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Maria Grazia Pia, INFN Genova Geant4 for Microdosimetry MMD 2005 Wollongong, 5-8 November 2005 DNA R. Capra, S. Chauvie, Z. Francis, S. Guatelli, S. Incerti,

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Presentation on theme: "Maria Grazia Pia, INFN Genova Geant4 for Microdosimetry MMD 2005 Wollongong, 5-8 November 2005 DNA R. Capra, S. Chauvie, Z. Francis, S. Guatelli, S. Incerti,"— Presentation transcript:

1 Maria Grazia Pia, INFN Genova Geant4 for Microdosimetry MMD 2005 Wollongong, 5-8 November 2005 DNA R. Capra, S. Chauvie, Z. Francis, S. Guatelli, S. Incerti, B. Mascialino, Ph. Moretto, G. Montarou, P. Nieminen, Maria Grazia Pia

2 Maria Grazia Pia, INFN Genova Object Oriented Toolkit for the simulation of particle interactions with matter An experiment of distributed software production and management software engineering methodologies An experiment of application of rigorous software engineering methodologies object oriented technology and object oriented technology to the particle physics environment also… Born from the requirements of large scale HEP experiments Widely used not only in HEP Space science and astrophysics Medical physics, medical imaging Radiation protection Accelerator physics Pest control, food irradiation Landmining, security etc. Technology transfer R&D phase: RD44, st release: December new releases/year since then

3 Maria Grazia Pia, INFN Genova Domain decomposition hierarchical structure of sub- domains Geant4 architecture Uni-directional flow of dependencies Interface to external products w/o dependencies in a nutshell in a nutshell Rigorous software engineering – Iterative-incremental software process – Object oriented methods – Quality assurance Geometry –Powerful and versatile geometry modelling –Multiple solid representations handled through the same abstract interface (CSG, STEP compliant solids, BREPs) –Simple placements, parameterised volumes, replicas, assembly-volumes etc. –Boolean operations on solids Physics independent from tracking Subject to rigorous, quantitative validation Electromagnetic physics –Standard, Low-Energy, Muon, Optical etc. Hadronic physics – Parameterised, data-driven, theory-driven models Interactive capabilities –Visualisation, UI/GUI –Multiple drivers to external systems

4 Maria Grazia Pia, INFN Genova Geant4 Collaboration Major physics laboratories: CERN, KEK, SLAC, TRIUMF, TJNL European Space Agency: ESA National Institutes: INFN, IN2P3, PPARC Universities: Budker Inst., Frankfurt, Karolinska Inst., Helsinki, Lebedev Inst., LIP, Lund, Northeastern etc. MoU based Development, Distribution and User Support of Geant4 ~100 members

5 Maria Grazia Pia, INFN Genova Dosimetry with Geant4 Radfet #2 Radfet #4 Radfet #1#3 S300/50 G300/50 D300/50 D690/15 DG300/50 G690/15 S690/15 DG690/15 Bulk Diode Space science Radiotherapy Effects on components Multi-disciplinary application environment Wide spectrum of physics coverage, variety of physics models Precise, quantitatively validated physics Accurate description of geometry and materials

6 Maria Grazia Pia, INFN Genova Dosimetry in Medical Applications Courtesy of L. Beaulieu et al., Laval Radiotherapy with external beams, IMRT Brachytherapy Hadrontherapy Radiation Protection Courtesy of J. Perl, SLAC Courtesy of P. Cirrone et al., INFN LNS Courtesy of S. Guatelli et al,. INFN Genova Courtesy of F. Foppiano et al., IST Genova

7 Maria Grazia Pia, INFN Genova Precise dose calculation Geant4 Low Energy Electromagnetic Physics package Electrons and photons (250/100 eV < E < 100 GeV) –Models based on the Livermore libraries (EEDL, EPDL, EADL) –Penelope models Hadrons and ions –Free electron gas + Parameterisations (ICRU49, Ziegler) + Bethe-Bloch –Nuclear stopping power, Barkas effect, chemical formulae effective charge etc. Atomic relaxation –Fluorescence, Auger electron emission, PIXE Fe lines GaAs lines Atomic relaxation Fluorescence Auger effect shell effects ions

