Eduardo C. M. Loureiro1, Fernando R. A. Lima2
and Alfredo L. Ferreira Filho2
1 Escola Politécnica da Universidade de Pernambuco – POLI/UPE
Rua Benfica, 455 - Madalena 50701 - 460 Recife, PE
[email protected]
2
Centro Regional de Ciências Nucleares – CRCN/CNEN - NE
Av. Professor Luiz Freire, 1 – Cidade Universitária 50740 – 540, Recife - PE
[email protected] ; [email protected]
™
Virtual CT image acquisition:
Anthropomorphic Models
+
Monte Carlo code
(Radiation Transport)
Projections
Allows dose evaluation
Reconstruction Algorithm
2-D Image
™
Virtual CT image acquisition:
Anthropomorphic Models
+
Monte Carlo code
(Radiation Transport)
Projections
Allows dose evaluation
Reconstruction Algorithm
2-D Image
™
Virtual CT image acquisition:
Anthropomorphic Models
+
Monte Carlo code
(Radiation Transport)
Projections
Allows dose evaluation
Reconstruction Algorithm
2-D Image
™
Virtual CT image acquisition:
Anthropomorphic Models
+
Monte Carlo code
(Radiation Transport)
Projections
Allows dose evaluation
Reconstruction Algorithm
2-D Image
™
Virtual CT image acquisition:
Anthropomorphic Models
+
Monte Carlo code
(Radiation Transport)
Projections
Allows dose evaluation
Reconstruction Algorithm
2-D Image
™
Material and Methods:
MCvoxEL.EXE (Loureiro et al, 2002)
3. Graphic results:
i.
Dose distribution
The Monte Carlo code
™
Material and Methods:
MCvoxEL.EXE (Loureiro et al, 2002)
4. Graphic results:
i.
X-ray photography simulation
The Monte Carlo code
™
Material and Methods:
MCvoxEL.EXE (Loureiro et al, 2002)
2. Simulated geometries:
i.
ii.
iii.
iv.
v.
Isotropic internal point source
Homogeneous organ source
External point source
External parallel source
Conventional CT source
The Monte Carlo code
™
Material and Methods:
Graphical Reconstruction Algorithm:
Reconstruction Algorithm
™
Bowtie filter (using weighting factor, w(φ)) for reconstruction purposes only:
IT
= w(φ )
I0
Without w(φ)
With w(φ)
number of interactions
per voxel, showing the
less attenuating deeper
regions
™
Effective inclusion of the bowtie filter in radiation transport simulation, for dose
evaluation:
™
Results:
Increasing quality by using larger sampling
360 views, 500 photons/ray
360 views, 4000 photons/ray
720 views, 4000 photons/ray
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Results: images with limited fan angle.
Increasing quality by using larger sampling
Normalized number of interactions per voxel
™
Results: images with reconstruction matrix limited by screen dimensions.
Image acquired using 700 x 700 pixels and field of view of 50 x 50 cm. Pixel size of 0.07 cm.
™
Aknowledgements:
9 Escola Politécnica de Pernambuco – POLI/UPE;
9 Centro Regional de Ciências Nucleares – CRCN – NE;
9Conselho Nacional de Desenvolvimento Científico e Tecnológico – CNPq.