Table 1.

– HU and mass density ranges used in PRIMO and Acuros computations

	PRIMO HU range	PRIMO mass density range (g/cm3)	Acuros HU range	Acuros mass density range (g/cm3)
Air	− 1000, − 957	0, 0.0204	−1000, − 957	0, 0.0204
Lung	−957, − 400	0.0204, 0.594	− 967, − 374	0.0104, 0.624
Adipose	− 400, − 59	0.594, 0.969	− 434, 1	0.551, 1.001
Muscle	− 59, 88	0.969, 1.075	−59, 117	0.969, 1.093
Cartilage	88, 298	1.075, 1.199	57, 971	1.056, 1.600
Cortical bone	298, 2832	1.199, 2.833	128, 2832	1.100, 2.830