Table 4.
Parameters of the IMRT test fields and gamma passing rates based on 2% DD, 2 mm DTA criteria for the 5 photon energies
| Fields | Description | Field size (cm2) | 6 MV | 10 MV | 18 MV | 6 MV FFF | 10 MV FFF |
|---|---|---|---|---|---|---|---|
| 10 × 10 | Absolute dose calibration | 10 × 10 | 99.3 | 93.5 | 91.5 | 97.6 | 91.3 |
| 20 × 20 | Flatness, symmetry | 20 × 20 | 96.4 | 94.4 | 93.0 | 96.0 | 97.6 |
| 3ABUT | 3 abutted segments | 6 × 24 | 98.9 | 89.5 | 93.0 | 92.0 | 95.5 |
| DMLC | MLC offset | 2 × 20 | 96.3 | 89.3 | 89.1 | 90.1 | 91.4 |
| HIMRT | IMRT performance | Variable | 99.7 | 94.3 | 94.2 | 99.9 | 94.8 |
| HDMLC | DMLC performance | Variable | 99.9 | 94.1 | 97.0 | 99.9 | 99.3 |
| 7SegA | Picket fence | 2 × 24 | 96.2 | 85.4 | 91.6 | 97.1 | 96.3 |
| FourL | 4 L‐shaped MLC segments | Variable | 93.6 | 76.9 | 85.8 | 91.4 | 90.3 |