THEORETICAL AND EXPERIMENTAL LIMITS OF TRIPLE PHOTON ENERGY ABSORPTIOMETRY IN THE MEASUREMENT OF BONE-MINERAL

Theoretical and experimental studies have been conducted to explore the possibilities of triple photon energy absorptiometry in the measurement of bone mineral content. The purpose of this technique is to correct the measured bone mineral density for fat and soft tissues. However, theoretical considerations lead us to doubt the precision and accuracy of such measurements. In a first approximation the absorption coefficient can be split into Compton and photoelectric energy-independent factors. A consequence of such a model is the impossibility of finding more than two independent mass attenuation coefficients for different energies. The existence of an energy-dependent third factor may justify the use of triple photon energy absorptiometry but experimental tests and numerical simulations have shown that its value is too low for triple photon energy absorptiometry to be considered as an adequate method for the measurement of bone mineral content.