Ionizing radiation causes the formation of strand breaks in cellular DNA, as well as other
types of lesions in the chromatin of cells. Some of the earliest investigations of the molecular
basis of radiation-induced damage and the implications of enzymatic repair were done by
Dr. HS Kaplan. The induction frequency of DNA double-strand breaks is of special
importance, and it is of interest to know the relative proportions of single-strand and double-
strand breaks. This ratio changes noticeably with the radiation quality (ionization density) …