First: what is radiation
Radiation refers to the source of the electromagnetic energy from the source of a part of the electromagnetic energy from the source of the field to spread to the distance, and then return to the field source of the phenomenon, the energy in the form of electromagnetic waves or particles (such as alpha particles, beta particles, etc.) outward diffusion.
Radiation itself is a neutral term, but radiation from certain substances can be harmful.
Secondly, what radiation is harmful
Nuclear radiation is harmful, such as γ-rays produced by cobalt-60, cesium-137, iridium-192 sources, etc.; β-rays produced by kr-85 sources, etc.; neutron rays produced by 241Am-Be sources, 24Na-Be sources, 124Sb-Be sources, and electron gas pedals with energies of more than 10M; β and alpha rays produced by unsealed sources; and β and alpha rays from various industrial and commercial sources.
Electromagnetic radiation, ordinary household appliances are not enough to produce harmful radiation dose.
Third, radiation damage to the human body
Fourth, do a CT radiation dose
Do a chest CT radiation dose of about 5.8 mSv.
There are highs and lows, depending on the specific test, and the lowest is a spiral CT scan.