Profound mitotic delay occurs when the doses are:
Smaller
Larger
Intermediate
No effect of doses
Radiation is especially damaging to rapidly dividing cell systems, such as skin and intestinal mucosa and hematopoietic tissues. Irradiation of such cell populations causes a reduction in size of the irradiated tissue as a result of mitotic delay (inhibition of progression of the cells through the cell cycle) and reproductive cell death (usually during mitosis).
The three mechanisms of reproductive death are:

DNA damage 
Bystander effect
Apoptosis

Note: Large dose of irradiation causes mitotic delay.