Table 2.

Quantitative results associated with different dose levels in the image space. The p value between the low-dose and the predicted standard-dose projections at each reduced dose level is given

Image space
Parameters	HD	PHD	QD	PQD	OD	POD
PSNR	2.68 ± 39.12	2.37 ± 42.49	2.72 ± 35.75	2.89 ± 40.17	2.74 ± 32.09	2.63 ± 33.44
	p value < 0.001		p value < 0.001		p value < 0.04
SSIM	0.01 ± 0.97	0.01 ± 0.99	0.02 ± 0.95	0.01 ± 0.98	0.04 ± 0.90	0.02 ± 0.95
	p value < 0.001		p value < 0.001		p value < 0.001
RMSE	0.96 ± 2.94	0.63 ± 1.99	1.48 ± 4.37	1.19 ± 2.93	2.04 ± 6.66	1.90 ± 5.70
	p value < 0.001		p value < 0.001		p value < 0.05

HD half-dose, PHD predicted half-dose, QD quarter-dose, PQD predicted quarter-dose, OD one-eighth-dose, POD predicted one-eighth-dose