Budker Inst. of Physics IHEP Protvino MEPHI Moscow Pittsburg University

MEDICAL APPLICATIONS S. Agostinelli 1, S. Chauvie 2,5, F. Foppiano 1, S. Garelli 1, F. Marchetto 2, P. Nieminen 3, M.G. Pia 4, V. Rolando 2, A. Solano 2 1 Istituto Nazionale per la Ricerca sul Cancro, Italy 2 Univ. of Torino and INFN Sezione di Torino, Italy 3 ESA/ESTEC, The Netherlands 4 INFN Sezione di Genova, Italy and CERN, Switzerland 5 IRCC Institute for Cancer Research and Treatment, Italy

- DNA Multi-disciplinary Collaboration of n astrophysicists and space scientists n particle physicists n medical physicists n biologists n physicians - sponsored project, in collaboration with Study of radiation damage at the cellular and DNA level in the space radiation environment (and other applications, not only in the space domain)

Object Oriented Toolkit for the simulation of the passage of particles through matter The transparency of physics Advanced functionalities in geometry, physics, visualisation etc. Extensibility to satisfy new user requirements thanks to the OO technology Adopts standards wherever available (de jure or de facto) Use of evaluated data libraries Quality Assurance based on sound software engineering Subject to independent validation by a large user community worldwide User support organization by a large international Collaboration of experts Geant4 provides various features relevant for medical applications

Low Energy Electromagnetic Physics Low Energy Electromagnetic package extends the coverage of physics interactions 250 eV down to 250 eV for electrons and  based on the LLNL data libraries shell effects ~ 1 keV down to ~ 1 keV for hadrons and ions Bethe-Block above 2 MeV Ziegler and ICRU parameterisations (with material dependence) free electron gas model quantal harmonic oscillator model charge dependence (Barkas effect)

Geant4 Low Energy Electromagnetic Physics Photon attenuation coefficient in water Ion ionisation

Geant4 allows a complete flexible description of the real geometry Brachytherapy Brachytherapy is a medical therapy used for cancer treatments Radioactive sources are used to deposit therapeutic doses near tumors while preserving surrounding healthy tissues

The dose deposition is not isotropic due to source geometry and auto- absorption, encapsulation and shielding effects Anisotropy Radioactive Decay Module is capable of handling the generation of the whole radioactive chain of the 192 Ir source

Isodose curves  -Selectron 192 Ir source The simulated source is placed in a 30 cm water box 1 million 1 mm 3 voxels

Pixel Ionisation Chamber Relative dose with 6 MV photons beam Dosimetric Studies Deposited energy vs Depth in water and experimental data

Bragg Peak of Protons in Water Magic Cube Relative dose with 270 MeV protons beam in water Deposited energy vs Depth in water and experimental data

Work in progress In vivo TLD dosimetry  Simulation of the energy deposition of low energy photons in TLD LiF100 nanodosimeters  Used to calculate dose to patient in radiodiagnostic examinations:  mammography  virtual colonscopy CT image interface  Interface between Geant4 and DICOM CT scan images format in order to perform in tissue simulation