Validation of the MC platform GATE for radiation therapy applications Evaluation of dose deposited by electrons. Yann Perrot, LPC, CNRS/IN2P3

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1 Validation of the MC platform GATE for radiation therapy applications Evaluation of dose deposited by electrons Yann Perrot, LPC, CNRS/IN2P3 1

2 PCSV 2

Projects @ PCSV Computation for life science Involvement in

effect of radiations on living beings Need of computing

radiations effects on life Simulation Tools Grid computing nm

3 PCSV Computation for life science Involvement in Medical Physics : To predict dose deposition To understand the effect of radiations on living beings Need of computing ressources : EGI Grid To establishmodelsto predict and describe radiations effects on life Simulation Tools Grid computing nm DNA breaks µm Cell survival mm-cm Dose to organs Experimental Verification 3

4 Validation of GATE for RT Applications Simulation Tools Grid computing nm DNA breaks µm Cell survival mm-cm Dose to organs Experimental Verification 4

radiotherapy applications GATE release 6.

4 libraries Ease to use : scripts command lines

5 The GATE Platform The GATE 6.1 platform New release dedicated to external radiotherapy applications GATE release 6.1 based on GEANT4 9.4 libraries Ease to use : scripts command lines Dedicated tools for dosimetryapplications : phase space approach, optimized navigation in voxelizedstructures, reduction variance techniques Brems. Splitting Dynamic simulations Region oriented CT image representation 5

dosimetric accuracy GATE 6.1 : MC simulation plateform making use of GEANT4 9.

6 GATE/GEANT4 : EM Physics Geant4 Standard EM physics for electrons: Huge improvements in particle transport management : Multiple Scattering (MSC) Boundary crossing algorithm Necessity to study : influence of the particle transport management and MSC model on dosimetric accuracy GATE 6.1 : MC simulation plateform making use of GEANT4 9.4 libraries Dedicated tools for dosimetry applications DPK 1 MeV withg4 9.4 StdEM PhysicsPackage G4 Standard EM physics validation for incorparation within GATE as guidelines for user community 6

7 Validation of GATE/G4 External electron beams 7

8 Requirements and Goals Need of validation : study of dose deposition by external electron beams Electron transport management in GEANT4 Adapted to clinical dosimetric requirements? 2% / 2 mm or 3% / 3 mm Goals: To validate EM Standard Physics Package for dosimetry To test GEANT4 abilities for realistic treatment planning in voxelized structures Dose Point Kernel Patient Anthropomorphic phantom Phantom Slabs Water Tank Realistic beam Pencil Beam Kernel Monoenergetic beam 8

9 Monoenergetic electrons in water Simple dose distributions in water with monoenergetic electrons : use of Standard EM Physics Package GEANT4 is useful for electron dose computation if E 50 kev Dose Point Kernel e-from15 kevto 4 MeV Validated r Pencil Beam Kernel e-from15 kevto20 MeV Validated z 9

6 & 20 MeV electron beams Medical linac at

Clinac 2100C 6MeV and 20MeV electron beams

implementation: GATE/GEANT4 : Standard EM

standard) Experimental measurements: Water :

1 % uncertainty) Multilayers phantoms : 1 %

10 6 & 20 MeV electron beams Medical linac at Centre Jean Perrin Clermont-Ferrand : Varian Clinac 2100C 6MeV and 20MeV electron beams Geometry specifications from constructor Beams implementation: GATE/GEANT4 : Standard EM Physics List Option 3 EGSnrc (MC gold standard) Experimental measurements: Water : diode (1.1 % uncertainty) Multilayers phantoms : diode (1.1 % uncertainty) Anthropomorphic phantom : TLD (3 % uncertainty) BEAMnrc PTW Diode E 10 mm GATE TLD 10

11 Validation in water 2% / 2 mm Gamma Index evaluation 6 MeV DDP Off-axis Profile GATE vs Measurements EGSnrc vs Measurements MeV DDP Off-axis Profile GATE vs Measurements EGSnrc vs Measurements MeV Off-axis profile SSD 108 cm, 10x10 cm² 6 MeV & 20 MeV DDP SSD 108 cm, 10x10 cm² 20 MeV Off-axis profile SSD 108 cm, 10x10 cm² 11

12 Validation in multilayers phantom 2% / 2 mm Gamma Index evaluation GATE vs EGSnrc 6 MeV Phantom1 SSD 100 cm, 10x10 cm² Max γvalue in air : statistics 6 MeV Phantom2 SSD 100 cm, 10x10 cm² Max γvalue MeV Phantom1 SSD 100 cm, 10x10 cm² after an inteface LowZ -> High Z sharp build-up 20 MeV Phantom2 SSD 100 cm, 10x10 cm² 12

13 Validation in anthropomorphic phantom Irradiation of the RANDO anthropomorphic phantom Comparisons with TLD measurements : LiF powder Comparisons with EGSnrc : 3%-3mm γ evaluation 20MeV electron beam, gantry 60, field size10x10cm 2 Gamma Index evaluation GATE vs EGSnrc: On the whole phantom 5.2% of the point exceed the acceptance criteria 3% -3 mm GATE isodoses and TL positions TL Position TLD (Gy) GATE vstld (%)

14 Using EGI Grid 14

15 Computation time GRID infrastructure direct submission: 20% of the jobs fail 15

Computation time To reach satisfactory statistical uncertainty, use of multiple ressources : EGI grid Weusedadvancedsubmissionswiththe GATE-Lab developedby the CREATIS Lab(phase test) Split of the

16 Computation time To reach satisfactory statistical uncertainty, use of multiple ressources : EGI grid Weusedadvancedsubmissionswiththe GATE-Lab developedby the CREATIS Lab(phase test) Split of the macro, submissionand monitoring of the simulation, mergeof the results No needof gridknowledge Important gain in CPU time : 1.25x10 9 primaries: linachead+ RANDO splitted ino 500 jobs GATE-Lab(dynamic simulation) :9 h standard submission: 37 h Very usefull and user-friendly but No handlingof phase spaces Onlyfor VO biomedusers 16

17 Conclusion 17

18 Conclusion Validation of GATE 6.1 / GEANT4 9.4 for RT applications GEANT4 Standard Models: Monoenergetic e- : validation15 kev to 20 MeV by comparisons with EGSnrc and MCNP4C Realistic e- beams : validation 6 MeV and 20 MeV by comparisons with measurements and EGSnrc Water 2% - 2mm Multilayers phantom : 2% - 2 mm Anthropomorphic phantom : 3% - 3mm Grid infrastructures : reduce considerably computation time but optimized submission required 18

Inhomogeneity effect in Varian Trilogy Clinac ix 10 MV photon beam using EGSnrc and Geant4 code system

Journal of Physics: Conference Series PAPER OPEN ACCESS Inhomogeneity effect in Varian Trilogy Clinac ix 10 MV photon beam using EGSnrc and Geant4 code system To cite this article: S Yani et al 2016 J.