Table 2 Uncertainty components for the verification method.
Uncertainty budget | |
|---|---|
Components for measurement | Uncertainty |
MatriXX Ionization chambers | 2% |
broadening of penumbra (low pass filter) | 1 mm |
positioning of IMRT-MatriXX | 1 mm |
monitur output fluctuation | 0.75% |
dose stability during gantry rotation | 2% |
stability gantry, collimator, and couch rotation | 0.75 mm |
MLC positioning | 1 mm |
Total | 2.9%, 1.9 mm |
Components for calculation | Uncertainty |
dose calculation of treatment planning system | 1% |
Basic data measurements | 2 mm |
Total | 1%, 2 mm |