A fast experimental beam hardening correction method for accurate bone mineral measurements in 3D μCT imaging system
Résumé
Bone mineral density plays an important role in the determination
of bone strength and fracture risks. Consequently,
it is very important to obtain accurate bone mineral density
measurements. The microcomputerized tomography system
provides 3D information about the architectural properties
of bone. Quantitative analysis accuracy is decreased by the
presence of artefacts in the reconstructed images, mainly due
to beam hardening artefacts (such as cupping artefacts). In
this paper, we introduced a new beam hardening correction
method based on a postreconstruction technique performed
with the use of off-line water and bone linearization curves
experimentally calculated aiming to take into account the
nonhomogeneity in the scanned animal. In order to evaluate
the mass correction rate, calibration line has been carried
out to convert the reconstructed linear attenuation coefficient
into bone masses. The presented correction method was then
applied on a multimaterial cylindrical phantom and on mouse
skeleton images. Mass correction rate up to 18% between uncorrected
and corrected images were obtained as well as a
remarkable improvement of a calculated mouse femur mass
has been noticed. Results were also compared to those obtained
when using the simple water linearization technique
which does not take into account the nonhomogeneity in the
object.