1. Monte Carlo simulation for treatment planning in conventional radiotherapy and in hadrontherapy
Faiza Bourhaleb
Dipartimento di fisica sperimentale
Università degli studi di Torino
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

2. index General description of a Monte Carlo for Treatment Planning
Monte Carlo validations.
Practical example of treatment planning with MC: modeling and verification in hadrontherapy.
Radiobiology and Monte Carlo.
Conclusion
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

3. General description of a Monte Carlo for Treatment Planning
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

4. General description of a MC for TP verification
MC for BDL
Particles
Transport
Beamline modeling 4
Scoring
Cutoffs 2 1
Optimized TP
MC of the TP
ANCOD++
Analytical TPS 3
Patient data
Patient modeling
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

5. Packages used for Monte Carlo use to verify the TPS
GEANT3 / GEANT4
Fluka / Fluka++
EGS / EGS4
MCNP / MCNPX
ETRAN
ITS
PENELOPE
VMC (Voxel Monte Carlo) / VCM++
4 Phases of a MC =>
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

6. Particle transport modeling
Electron and Photons:
Physics is very similar in most MC codes for electrons and photons transport.
Multiple scattering for e- is very important.
Proton and Carbon ion:
Physics is similar but for carbon ion the nuclear interaction and so the fragmentation are very important.
(Scattering + stragling effects)
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

7. 3D construction  CT input HU  Density+ Tissues specification
Patient modeling
Read and conversion CT
3D construction  CT input HU  Density+ Tissues specification
PS: beam type dependent
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

8. Upper part: components remaining Fixed (Patient not depending).
Beam Line Modeling
Primary Source
Primary source
Upper part: components remaining
Fixed (Patient not depending).
It is modeled only once
Phase space file
Secondary source
The phase space file is used as input for the transport of patient dependent beam modifiers  Virtual Source Model (parameterization of a phase space file consisting of several sub-sources particle generator for MC )
Secondary Source
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

9. Limitation on the voxel grid for the simulation
Scoring / Cutoffs
Limitation on the voxel grid for the simulation
Conversion to water-equivalent
Cutoffs (Energies, histories, particles considered…..)
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

10. Validation of the Monte Carlo simulation
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

11. Fragmentation of light ion
Light ion fragmentation reactions
Attenuate the primary beam
Lead to a build up of low Z reaction products
Long range fragments deposit dose beyond maximum range of carbon beam
Treatment planning
Physical beam model must consider fragmentation in addition to scattering and ionization
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

12. Fragmentation of light ion
Analytical
Transport equation based on experimental cross sections in water (GSI)
Monte Carlo
Increased interest for treatment planning exploiting parallel computing techniques
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

13. Codes handling fragmentation
PHITS (JAERI-Japan) (Particle and Heavy Ion Transport code System)
SHIELD-HIT (Karolinska / Russian Acad. Of Sciences)
FLUKA
GEANT4 (4.6.2)
Binary cascade model of light ion fragmentation
Use of GEANT4 to simulate light ion fragmentation experiments for the purpose of verification
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

14. Simulation of simple water tank
Test 1
Simulation of simple water tank
Physical beam model used in treatment
planning
Energy deposition w. depth for carbon beams in water
Extensively validated with experimental data (GSI)
depth
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

15. Test 1
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

16. Fragmentation of light ion beams in water
Test 2
Schall et al 1996 (GSI)
Fragmentation of light ion beams in water
Yield of fragments (Z > 4) with depth
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

17. Test 2 DE detector Target 1o beam diagnostics H2O t=0-25 cm
Ionisation Chambers
90% Ar, 10% CH4, 1 atm
t=50cm
DE detector
670 MeV/u
Target
1o beam diagnostics
H2O
t=0-25 cm
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

18. Test 2
C12
46%
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

19. Gunzert-Marx et al 2003 (GSI)
Test 3
Gunzert-Marx et al 2003 (GSI)
Fragmentation of a carbon beam in water
Spectroscopy of light fragments (A < 4)
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

20. Test 3 Water t=13 cm NE102 t=9mm BaF2 t=14.5cm DE-E detector 3m C12
200 MeV/u
Target
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

21. Test 3 neutrons protons deuterons tritons
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

22. alpha
helium-3
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

23. Practical example of Monte Carlo for treatment planning
in hadrontherapy: modeling and verification.
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

