MOTION-INDUCED MONTE CARLO DOSE CALCULATION USING DEFORMABLE TETRAHEDRAL MESHES
Résumé
The distribution patterns estimation of energy and dose
in respiratory-induced organ motion represents a technical
challenge for hadron therapy treatment planning. This paper
focuses on the comparison between deformable tetrahedral
meshes and the conventional voxel-based structures, used
as computational phantoms in four-dimensional dose calculations.
The movement issued from deformable image
registration of CT-images is used for both representations to
calculate the 4D dose distributions. An implementation of
the dose computation method for tetrahedral meshes on a
deformable anatomy in case of passive scattering beam line
is given using the Geant4 code. Tissue tracking is implicitly
performed by the fact that the meshes maintain their topology
during deformations, and the dose distribution is calculated
using time-dependent tetrahedral density map issued from
4D-CT scans. Our results show that dose distributions for
voxel and tetrahedral meshes are in good agreement, and
dose homogeneity is almost the same.