Mesure de la dose physique par lms radiochromiques et simulation Monte Carlo pour l'hadronthérapie

Abstract : Because of the increase in dose at the end of the range of ions, dose delivery during patient treatment with hadrontherapy should be controlled with high precision. Monte Carlo codes are now considered mandatory for validation of clinical treatment planing and as a new tool for dosimetry of ion beams. In this work, we aimed to calculate the absorbed dose using Monte Carlo simulation Geant4/Gate. The ejffect on the dose calculation accuracy of dierent Geant4 parameters has been studied for mono-energetic carbon ion beams of 300 MeV/u in water. The parameters are : the production threshold of secandary particules and the maximum step limiter of the particle track. Tolerated criterion were choosen to meet the precision required in radiotherapy (2%, 2mm) and to obtain the best compromise on dose distribution and computational time.We propose here the values of parameters in order to satisfy the precision required. In the second part of this work, we will study the response of radiochromic lms MD-v2-55 for quality control in proton and carbon ion beams. We have particularly observed and studie the quenching effect of dosimetric lms for high LET (20 KeV/m) irradiations in homogeneous and heterogeneous medium. This eject is due to the high ionization density around the track of the particule. We have developped a method to predict the response of radiochromic lms taking into account the saturation effect. This model is called the RADIS model forRAdiochromic films. Dosimetry for Ions using Simulations". It is based on the response of lms under photon irradiations and the saturation of lms due to high linear energy deposit calculated by Monte Carlo. Four beams were used in this study and aimed to validate the model for hadrontherapy applications : carbon ions, protons and photons at different energies. Experiments were performed at Grand Accélérateur National d'Ions Lourds (GANIL), Proton therpay center of Orsay (CPO), A. Lacassagne proton center (CAL) and Leon Berard cancer center (CLB). The model showed very good agreement between the measured and calculated optical density with an error less than 2%.
Document type :
Theses
Life Sciences. Université Claude Bernard - Lyon I, 2010. French. <NNT : 2010LYO10088>


https://tel.archives-ouvertes.fr/tel-00520876
Contributor : ABES STAR <>
Submitted on : Thursday, January 27, 2011 - 3:44:25 PM
Last modification on : Tuesday, March 19, 2013 - 10:36:08 AM

File

TH2010_Zahra_Mohamad_Nabil.pdf
fileSource_public_star

Identifiers

  • HAL Id : tel-00520876, version 2

Collections

Citation

Mohamad Nabil Zahra. Mesure de la dose physique par lms radiochromiques et simulation Monte Carlo pour l'hadronthérapie. Life Sciences. Université Claude Bernard - Lyon I, 2010. French. <NNT : 2010LYO10088>. <tel-00520876v2>

Export

Share

Metrics

Consultation de
la notice

416

Téléchargement du document

189