X-rays and Ultrasound

Veterinary medicine has made many advances in the last 10 years and many local veterinary practices will now be able to perform X-ray and ultrasound examinations.

Why does my vet need to do tests on my dog?

Your vet can get a lot of information about what might be wrong with your dog from talking to you and examining your dog. Sometimes your vet may need to take a blood sample to test for diseases. X-ray and ultrasound allow your vet to look at the organs inside your dog’s body without having to perform an operation.

How do X-rays work?

X-rays are like light except they can travel through the body. For an X-ray your dog will lie under the X-ray machine which sends a beam of X-rays through your dog's body onto a photographic plate. When the film is developed your vet will have a picture of the inside of your dog. This is called a radiograph.

Veterinary ultrasound machines are just like the ones used by human doctors to scan babies in the womb. As its name suggests ultrasound is a form of sound. Just as sound waves can pass through solid objects (like doors and walls when your neighbour has a party!), ultrasound can pass through the skin into your dog’s body. The sound waves are directed through the area your vet wants to look at and some of them are reflected back like an echo. These echoes are detected by a special computer which uses them to produce a map of the inside of your dog which your vet can read.

Will the examination hurt?

No, it is not possible to feel X-rays or ultrasound. For ultrasound examinations, fur will need to be shaved over the area where your vet is taking the picture. The ultrasound machine must be in contact with skin to let the sound waves get into the body. The hair should grow back quickly after the examination.

Why does my dog have to have an anaesthetic?

Taking an X-ray is a bit like taking a photograph of the inside of your dog. For X-ray examinations it is important that your dog lies still as the exposure is made or the final picture will be blurred. Nurses and vets take many X-rays every day and so they cannot hold all the patients or they would also be exposed to the X-rays which can be dangerous over a long period of time.

Ultrasound examinations can take up to an hour to perform. Although your pet can be held by a nurse while the vet performs the examination many dogs do not like to be held still for this length of time. Giving them a sedative makes them relax so that they are not worried by the examination.

Can the test do any damage to my dog?

X-rays, when used to produce pictures of your dog, will not cause side effects. Exposure to high doses, or over long periods of time, can be dangerous and this is why your vet cannot hold your dog for the examination.

There is no evidence that ultrasound examinations carry any risk at all.

The risk associated with the tests is that of upsetting a sick dog or one with breathing difficulties by struggling with it, or the risk of the anaesthetic or sedation in an ill dog. Your vet will discuss these risks to you and if you are in any doubt about the risk please ask your vet to explain why they need to do the tests. In almost all cases the risk of not finding out what is wrong with your dog (and therefore not being able to treat it) is far worse than the risk of the anaesthetic.

Why do I have to wait for the results of these tests?

Although your vet will be able to get the pictures from these examinations on the same day, they may want to send them to a specialist for a second opinion before giving you a final diagnosis. Some vets specialise only in reading X-rays and ultrasounds and may be less likely to miss some information on the pictures. Some veterinary practices now have a specialist in the practice or one who visits the practice regularly to perform these examinations.

Your vet will be happy to explain to you why they need to do such tests on your dog. If you do not understand the reasons please ask someone to explain the tests to you. If you are interested, your vet will probably be able to show you the pictures of your dog after the examination and explain what they can see.

Related Factsheets:
Tests - how they help your vet
Heart disease in your dog

If you want any other information on health issues concerning your dog please contact your veterinary surgeon who will be happy to advise you.