“…In fact, our data suggested that more than 15% of RBE difference exists between Bragg peak ͑L D = 3.19 keV/ m͒ and plateau ͑L D = 0.56 keV/ m͒. In Bettega et al, 21,22 it was shown that proton RBE determined via the formation of micronuclei in a heteroploid cell line with an epithelioid morphology ͑EUE line with a modal number of 60 chromosomes͒ were 1.7, 1.3, and 1.0 for proton beams of 8, 12, and 31 MeV, which had LET of 5.5, 4.0, and 1.8 keV/ m, respectively. 16 Our results, as well as the previous measurement of RBE at SOBP center, 7 were consistent with their results.…”