Montecarlo simulation of isodose distribution for Ir-192 brachytherapy
treatments with the GEANT4 toolkit
Garelli
1
S. ,
Foppiano
1
F. ,
Paoli
1
G. , Agostinelli
1,2
S. ,
Pia
3,4
M.G. ,
Tropeano
5
M.
1
Fisica Medica, Istituto Nazionale per la Ricerca sul Cancro, Genova - Italia
2 Istituto Nazionale di Fisica della Materia, Genova - Italia
3 Istituto Nazionale di Fisica Nucleare, Genova - Italia
4 European Organization of Nuclear Research, Geneva - Switzerland
5 Università di Genova, Dipartimento di Fisica di Genova - Italia
[email protected]
Source geometry
Brachytherapy facility installed at the National Cancer Institute of Genova:
5.0 mm
Microselectron High Dose Rate (HDR) afterloading system
0.6 mm
192Ir
source
1.1 mm
< E > = 356 keV
3.5 mm
3 mm steel cable
Active Ir-192 Core
For every new source:
• we perform calibration following the Italian Protocol for
Dosimetry in Brachyterapy
Procedure
verification
• we measure air kerma rate with a well-type PTW
ionisation chamber
Geant4 is a new toolkit for the simulation of the passage
of particles through matter. Its application areas include
high energy physics and nuclear experiments, medical,
accelerator and space physics studies. It is based on
Object Oriented technology and has been developed
using the C++ computer language
90
Simulation of anisotropy coefficient at a distance of
6 cm from the source with the variation of the
longitudinal axis angle
120
60
30
150
Results
cell dimension: 1 mm3
180
number of photons generated: 10.000.000
0
simulation time: 12 h on a Intel PC 300 MHz
1.2x10-4
Simulation of energy deposition in water along
transverse axis
Results
cell dimension: 1 mm3
number of photons generated: 10.000.000
E (MeV)/Photons
1.0x10-4
8.0x10-5
6.0x10-5
4.0x10-5
2.0x10-5
simulation time: 12 h on a Intel PC 300 MHz
0.0
0
2
4
6
8
10
12
Distance along transverse axis (cm)
Simulation of isodose distribution in water material
cell dimension: 1 mm3
number of photons generated: 2.000.000
simulation time: 2 h on a Intel PC 300 MHz
Results
14
16