OOAD… OOAD…

LowE Electrons

From HEP computing to medical research From HEP computing to medical research and vice versaand vice versa

BidirectionalBidirectional Technology transfer and application results

HEP world offers advanced software technologies to medical physics worldMedical physics turns in back feedback on the developed tools

Globalisation : sharing functionalities across diverse field

GEANT4 LOW ENERGY ELECTROMAGNETIC PHYSICS

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User Requirements Document Status: in CVS repository

Version: 2.4 Project: Geant4-LowE Reference: LowE-URD-V2.4 Created: 22 June 1999 Last modified: 26 March 2001 Prepared by: Petteri Nieminen (ESA) and Maria Grazia Pia (INFN)

UR 2.1The user shall be able to simulate electromagnetic interactions of positive charged hadrons down to < 1KeV. Need: Essential Priority: Required by end 1999 Stability: T. b. d. Source: Medical physics groups, PIXE Clarity: Clear Verifiability: Verified

Requirements for Geant4 LowEnergy package

Low Energy Processes for e-, hadrons,ions, gamma

Energy range: 250 eV up to 100 GeV

Based on EPDL97, EEDL and EADL evaluated data libraries cross sections sampling of the final state

Software architecture

LowE Hadrons and ions

What in a simulation software system is relevant to the

bio-medical community?

Use of evaluated data libraries

The transparency of physics Advanced functionalities in geometry, physics, visualisation etc.

Extensibility to accomodate new user requirements (thanks to the OO technology)

Adoption of standards wherever available (de jure or de facto)

Quality Assurance based on sound software engineering

Independent validation by a large user community

worldwide

User support from expertsA rigorous

software process

Specific facilities controlled by a friendly UI

•The transparency of the physics implementation is fundamental for “sensitive”

and critical applications, such as medical ones

Validation of Geant4 LowEnergy package Geant4 simulation results are compared to procol data (i.e. NIST) and/or to experimental data

The first user application … …. and the same requirements in HEP too

Seedcomponents

Silver core (250 µm)

Titanium shell (50 µm)

Iodine-125 seed

4.5 mm

Distance (nm)

10 keV electron in water

R. Taschereau, R. Roy, J. Pouliot

Centre Hospitalier Universitaire de Quebec, Dept. de radio

-oncologie, Canada Univ. Laval, Dept. de Physique, Canada

Univ. of California, San Francisco, Dept. of Radiation Oncology, USA

Exploiting X-ray fluorescence to lower

the energy spectrum of photons (and electrons)

and enhance the RBE

Similar requirements on both low energy e/gamma and hadrons, K-shell transitions etc.from “underground” HEP experiments collected ~1 year later Recent interest on these physics models from LHC for precision detector simulationThey profit of the fact that the code does already exist, has been extensively tested

and experimentally validated by other groups

HEP offers methodologies and tools

“It was noted that experiments have requirements for independent, alternative physics models. 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.”

Domain decomposition

Geant4 architecture

Uni-directional flow of dependencies

Software Engineering

plays a fundamental role in Geant4

User Requirements• formally collected• systematically updated• PSS-05 standard

Software Process• spiral iterative approach• regular assessments and improvements• monitored following the ISO 15504 model

Quality Assurance• commercial tools• code inspections• automatic checks of coding guidelines• testing procedures at unit and integration level• dedicated testing team

Object Oriented methods•OOAD• use of CASE tools

• essential for distributed parallel development• contribute to the transparency of physics

Use of Standards • de jure and de facto

ApplicationsIn Medical Physics

Verification of conventional radiotherapy treatment planning (as required by protocols)

Investigation of innovative methods in radiotherapy Radiodiagnostics

Brachytherapy

Dose distribution onplains at differentdistances from the source

Protontherapy

New projectsHadrontherapy studies In vivo dosimetry(mammography, colonscopy), Superposition and fusion of anatomic

and functional images PET Intra-operatory radiotherapy CT interfaceGEANT4- DNA

Study of radiation damage at the cellular and DNA level in the space radiation environment(and other applications,not only in the space domain)

Relevance for space: astronaut and airline

pilotradiation hazards, biological experiments

Applications in radiotherapy, radiobiology...