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Modellizzazione DICOM in Geant4
Gruppo italiano MC-INFN
Stéphane Chauvie
Santa Croce e Carle Hospital, Cuneo
DICOM example in Geant4
Developed in 2002
– L. Archambault, L. Beaulieu, V.-H. Tremblay (Univ. Laval and l'Hôtel-Dieu, Québec)
Donated to Geant4 for the common profit of the scientific community
– under the condition that further improvements and developments are made publicly available
to the community
Released with Geant4 5.2, June 2003 in an extended example
– with some software improvement by S. Guatelli and M.G. Pia
Navigation functionalities
– Pedro Arce (CIEMAT, Madrid)
Update and maintained
– Pedro Arce (CIEMAT, Madrid)
– Stéphane Chauvie (Santa Croce e Carle Hospital & INFN, Cuneo & Torino)
/examples/extended/medical/DICOM
extended example: Navigation
Is the only example in GEANT4 to offer 4 different navigation
functionalities:
– The 1D optimisation
It will be very slow because each time a track exits a voxel it has to loop to all
other voxels to know which one it may enter
– The 3D optimisation with G4SmartVoxel
a 3D grid is built, so that the location of voxels is fast, but it requires a lot of
memory
– Using G4NestedParameterisation
The search is done hierarchically in X, Y and Z. It is fast and does not require
big memory
– Using G4PhantomParameterisation/G4RegularNavigation
A special algorithm to navigate in regular voxelised geometries (see GEANT4
doc). This is the fastest way without any extra memory requirement (and it is the
default in this example). It includes an option (default) to skip frontiers between
voxels when they have the same material.
extended example: DICOM
interface
Reading image information
Transformation of pixel
data into densities
Association of densities to
a list of corresponding
materials
Defining the voxels
reverse engineering by S. Guatelli
– Geant4 parameterised
volumes
– parameterisation function:
material
HU to material
- relazione CT-tessuto
ICRU
Osso:
- linearità CT-el
- diluizione osso-midollo
Polmone:
linearità CT-
Interfaccia DICOM
Tessuti
molli:
Ti ho inserito anche la diapositiva di come fanno in Fluka
Bisogna ovviamente farla vedere ad uno di loro ma magari può
essere un ambito dove creare siergie tra i due gruppi
Ciao
Fluka
writegolem.f
CORRFACT to
account for
nuclear and
electromagnetic
interaactions (ratio
of stopping power)
NB: No reading
CT of variable
thickness
27 HU intervals and materials (Schneider) defined trough
elemental composition and “nominal” mean density (density
corresponding to the HU value at the centre of the considered
interval) -1000 a -120 9 materiali same compostion but different
nominal density UH>1600 come Schneider HU>3600 metallic
implants
Phys. Med. Biol. 52 (2007) 3369–3387 Clinical CT-based
calculations of dose and positron emitter distributions
in proton therapy using the FLUKA Monte Carlo code
K Parodi1,3, A Ferrari2, F Sommerer2 and H Paganetti1
Journal of Physics: Conference Series 74 (2007) A
MC tool for CT-based calculations of dose delivery
and β+-activation in proton therapy K Parodi1,3, A
Ferrari2, F Sommerer2 and H Paganetti1