Table 3.

Pearson correlation coefficients of the QPS quantitative parameters considering the actual standard-dose images as reference

Parameters	HD	PHD	QD	PQD	OD	POD
Defect	0.94	0.99	0.90	0.99	0.83	0.75
	p value < 0.001		p value < 0.001		p value < 0.03
Extent	0.87	0.99	0.83	0.97	0.71	0.70
	p value < 0.001		p value < 0.001		p value < 0.01
SSS / SRS	0.83	0.99	0.75	0.96	0.68	0.70
	p value < 0.001		p value < 0.001		p value < 0.01
SS% / SR%	0.82	0.99	0.75	0.97	0.66	0.70
	p value < 0.001		p value < 0.001		p value < 0.01
TPD%	0.88	0.99	0.82	0.98	0.76	0.76
	p value < 0.001		p value < 0.001		p value < 0.01
Volume	0.99	1.00	0.99	1.00	0.95	0.97
	p value < 0.001		p value < 0.03		p value = 0.29
Wall	0.98	1.00	0.97	1.00	0.93	0.96
	p value < 0.001		p value < 0.001		p value = 0.39
Shape Eccentricity	0.94	0.99	0.93	0.99	0.84	0.82
	p value < 0.001		p value < 0.001		p value < 0.01
Shape Index	0.72	0.95	0.60	0.88	0.54	0.72
	p value < 0.001		p value < 0.004		p value < 0.03

HD half-dose, PHD predicted half-dose, QD quarter-dose, PQD predicted quarter-dose, OD one-eighth-dose, POD predicted one-eighth-dose. p value between the low-dose and the predicted standard-dose projections at each reduced dose level