The evidence for one-hit chromosome exchanges.

Luchnik [5] has recently questioned the need for a one-hit chromosome exchange mechanism to explain the dicentric yield in human lymphocytes following irradiation by low LET radiations. An analysis of more recent experimental data is given and this shows that models which approximate to the sum of a term proportional to dose and a term proportional to dose squared fit the available data better than a simple two-hit model. The fits however, are generally poor which is probably due to underestimating the errors involved.