Development of Accurate Radiotherapy Treatment Planning System (ARTS) Presented by Song Gang FDS team Institute of Plasma Physics Chinese Academy of Sciences.
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Slide 1
Development of Accurate Radiotherapy Treatment Planning System
(ARTS) Presented by Song Gang FDS team Institute of Plasma Physics
Chinese Academy of Sciences [email protected] Http://www.fds.org.cn
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G.SONG, International Nuclear Physics Conference 2007, Tokyo,
Japan, June 3-8, 2007
Slide 2
Background
Slide 3
Objectives and Issues of Radiotherapy Objectives Kill tumor
cells to the great extent Protect the normal tissues and important
organs at the most Main Issues Normal tissues damaged in
radiotherapy Great difference (including material, structure,
sensibility to radiation, etc. ) individually Uncertainty of
radiation biological effect External exposure treatment
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G.SONG, International Nuclear Physics Conference 2007, Tokyo,
Japan, June 3-8, 2007
Slide 4
General View of Radiotherapy System Much fundamental research
was performed on the above key study points
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G.SONG, International Nuclear Physics Conference 2007, Tokyo,
Japan, June 3-8, 2007
Slide 5
Present Status 10 million newfound cancerous persons per year
in the world 70% cancerous persons need radiotherapy Great
application potential, but therapeutic effect is still uncertain in
some extent and should be improved: Now the radiotherapy technique
can not realize accurate radiotherapy essentially Error of dose
calculation: >3%; in extreme condition: up to 30%; Dose
verification: by standard homogeneous phantom or water phantom, not
actual human or emulated human phantom; Position: by laser lines
and marks on body, large error caused by change of contour;
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G.SONG, International Nuclear Physics Conference 2007, Tokyo,
Japan, June 3-8, 2007
Slide 6
Progress
Slide 7
Main Research Issues (1) 1.Recognition technique of human
physical information and model building method based on CT images;
2.Digital human model set up, calculation model and visualization
method of dose distribution. 3.Simulation of particle transport
(neutron, photon, and electron) in human body and development of
calculation algorithms for dose distribution in human body;
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G.SONG, International Nuclear Physics Conference 2007, Tokyo,
Japan, June 3-8, 2007
Slide 8
4.Algorithm for multi-objective optimization of inverse
planning; 5.Fast and precise video-based automatic positioning
method; 6.Design of emulated human phantom and development of
verification method; 7.Accurate/Advanced Radiation Therapy System
(ARTS), proposed and developed based on modern computer technology
and digital simulation method for nuclear physics.
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G.SONG, International Nuclear Physics Conference 2007, Tokyo,
Japan, June 3-8, 2007 Main Research Issues (2)
Slide 9
Automatic Model Set up Method From 3-D medical images (adding
material and density information) to calculation model, including
both geometrical and physical information ( CT/MRI images ->
Digital human model -> Calculation model ) MCAM
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G.SONG, International Nuclear Physics Conference 2007, Tokyo,
Japan, June 3-8, 2007 MORP Medical Images MCNP Input File
Visualization of Dose Calculation Model MCAM: Monte Carlo Automatic
Modeling SystemMORP: Modeling of Radiotherapy Program
Slide 10
Accurate & Fast Dose Calculation Method Regular Beam Model
(RBM) + Modified Batho homogeneity correction method: Error: below
3 %, speed: within 1 minute, for regular field Modified Pencil Beam
Model (fsPB) Error: below 3 %, speed: within 1 minute, for
irregular field Accurate and precise coupled dose Calculation
Method Analytic method: used in homogeneous region; Monte Carlo
method: used in inhomogeneous region; high precision & speed
The above dose calculation methods : all developed or modified by
ARTS team Monte Carlo methods: EGS4, MCNP, etc. Discrete coordinate
(SN) (1D/2D/3D) Nuclear Database
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G.SONG, International Nuclear Physics Conference 2007, Tokyo,
Japan, June 3-8, 2007 Research progress: Poster 264 & 267
Slide 11
Multi-dimension & Multi-field Visualization 3D dose
distribution 2D dose distribution
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G.SONG, International Nuclear Physics Conference 2007, Tokyo,
Japan, June 3-8, 2007 CDVH Outside contour of human body are gotten
by outside contour extraction based on CT numbers Improved edge
flag filling algorithm be used to fill objects Real-time
visualization for outside contour, object, field and overlapping of
which are implemented by surface rendering Visualization of key
information make TPS (ARTS) more valuable
Slide 12
Multi-objective Optimization of Inverse Planning Two
multi-objective optimization algorithms used in ARTS:
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G.SONG, International Nuclear Physics Conference 2007, Tokyo,
Japan, June 3-8, 2007 SAGA could obtain satisfactory solutions in
15 minutes NSGA-II could obtain satisfactory solutions in 5 minutes
Use above methods to optimize dose distribution on a slice of CT:
Introduced NSGA-II to ARTS with some improvement. NSGA- -II is a
fast and elitist multi-objective optimization algorithm. Research
progress: Poster 263 Hybrid multi-objective optimization algorithm
(SAGA) Combined Simulated annealing algorithm and genetic
algorithm, whose displacement is based on the evolutionary
calculation and improve the ability of global optimization.
