Table 3.

Comparison of the ICRP 103-based age-specific k-factors between Deak et al.⁽¹¹⁾ and the current study (NCI). The k-factors for head and neck scans assume use of the head CTDI phantom (16 cm) for paediatric and adult patients and the k-factors for other scans assume use of the body CTDI phantom (32 cm). The percent difference (% diff) was calculated as (NCI − Deak)/Deak × 100.

Scan type	0-y-old			1-y-old			5-y-old			10-y-old			Adult
	NCI	Deak	% diff	NCI	Deak	% diff	NCI	Deak	% diff	NCI	Deak	% diff	NCI	Deak	% diff
Head	0.009	0.009	0.8	0.006	0.005	10.1	0.004	0.004	23.8	0.003	0.003	9.0	0.002	0.002	−12.4
Neck	0.023	0.021	11.3	0.013	0.017	−23.4	0.009	0.012	−23.1	0.007	0.009	−28.1	0.005	0.005	−8.3
Chest	0.099	0.071	39.9	0.064	0.047	37.4	0.047	0.031	48.6	0.033	0.023	39.2	0.021	0.015	45.5
Abdomen	0.088	0.080	9.6	0.063	0.051	22.2	0.043	0.035	21.8	0.032	0.025	31.3	0.022	0.015	41.0
Pelvis	0.054	0.067	−19.8	0.041	0.043	−5.1	0.028	0.029	−3.8	0.017	0.022	−22.8	0.011	0.013	−16.2