Table 3: Annual QC tests and tolerances
levels for X-ray CT.
Test quantity |
Acceptable |
Achievable |
CT alignment lights |
± 5 mm |
± 1 mm |
|
± 2 mm |
± 1 mm |
CT number |
± 5 from baseline valuea |
± 4 |
Image Noise |
± 25% from baseline valuea |
±10% of the baseline |
Uniformity |
± 10 |
± 4 |
Artefact |
No artefacts to affect diagnostic confidence |
No visible artefacts |
CTDIvol |
< ± 20% manufacturer’s recommendations and console
displayed dose values |
|