A comparative analysis of the proton, helium-ion, and carbon-ion therapy for brain tumors

Abstract Charged particle therapy, including proton, helium-ion, and carbon-ion modalities, is increasingly utilized for brain tumor treatment due to their superior dose distribution. This study compares the flux and equivalent dose of primary and secondary particles delivered to tumors and healthy tissues using Monte Carlo simulations (MCNP code) with a Snyder head phantom. The equivalent dose delivered to the tumor by carbon-ion therapy was found to be 8.1 times higher than that of helium-ion therapy and 41.8 times higher than that of proton therapy. The equivalent dose to surrounding brain tissues ranged from 15–22 Sv for proton, 100–125 Sv for helium-ion, and 1000–1220 Sv for carbon-ion therapy. The flux of carbon particles in the head and tumor was 0.0068 #/cm2 and 0.0001 #/cm2, respectively, which is negligible compared to proton and helium-ion fluxes. Secondary neutron flux was highest in carbon-ion and helium-ion therapies, raising concerns about secondary cancer risk, while proton therapy showed the lowest secondary particle flux. Lateral dose analysis indicated broader peaks for carbon-ion therapy. In conclusion, although carbon-ion therapy achieves greater tumor dose coverage, proton therapy offers better sparing of healthy tissues and reduced secondary particle production, making it a more precise option for brain tumor radiotherapy.