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G4N
AM
U GEANT4North America Medical Users Organization
(G4NAMU)
GEANT4 in external beam therapyHarald Paganetti
G4N
AM
U TOPIC I:Beamline design and quality assurance
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U TOPIC II:Magnetic fields
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U TOPIC III:Absolute dosimetry
MUcGy
iFactorOutput
ic
calD
dFdp
dx
dE
W
ei
airair
icic
Volume for absolute dosimetry
Energy deposited / step / Wair
1 10
Par
ticl
es [
rel.
un
its]
0
20
40
60
80
100
120R=22 ; M=8
R=20 ; M=12
R=15.5 ; M=7.5
R=15.5 ; M=12
R=12 ; M=2.5
R=12 ; M=6
R=8.5 ; M=3.5
R=12 ; M=9.5
R=8.5 ; M=7.5
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U TOPIC IV:Patient dose calculation
FOCUS
FOCUS Monte Carlo
Monte Carlo
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U TOPIC V:Time dependent simulations
Solid lines: Patient in inhaleDashed lines: Considering the entire breathing phase
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U TOPIC VI:Radiation Protection
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U TOPIC VII:Radiation Risk
Red bone marrow
0.00001
0.0001
0.001
0.01
0.1
1
0 20 40 60 80Dose (Gy)
Fra
ctio
n vo
lum
e
LP RP
LA
© X. George Xu, RPI
© X. George Xu, RPI
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U TOPIC VIII:Detector Simulation
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U GEANT4 users in external beam radiation therapyin North America:
Issues:
• Correct and reliable physics lists
• Physics wish list for upcoming new G4 versions
• Tracking wish list for upcoming new G4 versions
• CT-formats (DICOM etc)
• Accuracy as a function of level of detail
• Benchmarking data set (exp, theo)
• G4NAMU and other Monte Carlo groups
• Teaching course
Possible problem in the elastic multiple scattering algorithm© J
oao
Sec
oR
oyal
Mar
sden
, Lon
don
, UK
Issues related to dose calculations on CT data
• Memory consumption for storing CT data• Conversion of CT Hounsfield units
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U
DICOM
http://bromley.phy.ulaval.ca/phys_med/DICOM/index.html
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U
0
2
4
6
8
10
12
14
16
18
1.5E-04 1.7E-04 1.9E-04 2.1E-04 2.3E-04 2.5E-04 2.7E-04 2.9E-04
Dose (Gy/300 m illion protons)
Vo
lum
e(%
)
50,000,000 protons per f ield
100,000,000 protons per f ield
240,000,000 protons per f ield
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U
Neutron energy distributions for 150 MeV protons incident on a 1cm water slab
© W
ang
and
Pag
anet
tiR
PI,
New
Yor
k;
MG
H, B
osto
n
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U Role of G4NAMU with respect to other groups :
Computational Medical Physics Working Group (CMPWG)American Nuclear Society (ANS)
Mathematics and Computations (M&C)Biology and Medicine (BMD)Radiation Protection and Shielding (RPSD)
Bernadette Kirk
AAPMTask Group 105: “Monte Carlo in Clinical Treatment Planning“
Bruce Curran and Indrin Chetty
