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
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
Approaches of human body models
Voxel phantoms
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, …
NRPB
MIRD5
(1969/1972)
Rosenstein
(1979)
Kramer/Drexler
(1982/1984)
Jones & Wall
(1985)
Susanna Guatelli
Hart et al.
(1994)
Based on digital images recorded
from Computer Tomography (CT)
scanning or
Magnetic Resonance Imaging
(MRI)
Williams et al.
Gibbs et al.
(1986)
(1984)
Veit et al.
Zankl & Wittmann (1989) Petoussi-Henss et al.
(2002)
Caon et al.
Saito et al.
(1997)
Dimbylow
(2001)
(1995)
Tanaka
al.
Xu et al. Spitzer & Whitlock
SPENVIS
and Geant4 et
Workshop
(1989)
(2000)
(1998)
(2001)
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
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
Scope of the project
Development of a Geant4 package to model
anthropomorphic phantoms
Susanna Guatelli
SPENVIS and Geant4 Workshop
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
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)
Susanna Guatelli
SPENVIS and Geant4 Workshop
and improved by S. Chauvie, S. Guatelli, A. Kimura, M. G. Pia, T. Sasaki
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)
http://homer.ornl.gov/vlab/VLabPhan.html

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)
Susanna Guatelli
SPENVIS and Geant4 Workshop
Established
reference data
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
Software process
• Quality and reliability of the software are essential
requirements
adopt a rigorous software process
• 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
Susanna Guatelli
SPENVIS and Geant4 Workshop
Summary of software products
User Requirements
Analysis and design
Implementation
Tests
Susanna Guatelli
SPENVIS and Geant4 Workshop
User Requirements
Susanna Guatelli
SPENVIS and Geant4 Workshop
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
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
Susanna
Guatelli
SPENVIS
andparticle
Geant4 Workshop
- The
user shall be able to visualize
the
tracks
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
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
Susanna Guatelli
SPENVIS and Geant4 Workshop
their
concrete classes
Builder
Implementation
G4Ellipsoid
Use of GDML
G4 Anthropomorphic phantoms
Susanna Guatelli
SPENVIS and Geant4 Workshop
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)
Susanna Guatelli
Geant4 Workshop
G4Ellipsoid
and G4Elliptical SPENVIS
Coneandavailable
from next public G4 Release
GDML: Geometry Description Markup Language
• 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
Solids
CSG solids:
- box
- tube
- cone
- sphere
- parallelepiped
- trapezoid
- general trapezoid
Boolean solids:
- union
- subtraction
- intersection
Material definitions
- isotopes
- elements
- complex materials
- molecules
- mixtures built from
elements and/or
other complex
materials by fractional
mass
• The GDML Processor is now
able to handle an ellipsoid
• The GDML package has been extended to create
parameterised volumes for the elliptical tube
Susanna Guatelli
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
Female ORNL Anthropomorphic Phantom
Skull
Three materials used to
model human tissues:
• Skeleton,
• Lungs,
• Soft tissue
Thyroid
Lungs
Breasts
Heart
Liver
Upper Large
Intestine
Uterus
Spine
Esophagus
Arm Bones
Spleen
Pancreas
Stomach
Kidneys
Pelvis
Ovaries
Lower Large Intestine
Urinary
Bladder
Susanna Guatelli
Not visible: SPENVIS and Geant4 Workshop
Brain (in the skull)
Leg Bones
Female ORNL Anthropomorphic Phantom
Susanna Guatelli
SPENVIS and Geant4 Workshop
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
Susanna Guatelli
TrackID: 2 -> LegBonesORNLVolume
TrackID: 2 -> BodyVolume
TrackID: 2 -> BodyVolume
TrackID: 2 -> BodyVolume
TrackID: 16 -> BodyVolume
TrackID: 23 -> BodyVolume
TrackID: 22 -> BodyVolume
TrackID: 21 -> BodyVolume
TrackID: 20 -> BodyVolume
SPENVIS and Geant4 Workshop
TrackID: 19 -> LegBonesORNLVolume
TrackID: 24 -> BodyVolume
-> Energy deposit: 3.4576726 MeV
-> Energy deposit: 5.1323606 MeV
-> Energy deposit: 5.1711365 MeV
-> Energy deposit: 701.06096 keV
-> Energy deposit: 807.59738 keV
-> Energy deposit: 1.497982 keV
-> Energy deposit: 2.3391091 keV
-> Energy deposit: 220.25512 eV
-> Energy deposit: 10.468365 keV
-> Energy deposit: 16.651015 keV
-> Energy deposit: 4.0614721 keV
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
Shielding study of vehicle concept
• Relative comparison of alternative shielding solutions for
transfer vehicles of astronauts to Mars
GCR protons are
incident on the vehicle
concept:
Simplified Inflatable
habitat complemented
by water shielding
phantom
GCR p, 106 events
Susanna Guatelli
SPENVIS and Geant4 Workshop
First results
• Calculation of the dose
in the anthropomorphic
phantom
Susanna Guatelli
SPENVIS and Geant4 Workshop
Conclusions
• Novel approach to model anthropomorphic phantoms
•
•
Voxel phantoms
Analytical phantoms
Mix and match voxel/analytical
in the same simulation environment
Analytical phantoms
Customized
Phantom
Voxel phantoms
(DICOM interface)
•
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
Susanna Guatelli
SPENVIS and Geant4 Workshop