Development of Software Framework
for Simulation in Radiotherapy
Status and Plan in 2005
Takashi Sasaki
KEKandCREST, JST
Takashi.Sasaki@kek.jp

The Project• “The Development of Software Framework
for Simulation in Radiotherapy”– funded by the Core Research for Evolutional
Science and Technology (CREST) programorganized by Japan Science and Technology
Agency (JST) from 2003 to 2008

• Joint project among Geant4 developers,
astro-physicists and medical physicists inJapan

Member Institutes•••
•
•••
•
•
•
•

High Energy Accelerator Research Organization (KEK)
Ritsumeikan University (RITS)
Kobe University
Naruto University of Education
Toyama National College of Maritime TechnologyJapan Aerospace Exploration Agency (JAXA)
National Institute of Radiological Science (NIRS)National Cancer Center, Kashiwa
Gunma University Faculty of Medicine
Hyogo Ion Beam Medical Center (HIBMC)
Kitasato University

Motivation• Geant4 is not simple software and not easy touse in some case, if– geometry is very complex, and– physics related is not trivial• most of physics process are covered already, but still setting
for selection or combination is difficult sometime• in very few case, new physics process is need to be
implemented• Simulation in particle therapy, especially, heavyion therapy is one of such cases and very
challenging for Geant4 developers’ too– Heavy ion physics also applicable to astro-physProject Goal
• Provide the framework and software toolkit for
simulation in radiotherapy, especially, particle
therapy– Well designed general purpose software– DICOM/DICOM-RT interface– Visualization/Interactivity– GRID computing– etc• Physics validation is also the important subject

The system structure
Knowledge DB

GRID Deployment
visualization/interactivity

framework for medical application
Scoring/Tally Package

DICOM interface

Geant4modeler

Physics Listfor Radiotherapy
Dose Calculation Engines

JQMD

EGS4...

What is Geant4?
Introduction
The project web page:
http://cern.ch/geant4• "GEANT4: A Simulation Toolkit", by theGeant4 Collaboration published in Nuclear
Instruments and Methods in Physics
Research A 506 (2003), 250-303.
– Geant4 is a toolkit for the simulation of the passage ofparticles through matter. Its application areas include
high energy physics and nuclear experiments,
medical, accelerator and space physics studies. It
includes a complete range of functionality including
tracking, geometry, physics models and hits. Thephysics processes offered cover a comprehensive
range, including electromagnetic, hadronic and opticalprocesses, a large set of long-lived particles,materials and elements, over a wide energy range
starting, in some cases, from 250 eV and extending inothers to the TeV energy range. It has been designed
and constructed to expose the physics models utilised,
to handle complex geometries, and to enable its easy
adaptation for optimal use in different sets ofapplications. The toolkit is the result of a worldwide
collaboration of physicists and software engineers.What is Geant4?
• Geant4 is the software toolkit to simulate interaction
between particles and matter• Geant4 is the successor of GEANT3, but designed andimplemented from the scratch using C++• Geant4 is designed to answer a variety of requirements
came from HENP, heavy ion physics, cosmic ray physics,
astrophysics, space science and medical applications using
an Object-Oriented techniques to take into account ofmaintainceabilty and extendability.
• In order to meet such requirements, a high degree offunctionality and flexibility are provided.

Advantages in Geant4••••

Detailed geometry description
Precise magnetic/electric field description
Easier material composition
Variety of physics process– Electro-magnetic• Down to 250 eV up to TeV• Optical photons– Hadronic– Heavy ion– User defined processes

•
•
•
•

Fast or precise visualization
Analysis tools and interactivity
Extendablity as software toolkit
Open sourceDisadvantage of Geant4• Learning curve– Learning C++ and UNIX oriented development
environment if you are new for these– If you are not a FORTRAN programmer, say a C orC++ programmer , this would be an advantage• Complex– As other Monte Carlo codes• Toolkit nature– Geant4 is not a black box to give correct results• Simulation without validation has no meaningGeant4
Collaboration

HARP

Univ. Barcelona
Lebedev

Helsinki Inst. Ph.
http://cern.ch/geant4

PPARC
Collaborators also from nonmember institutions, including
Budker Inst. of Physics
IHEP Protvino
MEPHI Moscow
Pittsburg University

Geant4 global architecture
The global design of Geant4 was doneby CERN and Japanese members in1994 based on Object-Oriented methodology.
The implementation is done in ANSI C++
language
From the beginning, application in multi area,HENP, space, medical and so on wasconsidered for the design. Always the design
is updated according to new requirements.
A class category maintained byan independent working groupJapanese contribution ismore than 90% 9/17

