A nanodosimetric model of radiation-induced clustered DNA damage yields.
We present a nanodosimetric model for predicting the yield of double strand breaks (DSBs) and non-DSB clustered damages induced in irradiated DNA. The model uses experimental ionization cluster size distributions measured in a gas model by an ion counting nanodosimeter or, alternatively, distributions simulated by a Monte Carlo track structure code developed to simulate the nanodosimeter. The model is based on a straightforward combinatorial approach translating ionizations, as measured or simulated in a sensitive gas volume, to lesions in a DNA segment of one-two helical turns considered equivalent to the sensitive volume of the nanodosimeter. The two model parameters, corresponding to the probability that a single ion detected by the nanodosimeter corresponds to a single strand break or a single lesion (strand break or base damage) in the equivalent DNA segment, were tuned by fitting the model-predicted yields to previously measured double-strand break and double-strand lesion yields in plasmid DNA irradiated with protons and helium nuclei. Model predictions were also compared to both yield data simulated by the PARTRAC code for protons of a wide range of different energies and experimental DSB and non-DSB clustered DNA damage yield data from the literature. The applicability and limitations of this model in predicting the LET dependence of clustered DNA damage yields are discussed.
Garty
G
G
Department of Particle Physics, Weizmann Institute of Science, Rehovot 76100, Israel. gyg2101@columbia.edu
Schulte
R
R
Shchemelinin
S
S
Leloup
C
C
Assaf
G
G
Breskin
A
A
Chechik
R
R
Bashkirov
V
V
Milligan
J
J
Grosswendt
B
B
D000465:Algorithms; D003198:Computer Simulation; D004247:DNA / Q000528:radiation effects*; D053903:DNA Breaks, Double-Stranded / Q000528:radiation effects; D004249:DNA Damage / Q000528:radiation effects*; D006371:Helium / Q000009:adverse effects; D008957:Models, Genetic; D009010:Monte Carlo Method; D036103:Nanotechnology / Q000295:instrumentation / Q000379:methods*; D010957:Plasmids / Q000528:radiation effects; D011336:Probability; D011522:Protons / Q000009:adverse effects; D011874:Radiometry / Q000295:instrumentation / Q000379:methods*; D015203:Reproducibility of Results; D012441:Saccharomyces cerevisiae; D012984:Software
D011522:Protons; D006371:Helium; D004247:DNA