Unravelling the impact of linear energy transfer on micronuclei induction from proton and photon irradiation.

Micronucleus (MN) formation has a strong link to radiation damage and is a common bio-dosimeter for acute radiation exposures. The percentage of cells containing MN (PCMN) has a strong relationship with dose, however variation between previous studies has made understanding the effect of linear energy transfer (LET) difficult. This study investigated the PCMN of seven cell lines in response to photon and proton irradiation at two different LETs (0.6 keV/ µm and 6.5 keV/ µm). MN production was scored via the cytokinesis block micronuclei assay. A linear relationship between dose and PCMN was noted for all cell lines and radiation types, with a large variability in the MN yield between cell lines. This dose-dependent increase in PCMN was independent of LET, with most cell lines showing similar responses to the radiation qualities. Overall, this data proposes a more complex relationship between dose, MN and LET.