1. Application examples for Space, Medicine, Biology
Sébastien Incerti
On behalf of the Geant4 collaboration

2. Content
Medical
Radiobiology
Space
Ray-tracing

3. Medical

4. GATE

5. GEANT4 based proton dose calculation in a clinical environment: technical aspects, strategies and challenges
H. Paganetti’s conclusions (Bordeaux, Nov 2005):
Routine use of (proton) Monte Carlo dose calculation (using GEANT4)
requires work in many different areas
of treatment head and patient modeling
requires establishing a link between
treatment planning and Monte Carlo
is being done at MGH
Harald Paganetti

6. gMocren
KEK

7. LIP Comparison with commercial treatment planning systems
M. C. Lopes 1, L. Peralta 2, P. Rodrigues 2, A. Trindade 2
1 IPOFG-CROC Coimbra Oncological Regional Center - 2 LIP - Lisbon
CT-simulation with a Rando phantom
Experimental data obtained with TLD LiF dosimeter
CT images used to define the geometry:
a thorax slice from a Rando anthropomorphic phantom
Agreement better than 2% between GEANT4 and TLD dosimeters
LIP

8. Hadrontherapy
KEK

9. Physics settings for using the Geant4 toolkit in proton therapy C
Physics settings for using the Geant4 toolkit in proton therapy C. Zacharatou Jarlskog, H. Paganetti, IEEE TNS 55 (2008)
Comparison of measured (squares) and simulated (histograms) longitudinal charge distributions in the Faraday cup for four combinations of EM physics (Standard or Low Energy) and models for p and n inelastic scattering (Bertini or binary cascade). The horizontal axes show the charge collector (‘channel’) number (with increasing depth) in the Faraday cup. The vertical axes show the collected charge normalized to the number of protons in the beam (160 MeV).
View of he Faraday cup consisting
of 66 absorbers (CH2) interspaced
by charge collectors (brass)

10. Assessment of organ-specific neutron equivalent doses in proton therapy using computational whole-body age-dependent voxel phantoms C. Zacharatou Jarlskog et al, Phys. Med. Biol. 53 (2008) 693–717
Organ equivalent dose
as a function of phantom
age averaged over eight
proton fields treating a lesion
In the brain
kidneys (circles)
small intestine (squares)
bladder (triangles)
Organ equivalent dose as a function of distance to organs segmented in the adult phantom for eight proton fields.
The distance (in cm) is based on the
distance between the center of the
brain (target) and the approximate
center position of the organ.

11. LOW DOSE RATE BRACHYTHERAPY contact e-mail: anatoly@uow.edu.au
I-125 seed migrated to the vertebral venous plexus – what effect does the bone have? Dose to bone ~100% greater when simulated as being bone.

12. MRI-LINAC HYBRID SYSTEMS contact e-mail: anatoly@uow.edu.au
ERE – the Electron Return Effect (exiting electrons return to patient increasing exit dose)
6MV beam 10x10 cm
30x30x20 cm phantom
Transverse B-field
electron paths shown only
10 micron thick voxels
up to 100% increase (0.2 T)
lower B-fields cause the largest
increase

13. PROTON COMPUTED TOMOGRAPHY contact e-mail: anatoly@uow.edu.au
Monoenergetic transmission proton beam
Silicon strip detectors,
record proton position and direction
Human head phantom
Scintillator crystal to record proton energy loss

14. PROTON COMPUTED TOMOGRAPHY
Digital Phantom
Reconstructed Image

15. PROTON THERAPY BEAM VERIFICATION
511keV g’s generated by b+ annihilation
Full energy collection in scintillator crystal
Use pCT detector modules as Compton Camera to record b+ activity distribution generated by proton treatment beam
Compton scatter in Si planes
If feasible, pCT detectors will provide complete planning and verification tool!

