Table 1.

Errors (MAE and RMSE) and similarities (PSNR, SSIM) relative between sCT and dCT in the test group

	Pelvis (n = 6)	Thorax (n = 6)	Abdomen (n = 6)	Total (n = 18)
U-net
MAE	56.3 ± 9.3	134 ± 27.8	150 ± 55.4	114 ± 54.7
RMSE	104 ± 7.0	168 ± 27.3	172 ± 22.9	148 ± 33.9
PSNR	27.9 ± 0.6	23.0 ± 1.7	22.9 ± 3.1	24.6 ± 3.1
SSIM	0.87 ± 0.04	0.89 ± 0.01	0.91 ± 0.01	0.89 ± 0.03
CycleGAN
MAE	55.3 ± 5.5	63.7 ± 3.8	58.8 ± 4.4	59.2 ± 5.8
RMSE	118 ± 9.3	119 ± 8.4	113 ± 9.3	117 ± 9.4
PSNR	26.8 ± 0.7	25.9 ± 0.5	26.3 ± 0.7	26.3 ± 0.7
SSIM	0.89 ± 0.05	0.90 ± 0.02	0.91 ± 0.01	0.90 ± 0.03

MAE Mean absolute error, RMSE Root mean square error, PSNR Peak signal-to-noise ratio, SSIM Structural similarity