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Table 3 Comparison of dosimetric parameters between salvage HyperArc and RapidArc for recurrent nasopharyngeal cancer patients

From: Dosimetric comparison between RapidArc and HyperArc techniques in salvage stereotactic body radiation therapy for recurrent nasopharyngeal carcinoma

Parameters

HyperArc Mean (SEM)

RapidArc Mean (SEM)

p value

Target

 CTV coverage (%)

97.71 (1.02)

95.72 (1.89)

0.214

 D2 (Gy)

38.32 (1.38)

38.42 (1.04)

0.508

 D98 (Gy)

35.73 (1.31)

31.85 (2.72)

0.445

 Mean dose

38.09 (1.05)

37.53 (1.01)

0.007*

 PTV coverage (%)

94.12 (1.48)

92.05 (2.24)

0.333

 D2 (Gy)

38.74 (0.93)

38.45 (1.03)

0.139

 D98 (Gy)

31.81 (2.71)

30.37 (2.94)

0.767

 Mean dose

37.75 (1.07)

37.02 (1.08)

0.005*

Organs at risk

 Spinal cord (Gy, Dmax)

3.35 (1.08)

3.32 (1.08)

0.878

 Spinal cord (Gy, mean)

1.84 (0.66)

1.30 (0.39)

0.203

 Brainstem (Gy, Dmax)

4.26 (1.41)

4.45 (1.38)

0.203

 Brainstem (Gy, mean)

0.68 (0.19)

0.64 (0.20)

0.445

 Optic nerve_right (Gy, Dmax)

2.22 (0.65)

1.62 (0.89)

0.059

 Optic nerve_left (Gy, Dmax)

1.82 (0.59)

1.00 (0.27)

0.005*

 Chiasma (Gy, Dmax)

2.46 (0.80)

1.00 (0.12)

0.013*

 Eye_right (Gy, Dmax)

1.22 (0.47)

1.79 (1.02)

0.959

 Eye_left (Gy, Dmax)

1.48 (0.55)

1.68 (1.03)

0.203

 Lens_right (Gy, Dmax)

0.46 (0.08)

0.48 (0.17)

0.093

 Lens_left (Gy, Dmax)

0.50 (0.10)

0.41 (0.10)

0.028

 Brain (Gy, Dmax)

24.40 (2.79)

26.46 (2.54)

0.017*

 Brain (Gy, mean)

1.50 (0.20)

0.76 (0.13)

0.009*

 Brain V12 (c.c.)

3.79 (1.04)

8.54 (2.39)

0.022*

 Temporal lobe (Gy, Dmax)

20.34 (2.82)

20.31 (3.22)

0.878

 Temporal lobe (mean)

4.28 (0.44)

2.13 (1.11)

0.074

 Body sum >100Gy (c.c.)

48.66 (9.63)

64.85 (11.16)

0.008*

Dose distribution metrics

 Conformity index

1.22 (0.04)

1.42 (0.05)

0.007*

 Homogeneity index

1.11 (0.02)

1.17 (0.05)

0.241

 High dose spillage

0.03 (0.01)

0.08 (0.04)

0.445

 Intermediate dose spillage

3.79 (0.40)

6.05 (0.55)

0.005*

 Gradient radius (cm)

0.83 (0.04)

1.21 (0.05)

0.005*

 Monitor units

21,390 (1561)

13,467 (1816)

0.037*

  1. Abbreviations: CTV Clinical target volume, PTV Planning target volume, D2 The radiation dose to 2% of the CTV or PTV, D98 The radiation dose to 98% of the CTV or PTV, Body sum >100Gy The body volume that received accumulated doses more than 100 Gy from the primary and salvage sessions. SEM, standard error of the mean; *, statistically significant, p < 0.05
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Radiation Oncology

ISSN: 1748-717X

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