What material is least likely to be penetrated by x-rays?


With the development of science and technology X-ray machines have appeared very frequently in our lives, especially in the security industry, food industry, medical industry and so on. As the x-ray machine is being used more and more widely, it seems that we also need to have some professional understanding of it, in the future the critical moment can reduce doubts and confusion.

First of all, let’s talk about X-rays. On November 8, 1895, the German physicist Prof. Röntgen discovered X-rays when he was experimenting with cathode rays in a glass test tube. Röntgen did not know what these rays were, so he called them “X-rays”. X-rays are powerful rays of light. X-rays are much more powerful than light waves, and they are much more penetrating, allowing them to pass through materials that ordinary light waves cannot penetrate. X-rays can penetrate many non-metallic materials, as shown in the figure below.

Different rays have different penetrating power, X-ray machine in addition to the use of the food industry, in other industries (such as airport baggage screening machine and hospital chest X-ray filming), will be used to X-ray inspection instruments. The x-ray machines in these application scenarios are the same in principle.

An X-ray system is a scanning device. As the X-ray beam passes through the product, the system takes an image of the entire product, and the X-rays scan the product in many small pieces, depending on the size of the detector diode, creating image data for each piece.
For example, with a detector diode size of 0.8 mm, a new line of image data is acquired for every 0.8 mm of movement in the direction of the product. All image data is represented using gray scale values ranging from 0 (all black) to 255 (all white).
Different densities in the product composition absorb different amounts of X-rays, resulting in different gray values. The thicker or denser a product is, the more X-rays it will absorb, the fewer rays the detector will sense, and the darker the grayscale of the image, the easier it will be to detect and reject.

Since many items have densities around 1, stainless steel is easier to detect than glass and glass is easier to detect than hard plastic, given the same size of foreign objects, based on the difference between the density of the foreign object and the density of those items. x-ray machines are unable to detect foreign objects that float on the surface of the water (i.e., that have a density less than those items), while those that sink quickly in the water (which suggests a high density) are readily detected by the x-ray machine.

X-ray absorption is directly proportional to the density and thickness of the product through which the rays pass. That is, the greater the density of the product, the thicker the thickness, the more X-rays adsorbed, so that for the same mixed foreign matter, the thicker the product and the detected foreign matter (such as metal or glass) will reduce the contrast between the gray value of the image and the sensitivity will be reduced.

About the contribution of x-ray machine in the medical treatment is multi-function digital DR set digital photography, digital fluoroscopy, digital imaging and other functions, multi-function digital DR clinical application is widely used, but also in the case of fluoroscopy for high-definition point film, multi-function digital DR this function for the diagnosis of the elderly disease is more meaningful, because of geriatrics often have clinical symptoms and signs of atypical, multi-disease coexistence as well as the condition of the heavy, change The function of multi-functional digital DR is more meaningful for the diagnosis of elderly diseases, because elderly diseases often have atypical clinical symptoms and signs, coexisting multiple diseases, and heavy and fast changing conditions. Multi-function digital DR can observe the lesions under continuous fluoroscopy, especially in observing the cardiopulmonary function of the elderly, it can quickly point out the film after discovering the lesions, and accurately obtain the high-definition images of the lesions, which is more conducive to the doctors to make a correct diagnosis.

The application of multi-function digital DR can effectively improve the diagnostic accuracy and disease detection rate in addition. Pride multi-function digital DR can also be whole-body digital photography, fluoroscopy, imaging, etc. The range of application scenarios can be extended to internal medicine, surgery, gynecology, pediatrics, orthopedics, emergency medicine, physical examination, etc., which is a cost-effective examination equipment that is multi-purpose and multi-talented in clinical practice.


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