Table 1.

OAC estimated by the exponential fitting, DRE, and ODRE methods from the uniform phantoms.

Concentration (%)	Exponential fitting (${\mathrm{mm}}^{-1}$)	DRE (${\mathrm{mm}}^{-1}$)	ODRE (${\mathrm{mm}}^{-1}$)
5	$1.18\pm 0.12$	$0.93\pm 0.16$	$1.16\pm 0.21$
10	$1.49\pm 0.08$	$1.03\pm 0.18$	$1.40\pm 0.26$
15	$2.12\pm 0.15$	$1.20\pm 0.18$	$2.05\pm 0.29$
20	$3.0\pm 0.17$	$1.36\pm 0.20$	$2.92\pm 0.22$