Estimating the mineral density of trabecular bone using Compton scattering.

This study proposes a technique based on Compton scattering to estimate trabecular bone mineral density (TBMD), which is important for understanding bone strength, and hence, is pivotal for estimating the condition of the bone. Bone phantoms (a mixture of paraffin wax and bone powder) with various concentrations of bone ash were prepared to simulate the trabecular bone. These samples were exposed to primary gamma photon flux from a137Cs (222 GBq) radioisotope source one after the other, and the scattered photon flux was detected using an NaI(Tl) detector. The presence of the cortical bone (using aluminum sheets) and fat (tertiary butyl alcohol) around the trabecular bone was also studied to determine whether the TBMD measurements had been affected. The correlation between bone ash contents and the intensity of Compton scattering was high with a coefficient of 0.97. The outcomes suggest that TBMD is independent of the presence of the cortical bone and overlying fat, with a statistical uncertainty of ±0.3% in the count rate. The intensity of Compton scattering increased by only 1.5% when the thickness of the aluminum sheet (simulating the cortical bone) becomes was increased by four times, and by less than 5% when the bone phantom was surrounded by tertiary butyl alcohol.

Non-destructive study of wood using the Compton scattering technique.

A simple nondestructive method is presented in this study to characterize woods having different densities, thus estimating the size and depth of inhomogeneities in given wood samples using the Compton scattering technique (CST). This technique uses a collimated beam of 662-keV energy from 137Cs radioactive source, and the scattered flux is detected by an NaI(Tl) detector. To characterize different wood samples on the basis of their densities, both scattering and transmission experiments were performed. The presence of inhomogeneities such as knots in wood was simulated by drilling cylindrical voids of diameter 9mm in the samples and then filling them with a high-density material (aluminum). Furthermore, different sizes of inhomogeneities (Al cylinders) were filled in the wood samples to estimate the depth and size of the inhomogeneity using the CST. A higher linear correlation (R2 ~ 0.96) was found between the scattered intensity and the density of different woods using the CST than that using the transmission (R2 ~ 0.83) method by measuring the density range. An increase of 24.6% in the average scattered intensity was observed at the location where the knot was present, and it was found that an inhomogeneity of the order of ~4mm or more could be detected by the CST.