Table 2.

Plan comparison among nine‐field IMRT, double‐arc RA, and triple‐arc RA plans (average over 20 patients).

Parameter	Nine‐field IMRT	Double‐arc RA	Triple‐arc RA	p a (IMRT vs. Triple RA)	p a (Double RA vs. Triple RA)
CN(${\text{PTV}}_{\mathrm{B}}$/${\text{PTV}}_{\mathrm{B}+\mathrm{N}}$)	$0.86\pm 0.02$	$0.85\pm 0.03$	$0.86\pm 0.02$	0.63	0.10
CN(${\text{PTV}}_{\mathrm{H}}$)	$0.86\pm 0.02$	$0.87\pm 0.02$	$0.87\pm 0.03$	0.20	0.26
HI (${\text{PTV}}_{\mathrm{B}}$/${\text{PTV}}_{\mathrm{B}+\mathrm{N}}$)	$5.14\pm 0.41$	$5.92\pm 0.38$	$5.30\pm 0.57$	0.43	0.00
${\mathrm{V}}_{<95\%}$(${\text{PTV}}_{\mathrm{B}}$/${\text{PTV}}_{\mathrm{B}+\mathrm{N}}$), %	$0.01\pm 0.02$	$0.00\pm 0.00$	$0.00\pm 0.00$	0.11	0.16
${\mathrm{V}}_{<95\%}$(${\text{PTV}}_{\mathrm{H}}$), %	$0.08\pm 0.09$	$0.10\pm 0.10$	$0.13\pm 0.12$	0.10	0.16
${\mathrm{V}}_{<100\%}$(${\text{PTV}}_{\mathrm{B}}$/${\text{PTV}}_{\mathrm{B}+\mathrm{N}}$), %	$2.64\pm 1.22$	$1.61\pm 0.68$	$1.23\pm 0.55$	0.00	0.02
${\mathrm{V}}_{<100\%}$(${\text{PTV}}_{\mathrm{H}}$), %	$1.31\pm 0.81$	$1.62\pm 0.65$	$1.52\pm 0.62$	0.25	0.81
${\mathrm{V}}_{<105\%}$(${\text{PTV}}_{\mathrm{B}}$/${\text{PTV}}_{\mathrm{B}+\mathrm{N}}$), %	$0.35\pm 0.91$	$7.84\pm 3.55$	$5.58\pm 2.02$	0.00	0.00
${\mathrm{D}}_{1\%}$(Brain stem), Gy	$49.56\pm 1.51$	$50.35\pm 1.20$	$49.12\pm 1.27$	0.23	0.00
${\mathrm{D}}_{1\%}$(PRV brain stem), Gy	$55.04\pm 1.48$	$54.38\pm 0.99$	$53.56\pm 1.20$	0.00	0.00
${\mathrm{D}}_{1\%}$(Spinal cord), Gy	$41.44\pm 1.63$	$41.28\pm 1.18$	$40.16\pm 0.84$	0.00	0.03
${\mathrm{D}}_{1\%}$(PRV spinal cord), Gy	$48.45\pm 1.40$	$46.31\pm 1.81$	$45.73\pm 1.49$	0.00	0.05
${\mathrm{D}}_{1\%}$ (Optic Chiasm), Gy	$16.23\pm 9.21$	$14.98\pm 7.90$	$14.90\pm 7.90$	0.53	0.72
${\mathrm{D}}_{1\%}$ (Lt Optic Nerve), Gy	$17.75\pm 10.83$	$15.60\pm 9.70$	$16.65\pm 9.18$	0.63	0.06
${\mathrm{D}}_{1\%}$(Rt Optic Nerve), Gy	$19.86\pm 12.96$	$16.64\pm 10.62$	$16.40\pm 10.80$	0.07	0.35
${\mathrm{D}}_{1\%}$(Brachial plexus), Gy	$60.58\pm 1.61$	$60.70\pm 1.32$	$60.49\pm 1.45$	0.72	0.30
${\mathrm{D}}_{\text{mean}}$(Lt parotid), Gy	$30.02\pm 3.27$	$31.60\pm 3.54$	$26.71\pm 2.53$	0.00	0.00
${\mathrm{D}}_{\text{mean}}$ (Rt parotid), Gy	$30.75\pm 4.82$	$32.06\pm 4.44$	$27.93\pm 4.28$	0.00	0.00
${\mathrm{V}}_{30\text{Gy}}$ (Lt parotid), %	$38.18\pm 8.69$	$44.11\pm 10.89$	$30.98\pm 6.13$	0.00	0.00
${\mathrm{V}}_{30\text{Gy}}$ (Rt parotid), %	$38.89\pm 11.33$	$44.72\pm 11.57$	$32.99\pm 9.67$	0.00	0.00
${\mathrm{D}}_{\text{mean}}$ (Lt lens)	$3.82\pm 0.42$	$4.30\pm 0.54$	$4.30\pm 0.33$	0.00	0.91
${\mathrm{D}}_{\text{mean}}$ (Rt lens)	$3.92\pm 0.51$	$4.11\pm 0.51$	$4.23\pm 0.48$	0.01	0.41
${\mathrm{D}}_{\text{mean}}$ (Lt eye)	$5.40\pm 1.19$	$6.04\pm 1.80$	$6.64\pm 2.94$	0.14	0.84
${\mathrm{D}}_{\text{mean}}$ (Rt eye)	$6.06\pm 1.64$	$5.66\pm 1.45$	$6.23\pm 1.95$	0.08	0.12
${\mathrm{D}}_{\text{mean}}$ (Pituitary)	$38.26\pm 10.94$	$36.11\pm 9.26$	$36.61\pm 9.26$	0.13	0.88
${\mathrm{D}}_{\text{mean}}$ (Lt ear)	$48.78\pm 4.05$	$46.29\pm 2.87$	$47.47\pm 3.39$	0.09	0.28
${\mathrm{D}}_{\text{mean}}$ (Rt ear)	$48.00\pm 3.05$	$45.85\pm 3.05$	$45.99\pm 5.06$	0.02	0.94

^aStatistical significance $(p<0.05)$ is reported between couples, IMRT vs. triple RA, and double RA vs. triple RA, from Wilcoxon signed rank test.