History of Geant4• Dec ’94 - Project start• Apr ’97 - First alpha release• Jul ’98 - First beta release• Dec ’98 - First Geant4 public release• …
• Dec ’03 - Geant4 6.0 release• Mar ’04 - Geant4 6.1 release• Jun ’04 - Geant4 6.2 release• Dec 17th, ’04 - Geant4 7.0 release– Feb 26th, ’05 - Geant4 7.0-patch01 release• two to three public releases every year and bimonthly beta
releases in between public releases

Achievement in our project
2003-2004

Concept of design and Strategy• Common software parts are provided assoftware toolkit– User can adopt for their own target with minimal
modification or addition of a class derived from thebase class provided• In many cases, the same or similar geometry are used
• Requirements on physics processes looks similar• Framework based on PYTHON for morefunctionality and usability• visualization and computer aided user
assistance tool will be provided as independentsoftware• Parallelization of simulation and GRID
computing• Independent DICOM-G4 interface– DICOM-RT is also taken into account• Standardization is not yet ready and need adoption
for different extension at each facility, anyway– DICOM example in the Geant4 distribution
has problems and should be fixed• Quick fixes are already in the new release• Validation against experiments– proton beam first then carbon

Use case and requirement
sampling• All of 6 facilities forparticle therapy in Japanand one in Italy have been WERC(Wakasa)
interviewed– NIRS– NCC-EAST
HBMC (Hyogo)– HIBMC– WERC
proton/heavy ion– SCCproton
SCC (Shizuoka)– University of Tsukuba– INFN LNS at Catania, Italy• Information oncomponents in beam line
and also treatment room
have been gathered also

PMRC (Tsukuba)

NCC-EAST (Kashiwa

NIRS,HIMAC (Chiba)

Alpha version of the class
diagram for geometry description.
Still further study is under going.

Validation against proton data
• Comparison between data taken at HIBMC andit’s simulation based on Geant4 has been
performed using rapid prototyping• Geant4 well reproduced the measurements
Patient Collimator
Multi-Leaf
Collimator

Block
Collimator

Flatness Monitor
Range Shifter
Ridge Filter
Main Monitor
Secondary Monitor

Scatter

Wobbler Magnet (Ｙ)Wobbler Magnet (X)Beam Extraction
Window
protonWater Phantom

Bragg peak
Dot: Meas.
Solid: G4

Comparison between measurement
at HIBMC and Geant4 simulation
proton beam with 150, 190 and 230 MeV

Spread Out Bragg Peak (SOBP)
SOBP 9cm

SOBP 12cm

Dot: Measured
Solid: Geant4150MeV

190MeVThe small bump in the measurement isthought to be a fan beam effect.

DICOM and visualization• Please look at the detailon the poster (Number10) by Dr. Akinori Kimuraat this conference• Geant4-DICOM andDICOM-RT(still HIBMConly) interface• Visualizer for DICOM
image + dose distribution+ analysis results
Visualizer prototype

DICOM interface
Dose distribution in the plastic phantom
visualized by Geant4 Open-GL package.
Proton 150MeVDENSITY in Simulation

150 MeV

ProtonDose around isocenter

150MeV

ProtonComputer aided geometry design
For a first example,
electron accelerator
head design tool has
been designed andimplemented.

With GUI, designchange can be
manipulated easily andC++ source code todescribe the geometry
setup for Geant4 will be
produced automatically.

Parallelism and GRID deployment• Event level parallelism has been implemented
for general purpose using MPI-C++ interface– No other component, but just MPI implementation isnecessary, such as MPICH• Independent from the TOP-C example in G4 distribution• Parallel simulation over the Internet is realized
by GRID middleware in our case Globus andalso LCG2• Web interface to access GRID from behind thehospital firewall is under developmentEvent parallelism using
MPI w/o TOP-C

PC farm: 2CPUx20 nodes
Equal number of slaves on each nodes

Simulation of protons in water
phantom at HIBMC

More than 10hours for singe
processing

MasterSlave# of events

Time(min）

efficiency

MasterSlave# of events

Time(min）

efficiency

1

101000000

80

88

140

1000000

26

671151000000

54

86

150

1000000

38

37

120

1000000

42

83

180

1000000

54

16

125

1000000

34

82

1100

1000000

62

11

130

1000000

30

78

1200

1000000

81

4

135

1000000

2774

1000000704（％）

Single process（％）

Firewall

GRID VO
Still under development

GRID awareolsco
web server androtpID
job broker
GRGRID protocols

httpGRID

Input parameters

protocols

Site A

Site BGRID virtual organization has beenrealized by CERN LCG2 middleware

Site C
File sharing across the sites on Internet
has been realized by San Diego Storage
Resource Broker

Summary• Geant4 is well established software toolkit for simulatinginteraction between particles and matter– Already applied in many fields and well reproduced
measurements• Our project is developing the software framework andtoolkit for particle therapy• Also validation against data are done very seriously• We welcome very much the contact from any otherfacility who have an interest to use our product for theirsimulation• We would like to visit and interview facilities in othercountries, too for sampling use cases and requirements