Previous Page  826 / 1245 Next Page
Information
Show Menu
Previous Page 826 / 1245 Next Page
Page Background

13

Evaluation of PDDs

Warsaw 2017

Statistical evaluation of the deviations between calculated and measured data of

the four 6 MV depth dose curves. Note that the confidence limits for the 5x5 cm2

and 20x20 cm2 do not fulfill the recommended 10% accuracy requirement of dose

calculations of a TPS in the build-up region.

Build-up region (0-2 cm)

Field size

Field size

Field size

Field size

5x5 cm

2

10x10 cm

2

15x15 cm

2

20x20 cm

2

Average deviation (%)

3.7

0.7

- 1.3

- 3.7

Standard deviation (%)

6.2

2.1

2.4

5.1

Confidence limit (%

)

13.0

3.9

5.0

11.3

Remaining curve (2-25 cm)

5x5 cm

2

10x10 cm

2

15x15 cm

2

20x20 cm

2

Average deviation (%)

- 0.1

0.2

0.1

- 0.6

Standard deviation (%)

0.3

0.3

0.3

0.5

Confidence limit (%

)

0.5

0.7

0.6

1.4

Tol. 10 %

Tol. 2 %