TY - JOUR
T1 - Efficient Monte Carlo based scatter artifact reduction in cone-beam micro-CT
AU - Zbijewski, Wojciech
AU - Beekman, Freek J.
N1 - Funding Information:
Manuscript received August 29, 2005; revised January 31, 2006. This work was supported in part by the Technology Foundation STW under Grant UPG. 5544, in part by the Applied Science Division of NWO, in part by the Technology Programme of the Dutch Ministry of Economic Affairs, and in part by the Medical Council of NWO under Grant 917.36.335. Asterisk indicates corresponding author. *W. Zbijewski is with the Department of Nuclear Medicine, Image Sciences Institute and Department of Pharmacology and Anatomy, Rudolf Magnus Institute of Neuroscience, STR5.203 3584 CG Utrecht, The Netherlands (e-mail: wojtek@isi.uu.nl).
PY - 2006/7
Y1 - 2006/7
N2 - Cupping and streak artifacts caused by the detection of scattered photons may severely degrade the quantitative accuracy of cone-beam X-ray computed tomography (CT) images. In order to overcome this problem, we propose and validate the following iterative scatter artifact reduction scheme. First, an initial image is reconstructed from the scatter-contaminated projections. Next, the scatter component of the projections is estimated from the initial reconstruction by a Monte Carlo (MC) simulation. The estimate obtained is then utilized during the reconstruction of a scatter-corrected image. The last two steps are repeated until an adequate correction is obtained. The estimation of the noise-free scatter projections in this scheme is accelerated in the following way: first, a rapid (i.e., based on a low number of simulated photon tracks) MC simulation is executed. The noisy result of this simulation is de-noised by a three-dimensional fitting of Gaussian basis functions. We demonstrate that, compared to plain MC, this method shortens the required simulation time by three to four orders of magnitude. Using simulated projections of a small animal phantom, we show that one cycle of the scatter correction scheme is sufficient to produce reconstructed images that barely differ from the reconstructions of scatter-free projections. The reconstructions of data acquired with a charge-coupled device based micro-CT scanner demonstrate a nearly complete removal of the scatter-induced cupping artifact. Quantitative errors in a water phantom are reduced from around 12% for reconstructions without the scatter correction to 1 % after the proposed scatter correction has been applied. In conclusion, a general, accurate, and efficient scatter correction algorithm is developed that requires no mechanical modifications of the scanning equipment and results in only a moderate increase in the total reconstruction time.
AB - Cupping and streak artifacts caused by the detection of scattered photons may severely degrade the quantitative accuracy of cone-beam X-ray computed tomography (CT) images. In order to overcome this problem, we propose and validate the following iterative scatter artifact reduction scheme. First, an initial image is reconstructed from the scatter-contaminated projections. Next, the scatter component of the projections is estimated from the initial reconstruction by a Monte Carlo (MC) simulation. The estimate obtained is then utilized during the reconstruction of a scatter-corrected image. The last two steps are repeated until an adequate correction is obtained. The estimation of the noise-free scatter projections in this scheme is accelerated in the following way: first, a rapid (i.e., based on a low number of simulated photon tracks) MC simulation is executed. The noisy result of this simulation is de-noised by a three-dimensional fitting of Gaussian basis functions. We demonstrate that, compared to plain MC, this method shortens the required simulation time by three to four orders of magnitude. Using simulated projections of a small animal phantom, we show that one cycle of the scatter correction scheme is sufficient to produce reconstructed images that barely differ from the reconstructions of scatter-free projections. The reconstructions of data acquired with a charge-coupled device based micro-CT scanner demonstrate a nearly complete removal of the scatter-induced cupping artifact. Quantitative errors in a water phantom are reduced from around 12% for reconstructions without the scatter correction to 1 % after the proposed scatter correction has been applied. In conclusion, a general, accurate, and efficient scatter correction algorithm is developed that requires no mechanical modifications of the scanning equipment and results in only a moderate increase in the total reconstruction time.
KW - Artifact removal
KW - Computed tomography
KW - Cone beam
KW - Image reconstruction
KW - Medical imaging
KW - Monte Carlo simulation
KW - Scatter
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U2 - 10.1109/TMI.2006.872328
DO - 10.1109/TMI.2006.872328
M3 - Article
C2 - 16827483
AN - SCOPUS:33645286933
SN - 0278-0062
VL - 25
SP - 817
EP - 827
JO - IEEE transactions on medical imaging
JF - IEEE transactions on medical imaging
IS - 7
M1 - 1644798
ER -