: The radiation hits water molecules in the cell, creating reactive oxygen species (free radicals) that then attack the DNA.
: Between treatments, both normal and tumor cells begin to grow again. The trick is to ensure the "kill rate" exceeds the "growth rate".
: Different tissues have inherent differences in how they respond to radiation. For example, lymphocytes and bone marrow are highly sensitive, while muscle and nerve tissues are more resistant. 3. High-LET vs. Low-LET Radiation
: Normal cells are often better at repairing sublethal DNA damage than cancer cells.
: Cells are most sensitive to radiation during certain phases of the cell cycle (like mitosis). Fractionating treatment (giving it in small daily doses) allows surviving cancer cells to move into these sensitive phases.