Table 3.

Relative linear stopping power comparisons for several Gammex tissue characterization plugs using Protocol

Gammex Material			RSLP ‐100 MeV
Name	Avg HU	ρ [g/cm−3]	RayStationa	Stoich.b	Fippelc	ICRU 49
Lung 300	−726	0.29	0.287	0.287	0.287	–
Lung 450	−548	0.45	0.452	0.452	0.454	–
Adipose	−95	0.94	0.955	0.960	0.963	0.946
Breast	−46	0.99	0.990	0.993	1.001	–
Water	−5	1.00	1.000	1.000	1.000	–
Brain	21	1.05	1.034	1.029	1.047	1.0287
Liver	1	1.10	1.074	1.077	1.078	–
Inner bone	223	1.15	1.112	1.140	1.123	–
B 200 bone material	242	1.16	1.121	1.149	1.130	–
CB 2%–30% CaCO3	471	1.34	1.262	1.262	1.266	–
CB 2%–30% CaCO3	845	1.56	1.431	1.447	1.427	–
Cortical bone	1263	1.82	1.626	1.650	1.620	1.659

^aPrivate communication with RaySearch Laboratories.

^bStoichiometric cal. performed on‐site by an indepdent proton physicist.

^cCalculated using Eq. 13 of Fippel and Soukup.