UK USIndia

Magic for Learning and Revision

Canned food manufacturers use X-ray machines.

# Medical Physics - X-rays

This GCSE Medical Physics quiz will challenge you on X-rays. X-rays are a type of electromagnetic radiation. X-rays were discovered in 1895 by William Roentgen by accident whilst he was experimenting with vacuum tubes. He noticed that a screen he used for a different experiment was glowing, even though there was no visible light hitting it. He carried out some experiments over a period of several weeks, to find out more of the properties of the newly-discovered rays and to ensure that his results were reliable before finally announcing his discovery at the end of December. He used the term X-rays because he had no idea what they were and adopted the mathematical idea of using the letter 'x' to denote an unknown quantity. During the course of his experiments, he took the very first X-ray photograph - it shows the bones of his wife's hand who said 'I have seen my own death'. His work earned him the very first Nobel Prize in physics (1901).

Within a year of Roentgen's discovery, the Glasgow Royal Infirmary had set up a radiology department and was producing X-ray images of things like a penny stuck in a child's throat and kidney stones. X-rays were also used during the Boer War and First World War to locate exactly where bones had been broken and the site of embedded shrapnel and bullets. In the early 1900s, the damaging properties of X-rays were already being used to fight cancers and skin diseases but it was eventually realised that this was ionising radiation and precautions needed to be taken to protect staff and patients from receiving dangerously high doses.

Now we have come to understand a lot about how X-rays work and how we can utilise them to our advantage. Protection for radiographers (the people who operate the X-ray machines), and allowed safe levels for patients, are well established. The invention of computers has enabled complex machines like Computer Axial Tomography (CAT) scanners to be built. These have an X-ray generator that is mounted in such a way that it can be moved right round the body. It takes X-ray images as it moves and a computer converts the data to three-dimensional images of the inside of the body. Roentgen had used a fluorescent screen in his first experiments which provided 'live' images rather than a photograph. This technique is still used and is now called 'fluoroscopy'. It is often used to examine patients with digestive system problems.

X-rays are a type of electromagnetic radiation that has a much shorter wavelength than visible light. They have the properties of being able to leave an image on photographic film, to be able to pass through opaque solids and they have a range of frequencies - the lower frequencies carry lower energies and are less ionising and less penetrating. More dense materials allow fewer X-rays to pass through so they appear lighter on images whereas less dense materials like skin allow almost all the X-rays through and appear darker.

1.
The wavelength of an X-ray is of the same order of magnitude as what?
A hair
A stone
An atom
An electron
They have very short wavelengths and therefore very high frequencies
2.
What can X-rays be used to diagnose?
Bone fractures
Dental problems
All of the above
X-rays are used in many medical situations. Simple X-ray machines work best when hard materials like bones, teeth and hard growths like kidney or gall stones are involved. Computers have allowed the development of CAT scanners which use X-rays to look at soft tissue as well
3.
Why do precautions need to be taken when X-ray machines are in use?
X-rays can cause cancer
X-rays can stop the growth of cells and even destroy them
X-rays can double cell growth causing internal issues
All of the above
X-rays are an example of ionising radiation
4.
In which place would you most likely find an X-ray machine?
Airport
Hospital
Baked bean factory
All of the above
Yes! - You would find an X-ray machine in all of those places. Canned food manufacturers use X-ray machines to check to make sure there are no foreign items packaged within their cans and airports use them to check inside bags for security
5.
Which electromagnetic wave has the most energy?
X-rays
Light
Microwaves
X-rays have the most energy followed by light, then microwaves and with the least energy, radio waves
6.
Which of the following absorbs the most X-rays?
Metal
Bone
Cloth
Both metal and bone
X-rays will travel through cloth easily
7.
X-rays affect photographic film in the same way as which other wave in the electromagnetic spectrum?
Gamma rays
Microwaves
Infrared waves
Light
X-ray photographs look very different to photographs taken using visible light
8.
X-rays are part of which spectrum?
Electromagnetic spectrum
Chemical spectrum
ZX spectrum
Frequency spectrum
X-rays are electromagnetic waves and as such are part of the electromagnetic spectrum. As an electromagnetic wave, they are able to travel through the vacuum of space without difficulty
9.
X-rays can be used to destroy which harmful cells?
Muscle cells
Cancer cells
Animal cells
Nerves
They need to be carefully targeted in order to avoid damaging surrounding cells
10.
Which electronic device allows images from X-rays to be formed electronically?
Microfilm
SD card
CCD (Charge-coupled device)
Mobile phone
CCDs are used to capture other forms of electromagnetic radiation too e.g. light in a digital camera
Author:  Martin Moore