Table 1.

CT parameters. Lower CTDI_vol is achieved in group B primarily by reductions in mAs_eff and kVp as compared to group A.

		Traditional weight-based protocols with FBP (Group A)				Reduced-CTDIvol protocols with FBP/IRT blend (Group B)
Section thickness (mm)			3				3
Section interval (mm)			1.5				1.5
Rotation time (s)			0.5 – 0.8				0.5
Pitch			0.7 – 1.0				0.9
Reconstruction filter			Standard B				Standard B
Patient weight (kg)	n	mAseff	kVp	Mean CTDIvol (mGy)	n	mAseff	kVp	Mean CTDIvol (mGy)
<9	3	70–75	120	4.6	4	56	100	2.2
9–17	3	80	120	4.9	1	52	100	2.1
	5				3
18–26	3	90	120	5.5	5	58–60	100	2.3
	7				0
27–35	2	100	120	6.3	2	64–68	100	2.5
	4				7
36–44	1	120	120	7.3	2	75–80	100	3.1
	9				7
45–67	5	150	120	9.3	6	95–96	120	6.3
	8				1
68–81	1	200	120	12.2	1	119–120	120	7.9
	6			2

FBP filtered back projection, IRT iterative reconstruction technique, mAs_eff effective milliampere-seconds, kVp peak kilovoltage, CTDI_vol volume CT dose index, n number of subjects