1. Geant4 anthropomorphic phantoms: models of the human body for radiation protection studies
S. Guatelli, G. Guerrieri, M. G. Pia
INFN Genova, Italy
SPENVIS and Geant4 Workshop,
Catholic University, Leuven, Belgium,
3-7 October 2005
Susanna Guatelli
SPENVIS and Geant4 Workshop

2. SPENVIS and Geant4 Workshop
Vision
A precise representation of the human body is important for accurate:
Dosimetry
Radiation protection studies
In space science:
To design shielding of astronauts’ habitats in transfer vehicles and surface habitats
To study the radiation effects in astronauts’ organs
Susanna Guatelli
SPENVIS and Geant4 Workshop

3. Approaches of human body models
Mathematical phantoms
The size and shape of the body
and its organs are described
by analytical expressions
(planes, circular and elliptical
cylinders,
spheres, cones, tori, …
Voxel phantoms
Based on digital images recorded
from Computer Tomography (CT)
scanning or
Magnetic Resonance Imaging
(MRI)
Williams et al.
(1986)
Gibbs et al.
(1984)
Veit et al.
(1989)
NRPB
MIRD5
(1969/1972)
Petoussi-Henss et al.
(2002)
Zankl & Wittmann
(2001)
Rosenstein
(1979)
Caon et al.
(1997)
Kramer/Drexler
(1982/1984)
Saito et al.
(2001)
Dimbylow
(1995)
Jones & Wall
(1985)
Xu et al.
(2000)
Hart et al.
(1994)
Tanaka et al.
(1989)
Spitzer & Whitlock
(1998)
Susanna Guatelli
SPENVIS and Geant4 Workshop

4. Interest on Anthropomorphic Phantoms
2005, April: Monte Carlo Topical Meeting, Tennessee
Session on “Tomographic Models for Radiation Protection Dosimetry”:
many talks about anthropomorphic phantom (mainly voxel-based models)
- GSF Male And Female Adult Voxel Models Representing ICRP Reference Man By K. Eckerman
- Effective Dose Ratios For The Tomographic Max And Fax Phantoms By R. Kramer
- Reference Korean Human Models: Past, Present and Future By C. Lee
- The UF Family of Paediatric Tomographic Models By W. Bolch and C. Lee
- Development And Anatomical Details Of Japanese Adult Male/ Female Voxel Models By T. Nagaoka
- Dose Calculation Using Japanese Voxel Phantoms For Diverse Exposures By K. Saito
- Stylized Versus Tomographic Models: An Experience On Anatomical Modelling At RPI By X. G. Xu
- Use Of MCNP With Voxel-Based Image Data For Internal Dosimetry Applications By M. Stabin
- Application Of Voxel Phantoms For Internal Dosimetry At IRSN Using A Dedicated Computational Tool
By I. Aubineay-Laniece
- The Use Of Voxel-Based Human Phantoms In FLUKA By L. Pinsky
- The Future Of Tomographic Modelling In Radiation Protection And Medicine (Panel discussion)
Susanna Guatelli
SPENVIS and Geant4 Workshop

5. Anthropomorphic phantoms in Geant4
Requirement from Space Science G4 User Community
Ion-Nuclear Models for the Analysis of Radiation Shielding and Effects (IONMARSE) – Contract Final Report (25 June 2004)
From QinetiQ
Executive Summary:
…More general requirements have also been identified in order to apply Geant4 to
interplanetary missions (i.e. not just restrict requirements that address nuclearnuclear
interaction physics):
A Geant4 geometry for an anthropomorphic phantom should be developed,
which can then be used in studies to more accurately determine the equivalent dose to
different human organs.This is important since the effects of self-shielding from different
parts of the body can be significant.
Susanna Guatelli
SPENVIS and Geant4 Workshop

6. Development of a Geant4 package to model anthropomorphic phantoms
Scope of the project
Development of a Geant4 package to model anthropomorphic phantoms
Susanna Guatelli
SPENVIS and Geant4 Workshop

7. Geant4 anthropomorphic phantom
Geant4 offers the capability to model both voxel and mathematical phantoms
Voxel phantom: parameterised volumes
Analytical phantoms: CSG and BREPS volumes
Accurate description of biological materials
Susanna Guatelli
SPENVIS and Geant4 Workshop

8. Voxel phantoms in Geant4
A DICOM interface is available in Geant4 to model human phantoms starting from DICOM files
3D patient anatomy
DICOM file
Acquisition of CT image
Developed by L. Archambault, L. Beaulieu, V.-H. Tremblay
(Univ. Laval and l'Hôtel-Dieu,Québec)
and improved by S. Chauvie, S. Guatelli, A. Kimura, M. G. Pia, T. Sasaki
Susanna Guatelli
SPENVIS and Geant4 Workshop

