Table 1 The table shows the average values and their standard deviation for FWHM, FWTM, width at − 100 HU, and AE in CT number for the different beam energies. p-values represent comparing metric scores to the 120 kV case. Artifact regions are shown in Fig. 2

FWHM (mm)

Difference % with 120 kV

4.91 ± 0.15

(p = 0.026)

11.3

2.37 ± 0.07 (p = 0.702)

−2.9

2.17 ± 0.04 (p = 0.885)

− 0.9

4.41 ± 0.09

2.44 ± 0.07

2.19 ± 0.02

4.51 ± 0.09

(p = 0.892)

2.3

2.31 ± 0.03

(p = 0.310)

− 5.3

1.98 ± 0.03

(p = 0.003)

− 9.6

4.25 ± 0.12 (p = 0.677)

− 3.6

2.08 ± 0.02 (p = 0.007)

− 14.8

1.88 ± 0.04 (p < 0.001)

− 14.2

FWTM (mm)

Difference % with 120 kV

10.06 ± 0.59

(p = 0.500)

− 10.8

3.81 ± 0.13 (p = 0.679)

− 5.9

7.42 ± 0.73 (p = 0.937)

− 3.5

11.28 ±

1.24

4.05 ± 0.34

7.69 ±

0.17

9.47 ± 0.29 (p = 0.296)

− 16.0

3.53 ± 0.02 (p = 0.225)

− 12.8

5.36 ± 0.34 (p = 0.016)

− 30.3

9.03 ± 0.41 (p = 0.169)

− 19.9

3.11 ± 0.08 (p = 0.029)

− 23.2

3.59 ± 0.01 (p < 0.001)

− 53.3

Width at −100 HU (mm)

Difference % with 120 kV

7.85 ± 0.30 (p = 0.569)

4.8

n/a

n/a

7.49 ± 0.23

n/a

n/a

5.97 ± 0.35 (p = 0.010)

− 20.3

n/a

n/a

4.89 ± 0.03 (p < 0.001)

− 34.7

n/a

n/a

AE in CT number (HU)

Difference % with 120 kV

479 ± 10

(p = 0.887)

2.4

1768 ± 69

(p = 0.130)

11.4

4379 ± 209

(p = 0.091)

10.5

468 ± 8

1587 ± 42

3963 ± 42

311 ± 29 (p < 0.001)

− 33.5

1113 ± 93 (p = 0.003)

− 29.9

4363 ± 145

(p = 0.150)

10.1

240 ± 3

(p < 0.001)

− 48.7

737 ± 48 (p < 0.001)

− 53.6

4361 ± 4 (p = 0.153)

10.0