Late cellular effects of C-12 ions

The expanding role of particle-based radiation treatment of cancer (hadrontherapy) requires a thorough understanding of its possible late effects at the cellular and tissue levels. The biological effectiveness of a C-12, ion beam in the induction of two biological endpoints, neoplastic transformation and premature cellular senescence,was studied in human cells in vitro and compared to that exhibited by low linear energy transfer (LET) radiation. Cells were exposed to the therapeutic C-12 ion beam used at GSI at various positions of the beam ionisation path, corresponding to the low-LET entrance channel (plateau), the high-LET Spread-Ont Bragg Peak (SOBP) or at 3.8cm past the SOBP. In the framework of the INFN-funded project ETIOPE, this paper reports preliminary results oil survival and neoplastic transformation after a physical close of 0.75 GY, and on the onset of cellular senescence after 0.5 or 2 Gy of plateau- and SOBP-irradiated cells. A three-dimensional approach to investigate tile effects C-12 ion beams oil the expression of cell adhesion molecules is also examined.