What are my objectives while studying this topic?

Healthcare professionals use a range of imaging techniques to diagnose illnesses or to monitor the health of an individual. By studying this topic you’ll learn about X-rays and CAT scans and why these are important as a means to diagnosing illnesses.

Why is this important?

Fitness professionals monitor people to assess their fitness to improve their performance.

Healthcare professionals use physiological measurements to monitor the health of patients, to diagnose ill health and determine specific treatment for patients.

Can I get an introduction to this topic?

Yes, why not have a look at the following clip:

So, let’s get to it: what are X-rays and CAT scans?

X-rays (radiographs) are the most common and widely available diagnostic imaging technique. Even if you also need more sophisticated tests, you will probably get an X-ray first.



(Hand mit Ringen (Hand with Rings): print of Wilhelm Röntgen's first "medical" X-ray, of his wife's hand, taken on 22 December 1895 and presented to Professor Ludwig Zehnder of the Physik Institut, University of Freiburg, on 1 January 1896.)


The part of your body being pictured is positioned between the X-ray machine and photographic film. You have to hold still while the machine briefly sends electromagnetic waves (radiation) through your body exposing the film to reflect your internal structure. The level of radiation exposure from X-rays is not harmful, but your doctor will take special precautions if you are pregnant.

Bones, tumors and other dense matter appear white or light because they absorb the radiation. Less dense soft tissues and breaks in bone let radiation pass through, making these parts look darker on the X-ray film. Sometimes, to make certain organs stand out in the picture, you are given barium sulfate or a dye.


You will probably be X-rayed from several angles. If you have a fracture in one limb your doctor may want a comparison X-ray of your uninjured limb. Your X-ray session will probably be finished in about ten minutes. The images are ready quickly.

broken - Fixed Arm


(Internal and external views of an arm with a compound fracture, both before and after surgery)

X-rays may not show as much detail as an image produced using newer, more powerful techniques.

Computed tomography (CAT scan) is a modern imaging tool that combines X-rays with computer technology to produce a more detailed, cross-sectional image of your body. A CAT scan lets your doctor see the size, shape and position of structures that are deep inside your body such as organs, tissues, or tumors.

You have to lie as still as possible on a table that slides into the center of the cylinder-like CAT scanner. The process is painless. An X-ray tube slowly rotates around you taking many pictures from all directions. A computer combines the images to produce a clear, two-dimensional view on a television screen.

Cat scan 2


(Typical screen layout for diagnostic software, showing one 3D and three MPR views)
You may need a CAT scan if you have a problem with a small, bony structure or if you have severe trauma to the brain, spinal cord, chest, abdomen, or pelvis. As with a regular X-ray, sometimes you may be given barium sulfate or a dye to make certain parts of your body show up better.


What will I be expected to be able to do after studying this topic?

  • Understand the health and safety considerations to be adhered to by the healthcare professionals when using the equipment to take X-ray images and CAT scans

  • Describe how an X-ray and CAT scan images are taken and produced

  • Explain the principles of the X-ray and CAT scan technique

  • Analyse X-ray and CAT scan images to identify features

What are the key words to learn and use for this topic?

  • X-ray

  • Radiographer

  • Computerized Axial Tomography (CAT)

How long will this topic take to study?

On average you’ll be looking at about one hour of taught time and independent study.

What are the main activities on this topic?


Check out the following links:


Webcam of room where x-ray is being taken

Virtual department of the Royal College of radiologists

The department from different perspectives- the radiologist, the patient, the equipment.

Library of x-ray images showing a variety of diseases diagnosed by this imaging method.


CAT scans

Virtual department of the Royal College of radiologists

The department from different perspectives - the radiologist, the patient, the equipment.

Virtual department of the Royal College of radiologists, the department from different perspectives- the radiologist, the patient, the equipment

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