%0 Journal Article
%T Geometrical and Monte Carlo projectors in 3D PET reconstruction
%A Aguiar, P.
%A Rafecas, M.
%A Ortuño, J. E.
%A Kontaxakis, G.
%A Santos, A.
%A Pavia, J.
%A Rosetti, M.
%J Medical Physics
%D 2010
%V 37
%N 11
%I Amer Assoc Physicists Medicine Amer Inst Physics
%@ 0094-2405
%G English
%F Aguiar_etal2010
%O ISI:000283747600015
%O exported from refbase (https://references.ific.uv.es/refbase/show.php?record=338), last updated on Tue, 13 Oct 2020 12:45:34 +0000
%X Purpose: In the present work, the authors compare geometrical and Monte Carlo projectors in detail. The geometrical projectors considered were the conventional geometrical Siddon ray-tracer (S-RT) and the orthogonal distance-based ray-tracer (OD-RT), based on computing the orthogonal distance from the center of image voxel to the line-of-response. A comparison of these geometrical projectors was performed using different point spread function (PSF) models. The Monte Carlo-based method under consideration involves an extensive model of the system response matrix based on Monte Carlo simulations and is computed off-line and stored on disk. Methods: Comparisons were performed using simulated and experimental data of the commercial small animal PET scanner rPET. Results: The results demonstrate that the orthogonal distance-based ray-tracer and Siddon ray-tracer using PSF image-space convolutions yield better images in terms of contrast and spatial resolution than those obtained after using the conventional method and the multiray-based S-RT. Furthermore, the Monte Carlo-based method yields slight improvements in terms of contrast and spatial resolution with respect to these geometrical projectors. Conclusions: The orthogonal distance-based ray-tracer and Siddon ray-tracer using PSF image-space convolutions represent satisfactory alternatives to factorizing the system matrix or to the conventional on-the-fly ray-tracing methods for list-mode reconstruction, where an extensive modeling based on Monte Carlo simulations is unfeasible.
%K 3D PET
%K iterative reconstruction
%K list-mode reconstruction
%K ray-tracing techniques
%K Monte Carlo simulation
%K system response matrix
%R 10.1118/1.3501884
%U https://doi.org/10.1118/1.3501884
%P 5691-5702