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Table 2 Comparison of PTV doses among the three techniques

From: Advanced nasopharyngeal carcinoma radiotherapy with volumetric modulated arcs and the potential role of flattening filter-free beams

Target

RA-FFF

RA

IMRT

p value

p 1

p 2

p 3

PTV70

       

D99%(Gy)

68.52 ± 0.46

68.69 ± 0.59

69.06 ± 0.22

0.122

—

—

—

D1%(Gy)

75.40 ± 1.32

74.08 ± 1.12

74.30 ± 0.62

0.007

0.005

0.028

0.878

Dmean(Gy)

72.80 ± 0.72

72.15 ± 0.68

71.95 ± 0.21

0.007

0.005

0.012

0.333

V70(%)

95.00 ± 0.00

95.00 ± 0.00

95.00 ± 0.00

—

—

—

—

CI

0.486 ± 0.213

0.609 ± 0.199

0.519 ± 0.220

0.014

0.007

0.445

0.037

HI

0.087 ± 0.023

0.067 ± 0.021

0.069 ± 0.011

0.008

0.005

0.028

0.646

PTV66

       

D99%(Gy)

65.26 ± 0.99

65.19 ± 0.98

66.07 ± 1.09

0.121

—

—

—

D1%(Gy)

72.74 ± 1.58

71.34 ± 1.46

72.25 ± 1.53

0.008

0.008

0.314

0.799

Dmean(Gy)

69.67 ± 0.99

68.90 ± 0.85

70.18 ± 1.18

0.001

0.008

0.155

0.008

V66(%)

97.65 ± 1.28

97.53 ± 1.37

99.08 ± 0.60

0.050

—

—

—

CI

0.209 ± 0.074

0.244 ± 0.074

0.226 ± 0.083

0.169

—

—

—

HI

0.108 ± 0.054

0.088 ± 0.052

0.080 ± 0.048

0.001

0.008

0.008

0.123

PTV60

       

D99%(Gy)

57.97 ± 0.84

57.88 ± 0.77

58.54 ± 0.71

0.006

0.508

0.009

0.009

D1%(Gy)

74.31 ± 1.08

73.38 ± 1.02

73.30 ± 0.61

0.025

0.009

0.022

0.799

Dmean(Gy)

66.23 ± 0.93

65.55 ± 1.08

66.47 ± 0.91

0.001

0.005

0.333

0.005

V60(%)

96.36 ± 0.87

96.13 ± 0.95

97.88 ± 0.44

0.002

0.445

0.005

0.007

CI

0.793 ± 0.025

0.811 ± 0.023

0.813 ± 0.025

0.002

0.005

0.022

0.575

HI

0.230 ± 0.040

0.217 ± 0.044

0.199 ± 0.038

0.001

0.047

0.005

0.005

  1. Abbreviations: CI = conformity index; HI = homogeneity index; D 99%  = dose received by 99% of the volume; p1 = Wilcoxon test p value between RA-FFF and RA plans; p2 = Wilcoxon test p value between RA-FFF and IMRT plans; p3 = Wilcoxon test p value between RA and IMRT plans. Other abbreviations as in Table 1.