In vitro bone mineral measurements by coherent scattering in phantoms and the calcaneus

Scattered and transmitted spectra were measured for 103 keV photons using solutions of K2HPO4. The ratios of both the number of coherently scattered photons to the number of transmitted photons and the number of coherently scattered to Compton scattered photons were measured. The sensitivity of the coherent/transmission ratio to change in effective atomic number was almost twice that of the coherent/Compton ratio. The coherent/transmission ratio was measured in vitro for three human calcanei submerged first in water and then in corn oil to simulate bone marrow. The reproducibility of the bone-in-water measurements was 3–7%. The standard deviations for the calcaneal measurements in water and in corn oil were similar. A clinical technique based on the coherent/transmission ratio could provide a sensitive method for the measurement of trabecular bone mineral concentration.