Chromosome damage by ionizing radiation: a review.

The exposure of living cells to ionizing radiation can induce chromosome aberrations (CAs), which consist of large-scale genome rearrangements following incorrect rejoining of chromosome fragments created by energy deposition in the DNA double helix. This biological endpoint is of peculiar interest, since CAs are strictly related to the fate of the cell: some aberration types generally lead to cell death, which is the main goal of radiotherapy, whereas others can lead to cell conversion to malignancy, which is what one wants to avoid in radiation protection. After defining the various aberration types, in this paper we will describe the main phenomenological aspects of chromosome aberration induction (including the dependence on radiation dose, type and energy), will discuss the relationship between CAs and cell death or carcinogenesis, and will provide examples of the use of aberrations as “biological dosimeters” following human exposure to radiation. The biophysical mechanisms underlying CA induction will be discussed, also reporting the early theories developed by Lea and Revell, and the main open questions will be outlined. Finally, three examples of theoretical models will be presented, discussing the assumptions adopted by the authors and the consequences of such assumptions on the modelling outcomes.