Transcript Geant4 Space Workshop

Applications in Medicine
Maria Grazia Pia
INFN Sezione di Genova
Symposium on Geant4 Applications
9th ICATPP Conference
Como, 17-21 October 2005
Maria Grazia Pia, INFN Genova
GEANT4 SYMPOSIUM PROGRAMME
20 Oct 2005
INDUSTRY
The Radiation Imager Virtual Laboratory
GENERAL ELECTRICS – by R.Thompson
MonteCarlo Simulation of PET Systems
SIEMENS - CPS – by M.Conti
SPACE
Applications of G4 for the ESA Space Programme
EUROPEAN SPACE AGENCY – by G.Santin
GEANT4 Applications for NASA Space Missions
SLAC - NASA GSFC - Vanderbilt U. – by M.Asai
Thanks to Simone Giani
for organizing this symposium!
MEDICINE
G4 in Development of New Radiotherapy Treatments
KAROLINSKA (Sweden) – by A.Brahme
GEANT4 Applications in Medicine
INFN (Italy) – by M.G.Pia
TECHNOLOGY
GEANT4 Application to Ion-Therapy in Japan
KEK (Japan) – by K.Amako
Open-GATE Project
INSERM (France) – by I.Buvat
Maria Grazia Pia, INFN Genova
PHYSICS
Detector Simulation in HEP
CERN (CH) – by J.P.Wellisch
GEANT4 Accelerator Applications
IMPERIAL COLLEGE (UK) – by M.Ellis
Medical applications
PET, SPECT
Courtesy of GATE Collaboration
Courtesy of B. Mascialino et al., INFN Genova
Radiotherapy with
external beams, IMRT
Courtesy of P. Cirrone et al., INFN LNS
Radiation
Protection
Maria Grazia Pia, INFN Genova
Courtesy of J. Perl, SLAC
Hadrontherapy
Brachytherapy
Courtesy of S. Guatelli et al,. INFN Genova
Courtesy of L. Beaulieu et al., Laval
Mars and Leukemia
Maria Grazia Pia
INFN Sezione di Genova
Symposium on Geant4 Applications
9th ICATPP Conference
Como, 17-21 October 2005
Maria Grazia Pia, INFN Genova
Astrophysics
Planetary exploration has grown
into a major player in the vision of
space science organizations like
ESA and NASA
The study of the effects of space radiation on astronauts is an
important concern of missions for the human exploration of the
solar system
The radiation hazard can be limited:
– selecting traveling periods and trajectories
– providing adequate shielding in the transport vehicles and surface habitats
Radiation Protection
Maria Grazia Pia, INFN Genova
Vehicle concepts
SIH - Simplified Inflatable Habitat
Conventional approach
Rigid Habitat
A layer of Al (structure element of the ISS)
Innovative concepts under study
Inflatable habitat
A multilayer structure consisting of:

MLI: external thermal protection blanket
- Betacloth and Mylar

Meteoroid and debris protection
- Nextel (bullet proof material) and open cell foam

Structural layer
- Kevlar
Materials and thicknesses by ALENIA SPAZIO

Rebundant bladder
- Polyethylene, polyacrylate, EVOH, kevlar, nomex
Maria Grazia Pia, INFN Genova
Surface Habitats
Innovative concepts under study
Use of local materials
Cavity in the planetary soil
+
Covering heap
Sketch by ALENIA SPAZIO
Maria Grazia Pia, INFN Genova
Radiation environment
Maria Grazia Pia, INFN Genova
Radiation protection with
Model the radiation spectrum according to current standards
– Galactic cosmic rays, Solar particle events
Geometrical configurations
– Model essential characteristics for dosimetry studies
– Model complex geometries of spacecrafts in detail
Vehicle concepts
Surface habitats
Astronaut
Physics
– Select appropriate models from the Geant4 Toolkit
– Verify the accuracy of the physics models
