The dose-response for low-LET radiation-induced DNA double-strand breakage: methods of measurement and implications for radiation action models.

There is considerable controversy over the form of the dose-response for DNA double-strand breakage (dsb) induction in mammalian cells by low-LET type radiation. This controversy centres on the techniques used for measuring DNA dsb. The applications and shortcomings of the four major techniques for estimating DNA size--sedimentation, viscoelastometry, electrophoresis, and non-denaturing filter elution--are examined. In particular, the criticisms of the results obtained using the non-denaturing filter elution technique, which have suggested that the DNA dsb dose-response is non-linear, are discussed. It is concluded that these results may require a re-evaluation of the basic assumptions of many radiation action models.