DNA double-strand breaks (DSBs) are one of the most lethal DNA damage occurs in mammalian cells. Improper repair of DSBs may leads to mutations, chromosomal translocations, apoptosis, genetic instability [1, 2], increases the chance to cancer development  and immune deficiency . In this study the confocal Raster scan Image Correlation Spectroscopy technique is used to study kinetics and dynamics of double stand break repair proteins after γ-irradiation of mammalian cells. Diffusion and binding constants were obtained by fitting with different physical models. Results were compared to ones obtained by creating high density DNA damage with a laser and subsequently performing Fluorescence Recovery after Photobleaching over the damage area. This work presents similarities and differences in double strand break repair response between γ-irradiation versus laser damage.