Table 4.
Uncertainty of the MOSFET dose for IMRT therapy given as 1 SD (high sensitivity)
| Uncertainty (%) | ||
|---|---|---|
| Step 1: MOSFET calibration (Ref Cond) | ||
| Dose measured with ionization chamber | 1.0% | |
| Reading of the MOSFET detector | 1.3% | |
| Reproducibility of the setting | 0.5% | |
| Combined uncertainty of step 1 | 1.7% | |
| Step 2: Correction factors | ||
| SSD correction factor | 1.4% | |
| CR value | 1.5% | |
| IMRT correction factor–MOSFET reading on solid water phantom | 1.3% | |
| Combined uncertainty of step 2 | 2.4% | |
| Step 3: Measurement on the patient | ||
| Reading of the MOSFET detector | 1.3% | |
| Positioning (2% over 2 mm radius) | 1.5% | |
| MOSFET detector long‐term stability over time | 3.0% | |
| Combined uncertainty of step 3 | 3.6% | |
|
Combined uncertainty of steps
|
4.6% |