– Distinguish e.m. and hadronic contributions to the dose
Electromagnetic processes
+ Hadronic processes
Evaluate energy deposit/dose in shielding configurations
– various shielding materials and thicknesses
Maria Grazia Pia, INFN Genova
Geant4 EM Physics Models
Verification of the Geant4 e.m. physics processes with respect to
protocol data (NIST reference data, ICRU Report 49)
Geant4 electromagnetic physics models are accurate
Compatible with NIST data within NIST accuracy (LowE p-value > 0.9)
“Comparison of Geant4 electromagnetic physics models against the
NIST reference data”
IEEE Transactions on Nuclear Science, vol. 52 (4), pp. 910-918, 2005
Optimal selection
Geant4 Low Energy Package for p, a, ions and their secondaries
Geant4 Standard Package for positrons
Maria Grazia Pia, INFN Genova
Geant4 Hadronic Physics
Complementary and alternative models
Parameterised, data driven and theory driven models
The most complete hadronic simulation kit available on the market
Models for p and a
Hadronic models for ions in progress
Intrinsic complexity of hadronic physics
Ample choice of models
Composition of different models over an extended energy range
to cover the spectrum of galactic cosmic rays and solar particle events
Maria Grazia Pia, INFN Genova
Dosimetry
The Astronaut is approximated as a phantom
– a water box, sliced along the longitudinal axis to evaluate
particle penetration in the body
– the transversal size is optimized to contain the shower
generated by the interacting particles
– the longitudinal size is a “realistic” human body thickness
The phantom is the volume where the energy deposit is collected
30 cm
– The energy deposit is given by the primary particles and all the secondaries created
Percent dose
Lateral profile
6MV – 10x10 field – 50mm depth
Maria Grazia Pia, INFN Genova
Distance (mm)
Z
IMRT Treatment Head
Doubling the shielding
thickness decreases the
energy deposit by ~10%
10 cm water
5 cm water
rigid/inflatable
habitats are equivalent
2.15 cm Al
e.m. physics + Bertini set
5 cm water
10 cm water
Maria Grazia Pia, INFN Genova
4 cm Al
shielding
materials
e.m.
physics
only
10 cm water
10 cm polyethylene
Strategy against SPE
Energy deposit (MeV) with respect to the
depth in the phantom (cm)
A shelter with additional
water shielding
(75 cm thickness)
SIH
Shelter
99.7% of the
SPE spectrum
is shielded
SPE p and a
with E > 130 MeV/nucl reach the shelter
with E > 400 MeV/nucl reach the phantom
(i.e. < 0.3% of the entire spectrum)
Maria Grazia Pia, INFN Genova
The shelter shields
~ 50% of the dose by GCR p
~ 67 % of the dose by GCR α
escaping the main shielding
Planetary surface habitats
4 cm Al
Moon as an intermediate step in
the exploration of Mars
Habitat built out of moon soil
4 cm Al
x = 0 - 3 m roof thickness
x
Habitat
vacuum
moon
soil
Phantom
GCR p
GCR α
e.m. + hadronic physics (Bertini set)
Energy deposit (GeV) in the phantom vs roof thickness (m)
A log of moon soil is as effective as
Al shielding, or even better
Maria Grazia Pia, INFN Genova
Dosimetry with Geant4
All the previous results are novel radiation protection
applications of Geant4
– first quantitative evaluation of space radiation effects for
interplanetary manned missions based on 3D Monte Carlo
calculations
– first quantitative comparison of innovative shielding concepts w.r.t.
