Chemistry

X Rays: General View

x rays

This post is also available in: العربية (Arabic)

شارك هذا

Introduction

X-rays are a type of electromagnetic radiation with more energy than visible light, and less energy than gamma rays. X-rays are a form of ionized beam, which is a beam resulting from the emission of energy from certain atoms in the form of electromagnetic waves. This spontaneous dissociation of atoms is called radioactivity. X-rays result from various electron-related interactions.

electromagnetic spectrum
electromagnetic spectrum

Discovery

It was discovered in 1895 by the German physicist Wilhelm Roentgen (1845-1923). He won the Nobel Prize for his discovery in 1901

Wilhelm Conrad Röntgen
Wilhelm Conrad Röntgen

He ejected an accelerated, high-kinetic electronic beam through a cathode tube, the appearance of a slight glow on a light-sensitive screen close to the device he was working on. Although he turned off the device and covered it, the glow remained. Which led him to conclude that there are high-energy rays emitted by the device, which he called X-rays, and in German “Röntgen rays.”

cathode tube
cathode tube

When electrons with high and accelerating energy collide with a metal, they are exposed to two possibilities: either they are slowed down, emitting an extra amount of energy; or they increase the energy of the electrons in the atoms they collide with, also producing extra energy. In either cases, x-rays appeared.

The ability of X-rays to penetrate through materials

X-rays can penetrate many materials even if they are transparent, depending on the density of matter, the atoms in them, and the atomic number of each atom. X-rays interact with the materials they penetrate. They collide with their atoms and transfer all their energy to them, sometimes part of their energy and scatter the rest of it.
Because of its ability to penetrate the organs in the human body, it has been widely used in the medical field. It is possible to know what is going on inside the human body now. as it is possible to produce a two-dimensional image of the internal organs in the body.

The bones of a hand with a ring on one finger, viewed through x-ray. Photoprint from radiograph by W.K. von Röntgen, 1895.
The bones of a hand with a ring on one finger, viewed through x-ray. Photoprint from radiograph by W.K. von Röntgen, 1895.

One of the characteristics of the bones is that they are dense as well as a large amount of calcium, an element with a relatively high atomic number, so the bones absorb X-rays well. Unlike soft tissues, they contain elements with a relatively small number of atomic numbers, such as oxygen, carbon, and hydrogen. Nor is it bone density. Therefore, X-rays are able to penetrate the lungs and muscles, and darken them to some degree in the final image.

One of the risks of X-rays is that they may cause mutations in the reproductive system and thyroid tissue, so this is what is advised to wear a dedicated apron during imaging that faces as much risks.

 Computed Tomography CT

During the passage of X-rays into the body, they interact with many different atoms as they pass through, so the final image is the result of these different interactions. To see what is happening inside the body more accurately, imaging is done through these rays from several angles, and through this a shape is created for the inner image of the body. This process is known as computed tomography.

CT scanner
CT scanner

Computed tomography is based on taking the image from multiple angles. Why? By taking an X-ray image from one angle it is possible to know the density changed related to a solid mass (tumor), but it is not possible to know how deep it is under the surface, so taking the image from multiple angles helps to locate the tumor and know its shape.
The rays are sent in the form of a conical beam, and then spirally rotated around the patient to be processed by certain detectors.
Spiral CT produces data that can be processed with enough detailed cross-sections images that can determine  anatomical features, tumors, blood clots, infections, heart disease and tooth cavities.

[1]https://www.nobelprize.org/prizes/physics/1901/rontgen/photo-gallery/ [2]https://www.hazemsakeek.net/%D8%A3%D9%86%D9%88%D8%A7%D8%B9-%D8%A7%D9%84%D8%A7%D8%B4%D8%B9%D8%A7%D8%B9/ [3]https://ed.ted.com/editor/1451025

x ray result
x ray result
المراجع    [ + ]
Previous post
Human memory: How does the brain handle informations and what is the role of memory?
Next post
A very touching story