9. Mathematical phantoms in Geant4
Development of the following analytical phantoms in Geant4:
K. F. Eckerman, M. Cristy, J. C. Ryman
(The ORNL Mathematical Phantom Series)
W. S. Snyder, M. R. Ford, G. G. Warner, H. L. Fisher jr
(MIRD Pamphlet # 5 Revised: “Estimates of absorbed fraction for monoenergetic photon sources uniformly distributed in various organs of a heterogeneous phantom”, J Nucl Med Suppl 3, 1969)
Established reference data
Susanna Guatelli
SPENVIS and Geant4 Workshop

10. SPENVIS and Geant4 Workshop
Geant4 Phantom Package
Novel approach thanks to an advanced OO design
Possibility to have both voxel and analytical phantoms in the same environment
Possibility to compose a phantom out of different analytical models
Mix and match voxel and analytical components
Optimize the CPU and memory resources and accuracy of the simulation
Susanna Guatelli
SPENVIS and Geant4 Workshop

11. adopt a rigorous software process
Quality and reliability of the software are essential requirements
Iterative and incremental process model
Develop, extend and refine the software in a series of steps
Get a product with a concrete value and produce results at each step
Assess quality at each step
Rational Unified Process (RUP) adopted as process framework
Mapped onto ISO 15504
adopt a rigorous software process
Susanna Guatelli
SPENVIS and Geant4 Workshop

12. Summary of software products
User Requirements
Analysis and design
Implementation
Tests
Susanna Guatelli
SPENVIS and Geant4 Workshop

13. SPENVIS and Geant4 Workshop
User Requirements
Susanna Guatelli
SPENVIS and Geant4 Workshop

14. Anthropomorphic phantom: URD (1)
The anthropomorphic model includes the body components
Body regions: trunk, neck, head, legs, male genitalia
Skeletal system: leg bone, arm bone, pelvis, spine, cranium, facial skeleton, skull,
rib cage, clavicles, scapulae
Gastrointestinal tract and contents: esophagus, stomach, intestine
Heart and contents: outer surface of heart, left ventricle, right ventricle, left atrium,
right atrium, heart
Organs: adrenals, brain, breasts, gall bladder, kidney, liver, lung, ovary, pancreas, skin,
spleen, testes, thymus, lobes of thyroid, urinary bladder, uterus
Susanna Guatelli
SPENVIS and Geant4 Workshop

15. Anthropomorphic phantom: URD (2)
Composition of tissues:
The user shall be able to define composition of each tissue
The user shall be able to associate a defined material to an organ of the phantom
Event:
The user shall be able to retrieve the position and material of the body region
traversed by tracks
User interface:
The user shall be able to select a phantom by the sex, age and the model
The user shall be able to define a phantom using parts derived from different
models
The user shall be able to create specific body region corresponding to subset of
the phantom
Visualisation:
The user shall be able to visualize the geometrical set-up
The user shall be able to visualize the particle tracks
Susanna Guatelli
SPENVIS and Geant4 Workshop

16. SPENVIS and Geant4 Workshop
Anthropomorphic phantom: design
Domain decomposition:
Abstraction of the process of the building a phantom
Abstraction of the description of a phantom model
Susanna Guatelli
SPENVIS and Geant4 Workshop

17. SPENVIS and Geant4 Workshop
Design patterns
The Builder design pattern has been adopted to control the definition of anatomy components in the phantom
Abstract Factory
The Abstract Factory design pattern is adopted to define anatomic structures
The user can select organs communicating with the abstract interface G4VBodyFactory, independently from their concrete classes
Builder
Susanna Guatelli
SPENVIS and Geant4 Workshop

18. G4Ellipsoid Use of GDML G4 Anthropomorphic phantoms
Implementation
G4Ellipsoid
Use of GDML
G4 Anthropomorphic phantoms
Susanna Guatelli
SPENVIS and Geant4 Workshop

19. New solid in Geant4: G4Ellipsoid
Most of the organs can easily be approximated by:
Ellipsoid
Circular and elliptical oblique cone
Elliptical cone
Torus with elliptical section
not implemented in the Geant4 Geometry!
G4Ellipsoid:
First version by G. Horton-Smith (Caltech, USA),
Revised by G. Guerrieri (INFN Genova) as part of this work and by D. Anninos (CERN, Cornell University, USA)
G4EllipticalCone:
Implemented by D. Anninos (CERN, Cornell University, USA)
G4Ellipsoid and G4Elliptical Cone available from next public G4 Release
Susanna Guatelli
SPENVIS and Geant4 Workshop

