Ionisation and ionising radiation

Ionisation is a process which occurs when radiation touching an atom or molecule has enough energy to remove an electron and change the properties of the atom or molecule as a result. Once these atoms/molecules have been changed, they can start chemical reactions.

To remove an electron from an atom or molecule, a very large amount of energy is needed. Due to this, only the types of radiation with high energy can cause ionisation. These are ultraviolet, x-rays and gamma rays. These forms of electromagnetic radiation are known as ionising radiation.

Ionisation and body cells
The cells in your body are home to lots of vital molecules, including DNA molecules. When cells are exposed to ionising radiation, their DNA molecules can be damaged. This damage can mutate the cells into cancerous cells. Cell division processes create many more copies of cancerous cells - this is how the cancer grows and develops.

If cells are exposed to extremely high amounts of radiation, they can be killed completely. This happens during radiation sickness.

There is a positive correlation between the amount of time the body is exposed to radiation and the amount of damage to the body which is caused by the radiation.