Table 4.
Quality control tests for teletherapy units (tolerances and action levels are specified in millimeters unless otherwise stated)
Designator | Test | Performance | |
---|---|---|---|
Tolerance | Action | ||
Daily | |||
DCO1 | Door interlock/last person out | Functional | |
DCO2 | Motion interlock | Functional | |
DCO3 | Couch brakes | Functional | |
DCO4 | Beam status indicators | Functional | |
DCO5 | Patient audiovisual monitors | Functional | |
DCO6 | Room radiation monitors | Functional | |
DCO7 | Emergency off | Functional | |
DCO8 | Beam interrupt/counters | Functional | |
DCO9 | Head swivel lock | Functional | |
DCO10 | Lasers/crosswires | 1 | 2 |
DCO11 | Optical distance indicator | 1 | 2 |
DCO12 | Optical back pointer | 2 | 3 |
DCO13 | Field size indicator | 1 | 2 |
Monthly | |||
MCO1 | Latching of wedges, trays | Functional | |
MCO2 | Wedge interlocks | Functional | |
MCO3 | Gantry angle readouts | 0.5° | 1° |
MCO4 | Collimator angle readouts | 0.5° | 1° |
MCO5 | Couch position readouts | 1 | 2 |
MCO6 | Couch rotation isocenter | 2 | 3 |
MCO7 | Optical distance indicator | 1 | 2 |
MCO8 | Crosswire centering | 1 | 2 |
MCO9 | Light/Radiation coincidence | 2 | 3 |
MCO10 | Field size indicator | 1 | 2 |
MCO11 | Relative dosimetry | 1% | 2% |
MCO12 | Shutter error | Reproducible | |
MCO13 | Beam symmetry (source position) | 2% | 3% |
MCO14 | Records | Complete | |
Annually | |||
ACO1 | Reference dosimetry | 1% | 2% |
ACO2 | Relative output factor reproducibility | 1% | 2% |
ACO3 | Central axis depth dose reproducibility | 1% | 2% |
ACO4 | Wedge transmission factor reproducibility | 1% | 2% |
ACO5 | Accessory transmission factor reproducibility | 1% | 2% |
ACO6 | Output reproducibility vs. gantry angle | 1% | 2% |
ACO7 | Beam symmetry reproducibility vs. gantry angle | 2% | 3% |
ACO8 | Timer linearity | 1% | 2% |
ACO9 | Shutter error | 0.03 min. | 0.05 min. |
ACO10 | Collimator rotation isocenter | 2 | 3 |
ACO11 | Gantry rotation isocenter | 2 | 3 |
ACO12 | Couch rotation isocenter | 2 | 3 |
ACO13 | Coincidence of collimator, gantry, couch axes | 2 | 3 |
ACO14 | Coincidence of isocenters | 2 | 3 |
ACO15 | Couch deflection | 3 | 5 |
ACO16 | Independent quality control review | Complete |