8 Maria Grazia Pia, INFN Genova A medical accelerator for IMRT Kolmogorov-Smirnov test p-value = 1 depth dose profile Simulation Exp. data rangeDp-value mm mm mm mm mm lateral dose profile Simulation Exp. data tumour healthy tissue

9 Maria Grazia Pia, INFN Genova MicroSelectron-HDR source Endocavitary brachytherapy Superficial brachytherapy Interstitial brachytherapy Bebig Isoseed I-125 source

10 Maria Grazia Pia, INFN Genova Dosimetry: protons and ions agreement with data better than 3% Further validation tests in progress WHOLE PEAK (N 1 =149 N 2 =66) Cramer – von Mises test Anderson – Darling test Test statistics p-value Electromagnetic only Inventory of Geant4 hadronic models

11 Maria Grazia Pia, INFN Genova Exotic Geant4 applications… FAO/IAEA International Conference on Area-Wide Control of Insect Pests Area-Wide Control of Insect Pests: Integrating the Sterile Insect and Related Nuclear and Other Techniques Vienna, May 9-13, 2005 K. Manai, K. Farah, A.Trabelsi, F. Gharbi and O. Kadri (Tunisia) Dose Distribution and Dose Uniformity in Pupae Treated by the Tunisian Gamma Irradiator Using the GEANT4 Toolkit

12 Maria Grazia Pia, INFN Genova Radiation protection for interplanetary manned missions

13 Maria Grazia Pia, INFN Genova 2.15 cm Al 10 cm water 5 cm water 4 cm Al rigid/inflatable habitats are equivalent 10 cm water 5 cm water Doubling the shielding thickness decreases the energy deposit by ~10% 10 cm water 10 cm polyethylene e.m. physics + Bertini set e.m. physics only shielding materials S. Guatelli et al., Geant4 Simulation for interplanetary manned missions, to be submitted December 2005

14 Maria Grazia Pia, INFN Genova Anthropomorphic Phantoms dose accumulated in organs at risk A major concern in radiation protection is the dose accumulated in organs at risk Development of anthropomorphic phantom models for Geant4 –evaluate dose deposited in critical organs Original approach –analytical and voxel phantoms –analytical and voxel phantoms in the same simulation environment Analytical phantoms Geant4 CSG, BREPS solids Voxel phantoms Geant4 parameterised volumes GDML for geometry description storage

15 Maria Grazia Pia, INFN Genova Radiation exposure of astronauts 5 cm water shielding Skull Upper spine Lower spine Arm bones Leg bones Womb Stomach Upper intestine Lower intestine Liver Pancreas Spleen Kidneys Bladder Breast Overies Uterus 10 cm water shielding Skull Upper spine Lower spine Arm bones Leg bones Womb Stomach Upper intestine Lower intestine Liver Pancreas Spleen Kidneys Bladder Breast Overies Uterus Dose calculation in critical organs external shielding Effects of external shielding self-body shielding self-body shielding Preliminary

16 Maria Grazia Pia, INFN Genova Object Oriented technology + Geant4 architecture Processes are handled transparently by Geant4 kernel through an abstract interface Geometry objects (solids, logical volumes, physical volumes) are handled transparently by Geant4 kernel through abstract interfaces So why not describing DNA? So what about mutagenesis as a process? DNA

17 Maria Grazia Pia, INFN Genova Biological models in Geant4 Relevance for space: astronaut and aircrew radiation hazards

18 Maria Grazia Pia, INFN Genova Physics From the Minutes of LCB (LHCC Computing Board) meeting on 21 October, 1997: It was noted that experiments have requirements for independent, alternative physics models. understand physics validation In Geant4 these models, differently from the concept of packages, allow the user to understand how the results are produced, and hence improve the physics validation. Geant4 is developed with a modular architecture and is the ideal framework where existing components are integrated and new models continue to be developed.

