Ionising radiation damages living cells because it is able to break molecules into ions.       These ions can take part in other chemical reactions.     Radiation dose is a measure of the possible harm done to the body. It is measured in sievert (Sv).       Radiation dose is based on: The amount of radiation. . The type of radiation.     A high dose of radiation would kill cells.     Lower doses of radiation can damage the DNA of cells.        There is a chance that the damaged cells will reproduce        in an uncontrollable way and cancer will develop.     Outside the body, alpha is less dangerous than beta and gamma.     Inside the body, alpha is more dangerous than beta and gamma.     Monitoring of radiation exposure                                                              Radiation badge        The risk of cancer increases if the exposure to ionising radiation increases.        Precautions should be taken by people working with ionising radiation.        Example: Wear radiation badge.        People who might be exposed to radiation such as workers in the nuclear industry or in        hospital radiotherapy departments wear radiation badges.        The radiation badge is developed regularly to check that the person wearing it has only        received a "safe" dose.