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Maria Grazia Pia, INFN Genova 1 Low Energy Electromagnetic Physics PART II Maria Grazia Pia INFN Genova on behalf of the Low Energy.

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Presentation on theme: "Maria Grazia Pia, INFN Genova 1 Low Energy Electromagnetic Physics PART II Maria Grazia Pia INFN Genova on behalf of the Low Energy."— Presentation transcript:

1 Maria Grazia Pia, INFN Genova 1 Low Energy Electromagnetic Physics PART II Maria Grazia Pia INFN Genova on behalf of the Low Energy Electromagnetic Working Group Geant4 Workshop Helsinki, October 2003

2 Maria Grazia Pia, INFN Genova 2 Technology transfer Particle physics software aids space and medicine Geant4 is a showcase example of technology transfer from particle physics to other fields such as space and medical science […]. CERN Courier, June 2002

3 Maria Grazia Pia, INFN Genova 3 CT-simulation with a Rando phantom Experimental data with TLD LiF dosimeter CT images used to define the geometry: a thorax slice from a Rando anthropomorphic phantom Comparison with commercial treatment planning systems M. C. Lopes IPOFG-CROC Coimbra Oncological Regional Center L. Peralta, P. Rodrigues, A. Trindade LIP - Lisbon Central-Axis depth dose Profile curves at 9.8 cm depth PLATO overestimates the dose at ~ 5% level

4 Maria Grazia Pia, INFN Genova 4 Brachytherapy Flexibility of modeling geometries and materials Radioactive Decay Module Low energy electromagnetic processes Interactive facilities: visualisation, analysis, UI Courtesy of R. Taschereau, UCSF

5 Maria Grazia Pia, INFN Genova 5 DosimetryDosimetry AIDA + AnaphePython Analysis of the energy deposit in the phantom resulting from the simulation Dose distribution Isodose curves for analysisfor interactivity may be any other AIDA-compliant analysis system Simulation of energy deposit through Geant4 Low Energy Electromagnetic package to obtain accurate dose distribution Production threshold: 100 m 2-D histogram with energy deposit in the plane containing the source

6 Maria Grazia Pia, INFN Genova 6 Distance along X (mm) Simulation Plato Data Distance along Z (mm) Simulation Plato Longitudinal axis of the source Difficult to make direct measurements rely on simulation for better accuracy than conventional treatment planning software Effects of source anisotropy Transverse axis of the source Comparison with experimental data validation of the software è validation of the software S. Agostinelli, F. Foppiano, S. Garelli, M. Tropeano Endocavitary brachytherapy Role of the simulation: precise evaluation of the effects of source anisotropy

7 Maria Grazia Pia, INFN Genova 7 Distance along Z (mm) Simulation Nucletron Data Experimental validation: Geant4 Nucletron data IST data Leipzig applicators F. Foppiano, M. Tropeano Superficial Brachytherapy Code reuse: still the same application as in the previous case only difference: the implementation of the geometry of the applicator, derived from the same abstract class No commercial software exists for superficial brachytherapy treatment planning!

8 Maria Grazia Pia, INFN Genova 8 Leipzig applicator MicroSelectron-HDR source Dosimetry Endocavitary brachytherapy Dosimetry Endocavitary brachytherapy Dosimetry Superficial brachytherapy Dosimetry Superficial brachytherapy

9 Maria Grazia Pia, INFN Genova 9 Dosimetry Interstitial brachytherapy Dosimetry Interstitial brachytherapy Bebig Isoseed I-125 source 0.16 mGy =100% Isodose curves

10 Maria Grazia Pia, INFN Genova 10 RBE enhancement of a 125 I brachytherapy seed with characteristic X-rays from its constitutive materials Percentage R. Taschereau, R. Roy, J. Pouliot Centre Hospitalier Universitaire de Québec, Dépt. de radio-oncologie, Canada Univ. Laval, Dépt. de Physique, Canada Univ. of California, San Francisco, Dept. of Radiation oncology, USA Goal: improve the biological effectiveness of titanium encapsulated 125 I sources in permanent prostate implants by exploiting X-ray fluorescence Titanium shell (50 µm) Silver core (250 µm) 4.5 mm All the seed configurations modeled and simulated with Distance away from seed RBE -- healthy tissues++ tumors

11 Maria Grazia Pia, INFN Genova 11 Hadron Therapy Medical Applications G.A. Pablo Cirrone On behalf of the CATANA – GEANT4 Collaboration Qualified Medical Physicist and PhD Student University of Catania and Laboratori Nazionali del Sud - INFN, Italy

12 Maria Grazia Pia, INFN Genova 12 Scattering system Modulator & Range shifter Monitor chambers Ligth field Laser CATANA hadrontherapy facility

13 Maria Grazia Pia, INFN Genova 13 Real hadron-therapy beam line GEANT4 simulation

14 Maria Grazia Pia, INFN Genova 14 Hadrontherapy: comparison of physics models to data Standard Processes Standard + hadronic Low Energy Low Energy + hadronic

15 Maria Grazia Pia, INFN Genova 15 LowE e.m. + hadronic (precompound) Difference below 3% even on the peak Beam Line Validation

