Numerical Evaluation of Image Contrast for Thicker and Thinner Objects among Current Intraoral Digital Imaging Systems

Table 2

Contrast-to-noise ratio for each detector.

Dose	Digora		VistaScan		Megadixel
	Pb (−)	Pb (+)	Pb (−)	Pb (+)	Pb (−)	Pb (+)
	mean (SD)	mean (SD)	mean (SD)	mean (SD)	mean (SD)	mean (SD)
Standard	0.31 (0.48)	2.63 (1.07)	5.46 (0.60)	5.63 (1.42)	10.70 (0.06)	10.28 (0.09)
Half	0.64 (0.47)	2.23 (1.27)	4.26 (0.26)	4.48 (0.98)	7.51 (0.10)	7.48 (0.19)
One-tenth	0.27 (0.29)	1.20 (0.52)	2.16 (0.17)	1.94 (0.07)	4.79 (0.20)	6.11 (0.33)

Each dose for CCD (Megadixel) is half of that for PSP (Digora and VistaScan).
Pb shows the existence of lead during exposure. (−) and (+) mean without and with lead.