Biological effectiveness of12C and20Ne ions with very high LET

Joanna Czub, Dariusz Banaś, Anna Błaszczyk, Janusz Braziewicz, Iwona Buraczewska, Jaroslaw Choiński, Urszula Górak, Marian Jaskóła, Andrzej Korman, Anna Lankoff, Halina Lisowska, Aneta Łukaszek (+2 others)
2008 International Journal of Radiation Biology  
Purpose: To determine the relationship between the relative biological effectiveness (RBE) for cell inactivation and linear energy transfer (LET) in the Bragg peak region of 12 C and 20 Ne ions. Materials and methods: Chinese hamster ovary (CHO-K1) cells were exposed to high LET 12 C (33.2 MeV, 20.3 MeV, 9.1 MeV at cell entrance) and 20 Ne ions (56.2 MeV, 34.7 MeV, 15 MeV at cell entrance) and to low LET x-rays. Technical details of the irradiation facility are presented which is based on the
more » ... h is based on the Monte Carlo simulation of the lateral spread of heavy ions as a result of the multiscattering small-angle process in physical conditions of the experimental set-up. Results: RBE has been measured for LET values close to the Bragg peak maximum, i.e., 440-830 keV/mm for 12 C and for 1020-1600 keV/mm for 20 Ne ions. RBE values at several levels of survival were estimated and were found to decrease with increasing LET. The inactivation cross sections were calculated from the final slope of dose-response curves and were found to increase with increasing LET. Conclusions: The RBE decreases with increasing LET in the range between 440 and 1600 keV/mm for the two types of radiations forming a single line when plotted together, pointing towards LET as the single determinant of RBE. The inactivation cross section describing the killing efficiency of a single particle at the end of particle range comes close to the size of the cell nucleus.
doi:10.1080/09553000802389652 pmid:18979317 fatcat:t6j2dacyvfholc5rokx62kcrum