Table 3. RMSE Values of Subtracted CT Volumes in Test 2.

Conversion Pairs (Input, Target Image)	Original	Converted	Differences (%)
From smooth to sharp kernel
B10f, B30f	15.02 ± 0.87	5.17 ± 0.45	−65.6 ± 2.3
B10f, B50f	53.50 ± 5.08	28.84 ± 4.52	−46.4 ± 4.0
B10f, B70f	109.50 ± 14.07	74.97 ± 13.46	−31.9 ± 4.0
B30f, B50f	40.68 ± 4.65	15.72 ± 2.15	−61.4 ± 1.5
B30f, B70f	98.50 ± 13.94	45.49 ± 7.47	−53.9 ± 1.5
B50f, B70f	60.63 ± 9.56	18.77 ± 2.70	−69.0 ± 0.7
From sharp to smooth kernel
B30f, B10f	15.02 ± 0.87	3.44 ± 0.18	−77.1 ± 0.8
B50f, B10f	53.50 ± 5.08	10.85 ± 1.16	−79.7 ± 1.1
B50f, B30f	40.68 ± 4.65	8.81 ± 1.10	−78.3 ± 1.3
B70f, B10f	109.50 ± 14.07	19.92 ± 2.15	−81.7 ± 1.3
B70f, B30f	98.50 ± 13.94	17.55 ± 1.56	−82.0 ± 1.5
B70f, B50f	60.63 ± 9.56	13.63 ± 1.63	−77.3 ± 1.3

Data are presented as mean ± SD (HU). Original: RMSE by subtracting between input and target images. Converted: RMSE by subtracting converted images from target images. Differences: 100 x (converted RMSE - original RMSE) / original RMSE