Low Energy Electromagnetic Physics PART II Maria Grazia Pia INFN Genova Maria.Grazia.Pia@cern.ch on behalf of the Low Energy Electromagnetic Working Group Geant4 Workshop Helsinki, 30-31 October 2003 http://www.ge.infn.it/geant4/training/

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

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

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

Dosimetry Simulation of energy deposit through Geant4 Low Energy Electromagnetic package to obtain accurate dose distribution Production threshold: 100 mm 2-D histogram with energy deposit in the plane containing the source Analysis of the energy deposit in the phantom resulting from the simulation Dose distribution Isodose curves AIDA + Anaphe Python for analysis for interactivity may be any other AIDA-compliant analysis system

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

Superficial Brachytherapy Distance along Z (mm) Simulation Nucletron Data F. Foppiano, M. Tropeano Superficial Brachytherapy Experimental validation: Geant4 Nucletron data IST data Leipzig applicators 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!

Dosimetry Dosimetry Endocavitary brachytherapy MicroSelectron-HDR source Dosimetry Superficial brachytherapy Leipzig applicator

Interstitial brachytherapy Dosimetry Interstitial brachytherapy Bebig Isoseed I-125 source 0.16 mGy =100% Isodose curves

Distance away from seed RBE enhancement of a 125I brachytherapy seed with characteristic X-rays from its constitutive materials Goal: improve the biological effectiveness of titanium encapsulated 125I sources in permanent prostate implants by exploiting X-ray fluorescence Distance away from seed RBE Titanium shell (50 µm) Silver core (250 µm) Percentage ++ tumors -- healthy tissues 4.5 mm All the seed configurations modeled and simulated with 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

Hadron Therapy Medical Applications In this talk I would like to explain the reasons are bring us to work with G4 and the goals we wold like to obtain with its use. We are the only italian prothontherapy center and actually we treated 15 patients 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

CATANA hadrontherapy facility Modulator & Range shifter Ligth field Laser Scattering system Monitor chambers CATANA hadrontherapy facility

Real hadron-therapy beam line GEANT4 simulation

Hadrontherapy: comparison of physics models to data Standard + hadronic Standard Processes Low Energy + hadronic Low Energy

LowE e.m. + hadronic (precompound) Beam Line Validation LowE e.m. + hadronic (precompound) Difference below 3% even on the peak

Lateral Dose Validation Difference in penumbra = 0.5 % Difference in FWHM = 0.5 % Difference Max in the homogeneity region = 2 %

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 1 33175 Gradignan France Email : incerti@cenbg.in2p3.fr Nuclear Science Symposium Portland, OR, USA October 19-25th, 2003

GEANT4 Need 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

Testing GEANT4 at the micrometer scale 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 Testing GEANT4 at the micrometer scale PROTONS ALPHAS 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

Probability to reach a given 10 µm circular surface : Beam on target cells AIR AIR VACUUM Beam initial energy distribution : 1 mm 10 µm In red : scattered by diaphragm In blue : no scattering Beam energy distribution on target : Probability to reach a given 10 µm circular surface : In vacuum : Taking into account the residual air ( 5.10-6 mbar ) :

GATE, a Geant4 based simulation platform, designed for PET and SPECT For the OpenGATE collaboration: Steven Staelens

Geometry: scanners +sources Overview Geometry: scanners +sources Interface with the user : scripting (macros)

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

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

LowE at very high energy... Fluorescence is an important effect in the simulation of ultra-high energy cosmic ray experiments Courtesy of Auger

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

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

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

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

...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