A large-angle coherent/Compton scattering method for measurement in vitro of trabecular bone mineral concentration

In this paper, experiments and related theoretical deductions on coherent/Compton scattering of 59.5-keV Am241 gamma line by bonelike materials are described. In particular, we demonstrate that a photon scattering mineralometer (PSM) can attain the best working conditions when it operates in a backscattering geometry mode. In fact, the large scattering angle we chose, theta = 135 degrees, allowed us to assemble a very compact source-detector device. Further, the relative sensitivity at 135 degrees turns out to be congruent to 1.7 and congruent to 6 times bigger than at 90 degrees and 45 degrees, respectively. The performances of the theta = 135 degrees PSM we assembled were experimentally investigated; i.e., in a measuring time of 10(3) s, a congruent to 5% statistical precision for bonelike materials, such as K2HPO4-water solutions, was obtained. The large-angle PSM device seems therefore to be very promising for trabecular bone mineral density measurements in vivo in peripheral anatomic sites.