Table 2.

Average technical parameters and radiation dose metrics across the included CT examinations

	Examinations		Protocols
Included units	907,992		1767
	Mean	Standard deviation	Mean	Standard deviation
Patient diameter (mm)	308	45	309	23
Technical parameters
mAs	178	87	178	63
Pitch	1.0	0.3	1.0	0.3
kV	118	8	118	7
Scan length (mm)	483	85	450	82
Number of phases	1.3	0.6	1.4	0.6
Collimation	37	17	35	17
Radiation dose metrics
Volumetric CT dose index (CTDIvol), mGy	13	7	13	5
Size-adjusted CTDIvol, mGy	11	5	12	5
Dose length product (DLP), mGy-cm	756	496	775	418
Size-adjusted DLP (mGy-cm)	657	352	669	361

The six technical parameters listed here were used as inputs in the k-means clustering analysis. DLP dose length product