Table IV.

Comparison between nominal and estimated RED values from HU of the reconstructed material inserts slice. Percentage difference is shown inside the parentheses.

Material	Nominal RED	Estimated RED 2.5 MV	Estimated RED 6MV MV	Estimated RED 6 MV FFF
Teflon	1.868	1.874 (0.3%)	1.858 (−0.5%)	1.858 (−0.6%)
Delrin	1.363	1.343 (−1.5%)	1.324 (−2.9%)	1.355 (−0.6%)
Bone20	1.084	1.111 (2.5%)	1.094 (0.9%)	1.112 (2.6%)
Acrylic	1.147	1.133 (−1.2%)	1.139 (−0.7%)	1.132 (−1.3%)
Polystyrene	0.998	0.993 (−0.5%)	1.012 (1.4%)	0.994 (−0.4%)
LDPE	0.945	0.944 (−0.1%)	0.977 (3.4%)	0.946 (0.1%)
Bone50	1.312	1.321 (0.7%)	1.329 (1.3%)	1.330 (1.3%)
PMP	0.853	0.848 (−0.6%)	0.853 (0.1%)	0.848 (−0.6%)