An Investigation of Calibration Phantoms for CT Scanners with Tube Voltage Modulation

Table 1

Parameters of FORBILD head phantom.

Label	Geometry	Position (cm)	Ellipsoid	Elliptical cylinder/cone	Φ (°)	𝜃 (°)
			half-axis length (cm, cm, cm)	(radius, radius, length); (cm, cm, cm)
1	Ellipsoid	(0, 0, 0)	(9.6, 12.0, 12.5)	N/A	0.0	0.0
2	Ellipsoid	(0, 0, 0)	(9, 11.4, 11.9)	N/A	0.0	0.0
3	Ellipsoid	(0, 8.4, 0)	(1.8, 3.0, 3.0)	N/A	0.0	0.0
4	Elliptical cylinder	(0, 3.6, 0)	N/A	(4, 1.2, 0.483)	60	90
5	Elliptical cylinder	(0, 9.6, 0)	N/A	(2, 0.525661, 0.4)	−90	−30
6	Ellipsoid	(−1.9, 5.4, 0)	(1.165, 0.406, 3)	N/A	0.0	−45
7	Ellipsoid	(1.9, 5.4, 0)	(1.165, 0.406, 3)	N/A	0.0	45
8	Elliptical cylinder	(−4.3, 6.8, −1)	N/A	(1.8, 0.24, 4)	0.0	−30
9	Elliptical cylinder	(4.3, 6.8, −1)	N/A	(1.8, 0.24, 4)	0.0	30
10	Cone	(0, −10.15, −0.2)	N/A	(0.5, 0.2, 1.5)	0.0	0.0