What are X-rays?

X-rays are a part of the Electromagnetic (EM) spectrum, which means that they are transverse waves having a certain wavelength and frequency and moving at the speed of light. In the EM spectrum, we have gamma rays, x-rays, ultraviolet rays, visible light, infrared waves, microwaves, and radio waves, respectively, if we move in order of decreasing frequencies or increasing wavelengths. Therefore, x-rays have a higher frequency than ultraviolet rays, and frequency is directly related to energy by following the formula.


Where E is energy in joules, h is Planck’s constant, and f is frequency. From this formula, it can be seen that x-rays have higher energy than ultraviolet rays.

X-ray imaging

In the x-ray imaging technique, x-rays are impinged on the part of a body and observed through the detector present on the other side. X-rays penetrate tissue and organs in the body as x-rays are not absorbed by these body parts, but they do not pass through the bones as bones have calcium that absorbs x-rays. This process is analogous to the creation of shadows by solid objects. We can consider solid objects as bones, and free space as tissues and other organs in the body. The shadow is created by the solid object since it stops the light, and the same is the case with bones under x-ray exposure.

Working of the X-ray imaging system

The electrons are generated from the cathode by the heating filament, and then these electrons are accelerated toward the anode. These electrons, upon striking the metal of the anode, produce x-rays. These x-rays are then deflected toward the object whose x-ray image is needed. Object, depending upon its constituents, either absorbs or transmits x-rays. These x-rays from the object are then captured by the detector and produce an x-ray image. This process is further explained in figure 1 below.

Working of an X-ray imaging system and generation of X-ray images
Figure 1: Working of an X-ray imaging system and generation of X-ray images.


Since X-rays carry very high energy, long exposure to X-rays is dangerous. X-rays are also attributed to higher cancer risks. However, usually X-ray images are taken in a very short interval of time, which is not dangerous.

In light of this issue, we should get an X-ray when it is extremely necessary or when stated by the physician.

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