TABLE 1

Summary of Regression Analyses in Phantom Studies

Target cylinder diameter, T/BG range	x vs. y	I (±SE)	S (±SE)	R² linear	R² 2nd poly.
2 cm, full T/BG range	True T/BG vs. CS	−0.20 (0.16)	1.04* (0.04)	0.987	0.997
	True T/BG vs. MS	0.60 (0.07)	0.47^† (0.02)	0.989	0.995
	CS vs. MS	0.70 (0.06)	0.45 (0.01)	0.991	0.992
2 cm, T/BG < 3.5	True T/BG vs. CS	0.13 (0.10)	0.86 (0.05)	0.982	0.984
	True T/BG vs. MS	0.71 (0.04)	0.41 (0.02)	0.988	0.994
	CS vs. MS	0.67 (0.07)	0.47 (0.04)	0.964	0.965
2.8 cm, full T/BG range	True T/BG vs. CS	−0.32 (0.13)	1.17* (0.03)	0.993	0.997
	True T/BG vs. MS	0.44 (0.06)	0.52^† (0.02)	0.992	0.994
	CS vs. MS	0.59 (0.07)	0.43 (0.02)	0.988	0.988
2.8 cm, T/BG < 3.5	True T/BG vs. CS	0.00 (0.08)	0.97 (0.04)	0.992	0.995
	True T/BG vs. MS	0.49 (0.08)	0.50 (0.04)	0.964	0.971
	CS vs. MS	0.50 (0.09)	0.51 (0.05)	0.953	0.953

↵* P < 0.02 (ANCOVA).
↵^† P < 0.05 (ANCOVA).
I = linear regression intercept; S = slope; R² linear = R² value of linear regression analyses (all P < 0.0001); R² 2nd poly. = R² value of second-order polynomial regression analyses (all P < 0.0001).