24. Hadron beams
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

25. Active scan tecnique Synchroton Linac Carbon source Proton source
dE/dz
Proton source Z Ec
Scanning magnets
Monitoring system
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

26. Modeling of Beam Delivery Line
Simulation with GEANT4 for the beam delivery line consisting of :
monitoring system
Ripple filter
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

27. Modeling of Beam Delivery Line
Proton beams
Carbon ion beams
look-up tables of the inv. PS from MC
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

28. Patient modeling and conversion
this work = Jäkel et al.
Maximum number of materials are defined.
PS: We usually use the CT resolution for the simulation different from the TP matrix.
simulation.
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

29. Treatment planning verification
Parameters of a specific TP optimized to use as input for the MC TP
Positions of the sources
Kinetic energies for single beams
Direction of the Field
Angles of single beams
Optimized Fluences
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

30. Treatment planning verification
Carbon Ion beams
Proton beams
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

31. Radiobiology and Monte Carlo simulation
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

32. TRiP (GSI) Dose [Gy] Depth [mm]
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

33. Radiobiology and Monte Carlo simulation
Alpha
Carbon ions
Sampling data inside a MC code
using the LEM (or an hybrid)
Principles of Local Effect Model (LEM)
Biological effect completely determined by the local distribution of dose inside the cell nucleus
Homogeneous cell nucleus with constant density and radiosensitivity
Locally, the effect of ions can be evaluated using the X-ray Linear Quadratic model:
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

34. Radiobiology and Monte Carlo simulation
Depth [mm]
Ed [keV]
What we can do with MC for the Radiobiological part?
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

35. Radiobiology and Monte Carlo simulation
“Data – Flow”
MC simulations (Geant)
Ion tracks
Analytical functions
Lookup tables
RBE
TPS
(Ancod++)
Survival curves
(α,β)
Kraft/Scholz model  (RBEsoft)
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

36. Radiobiology and Monte Carlo simulation
Radiobiology modeling
TP with the biological optimization how can we verify??
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

37. Conclusion
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

38. MC for hadron beams with Geant4 fully validated
Experiments of ion fragmentation in tissue substitutes useful for further verification studies
MC for radiobiology Biological Monte Carlo Treatment Planning (BMCTP)!?
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

39. References Knowledge F. Marchetto2, Iwan Cornellius, Andrea Attili2,
The Dosimetry of Ionizing Radiation, edited by Kase, Bjärngard, and Attix, Academic Press, 1990.
Dr. Schardt and Dr. Gunzert-Marx of GSI for experimental details and data
Dr. J.P. Wellisch and Dr. G. Folger of the GEANT4 hadronic physics group
Sven O. Groezinger of GSI for carbon therapy images
M. Kraemer et al (TRiP)
M. Scholz et al for the Local effect Model (LEM)
A treatment planning code for inverse planning and 3D-optimization in hadrontherapy. (F Bourhaleb et al) paper in preparation…
Knowledge
F. Marchetto2, Iwan Cornellius, Andrea Attili2,
Roberto Cirio2, Cristiana Peroni1
1 Dipartimento di fisica sperimentale, Università di Torino
2 Istituto Nazionale di Fisica Nucleare (INFN), Torino.
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

40. Thanks for your attention
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

41. Model Verification Simulate fragmentation experiments
Schall (GSI): Fragment yields (Z>4) for varying thickness water target
Matsufuji (NIRS): fragment yields (Z>1) for varying thickness PMMA target
Gunzert-Marx (GSI): fragment spectroscopy and angular dependence (n,p,d,t,He-3,a)
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

42. G4 Ion Physics G4MultipleScattering G4ionIonisation
G4HadronInelasticProcess
G4TripathiCrossSection
G4IonsShenCrossSection
G4BinaryLightIonReaction
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

43. Schall et.al. 1996 Beam : C-12 676 AMeV
Target : H2O (variable thickness, t)
Detection system : Ionisation Chamber f(DE)
Information : N(Z,t) /No
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici

44. 1. Results & Discussion DXpeak mm DEpeak % DEint % GEANT4 2.0 4 4.1
SHIELD-HIT
N/A
3.0
Il metodo Monte Carlo in radioterapia - pratica clinica e strumenti tecnologici