Comparisons of longitudinal and lateral dose profiles and relative biological effectiveness for DNA double strand breaks among 1H, 4He and 12C beams

Abstract Monte Carlo FLUKA and MCDS codes were used to study 1 H, 4 He and 12 C ion beams with similar ranges in water phantom. The longitudinal and lateral dose profiles and the relative biological effectiveness (RBE) were investigated. Simulations were performed with particular emphasis in the vicinity of the Bragg peak (BP). The impact of individual nuclear fragments created by the primary beams was examined. Comparisons were made for the BP width, lateral dose profile width, and RBE value at different depths in the phantom. RBE values for the induction of DNA double-strand breaks were estimated, particularly in the vicinity of the BP. Results showed that 12 C beam had the narrowest BP width, smallest lateral dose profile, and largest RBE value, followed by 4 He and 1 H beams. However, the differences between 4 He and 12 C were smaller than those between 1 H and 4 He. It also showed that the influence of nuclear fragments was significant for 12 C beam, moderate for 4 H beam, and minor for 1 H beam. This influence was important for 12 C at depths beyond the BP. Our results suggest that 4 He beam is also a promising option for cancer therapy.