conventional solutions
Key Geant4 features
– wide spectrum of physics coverage
– precise, quantitatively validated physics models selected as the most
appropriate for the application
– accurate description of materials
Same key features as in dosimetry for medical applications
Maria Grazia Pia, INFN Genova
A major concern in radiation protection is the
dose accumulated in organs at risk
Anthropomorphic
Phantoms
Development of anthropomorphic
phantom models for Geant4
– evaluate dose deposited in critical organs
Original approach
– analytical and voxel phantoms in
the same simulation environment
– mix & match
– facilitated by the OO technology
First release December 2005
– G. Guerrieri, Thesis, Univ. Genova, Oct. 2005
Maria Grazia Pia, INFN Genova
Sound software technology
and
rigorous software process
Analytical phantoms
Geant4 CSG, BREPS solids
Voxel phantoms
Geant4 parameterised volumes
GDML
for geometry description storage
Maria Grazia Pia, INFN Genova
Geant4 analytical phantoms
Current implementation
ORNL and MIRD5 phantoms
Male and Female
Geant4 analytical phantom
ORNL model, female
Maria Grazia Pia, INFN Genova
1 skull
2 thyroid
3 spine
4 lungs
5 breast
6 heart
7 liver
8 stomach
9 spleen
10 kidneys
11 pancreas
12 intestine
13 uterus and ovaries
14 bladder
15 womb
16 leg bones
17 arm bones
G4Lady
Maria Grazia Pia, INFN Genova
Effects of external shielding
Self-body shielding
Maria Grazia Pia, INFN Genova
Skull
Upper spine
Lower spine
Arm bones
Leg bones
Womb
Stomach
Upper intestine
Lower intestine
Liver
Pancreas
Spleen
Kidneys
Bladder
Breast
Overies
Uterus
Skull
Upper spine
Lower spine
Arm bones
Leg bones
Womb
Stomach
Upper intestine
Lower intestine
Liver
Pancreas
Spleen
Kidneys
Bladder
Breast
Overies
Uterus
Application
5 cm water shielding
10 cm water shielding
Dose calculation in critical organs
Total Body Irradiation
TBI is used as a method of preparation for
bone marrow transplantation for leukemias
and lymphomas
Low dose TBI is sometimes used to treat
disorders of the blood cells such as low grade
lymphoma and does not require bone marrow
transplant or stem cells
In TBI, the dose calculation is based on
dosimetry using a phantom
opens new ground for
precise dose calculation and TBI optimisation
Maria Grazia Pia, INFN Genova
Dosimetry with Geant4
Precise physics
Rigorous validation
Space science
Maria Grazia Pia, INFN Genova
Radiotherapy
Effects on components
Multi-disciplinary application environment
Geant4 Symposium 2015
DNA
Study of radiation damage at
the cellular and DNA level
Maria Grazia Pia, INFN Genova
http://www.ge.infn.it/geant4/dna
Maria Grazia Pia, INFN Genova
DNA
The concept of “dose” fails at cellular
and DNA scales
It is desirable to gain an understanding
to the processes at all levels
(macroscopic vs. microscopic)
Geant4-based “sister” activity to the Geant4 Low-Energy Electromagnetic
Working Group
– Follows the same rigorous software standards
International (open) collaboration
– ESA, INFN (Genova, Torino), IN2P3 (CENBG, Univ. Clermont-Ferrand), Univ. of Lund
Simulation of nano-scale effects of radiation at the DNA level
– Various scientific domains involved

medical, biology, genetics, physics, software engineering
– Multiple approaches can be implemented with Geant4
 RBE parameterisation, detailed biochemical processes, etc.
First phase: 2000-2001
– Collection of user requirements & first prototypes
Second phase: started in 2004
– Software development & release
Maria Grazia Pia, INFN Genova
Biological models in Geant4
Relevance for space:
astronaut and aircrew radiation hazards
Maria Grazia Pia, INFN Genova
Biological processes
Physical
processes
Biological
processes
Known,
available
Courtesy A. Brahme (KI)
Unknown,
not available
Courtesy A. Brahme
Maria Grazia
Pia, INFN Genova
(Karolinska
Institute)
