Key points about X-ray

  • An X-ray uses a small amount of radiation to create images of your bones and internal organs. 
  • X-rays are most often used to detect bone or joint problems, or to check the heart and lungs.
X-ray of both hands
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X-rays are a form of electromagnetic radiation, similar to visible light. However, X-rays have higher energy than light and can pass through most objects, including the body.

By placing an X-ray detector or plate on the other side of a person, an image will be formed that represents the “shadows” created by the objects inside the body.

Structures containing:

  • air (such as the lungs) will be black,
  • muscle, fat, and fluid will appear as shades of grey and
  • dense structures such as bones will block most of the X-ray particles, and will appear white.

Video: How Do X-rays Work?

The following video explains how X-rays work and makes this easier to understand. This video may take a few moments to load.

(National Institute of Biomedical Imaging & Bioengineering – NIBIB, National Institutes of Health – NIH, US, 2014)

You will be asked to remove your watch, jewellery or garments with metal closures from the part of your body being imaged. These items can block part of the image.

  • You may be asked to wear a gown.
  • You may be asked about your overall health or any medications you take.

Let the radiographer (the person who performs your X-ray) know if you:

  • are or may be pregnant
  • have had an X-ray of this part of your body before
  • have metal (eg, a pacemaker or a surgical pin) in the part of your body being imaged.

During your X-ray

  • You will be asked to lie on a table, sit or stand.
  • A lead apron may be draped over part of your body to shield it from the X-rays.
  • With an X-ray of your chest or abdomen, you will have to take a deep breath and hold it for a few seconds.
  • Having an X-ray is like having a photo taken. You need to hold still and you will not feel anything. 
  • While having an X-ray is painless, sometimes the position needed for the best view of the area being X-rayed is uncomfortable for a minute or two.
  • For best results, remain as still as you can during your X-ray exam.
  • These days, having an X-ray is very quick and most only take 5 to 10 minutes. 

After your X-ray

The films or images will be viewed by a radiologist (doctor who specialises in imaging) who will describe what the X-ray shows. This report will then be sent to your doctor who will discuss the test results with you during a follow-up appointment or over the phone.

Some people are concerned that having an X-ray increases your chance of getting cancer. However, it is also believed that you would have to be x-rayed many, many times to receive the amount of radiation that would be bad for your health. The amount of radiation you get from having a chest or limb X-ray is much less than the Earth’s natural radiation you are exposed to every day.

A chest x-ray is a ‘picture’ that shows the ribs, lungs, diaphragm and size of the heart. 

  • When someone is acutely unwell with shortness of breath, fever and cough, a chest X-ray might be ordered to look for signs of infection, (such as pneumonia) inflammation, fluid build up in the lungs or tumours or masses.
  • It is often used to assess people who have smoked for many years to look for signs of chronic lung disease and lung cancer.
  • A chest X-ray is also often done before an operation to check the lungs and heart appear normal.

 Image credit: Canva

  • If you have ongoing pain in a joint such as a hip, knee or hands, you may have an X-ray to look for signs of arthritis. 
  • Joint or limb X-rays are also done after an injury to look for broken bones or other causes of the pain. 
  • Structures containing air will be black, and muscle, fat, and fluid will appear as shades of grey.

In Aotearoa New Zealand, radiology services such as X-rays, are available through public and private providers. 

Public Services
Find radiology services in your region(external link) HealthPoint NZ

Private Services
Find private radiology services in your region(external link) HealthPoint NZ

X-ray – an introduction(external link) NHS, UK, 2022
X-rays – what are medical x-rays and how do they work?(external link) National Institute of Biomedical Imaging and Bioengineering (NIBIB), 2022
X-rays (plain radiography)(external link) InsideRadiology, The Royal Australian and New Zealand College of Radiologists
X-rays (Radiolography)(external link) RadiologyInfo, US

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Credits: Healthify editorial team. Healthify is brought to you by Health Navigator Charitable Trust.

Reviewed by: Dr Janine Bycroft, GP

Last reviewed:

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