Radiosensitive stage of cell cycle

Radiation and cell cycle M phase followed by g2-m interphase is when the cell is radiosensitive. (g2m interphase > G2 > M) The cell is vulnerable to radiation in the stage of mitosis (m), less so during synthesis (s) and relatively insensitive during resting periods.Four impoant processes that occur after radiation exposure can be summarized as the "four r&;s" of radiobiology*The first is repair. Repair is temperature dependent and is thought to represent the enzymatic mechanisms for healing intracellular injury.The second r is reoxygenation, a process whereby oxygen (and other nutrients) are actually better distributed to ble cells following radiation injury and cell killing*the third r is repopulation, the ability of the cell population to continue to divide and to replace dying and dead cells.*The fouh r is redistribution, which reflects the variability of a cell&;s radiosensitivity over the cell cycle.Ref: Principles of radiation therapy by Deeley, 27; Harrison&;s principles of internal medicine 16th edition, 435