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Table 2 The changes of dose-volumetric indicators according to the magnitudes of MLC misalignments in lung SBRT plans

From: The sensitivity of gamma-index method to the positioning errors of high-definition MLC in patient-specific VMAT QA for SBRT

  Percent differences compared to the original plan (%)
MLC error (mm) Class Target Organs at risk
V90% D95% Mean Trachea Max SC Max Rib Max Lung V12.4Gy Lung V11.6Gy Heart Max Esophagus Max
N 10 10 10 7 10 9 10 10 10 10
0.25 Out 1.2 ± 1.3 1.9 ± 0.9 1.5 ± 0.6 2.5 ± 1.5 1.7 ± 0.7 2.3 ± 1.0 16.7 ± 12.0 -1.1 ± 31.2 2.8 ± 1.2 2.4 ± 0.8
In -1.7 ± 1.5 -1.9 ± 0.9 -1.5 ± 0.6 -2.9 ± 1.7 -1.7 ± 0.6 -1.8 ± 1.0 -18.1 ± 15.7 -8.9 ± 4.4 -2.2 ± 1.0 -2.3 ± 0.8
0.5 Out 2.0 ± 2.4 3.8 ± 1.7 3.1 ± 1.3 5.4 ± 3.1 3.5 ± 1.1 4.4 ± 1.9 33.1 ± 22.8 9.3 ± 35.5 5.4 ± 2.2 4.8 ± 1.7
In -4.0 ± 3.1 -3.9 ± 1.6 -3.1 ± 1.2 -5.6 ± 3.0 -12.2 ± 27.4 -4.0 ± 1.9 -33.6 ± 25.3 -17.9 ± 8.8 -5.0 ± 1.8 -4.5 ± 1.5
1 Out 2.7 ± 3.4 6.6 ± 2.9 5.6 ± 2.3 9.1 ± 5.7 6.1 ± 1.6 7.6 ± 3.2 40.1 ± 56.1 21.3 ± 40.7 9.4 ± 4.0 7.9 ± 2.9
In -10.1 ± 6.4 -7.1 ± 2.8 -5.6 ± 2.2 -9.1 ± 5.1 -5.8 ± 1.3 -7.0 ± 3.2 -50.3 ± 29.6 -32.8 ± 16.8 -8.5 ± 3.1 -7.5 ± 2.8
Shift -0.4 ± 1.8 -1.3 ± 2.2 0.1 ± 0.6 -1.3 ± 4.1 0.4 ± 1.4 0.9 ± 1.5 1.3 ± 5.6 -0.5 ± 2.0 0.1 ± 2.0 -2.0 ± 6.0
2 Out 3.4 ± 4.6 12.3 ± 5.4 10.9 ± 4.5 17.8 ± 11.1 12.5 ± 3.0 15.8 ± 7.9 85.6 ± 86.9 49.8 ± 54.7 19.0 ± 8.1 15.6 ± 5.6
In -40.0 ± 19.2 -15.1 ± 5.6 -11.5 ± 4.4 -17.2 ± 9.0 -11.8 ± 2.7 -13.8 ± 6.3 -68.8 ± 35.1 -62.0 ± 30.6 -17.5 ± 6.5 -14.7 ± 4.9
Shift -2.4 ± 3.4 -3.0 ± 3.3 -0.1 ± 1.1 -2.1 ± 6.5 0.7 ± 2.6 2.5 ± 3.7 2.8 ± 9.5 -2.8 ± 5.5 0.1 ± 4.3 -0.7 ± 1.7
3 Shift -6.9 ± 5.4 -6.8 ± 5.6 -1.1 ± 1.8 -3.1 ± 8.7 1.4 ± 4.4 5.1 ± 6.0 1.1 ± 12.8 -5.4 ± 7.0 0.4 ± 7.2 -1.2 ± 2.5
  1. Abbreviations: MLC multi-leaf collimator, SBRT stereotactic body radiation therapy, V n% the volume irradiated at least n% of prescribed dose, Max maximum dose, D n% the dose received by the n% volume of the structure volume, SC spinal cord, N number of plans.