فهرست مطالب seyed ali mahdipour

Nowadays, due to the high costs and large dimensions of the conventional proton accelerators, other optimal methods for producing the proton beam have been studied. Using of Laser-driven proton accelerators is one of the important and new methods. In laser-driven ion acceleration, a highly ultra-intense laser pulse interacts with solid density targets and will create a plasma media that will accelerate ions and produce protons. Currently there are projects in this in field such as ELIMED, PMRC, DROT, HZDR and …. Due to the large angular dispersion of protons, reducing their dispersion and collimating them for transmission is very important. In this research, using the GEANT4 toolkit, the exact solenoid and its magnetics field for HZDR beamline have been simulated. The effect of solenoid on protons with a primary divergence of 5 degrees was investigated. The results show that consideration of the details of the solenoid has a direct effect on the calculation of the proton profiles and is necessary. The maximum of the solenoid magnetic field was calculated to ~20 Tesla to fit the proton selector system at a distance of one meter from the source.

In this research, in order to improve our calculations in treatment planning for proton radiotherapy of ocular melanoma, we improved our human eye phantom planning system in GEANT4 toolkit. Different analytical models have investigated the creating of Spread Out Bragg Peak (SOBP) in the tumor area. Bortfeld’s model is one of the most important analytical methods. Using convolution method, a new analytical model for the creating of SOBP in the eye tumors was introduced. Also, the GEANT4 Monte Carlo toolkit was implemented for the Bragg peak production in the water and realistic eye phantom. Two different phantoms are proposed to study the effect of defining realistic materials on the proton dose distribution. Moreover, for the clinical investigation, the SOBP curves are figured in the water and eye phantom, using CATANA beam line. For proton pencil beams, the SOBP width for the water and eye phantoms was 0.901 and 0.877 cm, respectively. Bragg peak and SOBP calculations show a good agreement between the results of GEANT4, proposed and Bortfeld models. Using the CATANA beam line, the SOBP width difference between the two water and eye phantoms is 0.11 cm.