16 Maria Grazia Pia, INFN Genova 16 Difference in penumbra = 0.5 % Difference in FWHM = 0.5 % Difference Max in the homogeneity region = 2 % Lateral Dose Validation

17 Maria Grazia Pia, INFN Genova 17 Simulation of cellular irradiation with the CENBG microbeam line using GEANT4 Sébastien Incerti representing the efforts of the Interface Physics - Biology group Centre d'Etudes Nucléaires de Bordeaux - Gradignan IN2P3/CNRS Université Bordeaux Gradignan France Nuclear Science Symposium Portland, OR, USA October th, 2003

18 Maria Grazia Pia, INFN Genova 18 N eed for a reliable simulation tool WHY A SIMULATION TOOL ? Technical challenge : to deliver the beam ion by ion, in air, keeping a spatial resolution compatible with irradiation at the cell level, i.e. below 10 µm A simulation tool will help to : understand and reduce scattering along the beam line as much as possible : collimator, diaphragm, residual beam pipe pressure… understand and reduce scattering inside the irradiation chamber : single ion detector, beam extraction into air, cell culture layer… predict ion transport (ray tracing) in the beam line magnetic elements dosimetry with high flexibility and integration.GEANT4

19 Maria Grazia Pia, INFN Genova 19 T esting GEANT4 at the micrometer scale horizontal error bars : 5% experimental uncertainty on the foil thickness value vertical error bars combine statistical fluctuations obtained by varying the number of incident particles in the simulation and systematic fluctuations of the FWMH values due to the 5 % error on the foil thickness ; they range from 1% to 4% for protons and from 5% to 7% for alphas. ICRU_R49p and ICRU_R49He electronic stopping power tables used (G4hLowEnergyIonisation) Important issue on cuts : - Default cutValue in PhysicsList.cc : 100 µm and above - Max step length in target foil logic volume (UserLimits) in DetectorConstruction.cc : foil thickness / 10 - low energy EM and standard packages give same results in the measured region of thickness PROTONS ALPHAS Reference Simulation of ion propagation in the CENBG microbeam line using GEANT4, S. Incerti et al., Nucl. Instr. And Meth. B 210 (2003) 92-97

20 Maria Grazia Pia, INFN Genova 20 P robability to reach a given 10 µm circular surface : In vacuum : Taking into account the residual air ( mbar ) : B eam on target cells VACUUMAIRAIR In red : scattered by diaphragm In blue : no scattering Beam initial energy distribution : Beam energy distribution on target : 10 µm 1 mm

21 Maria Grazia Pia, INFN Genova 21 GATE, a Geant4 based simulation platform, designed for PET and SPECT Steven Staelens For the OpenGATE collaboration:

22 Maria Grazia Pia, INFN Genova 22 Overview Geometry: scanners +sources Interface with the user : scripting (macros)

23 Maria Grazia Pia, INFN Genova 23 Courtesy ESA Space Environment & Effects Analysis Section X-Ray Surveys of Planets, Asteroids and Moons Induced X-ray line emission: indicator of target composition (~100 m surface layer) Cosmic rays, jovian electrons Solar X-rays, e, p Courtesy SOHO EIT Geant3.21 ITS3.0, EGS4 Geant4 C, N, O line emissions included low energy e / extensions were triggered by astrophysics requirements

24 Maria Grazia Pia, INFN Genova 24 Fluorescent spectrum of Icelandic Basalt (Mars-like) Experimental data: 6.5 keV photon beam, BESSY Courtesy of A. Owens et al., ESA Bepi Colombo ESA Bepi Colombo mission to Mercury Analysis of the elemental composition of Mercury crust through X-ray spectroscopy X-ray fluorescence, PIXE many more new features, no time to mention them all...

25 Maria Grazia Pia, INFN Genova 25 LowE at very high energy... Courtesy of Auger Fluorescence is an important effect in the simulation of ultra-high energy cosmic ray experiments

26 Maria Grazia Pia, INFN Genova 26 Geant4 simulation of test-mass charging in the LISA mission Very long base-line: 1 million km Very high precision: < 1nm – 1pm (!)

27 Maria Grazia Pia, INFN Genova 27 Physics List EM processes (LowE) Electrons, Gammas, etc Atomic de-excitation Hadrons (no hFluorescence) Secondaries Cuts: (250 eV), 1mm - 5mm Kill e- outside caging

28 Maria Grazia Pia, INFN Genova 28 Courtesy of Borexino lowE physics fluorescence radioactivity neutrons etc.. unique simulation capabilities: Underground astroparticle experiments Gran Sasso Laboratory, Italy Credit: O. Cremonesi, INFN Milano

29 Maria Grazia Pia, INFN Genova 29 Boulby Mine dark matter search Prototype Simulation LXe GXe PMT mirror source One High Energy event Courtesy H. Araujo and A. Howard, IC London ZEPLIN III

30 Maria Grazia Pia, INFN Genova 30...and much more No time to show all applications Very good relationship between Geant4 LowE Group and its user community –valuable feedback on applications –new user requirements to extend and improve the package Feel free to contact us! Many user applications become (simplified) advanced examples distributed with Geant4 –to help other groups in the user community to get started


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