هادرون تراپي تومور چشمي با پرتو پروتون و يون هليوم

Hadron therapy, due to the unique physical characteristic of the Bragg peak, is considered an optimal modality for the treatment of ocular tumors. This study was conducted to eva‎luate the dose distribution within the tumor an‎d surrounding healthy tissues using proton an‎d helium-4 ion beams. A three-dimensional model of the main ocular structures was developed using the Geant4 Monte Carlo code an‎d integrated into the stan‎dard MIRD phantom to provide a comprehensive anatomical model for simulation. Using this framework, the dose distributions of proton an‎d helium-4 ion beams in ocular structures an‎d adjacent tissues were investigated. To achieve adequate coverage of a tumor with a thickness of 8 mm, the optimal energy range for proton beams was determined to be 48–66 MeV, while for helium-4 ion beams it was calculated to be 194–260 MeV. The therapeutic gain at the optimal energy was found to be approximately 4.95 for proton beams an‎d about 5 for helium ion beams, indicating that both modalities exhibit very similar therapeutic effectiveness. The results also showed that the absorbed dose in distant tissues such as the brain an‎d skull was negligible. Considering the comparable therapeutic gain, along with the greater mass of helium ions relative to protons, their narrower Bragg peak, higher energy deposition per ion, an‎d more rapid dose fall-off beyond the tumor, helium ions appear to be a more suitable option for protecting the sensitive healthy tissues surrounding ocular tumors an‎d for enabling shorter treatment times. In contrast, proton beams remain a cost-effective an‎d practical option due to their wider availability an‎d lower accelerator costs.

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سجاد مري

مريم حسنوند , سروش شاكري