Computed tomography(CT) has become an indispensable diagnostic technique, if it is prescribed by a doctor and strictly according to indications. But its irrational and frequent use can lead to undesirable consequences for the body. Since CT refers to X-ray methods of examination, it carries a radiation load. In particular, when performing one study of the chest organs, the patient receives radiation equal to 11 millisieverts (mSv).
The fact is that the body accumulates radiation absorbed during its life in the form of irreversible changes in tissues and organs, as well as radionuclides deposited in internal tissues. Since some background radiation is constantly present in nature, a person accumulates a dose of 100 to 700 mSv during his life. This indicator is calculated for 70 years of life. It turns out that in a year we "should" collect the norm of 1.43 — 10 mSv, and in a day 0.004 — 0.027 mSv, respectively.
For an adult, the norm is the total annual radiation dose received up to 50 mSv. In exceptional cases (for example, oncology), it is allowed to increase this limit to 150 mSv. Going beyond this limit has a small, but still a danger to health and life. It is recommended to maintain an interval of 2-3 months between repeated tomographs, and CT is prohibited for pregnant women and children under 11 years of age.