Frequencies and Tolerances
Tolerances
What we’re checking | Tolerance |
SSD on patient | 5mm |
Collimator Axis of Rotation | 2mm |
Field Size Indicator Accuracy | 2mm |
Tx Couch Isocenter | 2mm |
Lasers | 2mm |
ODI | 2mm |
Field Light | 2mm |
Linear scales (indicating table direction) | 2mm |
Stability of Isocenter under Gantry Axis of Rotation | 2mm |
Dosimetry Process | 5% |
Entire conventional Tx process | 10% |
Film Processor (Diagnostic) | 5-10% |
Film Processor (Therapy ) | 15% |
Cobalt/ Linac Spot Check Dose Rate | 3% |
Cobalt/ Linac Spot Check Beam Penetration | 2% |
Cobalt/ Linac Calibration Dose Rate | 2% |
Cobalt/ Linac Calibration Beam Penetration | 2% |
Field Flatness and Symmetry | 2% across the inner 80% of the field |
Isodose Distributions/ Verify MU Clacs | 2% |
Collimator Rotation Digital Readout | 1° |
Gantry Rotation Digital Readout | 1° |
Frequencies
Daily | Weekly | Monthly | Yearly | Quarterly |
Room Condition | Chart Checks | Emergency OFF | Isodose Distributions/ Verify MU calcs | Limit Switches (Gantry Rotation) |
Communication devices | Tx Accessories | Field Light | Motor Reversal | |
Interlocks (Door, Wedge, Tray) | Over-Ride (Motion Enable Switch) | Cobalt Spot Check Dose Rate | Cobalt Calibration Dose Rate | |
Warning Lights | ODI | Cobalt Spot Check Penetration | Cobalt Calibration Penetration | |
Back Up Systems (Timers, MU2) | Linac Spot Check Dose Rate | Linac Calibration Dose Rate | ||
Lasers | Linac Spot Check Penetration | Linac Calibration Penetration | ||
Film Processor (Diagnostic) | Film Processor (Therapy ) | Linear Scales (Indicating table direction) | ||
Gantry Rotation Digital Readout | CT sim lasers | |||
Detector Calibration |
Other Frequencies
What we are checking | Frequency |
Tx couch isocenter | At time of Acceptance Testing |
Camera Calibration | Every Few Days |
Field Flatness & Symmetry | Weekly - Monthly |
Stability of Isocenter Under Gantry Access of Rotation | Weekly- Monthly |