A170Tm gamma scattering technique for the determination of absolute bone density

Abstract
A new technique for the determination of absolute bone density is described. The procedure is based on the measurement of both transmitted and scattered photons emitted from a 650 mCi radioisotope source of 170Tm in a narrow beam geometry. The method takes into consideration the change in the effective Z/A as a function of bone density which is due to the changing of the elementary composition of bone when bone material is resorbed. The experimental results show that the density of homogeneous materials can be measured with a reproducibility of 2 per cent. The bone density values for the 24 bone specimens measured by the new method show a good correlation (r=0 with 94) with results obtained by application of Archimedes' principle.