Skip to main content

Advertisement

Table 3 The changes of dose-volumetric indicators according to the magnitudes of MLC misalignments in spine 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
V100% D95% Mean SC V10Gy Esophagus Max Cauda equina V14Gy Brainstem Max Bowel Max
N 8 10 10 3 2 1 1 5
0.25 Out 5.1 ± 2.2 2.4 ± 1.2 1.6 ± 0.7 28.5 ± 9.2 4.0 ± 1.0 133 7.4 1.4 ± 0.3
In -6.6 ± 4.8 -1.9 ± 1.2 -1.6 ± 0.7 -22.9 ± 3.7 -5.5 ± 3.2 -45.9 -1.9 -1.3 ± 0.4
0.5 Out 10.0 ± 5.1 4.5 ± 2.2 3.1 ± 1.4 58.9 ± 13.4 10.3 ± 5.3 356.3 12.1 2.7 ± 0.7
In -15.0 ± 7.7 -4.1 ± 2.3 -3.2 ± 1.4 -44.7 ± 6.8 -10.9 ± 7.0 -70.5 -7.4 -2.7 ± 0.7
1 Out 16.7 ± 9.3 7.2 ± 3.6 5.6 ± 2.5 113.9 ± 28.3 20.5 ± 12.2 610.6 19.5 4.8 ± 1.3
In -32.2 ± 13.6 -7.7 ± 4.0 -5.8 ± 2.6 -71.7 ± 7.4 -19.0 ± 11.5 -91.8 -14.8 -4.8 ± 1.3
Shift 0.2 ± 1.5 1.1 ± 1.2 0.2 ± 0.3 36.8 ± 18.7 -9.6 ± 11.3 123.9 11.8 -2.4 ± 1.5
2 Out 28.5 ± 18.2 13.3 ± 6.4 10.9 ± 5.0 244.4 ± 41.9 45.0 ± 30.0 910.4 36.8 10.3 ± 1.8
In -65.5 ± 22.5 -16.6 ± 8.3 -11.8 ± 5.2 -98 ± 1.9 -33.8 ± 18.0 -100 -30.1 -9.3 ± 2.5
Shift -2.3 ± 2.8 -0.2 ± 1.9 -0.1 ± 0.7 66.4 ± 16.3 -15.2 ± 16.9 346.1 19.9 -4.3 ± 1.9
3 Shift -5.4 ± 5.3 -3.3 ± 3.7 -0.8 ± 1.1 109.3 ± 23.5 -19.6 ± 20.0 628.3 27.6 -5.3 ± 2.5
  1. Abbreviations: MLC multi-leaf collimator, SBRT stereotactic body radiation therapy, V n% the volume irradiated at least n% of prescribed dose, SC spinal cord, Max maximum dose, D n% the dose received by the n% volume of the structure volume, N number of plans.