Table 5.

Median volume computed tomography (CT) dose index (CTDI_vol) by body region, patient age, manufacturer and phantom, and relative CTDI_vol comparing 16-cm with 32-cm phantoms

Body region	Age category	CTDIvol in mGy
		Canon			GE			Siemens
		Phantom		Relative dose	Phantom		Relative dose	Phantom		Relative dose
		32-cm	16-cm		32-cm	16-cm		32-cm	16-cm
Brain	<1 y
	1–4 y				5	17	3.5
	5–9 y				10	27	2.8
	10–14 y				9	31	3.3	12	29	2.4
	15–17 y				11	37	3.3	8	35	4.1
Skull	< 1 y
	1–4 y				3	17	5.8
	5–9 y	6	11	1.8	2	18	7.9	3	11	4.4
	10–14 y	13	27	2.1	4	20	4.6	4	14	3.4
	15–17 y	17	29	1.7	13	23	1.8	11	15	1.4
Chest	<1 y				1	4	2.5
	1–4 y				2	6	3.1
	5–9 y				2	7	3.1
	10–14 y				4	10	2.3
	15–17 y				6	9	1.5
Abdomen	<1 y				2	3	1.7
	1–4 y	2	6	2.5	2	4	2.0
	5–9 y	4	7	1.9	4	5	1.2
	10–14 y				6	8	1.4
	15–17 y				6	11	1.8

Values are not shown when there were fewer than 5 CT examinations performed by age and body region using each phantom (numbers of scans can be derived from the n and percent values of Table 3). y years