Title: The application of GEANT4 simulation code to the verification of a brachytherapy calibration procedu
1The application of GEANT4 simulation code to the
verification of a brachytherapy calibration
procedure
- F. Foppiano1, S. Garelli1, P. Moresco1, G.
Paoli1, S. Agostinelli2 - 1 Istituto Nazionale per la Ricerca sul Cancro di
Genova, Italia - 2 INFM and Dipartimento di Fisica di Genova,
Italia
With the collaboration of Maria Grazia Pia3 and
Matteo Tropeano4 3 Istituto Nazionale di Fisica
Nucleare di Genova, Italia 4 Dipartimento di
Fisica di Genova, Italia
2Brachytherapy facility installed at National
Cancer Institute of Genova Microselectron High
Dose Rate (HDR) afterloading system
192Ir source
ltEgt 356 keV
3Every new source is supplied by Mallinckrodt
Medical B.V. Holland with a calibration
certificate that specifies the air kerma rate
measure at a distance of 1 m with uncertainty of
5
For every new source
For every new source
- we perform calibration following the protocol
for The Basic Dosimetry with Brachitherapy
Sources of the Italian Association of Biomedical
Physics (AIFB) using a 0.6 cc Capintec chamber
- we measure the air kerma rate using a well -
type chamber PTW Freiburg
4The Microselectron HDR Treatment Planning System
(PLATO), in order to account for the internal
absorption and source encapsulation uses a list
of anisotropy correction factors Fi(?) where ? is
the longitudinal axial angle
5Geant4 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.
Our application
- anisotropy correction factors of 192Ir source
- transverse axis energy deposition in water
- verification of the calibration procedure of
192Ir source
6- As a first test for Geant4 application we perform
the simulation of attenuation coefficient in
different material of interest - 1.000.000 photons generated
- 120 sec on an Intel PC 300 MHz
7Anisotropy
cell dimension 1 mm3 number of photons
generated 10.000.000 simulation time 12 h on a
Intel PC 300 MHz
8Energy deposition in water
cell dimension 1 mm3 number of photons
generated 10.000.000 simulation time 12 h on a
Intel PC 300 MHz
9Future developments
Use of the new Geant4 low energy model
Simulation of air kerma rate
Isodose distribution around shielded and
unshielded applicators
Conclusions
We have developed a procedure to test Geant4
toolkit, which provides a modern Montecarlo
implementation and robust physics modelling. We
have found a very interesting field of
application for Geant4 in brachytherapy.