Geometrical and Monte Carlo projectors in 3D PET reconstruction.

نویسندگان

  • Pablo Aguiar
  • Magdalena Rafecas
  • Juan Enrique Ortuño
  • George Kontaxakis
  • Andrés Santos
  • Javier Pavía
  • Domènec Ros
چکیده

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.

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عنوان ژورنال:
  • Medical physics

دوره 37 11  شماره 

صفحات  -

تاریخ انتشار 2010