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DNA damage depending on ionization density of radiation
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Radiation damage to DNA strongly depends on radiation quality, in particular
density of ionization along the track. Linear Energy Transfer (LET) is
one of the parameters to describe the ionization density, difined as energy
deposited from radation to materials per uint length or the radiation track
(keV/μm).
Schematic layouts of the radiation track depending on LET values are shown
in figures below.
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| Higher LET radiaiton caused much severe DNA damage. Typical LET values
are shown Table below. |
| Radiaion |
LET (keV/μm) |
| γ-rays （～MeV) |
0.2 |
| β-rays （～MeV) |
0.2 |
| X-rays |
2-5 |
| α particles （～5MeV from 239Pu) |
120 |
| C6+ions from an accelerator for cancer therapy |
>500 |
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αparticles or C ions shows much higher LET values than those of γ-, β- or X-rays. |
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