In this study, the nuclear fragmentation of the secondary particles produced when water is irradiated with protons and carbons were investigated. Proton beams with varying incident energies of 100 MeV, 130 MeV, 150 MeV and 160 MeV were used with corresponding 12C ion beams of about 187.50 MeV/u, 241.67 MeV/u, 285.42 MeV/u and 308.33 MeV/u respectively. The kinetic energy distribution and energy deposition of primary and secondary particles were studied via Monte Carlo simulation with the aid of GATE v.8.0 via GEANT4 simulation toolkit version 10.3.2 with 1 x 106 incident beams. The physics list used was QGSP_BIC (Quark Gluon String Pre-compound Binary Cascade). When the primary 12C ion and proton beams interact with water, secondary light-charged and heavy-charged particles are produced with atomic number Z > 2 are produced. In general, it was shown that the incident 12C ions are less scattered as they traverse mater compared to the incident protons. Thus, the energy deposition of 12C ions is well-defined and is better in terms of conformation.

In this study, the depth-dose profile in water, skeletal muscle, adipose tissue, and cortical bone irradiated using incident beams of protons and carbon ions were simulated at different incident energies using the open source software GEANT4 version 10.3.2 via GATE v.8.0. The depth where the Bragg peaks of protons with incident energies of 75 MeV, 100 MeV, 130 MeV, 150 MeV, and 160 MeV in different materials were determined and the results were compared with the experimental data from the National Institute of Standards and Technology (NIST) database. The corresponding energy for incident carbon ion beam that yields the same Bragg peak position as the incident proton beams were also investigated. The depth-dose profile obtained using carbon ions show better dose conformation, but the presence of dose tail was observed. This suggests that further investigation of the RBE of the secondary fragments is necessary to understand their underlying impact to the carbon ion treatment in general.

This is a Monte Carlo study in GATE V8.0 investigating the nuclear fragmentation when 12C beams were incident at varying energies on different biological media. The researchers used one million monoenergetic pencil beam primary carbons irradiated to water, adipose tissue, skeletal muscle and cortical bone phantoms. The target was a box with dimensions of 20 cm × 20 cm × 20 cm to approximate the size of a human head. The energy was varied at 186.7 MeV/u, 241.7 MeV/u and 308.3 MeV/u. We obtained the number of the secondary particles produced in the fragmentation. We then chose the ten most abundant fragments and determined their kinetic energy distributions. 12C was most abundant in the fragmentation followed by proton. Either 3He or 11B had the least entries. The kinetic energy was inversely proportional to particles atomic number. In most cases proton and deuteron had the largest kinetic energy. The number of secondary particles increased with increasing incident energy. The kinetic energy had maximum increase at the stopping range, whose depth varied directly with incident energy and inversely with density of each material. The results were in agreement with the Bethe-Bloch formula.