  Tissue and water equivalence of some phantom materials originally developed
for conventional radiation therapy was investigated on the ITEP medical proton
beam facility. The proton CSDA range in three variants of Plastic Water, lung,
adipose, muscle and compact bone substitute materials (CIRS Inc., USA) was
measured by a silicon diode as well as the residual proton range in liquid
water after passing a slab of each material under investigation. In addition,
the proton range in five materials of known elemental composition was
calculated by Monte Carlo technique. The obtained results were compared with
reference data from ICRU report 49 for respective biological tissues and water.
A total uncertainty of the proton range ratios was estimated to be from 0.9 to
1.5% (1SD). Within these uncertainties, Plastic Water, Plastic Water LR,
Plastic Water DT, muscle and compact bone demonstrated a good agreement with
the reference data. The range in adipose and lung substitutes is a few percents
lower than that in the respective tissues.
