A new model for Spread Out Bragg Peak in proton therapy of uveal melanoma

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.