Radiation dose\u2013response curves: cell repair mechanisms vs. ion track overlapping

Agata Kowalska,Konrad Czerski,Polina Kutsalo,Elena Nasonova,Eugen Krasavin

doi:10.1140/epjd/e2017-80013-2

Abstract

Chromosome aberrations in human lymphocytes exposed to different doses of particle radiation: 150 MeV and spread out Bragg peak proton beams, 22 MeV/u boron beam and 199 V/u carbon beam were studied. For comparison, an experiment with 60Co γ-rays was also performed. We investigated distributions of aberration frequency and the shape of dose–response curves for the total aberration yield as well as for exchange and non-exchange aberrations, separately. Applying the linear-quadratic model, we could derive a relation between the fitted parameters and the ion track radius which could explain experimentally observed curvature of the dose–response curves. The results compared with physical expectations clearly show that the biological effects of cell repair are much more important than the ion track overlapping.Graphical abstract

Highlights

Chromosome aberrations in human lymphocytes exposed to different doses of particle radiation: 150 MeV and spread out Bragg peak proton beams, 22 MeV/u boron beam and 199 V/u carbon beam were studied
The results compared with physical expectations clearly show that the biological effects of cell repair are much more important than the ion track overlapping
Damage of cells and tissues induced by ionizing radiation has different scenarios and mechanisms which depend on physical properties of investigated beam, delivered dose, dose rate, and depend on biological response of considered cell type [1,2,3]

Summary

Introduction

Damage of cells and tissues induced by ionizing radiation has different scenarios and mechanisms which depend on physical properties of investigated beam, delivered dose, dose rate, and depend on biological response of considered cell type [1,2,3]. A much more reliable indicator of radiation action can be study of chromosome aberrations (CA), which are directly correlated to the processing of the DNA double strand breaks (DSB). Rapid development of hadron radiotherapy in the last decades increased importance of the radiobiological research and understanding of the physical and biological response to ionizing radiation. Physical conditions like formation of ion tracks [4] and the processes of the DNA damage leading to chromosomal aberrations [5,6] are relatively well known. Recent Monte Carlo simulations starting with individual cross section values of traversing

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