Chromosome Aberrations Induced Along The Bragg Curve For Different Ions

Radiation-induced chromosome aberrations (CAs) are amongst the very few radiobiological endpoints that can provide valuable mechanistic insights in the underlying radiation-matter interaction nanoscale processes. The mosaic of simple- and complex-type rearrangements radiation exposure can give rise to (inter- and/or intra-chromosome exchanges) directly links energy deposition patterns and these biological consequences, known to be of relevance for human health [1]. For this reason, CAs have been extensively studied following radiations of varying quality, i.e. LET. Traditionally, densely ionizing radiation yields CA spectra shifted towards a higher degree of complexity, which is thought to reflect the greater amount of clusterization of DNA damage associated with such radiation type [2]. However, relatively few data exist on the variation of CA induction and type along the Bragg curve for various ions [3]. This is of interest to assess the varying radiobiological effectiveness of the particle along its penetration depth (which may be of relevance for hadrontherapy) as well as to study differences among same-LET ions, i.e. the dependence upon the ion Z, hence track-structure effects. To this end, as part of the INFN-funded research project MIMO-BRAGG, we have collected data on CAs following irradiation at LNS-INFN cyclotron (Catania, Italy) and Centro Nazionale di Adroterapia Oncologica (CNAO, Pavia, Italy) for pristine 18O and 20Ne ion beams and a therapeutic SOBP 12C beam. Results will be shown and tentative conclusions including preliminary Monte-Carlo based simulations will be discussed. [1] Bonassi et al., Cytogenet Genome Res, 104 (2004) [2] Hada et al., Mutat Res., 711 (2011) [3] Manti et al, NIM B, 259 (2007)