A reference Monte Carlo platform to assess radiation

quality in hadron therapy (protons & carbon ions).

IBA Particle Therapy BU

• Damien Prieels, Research Manager

• Damien Bertrand, Research Project Manager

Creatis-LRMN RIO Team

• David Sarrut, CNRS Researcher (PhD Director)

• Nicolas Freud, Assistant Professor

Loïc Grevillot PhD Student

ENLIGHT-PARTNER

Valencia IFIC 19/06/09

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Presentation Plan

Introduction Geographical context Goal of the project

Overview of the project Imaging & computing Irradiation system Validation

Conclusion Limitations of the project Status from January 2009 Early results

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Geographical context

ESR @ IBA, LLN, BelgiumETOILE, Lyon, France as a secondary partner

Léon Bérard Cancer CentreCreatis-LRMN lab

IBA

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Goal of the project

To be able to compare treatment plans from a commercial Treatment Planning System (TPS), with Monte Carlo (MC) simulations, for proton and carbon ion beams, focusing on active beam delivery.

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Overview of the project

Be able to compare treatment plans from a commercial TPS with my MC simulations, for protons and carbon ions beam, for active beam delivery only.

The research tool developed should be able to compute output relevant to radiobiology.

• Ray tracing• Pencil beam• Others ?

• Bragg peaks• SOBP• Spot size• Energy spread• etc. ?

• Energies• Intensities• Directions

• Beam

VA

LI

DA

TI

ON

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Overview of the project

Proton: “easy”:

• A lot of centres and experience

• Data are accessible for validation

• Commercial TPS exist

Carbon ions “real research begins”:

• Less centres and experience

• Less fundamental data accessible

• Need to merge biology within physics simulations

• No commercial TPS accessible

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Overview of the project

dd Imaging & Computing part

The irradiation system

Validation part

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Limitations of the project

Radiobiological models implementation• German model (LEM)• Japanese model• Czech Republic model• Other models?

Fundamental data limits• Carbon fragmentation• RBE uncertainty• Uncertainty on the ionizing

potential of water & human tissues

Collaborations are welcome!

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Status from January 2009

Working on protons only:

• Looking at the physics list

• Looking at the relevant parameters

=> First interesting results are waiting for validation against

measurements, that should be done this summer.

Objectives:

• To validate proton simulations.

• To simulate a proton plan with the Gate MC platform.

• To extend to carbon beams & address radiobiological issues.

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Early results

0 1 2 3 4 5 60

0,2

0,4

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69 MeV proton beam

Geant4-69MeVMesureGeant4-69MeV-DeltaE1%

Depth in water (cm)

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Early results

0 5 10 15 200

0,2

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164 MeV proton beam

Geant4-164MeVMesureGeant4-164MeV-DeltaE0,50%

Depth in water (cm)

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Early results

0 5 10 15 20 25 30 35 40 450

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231 MeV proton beam

Geant4-231MeVMesureGeant4-231MeV-DeltaE0,40%

Depth in water (cm)

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This work is performed within the PARTNER research programme, with financial support from the European Commission

(FP7-People/ITN Grant nr. 215 840).

Thank you!

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The computing part

dd

Computing & research part

Research part

• Energies• Intensities• Directions

• Medium• Stopping Power

Imaging & Computing part

• Beam:

• HU to convert into :

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The irradiation system

dd Computing part

Research part• Bragg peaks• SOBP• Spot size• etc. ?

The irradiation sytem

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The validation part

dd Computing part

Computing & research part

Validation part

• Gate/Geant4• Physics list

• Electromagnetic & Hadronic • Relevant parameters of a simulation

• Cut, Step size, ..., others?• Accuracy/Efficiency compromise

• Radiobiological models implementation

• Beam quality assessment:• LET by particle nature• Energy spectrum by particle nature• Particle spectrum in the medium• Biological dose calculation

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Status: early results , the cut parameter230 MeV proton beam.

315 320 325 330 335 340 345

0,00E+000

5,00E-002

1,00E-001

1,50E-001

2,00E-001

2,50E-001

1 mm0,5 mm0,2 mm0,1 mm0,05 mm0,02 mm0,01 mm0,001 mmMCNPX

6 mmcut 1 mm

cut 1 µmcut 0,1 mm

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Status : early results

e-e-

High cut e-

e-

e-

e- e-

e-e-

e- Low cut

e-e-e-

e-

High cut => high step => lower accuracy Low cut => lower step => better accuracy, but time issues

step

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0,001 0,010 0,100 1,000

328

329

330

331

332

333

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Range of a 230 MeV proton beam

NIST(CSDA approximation)GateMCNPX

Cut (mm)

Ran

ge (

mm

)

5,8 mm

0,001 0,010 0,100 1,000

1,00%

10,00%

100,00%

Time dependance with cut

T ime Ratio

Cut (mm)

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Status: early results , the cut parameter230 MeV proton beam.

Time issues