Dose response and repair kinetics for summarized gamma-H2AX foci number and total area per nucleus. A: number of IRIF per nucleus for dose response. B: IRIF area per nucleus for dose response. C: number of IRIF per nucleus for repair kinetics. D: IRIF area per nucleus for repair kinetics. Black circles = X-rays, white circles = alpha particles, white squares = mixed beam of 75% X-rays and 25% alpha particles, grey squares = predicted values for mixed beam (assuming additivity). Error bars represent standard deviations. Doses for repair kinetics: X-rays = 0.8 Gy. Alpha particles = 0.27 Gy. Mixed beams = 0.53 Gy. Dose response was scored 1 h after irradiation.