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

Monte Carlo FLUKA and MCDS codes were used to study ¹H, ⁴He and ¹²C 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 ¹²C beam had the narrowest BP width, smallest lateral dose profile, and largest RBE value, followed by ⁴He and ¹H beams. However, the differences between ⁴He and ¹²C were smaller than those between ¹H and ⁴He. It also showed that the influence of nuclear fragments was significant for ¹²C beam, moderate for ⁴H beam, and minor for ¹H beam. This influence was important for ¹²C at depths beyond the BP. Our results suggest that ⁴He beam is also a promising option for cancer therapy.