Table 3.

Contrast recovery and background variability values in % for each active sphere for different reconstruction parameters of the 3D OP-OSEM reconstruction algorithm when using CT-based AC

	aContrast recovery [%] │ aBackground variability [%]
	Sphere 10 mm		Sphere 13 mm		Sphere 17 mm		Sphere 22 mm
Iteration	172 x 172	344 x 344	172 x 172	344 x 344	172 x 172	344 x 344	172 x 172	344 x 344
1	13.8 │ 2.5	15.8 │ 2.8	28.1 │ 2.3	29.6 │ 2.5	48.5 │ 2.1	51.3 │ 2.3	53.7 │ 2.1	56.0 │ 2.2
2	24.3 │ 3.2	28.1 │ 3.5	43.8 │ 2.6	45.3 │ 2.8	66.8 │ 2.3	69.7 │ 2.3	70.0 │ 1.9	72.0 │ 2.2
3	30.5 │ 3.8	35.0 │ 4.3	50.5 │ 3.0	51.1 │ 3.2	72.9 │ 2.5	75.2 │ 2.6	74.5 │ 2.3	76.3 │ 2.4
4	34.3 │ 4.4	38.7 │ 4.9	53.4 │ 3.3	53.3 │ 3.5	75.4 │ 2.7	77.5 │ 2.8	76.5 │ 2.5	78.2 │ 2.6
5	36.8 │ 4.8	40.8 │ 5.3	54.8 │ 3.5	54.3 │ 3.8	76.9 │ 2.9	78.7 │ 3.0	77.6 │ 2.6	79.2 │ 2.7

^a4 mm Gaussian filtering and 21 subsets were kept constant for all reconstructions. The values represent the mean of four independent measurements