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Summary
Test
Priority
Level of
expertise*
Output repeatability
Output reproducibility
Filtration
Essential
Essential
Essential
MPE
MPE
MPE
Tube potential
Field size and alignment
Leakage
Essential
Essential
Essential
MPE
MPE
MPE
Quantitative image
Quality
Image density values
Uniformity and artifacts
Recommended
Essential
Display specific
Noise
Limiting resolution
Contrast detail
Geometrical accuracy
General condition
Patient dose
X-ray tube and
generator
Suggested
frequency
Action levels**
Mean ±10%
Baseline ±10%
< 2.5mm aluminium (of which 1.5mm
should be permanent)
In house/MPE
In house
12 monthly
12 monthly
When new, if output
changes or tube head
dismantled
12 monthly
12 monthly
When new and if damage
suspected
Monthly
Monthly
Recommended
Essential
Recommended
Essential
Essential
In house/MPE
In house/MPE
In house/MPE
In house/MPE
In house
12 monthly
12 monthly
12 monthly
12 monthly
Monthly
Monitor resolution
Patient dose index
Recommended
Recommended
In house
MPE
Monthly
12 monthly
Patient dose audit
Essential
In house/MPE
At least 3 yearly
> ±5% of intended kV
>10% expected field size
> 1000µGy hr-1 at maximum tube
rating.
>10% from baseline
Visible artefacts on the image or
>±10% of the mean
> ±10% from baseline
> ±20% from baseline
Dependent on method used.
within ±2mm and ±2º
Failure to resolve different contrasts
in test pattern/ not consistent between
monitors
Not consistent with baseline image
Outside ±15% of manufacturer’s
specification
> national or international reference
level
Notes
* Level of expertise: MPE indicates that this test would normally require the input of a medical physics expert with sophisticated test equipment whereas in
house indicates that the tests can normally be performed by clinic staff using standard phantoms
** Action level: Results outside these levels should be investigated and action taken. The advice of a medical physics expert or service engineer may be
required
N.B. This table represents initial guidance based on current experience of dental CBCT units. It should be kept under critical review as experience is gained in
testing such units.
33 SEDENTEXCT D3.4 Report – Appendix 1: Generic QA Protocol