| Autor: |
Testa A; a Territorial and Production Systems Sustainability Department, Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Rome, Italy., Ballarini F; b University of Pavia (Physics Department), via Bassi 6, I-27100 Pavia, Italy.; c INFN (Italian National Institute of Nuclear Physics), Section of Pavia, I-27100 Pavia, Italy., Giesen U; d Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig, Germany., Gil OM; e Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Bobadela-LRS, Lisbon, Portugal., Carante MP; b University of Pavia (Physics Department), via Bassi 6, I-27100 Pavia, Italy.; c INFN (Italian National Institute of Nuclear Physics), Section of Pavia, I-27100 Pavia, Italy., Tello J; b University of Pavia (Physics Department), via Bassi 6, I-27100 Pavia, Italy.; c INFN (Italian National Institute of Nuclear Physics), Section of Pavia, I-27100 Pavia, Italy.; f Universidade Estadual de Campinas, Campinas, SP, Brazil., Langner F; d Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig, Germany., Rabus H; d Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig, Germany., Palma V; a Territorial and Production Systems Sustainability Department, Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Rome, Italy., Pinto M; g National Institute of Ionizing Radiation Metrology, Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Rome, Italy., Patrono C; a Territorial and Production Systems Sustainability Department, Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Rome, Italy. |
| Abstrakt: |
There is a continued need for further clarification of various aspects of radiation-induced chromosomal aberration, including its correlation with radiation track structure. As part of the EMRP joint research project, Biologically Weighted Quantities in Radiotherapy (BioQuaRT), we performed experimental and theoretical analyses on chromosomal aberrations in Chinese hamster ovary cells (CHO-K1) exposed to α particles with final energies of 5.5 and 17.8 MeV (absorbed doses: ∼2.3 Gy and ∼1.9 Gy, respectively), which were generated by the microbeam at the Physikalisch-Technische Bundesanstalt (PTB) in Braunschweig, Germany. In line with the differences in linear energy transfer (approximately 85 keV/μm for 5.5 MeV and 36 keV/μm for 17.8 MeV α particles), the 5.5 MeV α particles were more effective than the 17.8 MeV α particles, both in terms of the percentage of aberrant cells (57% vs. 33%) and aberration frequency. The yield of total aberrations increased by a factor of ∼2, although the increase in dicentrics plus centric rings was less pronounced than in acentric fragments. The experimental data were compared with Monte Carlo simulations based on the BIophysical ANalysis of Cell death and chromosomal Aberrations model (BIANCA). This comparison allowed interpretation of the results in terms of critical DNA damage [cluster lesions (CLs)]. More specifically, the higher aberration yields observed for the 5.5 MeV α particles were explained by taking into account that, although the nucleus was traversed by fewer particles (nominally, 11 vs. 25), each particle was much more effective (by a factor of ∼3) at inducing CLs. This led to an increased yield of CLs per cell (by a factor of ∼1.4), consistent with the increased yield of total aberrations observed in the experiments. |
