Evaluation of dose distribution from 12C ion in radiation therapy by FLUKA code

Heavy ions have a high potential for destroying deep tumors that carry the highest dose at the peak of Bragg. The peak caused by a single-energy carbon beam is too narrow, which requires special measures for improvement. Here, carbon-12 (12C) ion with different energies has been used as a source for calculating the dose distribution in the water phantom, soft tissue and bone by the code of Monte Carlo-based FLUKA code. By increasing the energy of the initial beam, the amount of absorbed dose at Bragg peak in all three targets decreased, but the trend for this reduction was less severe in bone. While the maximum absorbed dose per bone-mass unit in energy of 200 MeV/u was about 30% less than the maximum absorbed dose per unit mass of water or soft tissue, it was merely 2.4% less than soft tissue in 400 MeV/u. The simulation result showed a good agreement with experimental data at GSI Darmstadt facility of biophysics group by 0.15 cm average accuracy in Bragg peak positioning. From 200 to 400 MeV/u incident energy, the Bragg peak location increased about 18 cm in soft tissue. Correspondingly, the bone and soft tissue revealed a reduction dose ratio by 2.9 and 1.9. Induced neutrons did not contribute more than 1.8% to the total energy deposited in the water phantom. Also during 12C ion bombardment, secondary fragments showed 76% and 24% of primary 200 and 400 MeV/u, respectively, were present at the Bragg-peak position. The combined treatment of carbon ions with neutron or electron beams may be more effective in local dose delivery and also treating malignant tumors. •Carbon-12 ion source was utilized for computing the dose distribution in three targets.•Absorbed dose at Bragg peak decreased by increasing energy source.•Bragg peak position in bone increased about 11 ± 0.15 cm by increasing from 200 to 400 MeV/u energy.•Respectively, the reduction dose rates were 2.9 and 1.9 for soft tissue and bone.•Induced neutrons did not contribute more than 1.8% to total energy deposited in water phantom. Three targets (water phantom, soft tissue and bone) under the radiation of three different energies of 12C ion beam (200, 300 and 400 MeV/u) were simulated by Monte Carlo-based FLUKA code. The Bragg peak position and dose distribution were compared. The bone and soft tissue demonstrated a reduction dose ratio by 2.9 and 1.9 with the increase in incident ion energy from 200 to 400 MeV/u, respectively. As the energy of the primary ion increased, the Bragg peak position was