E.g. generation
Chemical of free rad
icals
processes in the cell
Cellular level
Theories and models for cell survival
TARGET THEORY MODELS
 Single-hit model
 Multi-target single-hit model
 Single-target multi-hit model
in progress
MOLECULAR THEORY MODELS
 Theory of radiation action
 Theory of dual radiation action
 Repair-Misrepair model
 Lethal-Potentially lethal model
Analysis & Design
Implementation
Test
Critical evaluation of the models
done
Requirements
Problem domain analysis
Maria Grazia Pia, INFN Genova
Experimental validation of
Geant4 simulation models
TARGET
THEORY
SINGLE-HIT
TARGET
THEORY
MULTI-TARGET
SINGLE-HIT
S= e-D / D0
REVISED MODEL
MOLECULAR RADIATION ACTION
THEORY
S = 1- (1- e-qD)n
S = e –p ( αD + ßD
S = e-q1D [ 1- (1- e-qn D)n ]
2
)
In progress:
calculation of
model
parameters
from clinical
data
MOLECULAR DUAL RADIATION
ACTION
THEORY
S = S0 e
MOLECULAR REPAIR-MISREPAIR
THEORY
LIN REP / QUADMIS
S = e-αD[1 + (αDT / ε)]ε
MOLECULAR REPAIR-MISREPAIR
THEORY
LIN REP / MIS
S = e-αD[1 + (αD / ε)]εΦ
MOLECULAR LETHAL-POTENTIALLY
LETHAL
THEORY
NPL
S = exp[ - NTOT[1 + ε (1 – e- εBAtr) ]ε ]
MOLECULAR LETHAL-POTENTIALLY
LETHAL – LOW DOSE
THEORY
S = e-ηAC D
MOLECULAR LETHAL-POTENTIALLY
LETHAL – HIGH DOSE
THEORY
- ln[ S(t)] = (ηAC + ηAB) D – ε ln[1 + (ηABD/ε)(1 – e-εBA tr)]
MOLECULAR LETHAL-POTENTIALLY
LETHAL – LQ APPROX
THEORY
- ln[ S(t)] = (ηAC + ηAB e-εBAtr ) D + (η2AB/2ε)(1 – e-εBA tr)2 D2]
Maria Grazia Pia, INFN Genova
2
- k (ξ D + D )
Low Energy Physics extensions
DNA level
Current Geant4 low energy electromagnetic processes:
down to 250/100 eV (electrons and photons)
– not adequate for application at the DNA level
Specialised processes down to the eV scale
– at this scale physics processes depend on material, phase etc.
– some models exist in literature (Dingfelder et al., Emfietzoglou et al. etc.)
In progress: Geant4 processes in water at the eV scale
Status: first release in December 2005
Maria Grazia Pia, INFN Genova
Scenario
for Mars (and hospitals)
Geant4 simulation
treatment
source
space
environment
+
geometry
CT image
spacecraft,from
shielding
etc.
or
+
anthropomorphic phantom
Dose in organs
at risk
Geant4 simulation
with biological
processes at cellular
level (cell survival,
cell damage…)
Oncological risk to
astronauts/patients
Risk of nervous
system damage
Phase space input
to nano-simulation
Maria Grazia Pia, INFN Genova
Geant4 simulation with
physics at eV scale
+
DNA processes
for medicine
Macroscopic
– calculation of dose
– already feasible with Geant4
– develop useful associated tools
Complexity of
software, physics and biology
Cellular level
addressed with an iterative and
incremental software process
– cell modelling
– processes for cell survival, damage etc.
DNA level
Parallel development
at all the three levels
– DNA modelling
(domain decomposition)
– physics processes at the eV scale
– processes for DNA strand breaking, repair etc.
Maria Grazia Pia, INFN Genova
Exotic Geant4 applications…
FAO/IAEA International Conference on
Area-Wide Control of Insect Pests:
Integrating the Sterile Insect
and Related Nuclear and Other Techniques
Vienna, May 9-13, 2005
K. Manai, K. Farah, A.Trabelsi, F. Gharbi and O. Kadri (Tunisia)
Dose Distribution and Dose Uniformity in Pupae Treated by
the Tunisian Gamma Irradiator Using the GEANT4 Toolkit
Maria Grazia Pia, INFN Genova
Thanks
Riccardo Capra, Susanna Guatelli, Giorgio Guerrieri,
Barbara Mascialino, Michela Piergentili (INFN Genova)
Petteri Nieminen (ESA)
Alenia Spazio (Torino)
Sébastien Incerti, Philippe Moretto (CENBG)
Ziad Francis, Gérard Montarou (Univ. Clermont-Ferrand)
Stéphane Chauvie (INFN Torino)
Joseph Perl (SLAC)
Thanks to many Geant4 users worldwide, even if not all their Geant4
applications in medicine were mentioned in this presentation
Maria Grazia Pia, INFN Genova