All diagramsSafety · Radiation Biology
Watch radiation damage DNA directly and through free radicals from ionized water, then compare sparse and dense tracks and how RBE rises with LET.
Step 3 of 3
- An x-ray photon enters the cell nucleus.
- The photon ionizes an atom in the DNA molecule itself.
- The ionization breaks a chemical bond, and one strand of the DNA is severed.
- Direct action
- Radiation ionizes the DNA molecule itself, and the ionization can break the molecule's chemical bonds.
- Which radiation causes it
- Direct action can happen with any radiation, but it is much more likely with high-LET radiation such as alpha particles.