16. VALIDATION: OCULAR BRACHYTHERAPY Contact e-mail: maigne@clermont.in2p3.fr

17. TURIN UNIVERSIY AND INFN, ITALY contact e-mail: bourhale@to.infn.it
INFN section of Turin (F Bourhaleb. A. Attili, F. Marchetto, I. Cornelius, I. Rinaldi, V. Monaco)
Simulation of proton and Carbon ion beams interactions with water phantoms
study of fragmentation products
simulation of on line devices for measures of delivered dose to the patient
study of radiobiological effects for carbon ion beams

18. PISA UNIVERSIY AND INFN, ITALY contact e-mail: valeria. rosso@pi. infn
PISA UNIVERSIY AND INFN, ITALY contact
INFB section of Pisa (F. Attanasi, N. Belcari, M. Camarda, A. Del Guerra, N. Lanconelli, V. Rosso , S. Vecchio)
DOPET project: proton therapy monitoring device
geant4 Monte Carlo simulation of the prototype, composed by two planar active heads
comparisons with experimental data from CATANA beam line at LNS – INFN, Catania (70 MeV proton beam on PMMA phantom)

19. Radiobiology

20. Geant4 DNA
Geant4 is currently being extended and improved for microdosimetry applications et the eV scale : the Geant4 DNA project
Expected developments include :
Physics : complementary/additional theoretical models, for other target materials (DNA, Silicon,…), merging with standard EM Physics design
Physico-chemical and chemistry for the production of radical species
Geometry : atomistic approach (Protein Data Bank), voxellized approach
Biological damage stage, benefiting from experimental validation (ex. microbeam cellular irradiation at CENBG)
New examples will be delivered for Geant users
Cellular phantoms
DNA molecule
Biological damages (DSB)

21. Nanodosimetric modelling of low energy electrons in a magnetic field
Purpose : investigate possible biological effect enhancement of low energy electrons in a magnetic field
Simulated setup
Two target geometries :
DNA-segment : represented by water cylinder of diameter 2.3 nm and height 3.4 nm
Nucleosome : represented by water cylinder of diameter 6 nm and height 10 nm
Incident particle : 50 eV – 10 keV electrons
Magnetic field : 1-10 T
Physics processes : Geant4 DNA
Comparison between Geant4 and PTB code (B. Grosswendt et al., PTB Braunschweig)
Kindly provided by Marion Bug & Anatoly Rosenfeld
Centre for Medical Radiation Physics
University of Wollongong, Australia Presented at the 13th Geant4 collaboration workshop

22. Comparison of cluster-size distribution
Good agreement between the two codes for both volumes
PTB-code shows lower mean cluster-size for electrons < 1 keV (left)
Confirmed in probability distribution (right): higher number of large cluster-sizes produced in G4-code than in PTB-code
Due to different cross-sections, statistical error (?)
RBE enhancement in magnetic field under investigation
Probability VS cluster size
Cluster size VS Energy
A cluster size is the number of ionisations in the volume, resulting from
one track. Multiple tracks lead to a distribution of cluster sizes, which
follows Poisson's law for small volumes. From this frequency distribution
I calculated the probability distribution.
The first moment of the probability distribution gives the mean cluster
size.
Mean ionisation cluster-size vs. electron energy, comparison of our data (G4) with the MC-code from PTB
Probability of cluster size. Comparison of G4-code (solid lines) with MC-code from PTB (dashed lines)

23. Predicting cell lesions
Kindly provided by Djamel Dabli & Gérard Montarou
Laboratoire de Physique Corpusculaire Université Blaise Pascal, IN2P3/CNRS, Aubière, France
Predicting cell lesions
The mean number of lethal lesions in a biological nucleus can be expressed with a linear quadratic formula (Kellerer et al. 1978)
sub-lesions can combine in pairs to induce lethal lesions
t(x) is the is the physical proximity function, representing the probability distribution of all distances between pairwise energy transfer points in the track
g(x) is the biological proximity function representing the distribution of sensitives sites in a nucleus.
t(x) can be calculated from Geant4 electromagnetic interactions (Standard, Low Energy, Geant4 DNA) in liquid water

24. Proximity functions
good agreement between Dabli’s and Montarou’s results with Geant4DNA physics models and the estimation of Chen and Kellerer (2006).
Proximity function

25. Cellular irradiation @ CENBG1 2 3
Cytoplasm
Confocal microscopy
of HaCat cell
Cellular irradiation
3 MeV alphas
Ion beam analysis with protons
(PIXE, RBS) 3
Nucleus 1 2
3D high resolution phantom a b
Microdosimetry
Geant4
Chemical composition
Mean dose in nucleus (Gy)
Liquid water
0.14 ± 0.02
Reference cell (ICRU)
0.32 ± 0.06
CENBG measurements
0.38 ± 0.07 c d

26. Space science

27. X-ray Multi-Mirror mission (XMM)
Launch December 1999
Perigee 7000 km
apogee km
Flight through the radiation belts
Telescope tube
X-ray detectors (CCDs)
Mirrors
Chandra X-ray observatory, with similar orbit, experienced unexpected degradation of CCDs
Possible effects on XMM?
Baffles

