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Table 2 Summary of setup variation in translational and rotational direction (mm) for 13 patients

From: Positioning accuracy during VMAT of gynecologic malignancies and the resulting dosimetric impact by a 6-degree-of-freedom couch in combination with daily kilovoltage cone beam computed tomography

 

Initial inter-fraction error

Residual inter-fraction error

Intra-fraction error

Direction

M

SD

Range

PDE

M

SD

Range

PDE

M

SD

Range

PDE

ML (mm)

−0.3

3.1

−9.0-7.0

51.6%

0.2

0.6

−1.8-1.8

0%

0.2

0.7

−1.8-2.5

1.6%

SI (mm)

2.0

3.7

−7.8-17.4

57.0%

0.0

0.7

−3.3-1.7

2.3%

0.0

1.1

−6.3-4.0

5.5%

AP (mm)

−1.4

2.7

−9.2-5.5

49.2%

−0.1

0.5

−1.6-3.0

0.8%

−0.4

0.7

−6.0-0.9

2.3%

Pitch (°)

−0.2

1.3

−3.8-2.9

14.1%

−0.1

0.5

−1.8-1.6

0.0%

−0.2

0.6

−2.4-1.5

2.3%

Roll (°)

−0.4

1.2

−8.0-2.5

10.2%

0.4

0.4

−0.8-1.1

0.0%

0.1

0.3

−1.0-1.0

0.0%

Yaw (°)

−0.1

0.6

−1.7-1.6

0.0%

0.1

0.2

−0.7-0.9

0.0%

0.1

0.3

−0.8-1.3

0.0%

  1. Abbreviations: M overall population mean, SD standard deviation, PDE percentage of displacements exceeding ± 2 mm or ± 2°.