20. GDML: Geometry Description Markup Language
Solids
CSG solids:
- box
- tube
- cone
- sphere
- parallelepiped
- trapezoid
- general trapezoid
Boolean solids:
- union
- subtraction
- intersection
GDML is used to define organs in terms of geometry, position and rotation in the experimental set-up, material
GDML has been extended with the ellipsoid
The GDML Processor is now able to handle an ellipsoid
Material definitions
- isotopes
- elements
- complex materials
- molecules
- mixtures built from
elements and/or
other complex materials by fractional mass
The GDML package has been extended to create parameterised volumes for the elliptical tube
Susanna Guatelli
SPENVIS and Geant4 Workshop

21. SPENVIS and Geant4 Workshop
How to use the G4Phantom
Work in progress, current status below:
The GDML files contain the information concerning the organs
The user can choose to define the entire anthropomorphic phantom (ORNL or MIRD) or just some organs through the interactive session
The user can choose interactively:
phantom by sex
phantom by model (ORNL, MIRD or mix)
The user can set organs sensitive
The energy deposit given by both primary and secondary particles is collected in sensitive volumes
Susanna Guatelli
SPENVIS and Geant4 Workshop

22. Female ORNL Anthropomorphic Phantom
Thyroid
Skull
Lungs
Arm Bones
Spine
Esophagus
Spleen
Stomach
Kidneys
Pelvis
Ovaries
Lower Large Intestine
Leg Bones
Urinary Bladder
Uterus
Upper Large Intestine
Liver
Breasts
Heart
Not visible: Brain (in the skull)
Pancreas
Three materials used to model human tissues:
Skeleton,
Lungs,
Soft tissue
Susanna Guatelli
SPENVIS and Geant4 Workshop

23. Female ORNL Anthropomorphic Phantom
Susanna Guatelli
SPENVIS and Geant4 Workshop

24. Female ORNL Anthropomorphic Phantom > Run 1 <
Particle: gamma
Energy: 100. MeV
no. Particle: 20
Beam Direction: along Z axis
Visualization system: OpenGL
Output of run 1
TrackID: > LegBonesORNLVolume -> Energy deposit: MeV
TrackID: > BodyVolume > Energy deposit: MeV
TrackID: > BodyVolume > Energy deposit: MeV
TrackID: > BodyVolume > Energy deposit: keV
TrackID: > BodyVolume > Energy deposit: keV
TrackID: > BodyVolume > Energy deposit: keV
TrackID: > BodyVolume > Energy deposit: keV
TrackID: > BodyVolume > Energy deposit: eV
TrackID: > BodyVolume > Energy deposit: keV
TrackID: > LegBonesORNLVolume -> Energy deposit: keV
TrackID: > BodyVolume > Energy deposit: keV
Susanna Guatelli
SPENVIS and Geant4 Workshop

25. Use of the ORNL phantom in a radioprotection study
The anthropomorphic phantom can be used in Geant4 application to evaluate the dose in human organs
The anthropomorphic phantom has been integrated in the REMSIM Geant4 application for a radioprotection study in the interplanetary space
The anthropomorphic phantom can be used also in other Geant4 space science applications
Susanna Guatelli
SPENVIS and Geant4 Workshop

26. Shielding study of vehicle concept
Relative comparison of alternative shielding solutions for transfer vehicles of astronauts to Mars
GCR p, 106 events
phantom
GCR protons are incident on the vehicle concept:
Simplified Inflatable habitat complemented by water shielding
Susanna Guatelli
SPENVIS and Geant4 Workshop

27. SPENVIS and Geant4 Workshop
First results
Preliminary
Calculation of the dose in the anthropomorphic phantom
Preliminary
Preliminary
Susanna Guatelli
SPENVIS and Geant4 Workshop

28. SPENVIS and Geant4 Workshop
Conclusions
Analytical phantoms
Novel approach to model anthropomorphic phantoms
Voxel phantoms
Analytical phantoms
Mix and match voxel/analytical
in the same simulation environment
Analytical anthropomorphic phantoms have been implemented in Geant4
Further developments in progress
The MIRD and ORNL analytical models will be released in a Geant4 advanced example in December 2005
The G4 anthropomorphic phantom is easy to integrate in Geant4 applications
Customized
Phantom
Voxel phantoms
(DICOM interface)
Susanna Guatelli
SPENVIS and Geant4 Workshop