X-ray photographic suit

The "ionizing radiation" produced by CT machine, DSA machine, transmission machine and X-ray machine in radiology department is mainly X-ray.

The x-rays of this equipment come from electricity.

X-ray is an electromagnetic wave, just like the essence of light, but with higher energy. Therefore, it can penetrate tissues that ordinary light cannot penetrate, thus penetrating the human body. However, because the energy of radiation is relatively high, it may damage cells.

X-ray is actually a special kind of light, which can be imagined as a special light bulb. Ordinary light bulbs emit visible light, and X-ray tubes emit X-rays. ?

Ordinary light bulbs will go out when power is cut off, and so will X-ray tubes. After the power is cut off, the electromagnetic wave disappears. Electromagnetic waves are energy, not matter, so there is no residue after the CT scanning equipment is turned off.

It is rumored that X-rays will produce radiation and cause harm to human body, mainly because the energy of X-rays is absorbed by molecules, which will lead to the breaking of chemical bonds and the derivation of chemical reactions. These secondary chemical reactions are an important mechanism of radiation damage to cells.

The rays that can convert non-radioactive substances into radioactive substances are "neutron rays".

Neutrons are the components that make up the nucleus. When a beam of neutrons is directed at matter, some neutrons can be forcibly inserted into other nuclei, and foreign neutrons may also destroy stable nuclei. Unstable nuclei will split to become stable. The process of division releases energy in the form of rays.

Take bone mineral density examination as an example. The radiation dose for a bone mineral density examination is 1 microsievert (μSv), for a chest X-ray, 10000 microsievert (μSv), for a whole body CT and for a lumbar X-ray.

At present, the internationally recognized personal safety dose limit is 2 millisieverts/year = 2,000 microsieverts/year. (1 Sieverts Sv= 1000 milliSieverts mSv= 1000000 micro Sieverts μSv).

Therefore, the radiation dose generated by a CT scan is very small, so there is no need to worry about the radiation brought by radiation equipment such as CT scanning.

Extended data:

CT radiation damage dose

The radiation dose of CT comes from radionuclide and CT. Most of the radioactive radiation used in CT comes from fluorine-18( 18F), and 18F emits positrons to generate high-energy gamma rays, and the radiation dose is about 7mSv/370MBq, that is, 0.7mSv/mCi.

The dose of radiopharmaceuticals used in the new PET/CT is relatively reduced. The dose standard is the body weight multiplied by 0. 1 ~ 0. 15 (the coefficient of some new equipment is lower than 0. 1), which generally does not exceed 10mCi. The radiation dose received by the patient in one examination is about 7mSV (taking 10mCi as an example).

In the second part, the radiation dose mainly comes from CT scanning. High-end PET/CT is equipped with 3D automatic mA technology (different manufacturers have different names), and the mAs given at different levels is determined according to the positioning phase. Compared with fixed mAs, the whole body dose is greatly reduced. The total radiation dose of whole-body PET/CT examination is generally around 15mSv, which is lower than that of conventional local enhanced CT scanning (for example, the liver is enhanced at least three times in the same part).

It is safe to receive radiation dose below 50mSv at one time, and the risk of direct radiation injury may occur only when it exceeds 100mSv (there is a risk of definite radiation effect), and the radiation dose reaching 250mSv is subclinical (asymptomatic excessive radiation may cause a small amount of biological cell damage, which can be repaired or compensated by human body without causing clinical symptoms).

Radiation exposure exceeding 500mSv can cause radiation injury symptoms in 5% of the exposed personnel, and radiation exposure exceeding 1000mSv can cause radiation injury symptoms in 25% of the exposed personnel.