Radiation Health & SafetyQuestion 21 of 100
Most radiation damage in soft tissue happens indirectly. Which mechanism explains this indirect effect?
a.X-rays ionize water in the cell, forming free radicals that then damage other molecules
b.X-rays strike DNA directly and always break both strands
c.X-rays heat the cytoplasm until proteins denature
d.X-rays add electrons to the cell nucleus, making it more stable
Explanation
Because cells are largely water, most photons ionize water molecules and create highly reactive free radicals, which then damage DNA and other critical molecules; this is the indirect theory. A direct hit on DNA does occur but is far less common, and it does not always break both strands. Radiation injury is ionizing, not thermal, and ionization removes electrons rather than adding them.
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