Since DSB repair deficiencies were shown to be morehighly correlated with radiosensitivity than SSB repair impairment,a number of comet data obtained in alkaline conditions (mainlyreflecting SSB repair) were in discrepancy with the clonogenicsurvival data. In the 90’s, pulsed-field gel electrophoresis (PFGE)became more popular than comet. Such technique enables themigration of 15-megabase sized DNA fragments, which providedan interesting precision for studying DNA scaffolds. However, usingeither alkaline or neutral conditions, PFGE had the disadvantageof requiring very high doses of radiation (more than 10 Gy, whichdoes not correspond to any single medical exposure), in order toget a sufficient number of small DNA fragments