  The development of new x-ray imaging techniques often requires prior
knowledge of tissue attenuation, but the sources of such information are
sparse. We have measured the attenuation of adipose breast tissue using
spectral imaging, in vitro and in vivo. For the in-vitro measurement, fixed
samples of adipose breast tissue were imaged on a spectral mammography system,
and the energy-dependent x-ray attenuation was measured in terms of equivalent
thicknesses of aluminum and poly-methyl methacrylate (PMMA). For the in-vivo
measurement, a similar procedure was applied on a number of spectral screening
mammograms. The results of the two measurements agreed well and were consistent
with published attenuation data and with measurements on tissue-equivalent
material.