28. g astrophysics FGST AGILE g-ray bursts FGST GLAST AGILE
Typical telescope:
Tracker
Calorimeter
Anticoincidence
g conversion
electron interactions
multiple scattering
d-ray production
charged particle tracking

29. MAXI
ISS Columbus
AMS
EUSO
Bepi Colombo
SWIFT
LISA
Smart-2
ACE
INTEGRAL
Astro-E2
JWST
GAIA
Herschel
Cassini
FGST
XMM-Newton

30. ISS
Courtesy T. Ersmark, KTH Stockholm

31. X-Ray Surveys of Asteroids and Moons
ESA Space Environment & Effects Analysis Section
Cosmic rays,
jovian electrons
X-Ray Surveys of Asteroids and Moons
Solar X-rays, e, p
Geant3.21
G4 “standard”
Courtesy SOHO EIT
Geant4 low-E
Induced X-ray line emission:
indicator of target composition
(~100 mm surface layer)
C, N, O line emissions included

32. Bepi Colombo: X-Ray Mineralogical Survey of Mercury
Space Environments
and Effects Section
Bepi Colombo: X-Ray Mineralogical Survey of Mercury
Alfonso Mantero, Thesis, Univ. Genova, 2002
BepiColombo
ESA cornerstone mission to Mercury
Courtesy of ESA Astrophysics

33. PLANETOCOSMICS by L. Desorgher et al.
Planets
Planetary radiation environments
PLANETOCOSMICS by L. Desorgher et al.
L. Desorgher, Bern U.

34. Radiation damage

35. X- and Gamma-ray astronomy
“Suzaku” Observatory (ISAS/JAXA and many universities)
The 5th Japanese X-ray
astronomy satellite
Launched on
High-precision and Low-noise
detector systems
XIS (X-ray CCD camera) [0.3—12 keV]
HXD (Hard X-ray Detector) [10—600 keV] 35

36. Background-event spectrum of XIS
Physics processes
Electromagnetic Interaction
(down to 250eV)
Hadronic Interaction
Primary events from 4p Sr
Used Geant4 outputs:
Physics process of particle
generation, position,
energy, solid-ID
Energy deposition and its
physics process
ParentID、TrackID、
StepNumber
Geant4 simulation (energy deposition)
+ charge-diffusion simulation in CCD
Succeeded in representing the BGD spectrum and resolving the BGD generation mechanism 36

37. Suzaku Hard X-ray Detector (HXD)
　PIN*64
BGO
GSO*16
(10～60keV)
(30～600keV)
Si-PIN [2mm thick](10—60 keV)
GSO [5mm thick](30—600keV)
BGO: Shield + Phoswitch
BGO well + Fine Collimator:
narrow FOV as a non-imaging detector
-> Low Background
-> High Sensitivity
Complex Response for incident photons
Performance Key: Monte Carlo simulator
13th Geant4 Workshop
5th Space Users' Workshop and Japan's activity ( ) 37

38. ESA / space resources http://geant4.esa.int/ GRAS PLANETOCOSMICS
MULASSIS
SPENVIS
SSAT
GEMAT…
ESA / space resources

39. Ray tracing

40. Geant4 for beam transportation
Courtesy of V.D.Elvira (FNAL)

41. Courtesy of G.Blair (CERN)

42. Sub-micron raytracing @ CENBG : nanobeam line design
3D field map
OM50 quadrupoles
DOUBLET
TRIPLET
Electrostatic deflection
4565
5100
Diaphragm
Diaphragm
Object collimator
3150
400 40 40
400
250 X
Image plan
Switching magnet
90° analysis magnet
300
100
100
11°
90°
Singletron incident beam
Intermediate image 60 nm x 80 nm
Image < 50 nm FWHM
same prediction as Oxray, Zgoubi…
Object
5 µm in diameter

43. G4BeamLine

44. Where to find information
Geant4 novice/extended/advanced examples :
Space resources at ESA :
GATE/ThIS :
G4beamline :
More applications presented during Geant4 workshops

45. ATLAS, CMS, LHCb, ALICE @ CERN
BaBar, ILC…
Brachytherapy
PET Scan (GATE)
Hadrontherapy
DICOM dosimetry
Medical linac
Earth magnetosphere
ISS
GAIA
FGST
Physics-Biology