GATE Simulations of Preclinical andclinical Scans in Emission Tomography, Transmission Tomography and Radiation Therapy Using GATE Quick tour & Highlights! GATE Training, INSTN-Saclay, October 2015 Albertine Dubois IMNC CNRS Orsay, France dubois@imnc.in2p3.fr Simon Stute SHFJ CEA Orsay, France simon.stute@cea.fr Sebastien Jan SHFJ CEA Orsay, France sebastien.jan@cea.fr
GATE structure Simulation platform for medical applications # C R Y S T A L /gate/block/daughters/name crystal User scripts Application classes /gate/block/daughters/insert box /gate/crystal/placement/settranslation 0 0 0 cm /gate/crystal/geometry/setxlength 3.0 cm /gate/crystal/geometry/setylength 3.0 mm /gate/crystal/geometry/setzlength 3.8 mm /gate/crystal/setmaterial Air /gate/crystal/vis/setvisible 0 Framework Geant4 - PET - SPECT - CT - Optical - Radiotherapy GATE Geant4 2
Detector and system description Standard Geant4 volumes Movement & Time Management Using every materials Siemens - ECAT EXACT HR+ From simple volumes TO a complete device Elekta - Precise Philips - Allegro GE - Advance 3
Geometry & Phantom description Whole body - Morphologic description - Voxelized or analytical approach - Realistic material database - Organ motion description Clinical Pre-clinical Organ motion Radiation Therapy: CT patient images GATE converts HU values to the Geant4 material composition Brain imaging 4
Data output management List mode oriented ROOT (most general output) ; ASCII LMF (cylindricalpet system) Imaging applications Interfile projection (Optical or SPECT system) ECAT 7 (PET system) RAW sinogram (PET system) RAW projection (CT system) easy to add a dedicated output Radiotherapy and dosimetry applications Actors + Filters based on G4 scorers and G4Filters 3D dose scorer (dose map Analyze format) Simulation statistic Track killer.. 5
GATE Available features Imaging 6
Oncology: Simulation of whole body scan GATE Simulation - Start acqui. : 264 MBq - 7 bed positions - 7 per bed position Simulation set-up + Tumor volume 22 ml Simulation result Since 2009: new navigator Speed-up factor of 10 to 20 7
Brain: Metabolism & Receptor imaging Protocol [ 18 F]FluoroDOPA : real data against simulation Real scan (Frame 0 to 8) Patlak analysis - Exam LDOPA Uptake Ratio 3 2,5 2 1,5 1 0,5 Cd D /occ Cd G /occ Put D /occ Put G /occ 0 0 50 100 150 Patlak time - min. GATE Simulation (Frame 0 to 8) 3,00 Patlak analysis - Simulation LDOPA 2,50 Uptake Ratio 2,00 1,50 1,00 Cd D /occ Cd G /occ Put D /occ Put G /occ 0,50 0,00 0,00 20,00 40,00 60,00 80,00 100,00 120,00 140,00 Patlak time - min. 8
Molecular and pre-clinical imaging CT scan: attenuation Full numerical phantom [ 18 F]FDG scan simulation - micropet FOCUS 220 system - Injected dose: 200 µci - Start acquisition: 45 min. after injection - Acquisition time: 15 GATE simulation Simulation result 9
Molecular and pre-clinical imaging 4D MOBY phantom GATE simulation CT scan simulation - PIXSCAN-XPAD3 developed in CPPM, Marseille - X ray beam 17 kev - Coupled with prototype PET scan - Cluster of 10 CPUs & CPU time : 24h Simulation result 10
Molecular and pre-clinical imaging New Feature : Optical Imaging Optical physics processes in GATE: - Absorption by the bulk - Scattering process (Rayleigh or Mie) - Process at boundary (transmission or reflection) A set of parameters is defined for each tissue type: - refractive index - absorption length - scattering length - anisotropy coefficient A set of parameters is defined for each surface type: - roughness - reflectivity - transmittance (when the medium refractive index is unknown) - specular and diffuse reflection coefficient 11
Molecular and pre-clinical imaging New Feature : Optical Imaging Fluorescence process using GATE Comparison Data/MC Fluorescent photon energy spectrum after a fluorophorewas excited by a 400 nm wavelength light GATE accurately reproduces the well-known Rhodamine B and Fluorescein emission spectra 12
Molecular and pre-clinical imaging New Feature : Optical Imaging Simulation of a bioluminescence experiment Mouse water model An optical probe: wavelenght 560nm and located in the kidney 2D projection of the optical photons Displayed it on the anatomical CT image of the mouse 13
GATE Available features Radiation Therapy 14
Radiotherapy ans Dosimetry Questions are related to dose distribution Radiotherapy: therapy with photon Hadrontherapy: therapy with hadron Other radiation simulations Brachytherapy Dose during X-Ray imaging Research experiments (biology, physics) Simulated with GATE Beam(s) Target (CT) Output = dose distribution
Radiotherapy ans Dosimetry Complete beam modelling with GATE: Beam and patient parts 16
Radiotherapy ans Dosimetry Performing Dicom-RT-plan simulation with Gate and comparison with a commercial TPS Convert dicom plan into Gate simulation Dose to water vs dose to medium calculation in Gate Compare with Xio (Elekta) TPS 17
Radiotherapy ans Dosimetry TPS and GATE comparison patient case1 Dose scoring difference due to gas in the rectum region 18
Hadron-PET : Feasibility test with Gate Monitoring of the deposited dose using PET imaging for a 12 C treatment Principle Fragmentation: 12 C 15 O Radiotherapy ans Dosimetry 11 C Simulation Set-Up Phantom: CT scan Tumor Head ø 2 cm - segmentation 1 beam - 9.108 12C Phantom: CT scan Real lung tumor 3 beams - 108 12C / beam Hounsfield number Hounsfield number PET scan simulation 10 min post-irradiation acquisition commercial scanner 19
Radiotherapy ans Dosimetry 12 C deposited dose Inverse model 11 C PET scan a.u. Depth pixel unit 12 C deposited dose 11 C PET scan 15 O PET scan Hyper realistic simulation in term of statistic events: Radiation + PET acquisition 20000 hours 2 days with a cluster of 400 processors 20