CT dose and image quality in the last three scanner generations

Table 1 Reduction of noise and dose using iterative reconstruction and the stellar detector

		Soft tissue				Air				Bone
		Lowest dose		Highest dose		Lowest dose		Highest dose		Lowest dose		Highest dose
	Δ HUsd	Range			Δ HUsd	Range			Δ HUsd	Range
Noise reduction from FBP to IR	10 (31%)	15 (30%)	to	7 (31%)	31 (44%)	53 (49%)	to	22 (41%)	64 (30%)	128 (37%)	to	28 (21%)
Noise reduction from IR to IR with Sd	7 (32%)	16 (42%)	to	4 (24%)	12 (31%)	19 (34%)	to	9 (28%)	24 (15%)	51 (22%)	to	9 (7%)
	Δ DLP	Range			Δ DLP	Range			Δ DLP	Range
Dose reduction from FBP to IR for the same noise level	53 (52%)	116 (55%)	to	25 (50%)	133 (80%)	165 (78%)	to	106 (81%)	48 (30%)	24 (12%)	to	40 (55%)
Dose reduction from IR to IR with Sd for the same noise level	69 (54%)	96 (39%)	to	46 (65%)	106 (70%)	166 (67%)	to	65 (72%)	35 (27%)	33 (21%)	to	25 (43%)

HUsd: Noise (sd of Hounsfield Units); FBP: Filtered back projection; IR: Iterative reconstruction; Sd: Stellar detector; DLP: Dose length product.