The single-cell electrophoresis (comet) assay is an established method for 
measuring radiation-induced strand breaks in DNA. The extent of damage is 
quantified in individual cells by assessing the intensity and distribution of a 
fluorescent DNA-binding dye using image analysis software. Using the Kinetic 
Imaging Komet3 system, it is demonstrated that the fluorochrome SYBR Green I 
improves the resolution and sensitivity of the comet assay, particularly for 
measuring radiation-induced double strand breaks.