Table 5.
PTV margins by BMI cohort
| All | BMI ⩽ 25 | BMI > 25 | |
|---|---|---|---|
|
| |||
| MSTa (mm) | |||
| x-axis | 9.5 | 7.8 | 10.7 |
| y-axis | 11.3 | 10.0 | 12.1 |
| z-axis | 12.8 | 7.5 | 15.3 |
| 3D | 16.6 | 12.7 | 18.7 |
| MVHb (mm) | |||
| x-axis | 11.1 | 9.0 | 12.5 |
| y-axis | 13.4 | 11.7 | 14.3 |
| z-axis | 15.0 | 8.5 | 18.0 |
| 3D | 19.6 | 14.8 | 22.2 |
Abbreviations: PTV = planning target volume.
a
Stroom margin (MST) calculated via the method of Stroom and Heijmen, where MST = 2Σ + 0.7σ (Σ denotes systematic error, and σ random error) [17].
b
van Herk margin (MVH) calculated via the method of van Herk et al., where MVH = 2.5Σ + 0.7σ (Σ denotes systematic error, and σ random error) [16].