Risks of radiation in medical imaging

[Lizzy Liz]

Imaging tests that use radiation, usually x-rays, are a valuable tool in diagnosis, but exposure to radiation has some risks (see also Radiation Injury).
Different diagnostic tests require different amounts of radiation (see table Comparing Radiation Doses), but most of them use low doses that are generally considered safe. For example, the radiation dose from one chest x-ray is more than 100 times lower than the average yearly dose of radiation from the environment (background radiation). However, exposure to radiation is cumulative, regardless of the interval between tests. This means that if people have many diagnostic tests that use low doses or several tests that use high doses, they may be exposed to a relatively large amount of radiation.