19 Maria Grazia Pia, INFN Genova Toolkit A set of compatible components specialised each component is specialised for a specific functionality refined each component can be refined independently to a great detail integrated components can be integrated at any degree of complexity alternative it is easy to provide (and use) alternative components customised the user application can be customised as needed extensionevolution Openness to extension and evolution new implementations can be added w/o changing the existing code maintenance Robustness and ease of maintenance protocols dependencies protocols and well defined dependencies minimize coupling OO technology Strategic vision

20 Maria Grazia Pia, INFN Genova Sister activity to Geant4 Low-Energy Electromagnetic Physics –Follows the same rigorous software standards International (open) collaboration –ESA, INFN (Genova, Torino), IN2P3 (CENBG, Univ. Clermont-Ferrand), Univ. of Lund Simulation of nano-scale effects of radiation at the DNA level –Various scientific domains involved medical, biology, genetics, physics, software engineering –Multiple approaches can be implemented with Geant4 RBE parameterisation, detailed biochemical processes, etc. First phase: –Collection of user requirements & first prototypes Second phase: started in 2004 –Software development & open source release The concept of dose fails at cellular and DNA scales It is desirable to gain an understanding to the processes at all levels (macroscopic vs. microscopic) DNA

21 Maria Grazia Pia, INFN Genova Multiple domains in the same software environment Macroscopic level –calculation of dose –already feasible with Geant4 –develop useful associated tools Cellular level –cell modelling –processes for cell survival, damage etc. DNA level –DNA modelling –physics processes at the eV scale –bio-chemical processes –processes for DNA damage, repair etc. Complexity of software, physics and biology addressed with an iterative and incremental software process Parallel development at all the three levels (domain decomposition)

22 Maria Grazia Pia, INFN Genova

23 Courtesy A. Brahme (KI) Courtesy A. Brahme (Karolinska Institute) Biological processes Physical processes Biological processes Chemical processes Known, available Unknown, not available E.g. generation of free radicals in the cell

24 Maria Grazia Pia, INFN Genova Requirements Problem domain analysis Theories and models for cell survival TARGET THEORY MODELS Single-hit model Multi-target single-hit model Single-target multi-hit model MOLECULAR THEORY MODELS Theory of radiation action Theory of dual radiation action Repair-Misrepair model Lethal-Potentially lethal model Analysis & Design Implementation Test Experimental validation of Geant4 simulation models Critical evaluation of the models in progress Cellular level Geant4 approach: variety of models all handled through the same abstract interface

25 Maria Grazia Pia, INFN Genova Target theory models Single-hit model Multi-target single-hit model Single-target multi-hit model Joiner & Johns model No hits: cell survives One or more hits: cell dies S(ρ, Δ ) = P SURV (ρ 0, h=0, Δ ) = (1- ρ 0 ) Δ = exp[Δ ln (1- ρ 0 )] P SURV (q,b,n,D) = B(b) (e -q D ) (n-b) (1- e -q D ) b n! b! (n -b)! Extension of single-hit model S = e -α R [1 + ( α S / α R -1) e ] D – ß D - D/D C Cell survival equations Cell survival equations based on model-dependent assumptions S= e -ßD 2 two hits No assumption on: Time Time Enzymatic repair of DNA Enzymatic repair of DNA

26 Maria Grazia Pia, INFN Genova Molecular theory of radiation action (linear-quadratic model) Theory of dual radiation action Repair or misrepair of cell survival Lethal-potentially lethal model Chadwick and Leenhouts (1981) Tobias et al. (1980) Kellerer and Rossi (1971) Curtis (1986) Molecular models for cell death More sophisticated models

