Table 3 Mean ± SD values of dosimetric parameters and differences between big model versus single-institution model.

From: Multi-institution model (big model) versus single-institution model of knowledge-based volumetric modulated arc therapy (VMAT) planning for prostate cancer

 

Case I

Case II

Big model

Single-institution model

Difference (p-value)

Big model

Single-institution model

Difference (p-value)

PTV

D98

71.2 ± 4.1

71.6 ± 4.2

 − 0.3 ± 0.8 (0.588)

72.1 ± 3.5

72.2 ± 3.9

0.0 ± 0.8 (0.812)

D95

72.8 ± 4.2

72.9 ± 3.9

 − 0.2 ± 0.6 (0.584)

74.3 ± 2.8

73.6 ± 3.4

0.7 ± 1.8 (0.789)

D50

79.0 ± 1.6

78.7 ± 0.5

0.3 ± 1.1 (0.416)

78.9 ± 1.5

78.8 ± 0.5

0.1 ± 1.2 (1.0)

D2

81.5 ± 1.8

81.6 ± 2.0

 − 0.1 ± 1.5 (0.812)

81.2 ± 1.7

81.3 ± 1.6

0.0 ± 1.5 (0.786)

HI

0.13 ± 0.06

0.13 ± 0.07

0.00 ± 0.03 (1.0)

0.12 ± 0.05

0.12 ± 0.07

0.00 ± 0.03 (1.0)

Rectum

V90

6.6 ± 4.0

8.4 ± 3.6

 − 1.8 ± 1.6 (0.0625)

4.3 ± 2.7

6.0 ± 3.4

 − 1.7 ± 1.9 (0.0625)

V80

12.0 ± 3.9

16.8 ± 1.5

 − 4.8 ± 3.7 (0.0625)

9.3 ± 2.7

13.7 ± 1.8

 − 4.3 ± 2.7 (0.0625)

V50

32.4 ± 3.8

46.6 ± 15.4

 − 14.1 ± 13.8 (0.0625)

30.4 ± 3.9

42.5 ± 14.1

 − 12.1 ± 15.2 (0.125)

Bladder

V90

13.8 ± 1.8

13.3 ± 4.3

0.5 ± 3.3 (1.0)

7.2 ± 1.0

7.0 ± 2.3

0.2 ± 1.9 (1.0)

V80

19.4 ± 1.6

18.7 ± 4.1

0.7 ± 3.7 (1.0)

10.1 ± 0.8

10.0 ± 2.0

0.2 ± 1.8 (1.0)

V50

39.9 ± 2.0

38.4 ± 5.2

1.5 ± 5.6 (0.812)

21.5 ± 0.9

21.2 ± 2.6

0.3 ± 3.0 (0.855)

  1. D98, D95, D50, and D2 Minimum dose in Gy to 2%, 50%, 95%, and 98% of the PTV; HI Homogeneity index; V90, V80, and V50 Volume ratio receiving 90%, 80%, and 50% of the prescribed dose.
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