Observed and predicted relative frequency and area of large gamma H2AX foci per nucleus. A: Relative LF number. B: Relative LF area. Black bars = Predicted. Gray bars = Observed. * = significant, p ≤ 0.05. *** = significant, p ≤ 0.001. Error bars represent standard deviations. Mixed beams dose = 0.53 Gy (0.4 X-rays + 0.13 alpha particles).