27 Maria Grazia Pia, INFN Genova TARGET THEORY SINGLE-HIT TARGET THEORY MULTI-TARGET SINGLE-HIT MOLECULAR THEORY RADIATION ACTION MOLECULAR THEORY DUAL RADIATION ACTION MOLECULAR THEORY REPAIR-MISREPAIR LIN REP / QUADMIS MOLECULAR THEORY REPAIR-MISREPAIR LIN REP / MIS MOLECULAR THEORY LETHAL-POTENTIALLY LETHAL MOLECULAR THEORY LETHAL-POTENTIALLY LETHAL – LOW DOSE MOLECULAR THEORY LETHAL-POTENTIALLY LETHAL – HIGH DOSE MOLECULAR THEORY LETHAL-POTENTIALLY LETHAL – LQ APPROX S= e -D / D 0 S = 1- (1- e -q D ) n S = e –p ( αD + ßD ) 2 S = S 0 e - k (ξ D + D ) 2 S = e -αD [1 + (αD / ε) ] εΦ S = e -αD [1 + (αDT / ε) ] ε S = exp[ - N TOT [1 + ] ε ] ε (1 – e - εBAtr ) N PL S = e -η AC D - ln[ S(t)] = (η AC + η AB ) D – ε ln[1 + ( η AB D/ ε)(1 – e -εBA tr )] - ln[ S(t)] = (η AC + η AB e -εBAtr ) D + ( η 2 AB /2 ε)(1 – e -εBA tr ) 2 D 2 ] S = e -q 1 D [ 1- (1- e -q n D ) n ] REVISED MODEL In progress: evaluation of model parameters from clinical data

28 Maria Grazia Pia, INFN Genova Low Energy Physics extensions Specialised processes down to the eV scale –at this scale physics processes depend on material, phase etc. –in progress: Geant4 processes in water at the eV scale – -release winter 2006 Processes for other material than water to follow –interest for radiation effects on components DNA level Current status

29 Maria Grazia Pia, INFN Genova Development process Complex domain –physics –software Collaboration with theorists Innovative design introduced in Geant4 –Policy-based class design –Parameterised classes: policies are cross section models, models for final state calculation etc. –Flexibility of modelling + performance optimisation Collaboration with experimentalists for model validation would be helpful –Geant4 physics validation at low energies is difficult!

30 Maria Grazia Pia, INFN Genova Cross sections Final state generation Process kinematics

31 Maria Grazia Pia, INFN Genova Elastic scattering Total cross section Angular distribution Phys. Med. Biol. 45 (2000) Solid line: our model Brenner Emfietzoglou 10 eV 100 eV 200 eV 500 eV 1 keV J. Phys. D 33 (2000) Preliminary

32 Maria Grazia Pia, INFN Genova Excitation Testing still in progress (m 2 ) E(eV) p + H 2 0 p + H 2 0 * Rad. Phys. Chem. 59 (2000) m 2 ) E(eV) e - + H 2 0 e - + H 2 0 * Preliminary

33 Maria Grazia Pia, INFN Genova Excitation E(eV) He + H 2 O He + H 2 O * He + + H 2 O He + + H 2 O * He ++ + H 2 O He ++ + H 2 O * (m 2 ) E(eV) Rad. Phys. Chem. 59 (2000) Preliminary

34 Maria Grazia Pia, INFN Genova Charge transfer Charge transfer by protons/Hydrogen is implemented Charge transfer by Helium is still to be implemented E(eV) (m 2 ) Helium p + H 2 0 H + H E H + H 2 0 p + e - + H 2 0 Preliminary

35 Maria Grazia Pia, INFN Genova Ionisation Proton (< 500 keV) and Hydrogen ionisation implemented Development of remaining ionisation processes still ongoing ln(E/eV) (m 2 ) H + H 2 0 H + e - + H p + H 2 0 p + e - + H Preliminary

36 Maria Grazia Pia, INFN Genova Scenario for Mars (and earth…) Geant4 simulation space environment + spacecraft, shielding etc. + anthropomorphic phantom Dose in organs at risk Geant4 simulation with biological processes at cellular level (cell survival, cell damage…) Phase space input to nano-simulation Geant4 simulation with physics at eV scale + DNA processes Oncological risk to astronauts/patients Risk of nervous system damage Geant4 simulation treatment source + geometry from CT image or anthropomorphic phantom

37 Maria Grazia Pia, INFN Genova Conclusions Geant4 offers powerful geometry and physics modelling in an advanced computing environment Wide spectrum of complementary and alternative physics models Multi-disciplinary applications of dosimetry simulation Precision of physics, validation against experimental data Geant4-DNA: extensions for microdosimetry –physics processes at the eV scale –biological models Multiple levels addressed in the same simulation environment –conventional dosimetry –processes at the cellular level –processes at DNA level OO technology in support of physics versatility: openness to extension, without affecting Geant4 kernel


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