Table 1. Standard CT protocol parameters by age group for brain, chest and abdomen/pelvis examinations.

Examination	Age group	Set parameters
		Voltage (kV)	Qrefa (mAs)	Rotation time (s)	Pitch	Detector configuration	Beam collimation (mm)
CT brain	0–6 months	120	150	0.75	Axial	12×1.5 mm	18
	6 months to 3 years	120	150	0.75	Axial	12×1.5 mm	18
	3–6 years	120	200	0.75	Axial	12×1.5 mm	18
	6–10 years	120	240	0.75	Axial	12×1.5 mm	18
	>10 years	120	270	0.75	Axial	12×1.5 mm	18
CT chest	<5 years	80	65	0.50	1.00	16×1.5 mm	24
	5–10 years	100	80	0.50	1.00	16×1.5 mm	24
	>10 years	120	80	0.50	1.00	16×1.5 mm	24
CT abdomen/pelvis	<5 years	80	80	0.50	1.25	16×1.5 mm	24
	5–10 years	100	80	0.50	1.25	16×1.5 mm	24
	>10 years	120	60	0.50	1.25	16×1.5 mm	24

^aQ_ref is the imaging quality reference mAs, which is a setting specific to Siemens (Erlangen, Germany) that is used for automatic tube current modulation (CARE Dose4D^TM; Siemens), which is defined by the user for each protocol. This value is adjusted based on image quality requirements and the amount of noise acceptable in the image. It is defined in terms of the effective mAs (actual mAs divided by pitch).