Table 4.

Warning and Action thresholds for full‐fan kV CBCT mode based on run chart analysis

	Warning	Action
Uniformity (HU/HU)	6%	12%
Noise (HU)	6%	12%
Spatial Resolution (lp/mm)
${\mathrm{f}}_{30}$	9%	18%
${\mathrm{f}}_{40}$	9%	18%
${\mathrm{f}}_{50}$	8%	16%
HU Constancy (HU)
Lung	3%	6%
Water	6%	12%
Bone	2%	4%
Geometric Distortion (mm)
AP	1%	2%
LAT	1%	2%
Slice thickness (mm)	6%	12%
Dose (mGy)
Center	1%	2%
Periphery	1%	2%

Sample size of 60 measurements taken over four‐month time period.