Table 1. Projected excess lifetime risk (ELR) and uncertainty intervals of all cancers incidence per 1000 CT scans, according to the time period of scan, the scanned body part, and patient's gender and age.

			ELR (90% uncertainty interval) by time period			Relative difference between time periods, (%)a
Scanned body part	Age (in years)	Gender	1990–1994 (1)	1995–1999 (2)	2000–2008 (3)	(2) vs (1)	(3) vs (2)	(3) vs (1)
Head	0	Male	2.4 (1.2–4.8)	1.6 (0.6–4.1)	0.9 (0.4–2.3)	−33	−44	−63
		Female	2.1 (1.0–4.0)	1.5 (0.7–3.2)	0.8 (0.4–2.0)	−29	−47	−62
	5	Male	1.4 (0.7–2.7)	1.0 (0.4–2.7)	0.7 (0.3–1.7)	−29	−30	−50
		Female	1.2 (0.6–2.0)	0.9 (0.4–1.8)	0.6 (0.3–1.3)	−25	−33	−50
	15	Male	0.9 (0.4–1.8)	0.4 (0.2–1.3)	0.4 (0.2–1.2)	−56	00	−56
		Female	0.6 (0.3–1.0)	0.3 (0.1–0.8)	0.3 (0.1–0.6)	−50	00	−50
Chest	0	Male	3.7 (1.8–8.7)	1.9 (0.8–5.0)	1.4 (0.5–6.0)	−49	−26	−62
		Female	13.3 (6.5–24.8)	6.3 (2.7–16.3)	4.5 (1.5–16.5)	−53	−29	−66
	5	Male	3.0 (1.4–7.1)	1.5 (0.7–4.1)	1.1 (0.4–4.9)	−50	−27	−63
		Female	10.5 (5.0–18.3)	4.9 (2.1–12.6)	3.3 (1.1–12.8)	−53	−33	−69
	15	Male	2.2 (1.2–4.3)	1.3 (0.6–3.2)	0.9 (0.4–2.1)	−41	−31	−59
		Female	7.3 (4.2–11.4)	4.4 (1.9–8.8)	2.6 (1.3–6.4)	−40	−41	−64
Abdomen and pelvis	0	Male	6.2 (3.0–12.4)	3.1 (1.4–7.7)	2.1 (0.8–7.1)	−50	−32	−66
		Female	10.6 (5.5–20.0)	5.4 (2.7–11.7)	3.8 (1.5–10.9)	−49	−30	−64
	5	Male	5.2 (2.5–10.1)	2.6 (1.2–6.3)	1.8 (0.7–5.8)	−50	−31	−65
		Female	8.5 (4.4–16.1)	4.3 (2.2–9.4)	3.1 (1.2–8.6)	−49	−28	−64
	15	Male	3.8 (2.1–7.4)	2.4 (1.2–5.3)	1.5 (0.7–3.6)	−37	−38	−61
		Female	5.3 (3.2–9.9)	3.5 (1.6–7.0)	2.2 (1.1–4.5)	−34	−37	−58

Abbreviation: CT=computed tomography. ELR: median simulated value of ELR per 1000 scans.

^aRelative differences of median ELR values between the two time periods indicated in parentheses.