@misc{oai:repo.qst.go.jp:00071104,
 author = {Nakajima, Nakako and Hirayama, Ryoichi and Fujimori, Akira and Okayasu, Ryuichi and et.al and 中島 菜花子 and 平山 亮一 and 藤森 亮 and 岡安 隆一},
 month = {May},
 note = {Heavy particle irradiation produces complex DNA double strand breaks (DSBs) which can arise from primary ionisation events within the particle trajectory. Additionally, secondary electrons, termed delta-electrons, which have a range of distributions can create low linear energy transfer (LET) damage within but also distant from the track.DNA damage by delta-electrons distant from the track has not previously been carefully characterised. Using imaging with deconvolution, we show that at 8 hours after exposure to Fe (~200 keV/micrometer) ions, gamma-H2AX foci forming at DSBs within the particle track are large and encompass multiple smaller and closely localised foci, which we designate as clustered gamma-H2AX foci. These foci are repaired with slow kinetics by DNA non-homologous end-joining (NHEJ) in G1 phase with the magnitude of complexity diminishing with time. These clustered foci (containing 10 or more individual foci) represent a signature of DSBs caused by high LET heavy particle radiation. We also identified simple gamma-H2AX foci distant from the track, which resemble those arising after X-ray exposure, which we attribute to low LET delta-electron induced DSBs. They are rapidly repaired by NHEJ. Clustered gamma-H2AX foci induced by heavy particle radiation cause prolonged checkpoint arrest compared to simple gamma-H2AX foci following X-irradiation. However, mitotic entry was observed when ~10 clustered foci remain. Thus, cells can progress into mitosis with multiple clusters of DSBs following the traversal of a heavy particle., HITSRS2013},
 title = {Visualisation of H2AX foci caused by heavy ion particle traversal; Distinction between core track versus non-track damage},
 year = {2013}
}