Table 2.

Raw CT numbers obtained from all 22 scanner/protocols for the 3 reference foams, air, water, and the lung foam (backing foam), along with the kVp and dose settings. A shifted CT number $H_{raw}$ = (raw CT number)/1000 + 1 is used for subsequent analysis

Scanner	Foam 1	Foam 2	Foam 3	Air	Water	Lung	kVp (kV)	Dose (mGy)
1	−940.53	−823.05	−698.58	−1001.40	1.91	−855.72	100	1.5
	−940.27	−822.26	−697.56	−1001.53	0.84	−855.69	120	1.5
	−940.16	−822.86	−698.28	−1001.61	2.12	−855.14	100	3.0
	−939.83	−822.42	−697.09	−1001.85	1.30	−855.29	120	3.0
	−940.11	−823.04	−698.18	−1001.96	2.55	−855.06	100	6.0
	−940.14	−822.32	−697.23	−1002.13	1.48	−855.24	120	6.0
2	−942.65	−822.21	−698.42	−1002.70	3.88	−859.86	120	3.0
3	−936.48	−820.92	−696.00	−995.38	−0.91	−852.24	100	1.5
	−935.52	−819.08	−695.17	−994.04	−1.14	−851.71	120	1.5
	−935.28	−818.18	−694.68	−993.92	−0.76	−851.70	140	1.5
	−936.78	−820.97	−695.85	−997.35	−1.15	−852.43	100	3.0
	−936.02	−819.73	−695.00	−997.21	−1.29	−852.37	120	3.0
	−935.77	−818.97	−694.45	−996.54	−0.92	−852.01	140	3.0
	−936.50	−820.76	−695.67	−998.37	−1.07	−852.34	100	6.0
	−935.94	−819.40	−694.74	−997.79	−1.45	−852.25	120	6.0
	−935.40	−818.64	−694.29	−997.19	−1.11	−851.90	140	6.0
4	−940.65	−826.08	−699.66	−1002.31	0.44	−858.55	100	3.0
	−940.37	−824.64	−699.18	−1002.44	0.16	−858.03	120	3.0
	−940.38	−823.94	−698.84	−1002.22	−0.08	−857.73	135	3.0
	−940.59	−825.90	−699.83	−1002.23	0.25	−858.28	100	6.0
	−940.55	−824.57	−699.37	−1002.36	0.01	−857.88	120	6.0
	−940.35	−823.86	−699.04	−1002.28	−0.22	−857.55	135	6.0

Raw CT number (HU) reported for each scanner‐protocol.