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Table 1 The tumor position reproducibility, the vertebral bone uncertainties and the change in the tumor position relative to the vertebral bone (mm)

From: Implementation of single-breath-hold cone beam CT guided hypofraction radiotherapy for lung cancer

 

The vertebral bone uncertainties

The tumor position reproducibility

The change in the tumor position

 

ML

CC

AP

ML

CC

AP

ML

CC

AP

Pre-correction CBCT

Σ

4.2

5.5

3.4

4.5

5.1

4.0

2.4

4.0

2.7

σ

4.5

5.0

4.9

2.6

4.8

3.6

3.1

4.7

4.1

SM

14.2

18.0

12.6

13.5

16.8

13.0

8.6

13.8

10.3

Second CBCT

Σ

2.5

3.3

2.7

1.1

1.7

1.1

2.3

3.4

2.5

σ

2.4

3.7

3.2

1.7

2.9

2.2

1.9

4.1

2.8

SM

8.2

11.3

9.4

4.3

6.6

4.6

7.3

12.0

8.5

Third CBCT

Σ

1.7

4.4

3.2

1.2

2.0

1.4

2.2

4.1

3.1

σ

1.6

3.6

3.4

1.9

2.8

2.7

2.0

4.4

3.3

SM

5.5

14.1

10.9

4.7

7.4

5.7

7.2

13.9

10.4

  1. Notes: Σ: the SD of the individual means; σ: the root-mean-square of the individual SD; SM = set-up PTV margin = 2.5 + β σ 2 + σ p 2 - β σ p , where σ p  = 0.64 for lung, β = 0.84 for SBRT (80% isodose line).