Table 1. Summary data for several relevant configurations. Also shown with FOM is the optimal dose allocation at which the optimal value occurred. For the case of gold and beam energies of 139 kVp and 140 kVp, higher precision was used in order to resolve differences in the FOM.

Contrast Element	Beam Energy (low, high)	Optimal Dose Allocation (low:high)	FOM (keV−1/2)	Notes on Configuration
GOLD	46 , 81 keV	0.4 , 0.6	6.4 × 10−6	Monoenergetic beams with ideal detector
	80 , 139 kVp		1.6523 × 10−6	Optimal polyenergetic configuration
	80 , 140 kVp		1.6522 × 10−6	Reference configuration
			2.54 × 10−6	Reference configuration w/ optimal filter thickness
IODINE	33 , 44 keV	0.6 , 0.4	3.1 × 10−6	Monoenergetic beams with ideal detector
	33 , 52 kVp		2.2 × 10−6	Optimal polyenergetic configuration
	70 , 150 kVp	0.4 , 0.6	6.6 × 10−7	Optimal polyenergetic configuration above the low energy cutoff.
	80 , 140 kVp		5.0 × 10−7	Reference configuration
		0.3 , 0.7	1.0 × 10−6	Reference configuration w/ optimal filter thickness