With the advancement of science and technology and the development of medical technology, the chances of people being exposed to X-rays when they go to the hospital have also greatly increased. Everyone knows that chest X-rays, CT, color ultrasound and X-ray machines can emit X-rays to penetrate the human body to observe the disease. They also know that X-rays emit radiation, but how many people really understand X-ray machines. What about the emitted rays?
First, how are the X-rays in an X-ray machine produced? The conditions required for the production of X-rays used in medicine are as follows: 1. X-ray tube: a vacuum glass tube containing two electrodes, cathode and anode; 2. Tungsten plate: metal tungsten with high atomic number can be used to make X-ray tubes The anode is the target for receiving electron bombardment; 3. Electrons moving at high speed: apply high voltage at both ends of the X-ray tube to make the electrons move at high speed. Specialized transformers step up the living voltage to the required high voltage. After the tungsten plate is hit by electrons moving at high speed, the atoms of tungsten can be ionized into electrons to form X-rays.
Secondly, what is the nature of this X-ray, and why can it be used to observe the condition after penetrating the human body? This is all because of the properties of X-rays, which have three major properties:
1. Penetration: Penetration refers to the ability of X-rays to pass through a substance without being absorbed. X-rays can penetrate materials that ordinary visible light cannot. Visible light has a long wavelength, and photons have very little energy. When it hits an object, part of it is reflected, most of it is absorbed by matter, and cannot pass through the object; while X-rays are not, because of their short wavelength, energy When it shines on the material, only a part is absorbed by the material, and most of it is transmitted through the atomic gap, showing a strong penetrating ability. The ability of X-rays to penetrate matter is related to the energy of X-ray photons. The shorter the wavelength of X-rays, the greater the energy of the photons and the stronger the penetrating power. The penetrating power of X-rays is also related to the density of the material. The denser material absorbs more X-rays and transmits less; the denser material absorbs less and transmits more. Using this property of differential absorption, soft tissues such as bones, muscles, and fats with different densities can be distinguished. This is the physical basis of X-ray fluoroscopy and photography.
2. Ionization: When a substance is irradiated by X-rays, the extranuclear electrons are removed from the atomic orbit. This effect is called ionization. In the process of photoelectric effect and scattering, the process in which photoelectrons and recoil electrons are separated from their atoms is called primary ionization. These photoelectrons or recoil electrons collide with other atoms while traveling, so that the electrons from the hit atoms are called secondary ionization. in solids and liquids. The ionized positive and negative ions will recombine quickly and are not easy to collect. However, the ionized charge in the gas is easy to collect, and the amount of ionized charge can be used to determine the amount of X-ray exposure: X-ray measuring instruments are made based on this principle. Due to ionization, gases can conduct electricity; certain substances can undergo chemical reactions; various biological effects can be induced in organisms. Ionization is the basis of X-ray damage and treatment.
3. Fluorescence: Due to the short wavelength of X-rays, it is invisible. However, when it is irradiated to certain compounds such as phosphorus, platinum cyanide, zinc cadmium sulfide, calcium tungstate, etc., the atoms are in an excited state due to ionization or excitation, and the atoms return to the ground state in the process, due to the energy level transition of valence electrons. It emits visible or ultraviolet light, which is fluorescence. The effect of X-rays causing substances to fluoresce is called fluorescence. The intensity of fluorescence is proportional to the amount of X-rays. This effect is the basis for the application of X-rays to fluoroscopy. In X-ray diagnostic work, this kind of fluorescence can be used to make fluorescent screen, intensifying screen, input screen in image intensifier and so on. The fluorescent screen is used to observe the images of X-rays passing through human tissue during fluoroscopy, and the intensifying screen is used to enhance the sensitivity of the film during photography. The above is a general introduction to X-rays.
We Weifang NEWHEEK Electronic Technology Co., Ltd. is a manufacturer specializing in the production and sales of X-ray machines. If you have any questions about this product, you can contact us. Tel: +8617616362243!
Post time: Aug-04-2022