Importantly, Mb@Gd-NTs achieved more significant enhancement of RT efficacy, and the tumor growth inhibition was much stronger than the calculated predicted additive effect of Gd-NTs and Mb@NTs (Fig. 4b, c), i.e., the radiosensitization efficacy of Mb@Gd-NTs > Gd-NTs + Mb@NTs, “1 + 1 > 2”, indicating a synergistic effect caused by Gd-NTs and Mb based O2 delivery. This evidence concerns the gene MB and neoplasm.