Non-dominated Sorting Genetic Algorithm-II (NSGA-II)
Slide 13
Video-Based Fast and Accurate Positioning Method Video
positioning method with marks on body surface Breathe gate system
Video positioning method without marks on body surface Based on the
stereo vision and photogrammetry technique to calibrate the video
camera with special demarcated lock Based on dynamic template
matching technique to reduce the influence caused by the contour
change of patient Positioning error is less than 1mm Positioning
process takes less than 30 seconds Rebuild 3-D images with virtual
net technique Compute the positioning error with inverse
reconstruction Contour matching technique Eliminate the positioning
error caused by the patients breath and organs movement Easy
realization Three positioning methods developed and used in
ARTS:
Slide 14
Dose Verification Traditional dose verification: water-to-man
dose verification simple homogenous phantom / water phantom
Complex, time-consuming To be developed: man-to-man dose
verification Use the external dose information of the practical
case to inverse the internal dose distribution. Simple, less-work,
and real time Progress : Rapid and accurate inversion calculation
of three-dimensional electron dose based on hybrid pencil beam
model Applied the method of nonlinear inversion for parameter based
on hybrid pencil beam model (HPBM), and used external dose
information of the practical case to inverse the internal dose
distribution, a "man- to-man " dose verification method. Research
progress: Poster 265
Slide 15
Results Homogeneous case (Fig.1): inversion time: about 3s
(CPU: 2.0GHz, Win XP), and mean accuracy: 99.86% Inhomogeneous case
(Fig. 2): inversion time: about 5s (CPU: 2.0GHz, Win XP), and mean
accuracy: 99.5% Conclusion: Formed "man-to-man" dose verification
Method; Developed the inversion algorithm of electron dose field
based on HPBM, in both homogenous and inhomogeneous rapidly and
accurately. Figure 2. Off-axis to on-axis dose in water-lung- water
model (1cm-2cm-100cm), data from our Monte Carlo (EGSnrc)
simulation, 10x10cm 2 applicator,10x10cm 2 field, 10MeV electron
energy. Figure 1. Off-axis to on-axis dose in water. 10 cm x10 cm
applicator, 10x10cm2 field, 10MeV electron energy, SSD=95cm in
water, and data from our experiment with PDD.
Slide 16
The emulated phantom can realize the following similarities:
External shape / chemical component / internal structure / energy
deposit Emulated Phantom Development and Dose Distribution
Verification
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G.SONG, International Nuclear Physics Conference 2007, Tokyo,
Japan, June 3-8, 2007 Dose verification experiment was carried out
by the phantom to verify the RBM+ Modified Batho dose calculation
method. Varian 23EX accelerator, SSD 100cm, 10cm 10cm field, 6MV
photon: Meaning error between calculation and measurement: below
3%
Slide 17
Interface of ARTS
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G.SONG, International Nuclear Physics Conference 2007, Tokyo,
Japan, June 3-8, 2007
Slide 18
Summary
Slide 19
1. ARTS team of ASIPP is developing an advanced treatment
planning system to solve current problems in radiotherapy; 2.
Visualization, dose calculation, dose verification, inverse
calculation, position, optimization, and biological effect are
studied within the frame of ARTS; 3.Based on the above study, a
prototype TPS system (ARTS) has been developed; 4.Some problems,
especially on biological effect and fast/accurate dose calculation
method, to be solved.
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G.SONG, International Nuclear Physics Conference 2007, Tokyo,
Japan, June 3-8, 2007
Slide 20
Study Progress and Introduction Materials of MCAM & ARTS:
Poster 263, 264, 265 and 267 now! B1F Lobby Gallery at Glass
Building
Slide 21
Thank you
Slide 22
Staff: ~600 Students: ~ 300 Academy of Sciences, Institute of
Plasma Physics ASIPP ( http://www.ipp.ac.cn )
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G.SONG, International Nuclear Physics Conference 2007, Tokyo,
Japan, June 3-8, 2007 Preparatory
Slide 23
FDS team FDS team Fusion Driven (Subcritical) System Fusion
Design Study Fusion Digital Simulation Staff: ~20 Students: ~40 ~30
Ph.D ~20 M.D
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G.SONG, International Nuclear Physics Conference 2007, Tokyo,
Japan, June 3-8, 2007 Photo Album of FDS team Preparatory
Slide 24
Seven research groups: 1. Neutron (photon, electron) physics
2.Radiation Safety (Accurate radiotherapy, Radiation Protection)
3.Thermohydraulics & structure 4.Nuclear material &
cladding technology 5.Radiochemistry (Nuclear waste disposal)
6.System engineering (Optimization, Risk, Economy 7.Computer
technique Research Field and Structure of FDS Team Four
laboratories: 1.Radiation safety & environment protection
2.Nuclear material & cladding technology 3.Nuclear waste
disposal 4.Digital simulation & Visualization Advantages of FDS
team: 1. Multi-disciplinary research physics / heat engineering /
material / chemistry / safety / economics / medicine / computer
technique / mathematics / electronics 2. Fundamental research of
CAS, long-time fund support 3. Broad international cooperation
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G.SONG, International Nuclear Physics Conference 2007, Tokyo,
Japan, June 3-8, 2007 Preparatory
Slide 25
Multi-disciplinary Team Radiation physics Reactor Technology
Division, ASIPP one of the strongest groups in the relevant area in
the world H. Iida ITER-NAKA Computer technology Digital simulation
& visualization Team of 100 Talents Programme of The Chinese
Academy of Sciences Radiation biology Ion beam engineering major
laboratory of the Chinese Academy of Sciences Team supported by
National Science Fund for Distinguished Young Scholars
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G.SONG, International Nuclear Physics Conference 2007, Tokyo,
Japan, June 3-8, 2007 Preparatory