Table 2.

Measured second half value layer (HVL₂) in mm Al for each scanner∕bowtie combination at each available beam energy.

Beam energy (kVp)	Scanner∕bowtie filter combination							Mean	Minimum	Maximum
	A	B	C	D	E	F	G
80	13.30	10.99	12.20	13.69	10.63	8.35	10.66	11.40	8.35	13.69
100	16.20	13.49	15.18	⋯	13.16	10.70	13.23	13.66	19.70	16.20
120	18.80	15.52	17.04	19.63	15.97	13.59	16.06	16.66	13.59	18.80
135	⋯	17.25	⋯	⋯	⋯	14.74	⋯	16.00	14.74	17.25
140	21.00	⋯	19.83	21.96	18.29	⋯	17.76	19.77	17.76	21.00