  Spectral molecular imaging is a new imaging technique able to discriminate
and quantify different components of tissue simultaneously at high spatial and
high energy resolution. Our MARS scanner is an x-ray based small animal CT
system designed to be used in the diagnostic energy range (20 to 140 keV). In
this paper, we demonstrate the use of the MARS scanner, equipped with the
Medipix3RX spectroscopic photon-processing detector, to discriminate fat,
calcium, and water in tissue. We present data collected from a sample of lamb
meat including bone as an illustrative example of human tissue imaging. The
data is analyzed using our 3D Algebraic Reconstruction Algorithm (MARS-ART) and
by material decomposition based on a constrained linear least squares
algorithm. The results presented here clearly show the quantification of
lipid-like, water-like and bone-like components of tissue. However, it is also
clear to us that better algorithms could extract more information of clinical
interest from our data. Because we are one of the first to present data from
multi-energy photon-processing small animal CT systems, we make the raw,
partial and fully processed data available with the intention that others can
analyze it using their familiar routines. The raw, partially processed and
fully processed data of lamb tissue along with the phantom calibration data can
be found at [http://hdl.handle.net/10092/8531].
