	0.381	$<\mathit{0.001}$
${\mathrm{V}}_{50\text{Gy}}$ of Bladder (%)	$39.6\pm 17.3$	$41.0\pm 17.7$	$39.8\pm 17.7$	$<\mathit{0.001}$	0.538	$<\mathit{0.001}$
${\mathrm{V}}_{40\text{Gy}}$ of Bladder (%)	$47.4\pm 19.4$	$47.5\pm 19.1$	$47.5\pm 19.6$	0.968	0.962	0.974
${\mathrm{V}}_{20\text{Gy}}$ of Bladder (%)	$65.6\pm 21.7$	$65.9\pm 20.5$	$64.3\pm 21.5$	0.718	0.117	0.008
${\mathrm{D}}_{50\%}$ of Bladder (Gy)	$35.57\pm 19.53$	$37.52\pm 20.19$	$35.72\pm 20.47$	0.002	0.725	$<\mathit{0.001}$
Max dose to Femoral Heads (Gy)	$55.22\pm 8.93$	$48.01\pm 6.58$	$47.50\pm 6.73$	$<\mathit{0.001}$	$<\mathit{0.001}$	0.432
Mean Dose to Femoral Heads (Gy)	$31.67\pm 6.53$	$26.32\pm 5.36$	$26.16\pm 4.92$	$<\mathit{0.001}$	$<\mathit{0.001}$	0.728
${\mathrm{V}}_{50\text{Gy}}$ of Femoral Heads (%)	$4.9\pm 8.8$	$0.6\pm 1.6$	$0.4\pm 1.1$	0.019	0.022	0.186
${\mathrm{V}}_{45\text{Gy}}$ of Femoral Heads (%)	$9.5\pm 12.7$	$2.4\pm 5.3$	$1.7\pm 4.1$	0.002	0.002	0.049
${\mathrm{V}}_{30\text{Gy}}$ of Femoral Heads (%)	$58.9\pm 24.9$	$32.4\pm 20.8$	$31.8\pm 19.9$	$<\mathit{0.001}$	$<\mathit{0.001}$	0.799
${\mathrm{D}}_{50\%}$ of Femoral Heads (Gy)	$31.77\pm 5.94$	$25.86\pm 5.30$	$25.86\pm 4.86$	$<\mathit{0.001}$	$<\mathit{0.001}$	0.994
${\mathrm{V}}_{24.3\text{Gy}}$ of Body (cc)	$2,324\pm 507$	$2,059\pm 466$	$2,125\pm 482$	$<\mathit{0.001}$	$<\mathit{0.001}$	$<\mathit{0.001}$
Integral Dose (${10}^5$ Gy‐cc)	$1.18\pm 0.26$	$1.10\pm 0.24$	$1.10\pm 0.25$	$<\mathit{0.001}$	$<\mathit{0.001}$	0.110
Average MU h	$952\pm 124$	$871\pm 80$	$966\pm 61$	0.001	0.551	$<\mathit{0.001}$

^a P‐value (6 vs. 15) means p‐value from the comparison of the results between 6 MV IMRT and 15 MV IMRT plans.

^b P‐value (6 vs. Mixed) means p‐value from the comparison of the results between 6 MV IMRT and mixed‐energy IMRT plans.

^c P‐value (15 vs. Mixed) means p‐value from the comparison of the results between 15 MV IMRT and mixed‐energy IMRT plans.

^d ${\text{PTV}}_{\mathrm{P}}$ means the primary planning target volume.

^e ${\text{PTV}}_{\mathrm{B}}$ means the boost planning target volume.

^f ${\mathrm{V}}_{\text{nGy}}$ means the percentage volume irradiated by n Gy or more of a certain structure.

^g ${\mathrm{D}}_{\mathrm{n}\%}$ means the dose received by the n% volume of the target volume.

^hMU is monitoring unit.