Why are X-rays named after a letter of alphabet? What makes the X-rays pass through solid objects?

X-rays play a centrifugal role in medical science today. It used to detect diseases that are otherwise physically not visible to the naked eye. Roentgen stumbled on X-rays while he was experimenting with Crookes tubes and Lenard tubes. At the time, it was something that was not understood by him. Even today, the rays concept is not understood as Roentgen had his lab notes burned after his death. 

William Roentgen first used the rays to make a picture of his wife on a photographic plate. The picture was made using X-rays. His wife’s hand was the first photograph of the human body captured by X-rays. As soon as X-rays were discovered, scientists and researchers of the time were beyond amazed by the discovery. As many as 1044 articles and 49 essays were published on the same topic. 

When scientists are not able to understand some phenomenon thoroughly they use the symbol X to denote it. The German physicist Wilhelm Roentgen who discovered X-rays in 1895 had not properly understood the mysteries of his own discovery. So the newly discovered rays came to be denoted by the symbol X.

The X-rays are very penetrative rays having much shorter wavelength than that of the visible light. So they are able to penetrate some objects which are opaque for the visible light. E.g. when X-ray photograph of a patient is taken these rays fully penetrate the soft muscles, are somewhat absorbed in highly dense muscles and are absorbed to a great extent in hard boned. The image in X-ray photograph shows the skin and soft muscles as completely black portion through which X-rays have penetrated and as white portion those parts of the body in which X-rays have been absorbed.

X-rays differ in types as well. Some X-rays are used to detect soft tissues while others visit the depths and detect bones and fractures etc. Depending on the density, X-rays penetrate differently through objects. Not only is it used in the medical field today but industrially as well. To obtain an image using X-rays, the affected area of the body is positioned between the X-ray source and an X-ray detector.

 As the X-rays make their way through the body, images depending on the tissues, start to appear as black and white images on a plastic-type sheet. For instance, our bones absorb calcium, and therefore, the bone density is bound to be more. As a result, your bones will appear white on X-rays. Whereas, if a bone happens to be fractured, it will appear as a dark area. 

More importantly, X-rays are today used to scan pregnant women as well. A lot of people are skeptical about its side effects, but they are minimal. However, it should be made sure that the developing fetus is protected from harm. Before getting an X-ray done, you should always inform the health-care professional of your pregnancy status. 

X-rays could be categorized into different types:


Mammography is a special type of X-ray radiograph that is used to detect breast cancer. Since, breast cancer is on the rise amongst women, getting it done before time shall save one’s life.

CT scans

CT scans are basically a result of the combination between a computer and an X-ray. It produces detailed pictures of the body’s cross-sections that are then combined to come up with a three-dimensional X-ray image.


Fluoroscopy is used to detect moving body parts, such as the heart. Furthermore, it could also be used by swallowing or injected and observing the blood flow or digestive processes. Lastly, Fluoroscopy is also used to place instruments precisely within the body during operations.

How is an X-ray performed?

To perform an X-ray, you are required to lay flat on a table or stand. It is made sure that your body is properly placed for the rays to pass through. Furthermore, you will be asked to stay still until the process is over. A radiology technician will place the x-ray machine right over the affected area and then turn on the machine. While the X-ray is being done, you will feel nothing and will only take a few moments. Once the X-ray is done, you will be provided a copy of the image created. 

Although X-rays may be expensive, but they help doctors and surgeons to pinpoint the exact problem and location of the affected area. This, as a result, helps them to prepare and perform beforehand for the operation.

Additional reading:

X-ray (Wikipedia)

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