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Table 2 Dosimetric comparison for PTV, OARs, and MUs between VMAT and non-coplanar IMRT using 7-, 11-, and 15-beam

From: A dosimetric comparison of volumetric modulated arc therapy (VMAT) and non-coplanar intensity modulated radiotherapy (IMRT) for nasal cavity and paranasal sinus cancer

 

VMAT Mean (SD)

7-beam IMRT Mean (SD)

11-beam IMRT Mean (SD)

15-beam IMRT Mean (SD)

p value (VMAT vs.)

7-beam IMRT

11-beam IMRT

15-beam IMRT

HI of PTV

0.07 (0.01)

0.10 (0.03)

0.09 (0.03)

0.10 (0.02)

0.004*

0.012*

0.005*

CI of PTV

1.05 (0.03)

1.13 (0.03)

1.10 (0.05)

1.10 (0.04)

0.002*

0.008*

0.016*

Ipsilateral optic nerve Dmax (Gy)

47.9 (2.16)

46.9 (3.15)

46.3 (3.21)

46.0 (3.91)

0.492

0.492

0.193

D1% (Gy)

45.7 (2.36)

44.1 (2.95)

43.0 (2.40)

43.1 (3.17)

0.322

0.084

0.064

Contralateral optic nerve Dmax (Gy)

47.0 (2.86)

46.0 (2.86)

46.8 (2.79)

46.0 (2.87)

0.275

0.695

0.322

D1% (Gy)

45.3 (2.65)

43.1 (2.79)

44.2 (2.21)

43.6 (2.55)

0.129

0.275

1.000

Optic chiasm Dmax (Gy)

46.7 (2.64)

45.3 (3.46)

45.6 (2.67)

45.0 (2.87)

0.275

0.322

0.193

D1% (Gy)

46.6 (2.48)

42.7 (3.01)

42.9 (2.45)

42.5 (2.96)

0.193

0.166

0.131

Brainstem Dmax (Gy)

44.2 (3.31)

46.0 (2.33)

44.5 (2.45)

45.1 (2.24)

0.105

0.770

0.322

D1% (Gy)

39.8 (3.05)

41.7 (1.77)

40.9 (1.77)

41.8 (1.62)

0.160

0.359

0.064

Ipsilateral eye Dmax (Gy)

43.1 (3.56)

48.8 (4.51)

46.1 (4.59)

45.9 (3.30)

0.004*

0.064

0.037*

D1% (Gy)

38.8 (3.45)

39.8 (3.89)

37.6 (3.36)

37.4 (2.56)

0.322

0.322

0.275

Contralateral eye Dmax (Gy)

41.1 (3.15)

44.7 (2.94)

42.7 (4.37)

42.4 (3.86)

0.004*

0.492

0.322

D1% (Gy)

36.7 (3.70)

35.7 (2.89)

34.4 (4.03)

33.9 (3.84)

0.264

0.078

0.064

Ipsilateral lens Dmax (Gy)

10.5 (1.36)

12.1 (2.28)

12.6 (1.99)

13.6 (1.79)

0.193

0.020*

0.002*

D1% (Gy)

9.77 (1.19)

11.9 (2.32)

12.2 (2.10)

13.3 (1.96)

0.014*

0.006*

0.002*

Contralateral lens Dmax (Gy)

10.2 (1.17)

11.6 (2.18)

11.8 (2.19)

12.6 (2.12)

0.193

0.084

0.006*

D1% (Gy)

9.49 (0.93)

11.2 (2.36)

11.4 (2.26)

12.2 (2.29)

0.053

0.012*

0.04*

Ipsilateral lacrimal gland Dmax (Gy)

28.5 (10.3)

15.2 (6.37)

18.1 (9.93)

16.5 (6.27)

0.004*

0.004*

0.002*

D1% (Gy)

27.1 (1.02)

14.1 (5.50)

17.0 (9.41)

15.4 (5.71)

0.002*

0.004*

0.002*

Contralateral lacrimal gland Dmax (Gy)

22.1 (4.44)

11.4 (6.06)

12.4 (6.02)

11.0 (5.27)

0.002*

0.002*

0.002*

D1% (Gy)

21.0 (4.69)

10.8 (5.77)

11.3 (5.74)

10.4 (5.17)

0.002*

0.002*

0.002*

Ipsilateral parotid gland Dmean (Gy)

12.5 (9.91)

12.2 (8.75)

12.7 (8.93)

11.8 (8.45)

0.922

0.625

0.625

Contralateral parotid gland Dmean (Gy)

9.84 (7.80)

8.84 (6.87)

9.27 (6.80)

8.07 (5.87)

0.131

0.492

0.084

Monitor units

485 (66.3)

2224 (423)

2350 (451)

2475 (384)

0.002*

0.002*

0.002*

Treatment delivery time (Minutes)

4.34 (0.00)

11.72 (0.71)

15.65 (0.75)

19.58 (0.64)

0.002*

0.002*

0.002*

  1. *p value < 0.05.
  2. PTV, planning target volume; OARs, organs at risk; MUs, monitor units; SD, standard deviation; HI, heterogeneity index; CI, conformity index; Dmax, maximum dose; Dmean, mean dose; D1%, minimum dose delivered 1% of the PTV.
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Radiation Oncology

ISSN: 1748-717X

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