Table 3.

Gammex phantom spectral contrast measurements (HU).

ROI	Material	XB	XB - XA	XB - XAB	XB - YB	Iodine(a) (YA, YB)
1	Blood Iodine (2 mg/mL)	67.49	−32.11	−1.00	−0.26
2	Muscle	33.96	−8.39	1.37	−0.08
3	Blood	104.45	−9.76	27.08	0.25
4	Muscle	35.99	−6.02	3.31	0.23
5	Brain	28.75	−1.92	3.70	0.30
6	Iodine (5 mg/mL)	58.29	−68.74	−26.82	−0.13	5.00(b)
7	Calcium (50 mg/mL)	160.39	−37.60	31.86	0.04
8	Adipose	−55.63	9.97	−8.04	−0.12
9	Calcium (100 mg/mL)	257.90	−78.20	39.57	0.33
10	Muscle	37.63	−4.21	4.53	1.22
11	Iodine (2 mg/mL)	28.79	−27.98	−13.61	−17.34	0.80
12	Muscle	38.09	−3.55	5.22	2.28
13	Muscle	38.81	−2.12	6.44	2.55
14	Iodine (15 mg/mL)	191.55	−205.07	−69.03	−28.89	12.90
15	Muscle	37.76	−0.43	6.98	3.49
16	Iodine (2 mg/mL)	28.79	−24.21	−8.87	−16.05	0.37
17	Iodine (15 mg/mL)	191.55	−203.11	−67.84	−27.26	12.88

Notes: Bold text indicates minimum HU errors by magnitude relative to X_B. Underlined text indicates assumed values.

^(a)Units of mg/mL.

^(b)Reference iodine measurement.

ROIs 1–9: within 20 cm mask. 10–15: within 30 cm mask. 16–17: extended 50 cm FoV.