Indirect Action to Damage DNA

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  • Indirect Action is “damage to the DNA by free radicals” formed by ionization of water molecules.
    • The incident photon or particle ionizes a water molecule close to DNA.
    • The free electron from this ionization moves through the medium in approximately 10-15 seconds.
    • The ion radical is formed (its lifetime is 10-10 sec) before reacting.
    • Free radicals (H3O+ and HO-) reacts chemically (10-5 sec).
    • Chemical changes due to these actions breaks the DNA molecule.
    • The DNA repaired incorrectly may be expressed as a biological effect many years later (cancer/leukemia).


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