Table 2.
Minimum equipment QA and tolerances for robotic linac systems
| Frequency | Test | Tolerance |
|---|---|---|
|
Daily* *On days of clinical use |
Head laser alignment check | 1.0 mm |
| Safety interlocks | Functional | |
|
Automatic QA (AQA) test* *If the clinic has both fixed cones and Iris TM collimator, the AQA test should alternate between fixed cones and Iris TM , with each system tested at least weekly |
Total targeting ≤1.0 mm from baseline, not exceeding manufacturer's specification | |
| Accelerator output constancy | ±3% | |
| Monthly | Energy constancy | ±2% |
| Beam symmetry, relative | ±3% for 40 mm field, ±4% for 60 mm field | |
| Accelerator output constancy | ±2% | |
| Imager alignment | 1 mm or center pixels ±2 pixels | |
| IrisTM field size spot check (3 or more field sizes ≥10 mm) | 0.5 mm | |
| Picket fence for MLC (if applicable) | Visual check | |
| Quarterly |
E2E localization assessment (Each tracking mode used clinically) |
1.0 mm static target, 1.5 mm motion tracking |
| Annually | Emergency Power Off (EPO) button, safety interlocks | Functional |
| Accelerator output | ±2.0% | |
| MU linearity (>10 MU to highest MU used clinically) | ±2% | |
| Path verification | ≤0.5 mm maximum per node, ≤0.3 mm average | |
| Imager kVp accuracy, mA station exposure linearity, isopost alignment with center pixel | ±10%, ±20%, and 1 mm, respectively | |
| Beam laser and radiation beam alignment for cone, IrisTM, and MLC | 0.5 mm from baseline | |
| AQA baseline | Recheck AQA baseline | |
| Beam data verification — Relative output factors for cones, IrisTM, and/or MLC covering the range used clinically | ±2% from baseline for >1.0 cm apertures, ±5% from baseline for ≤1.0 cm apertures |